Exam 2 - Anatomy

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Exam 2 - Anatomy
2013-03-29 09:48:22

Thorax, Abdomen, Pelvis
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  1. superior thoracic aperture
    anatomical thoracic inlet, conveys large vessles, important nerves, the thoracic lymphatic duct, the trachea, and the esophagus between the neck and thorax.
  2. inferior thoracic aperture
    anatomical thoracic outlet, conveys the inferior vena cava (IVC), aorta, esophagus, nerves, and thoracic lymphatic duct between the thorax and the abdominal cavity.
  3. Superior mediastinum:
    • a midline compartment that lies above an imaginary horizontal plane that passes through the manubrium of the sternum ("sternal angle of Louis") and the intervertebral disc between the T4 and T5 vertebra. Contains:
    • Thymus gland (largely involuted and replaced by fat in older adults)
    • Brachiocephalic veins
    • SVC
    • Aortic arch and its three arterial branches
    • Trachea
    • Esophagus
    • Phrenic and vagus nerves
    • Thoracic duct and lymphatics
  4. Inferior mediastinum:
    the midline compartment below this same horizontal plane, which is further subdivided into an anterior, middle (contains the heart), and posterior mediastinum.
  5. Jugular (suprasternal) notch:
    a notch marking the level of the second thoracic vertebra, the top of the manubrium, and the midpoint between the articulation of the two clavicles
  6. Sternal angle (of Louis):
    marks the articulation between the manubrium and body of the sternum, the dividing line between the superior and inferior mediastinum, and the site of articulation of the second ribs (useful for counting ribs and intercostal spaces)
  7. Nipple:
    marks the T4 dermatome and approximate level of the dome of the diaphragm on the right side
  8. Xiphoid process:
    marks the inferior extent of the sternum and the anterior attachment point of the diaphragm
  9. Sternum
    Long flat bone: composed of the manubrium, body, and xiphoid process
  10. True ribs
    Ribs 1-7: articulate with the sternum directly
  11. False ribs
    Ribs 8-12: articulate to costal cartilages of the ribs above
  12. Floating ribs
    Ribs 11 and 12: articulate with vertebrae only
  13. muscles of the anterior thoracic wall
    • include several muscles that attach to the thoracic cage but actually are muscles that act on the upper limb. These muscles are as follows
    • Pectoralis major
    • Pectoralis minor
    • Serratus anterior
  14. true anterior thoracic wall muscles
    fill the intercostal spaces or support the ribs, act on the ribs (elevate or depress the ribs), and keep the intercostal spaces rigid, thereby preventing them from bulging out during expiration and being drawn in during inspiration
  15. Capsule
    • Clavicle and manubrium
    • Allows elevation, depression, protraction, retraction, circumduction
    • Sternoclavicular (Saddle-Type Synovial) Joint with an Articular Disc
  16. Sternoclavicular
    • Clavicle and manubrium
    • Consists of anterior and posterior ligaments
    • Sternoclavicular (Saddle-Type Synovial) Joint with an Articular Disc
  17. Interclavicular
    • Between both clavicles
    • Connects two sternoclavicular joints
    • Sternoclavicular (Saddle-Type Synovial) Joint with an Articular Disc
  18. Costoclavicular
    • Clavicle to first rib
    • Anchors clavicle to first rib
    • Sternoclavicular (Saddle-Type Synovial) Joint with an Articular Disc
  19. First sternocostal
    • First rib to manubrium
    • Allows no movement at this joint
    • Sternocostal (Primary Cartilaginous [Synchondroses]) Joints
  20. Radiate sternocostal
    • Ribs 2-7 with sternum Permit some gliding or sliding movement at these synovial plane joints
    • Sternocostal (Primary Cartilaginous [Synchondroses]) Joints
  21. Cartilage
    • Costal cartilage to rib
    • Allow no movement at these joints
    • Costochondral (Primary Cartilaginous) Joints
  22. Interchondral
    • Between costal cartilages
    • Allow some gliding movement
    • Interchondral (Synovial Plane) Joints
  23. External intercostal
    • Inferior border of rib to Superior border of rib below
    • Intercostal nerve
    • Elevate ribs
  24. Internal intercostal
    • Inferior border of rib to Superior border of rib below
    • Intercostal nerve
    • Elevate ribs (upper four and five); others depress ribs
  25. Innermost intercostal
    • Inferior border of rib to Superior border of rib below
    • Intercostal nerve
    • Probably elevate ribs
  26. Transversus thoracis
    • Posterior surface of lower sternum to Internal surface of costal cartilages 2-6
    • Intercostal nerve
    • Depress ribs
  27. Subcostal
    • Internal surface of lower rib near their angles to Superior borders of second or third ribs below
    • Intercostal nerve
    • Elevate ribs
  28. Levator costarum
    • Transverse processes of C7 and T1-T11 to Subjacent ribs between tubercle and angle
    • Dorsal primary rami of C8-T11
    • Elevate ribs
  29. intercostal neurovascular bundles
    (vein, artery, and nerve) lie inferior to each rib, running in the costal groove deep to the internal intercostal muscles. The veins largely correspond to the arteries and drain into the azygos system of veins or the internal thoracic veins.
  30. intercostal nerves
    are the primary ventral rami of the first 11 thoracic spinal nerves. The 12th thoracic nerve gives rise to the subcostal nerve, which courses inferior to the 12th rib. The nerves give rise to lateral and anterior cutaneous branches and branches innervating the intercostal muscles.
  31. Internal thoracic artery
    Arises from subclavian and terminates by dividing into superior epigastric and musculophrenic arteries
  32. Intercostals artery
    Anterior and posterior segments that arise from internal thoracic and aorta, respectively, and anastomose
  33. Subcostal artery
    From aorta, courses inferior to the 12th rib
  34. Pericardiacophrenic artery
    From internal thoracic and accompanies phrenic nerve
  35. Breast:
    fatty tissue containing glands that produce milk; lies in the superficial fascia above the retromammary space, which lies above the deep pectoral fascia enveloping the pectoralis major muscle
  36. Areola:
    circular pigmented skin surrounding the nipple; it contains modified sebaceous and sweat glands that lubricate the nipple and keep it supple
  37. Nipple:
    site of opening for the lactiferous ducts; usually lies at about the level of the fourth intercostal space
  38. Axillary tail (of Spence):
    extension of mammary tissue superolaterally toward the axilla
  39. Lymphatic system of Breast:
    lymph is drained from breast tissues; about 75% of lymphatic drainage is to the axillary lymph nodes (Figs. 3-9 and 7-11), and the remainder drains to infraclavicular, pectoral, or parasternal nodes.
  40. arterial supply to the breast includes the following:
    • Anterior intercostal branches of the internal thoracic (mammary) arteries (from the subclavian artery)
    • Lateral thoracic artery (branch of the axillary artery)
    • Thoracodorsal artery (branch of the axillary artery)
  41. three compartments of the thorax:
    • Right pleural space
    • Left pleural space
    • Mediastinum (a "middle septum" lying between the pleural spaces)
  42. Apex:
    superior part of the upper lobe that extends into the root of the neck (above the clavicles)
  43. Hilum:
    area located on the medial aspect through which structures (bronchus, vessels, nerves, lymphatics) enter and leave the lung
  44. Costal:
    anterior, lateral, and posterior aspects of the lung in contact with the costal elements of the internal thoracic cage
  45. Diaphragmatic:
    inferior part of the lung in contact with the underlying diaphragm
  46. Lobes of lungs
    Three lobes (superior, middle, inferior) in right lung; two in left
  47. Horizontal fissure of lung
    Only on right lung, extends along line of fourth rib
  48. Oblique fissure of lung
    On both lungs, extends from T2 vertebra to sixth costal cartilage
  49. Impressions on lungs
    Made by adjacent structures, in fixed lungs
  50. Lingula of lung
    Tongue-shaped feature of left lung
  51. Cardiac notch of lung
    Indentation for the heart, in left lung
  52. Pulmonary ligament of lung
    Double layer of parietal pleura hanging from the hilum that marks reflection of visceral pleura to parietal pleura
  53. Bronchopulmonary segment of lungs
    10 functional segments in each lung supplied by a segmental bronchus and a segmental artery from the pulmonary artery
  54. chest drainage tube insertion for pneumothorax
    2nd or 3rd interspace at midclavicular line
  55. chest drainage tube insertion for hemothorax
    5th interspace at midaxillary line
  56. bronchial arteries
    lungs are supplied by several small bronchial arteries that arise from the proximal portion of the descending thoracic aorta.
  57. bronchial veins
    Although much of the blood (supplied by brochial arteries) in the lungs returns to the heart via the pulmonary veins, some also collects into small bronchial veins that drain into the azygos system of veins.
  58. lymphatic drainage of both lungs
    to pulmonary (intrapulmonary) and bronchopulmonary (hilar) nodes, which then drain into tracheobronchial nodes
  59. Pancoast syndrome
    • lung cancer tumor may spread to involve the sympathetic trunk and compromise the sympathetic tone to the head. This may lead to Horner's syndrome, which is characterized by the following symptoms:
    • Miosis: constricted pupil
    • Ptosis: minor drooping of the upper eyelid
    • Anhidrosis: lack of sweating
    • Flushing: subcutaneous vasodilation
  60. trachea
    single midline airway that extends from the cricoid cartilage to its bifurcation at the sternal angle of Louis. It lies anterior to the esophagus and posterior to aortic arch and is rigidly supported by 16 to 20 C-shaped cartilaginous rings. Is approximately 5 inches long and 1 inch in diameter
  61. Cartilaginous rings
    Are 16-20 C-shaped rings
  62. Bronchus
    Divides into right and left main (primary) bronchi at the level of the sternal angle of Louis
  63. Right bronchus
    Is shorter, wider, and more vertical than left bronchus; aspirated foreign objects more likely to pass into this bronchus
  64. Carina
    Is internal, keel-like cartilage at bifurcation of trachea
  65. Secondary bronchi
    Supply lobes of each lung (three on right, two on left)
  66. Tertiary bronchi
    Supply bronchopulmonary segments (10 for each lung)
  67. Fibrous pericardium
    Tough, outer layer that reflects onto great vessels
  68. Serous pericardium
    Layer that lines inner aspect of fibrous pericardium (parietal layer); reflects onto heart as epicardium (visceral layer)
  69. Innervation of pericardium
    Phrenic nerve (C3-C5) for conveying pain; vasomotor innervation via sympathetics
  70. Transverse sinus of pericardium
    Space posterior to aorta and pulmonary trunk; can clamp vessels with fingers in this sinus and above
  71. Oblique sinus of pericardium
    Pericardial space posterior to heart
  72. Cardiac Tamponade
    Cardiac tamponade can result from fluid accumulation or bleeding into the pericardial sac. Bleeding may be caused by a ruptured aortic aneurysm, a ruptured myocardial infarct, or a penetrating injury that compromises the beating heart and decreases venous return and cardiac output. The fluid can be removed by a pericardial tap (i.e., withdrawn by a needle and syringe at Larrey's point).
  73. Anterior (sternocostal) of the heart:
    the right atrium, right ventricle, and part of the left ventricle
  74. Posterior (base) of the heart:
    the left atrium
  75. Inferior (diaphragmatic) of the heart:
    mostly the left ventricle
  76. Acute angle of the heart:
    the sharp right ventricular margin of the heart
  77. Obtuse angle of the heart:
    the more rounded left margin of the heart
  78. Apex of the heart:
    the inferolateral part of the left ventricle at the fourth to fifth intercostal space
  79. Right coronary artery
    Consists of major branches: sinoatrial (SA) nodal, right marginal, posterior interventricular (posterior descending), atrioventricular (AV) nodal
  80. Left coronary artery
    Consists of major branches: circumflex, anterior interventricular (left anterior descending [LAD]), left marginal
  81. Great cardiac vein
    Parallels LAD artery and drains into coronary sinus
  82. Middle cardiac vein
    Parallels posterior descending artery (PDA), and drains into coronary sinus
  83. Small cardiac vein
    Parallels right marginal artery, and drains into coronary sinus
  84. Anterior cardiac veins
    Are several small veins that drain directly into right atrium
  85. Smallest cardiac veins
    Drain through the cardiac wall directly into all four heart chambers
  86. atrioventricular groove
    (coronary sulcus) separates the two atria from the ventricles and marks the locations of the right coronary artery and the circumflex branch of the left coronary artery.
  87. anterior and posterior interventricular grooves
    mark the locations of the left anterior descending (anterior interventricular) branch of the left coronary artery and the posterior descending (posterior interventricular) artery, respectively.
  88. Angina Pectoris
    (The Referred Pain of Myocardial Ischemia) Angina pectoris is usually described as pressure, discomfort, or a feeling of choking or breathlessness in the left chest or substernal region that radiates to the left shoulder and arm, as well as the neck, jaw and teeth, abdomen, and back. The pain also may radiate to the right arm. This radiating pattern is an example of referred pain, in which visceral afferents from the heart enter the upper thoracic spinal cord along with somatic afferents, both converging in the spinal cord's dorsal horn. The higher brain center's interpretation of this visceral pain may initially be confused with somatic sensations from the same spinal cord levels.
  89. Coronary Angiogenesis
    Angiogenesis occurs by the budding of new blood vessels. Hypoxia and inflammation are the two major stimuli for new vessel growth. Revascularization of the myocardium after an ischemic episode, bypass surgery, or percutaneous coronary intervention is vital for establishing new vessels (angiogenesis) and for creating anastomoses (interconnections) with existing vessels.
  90. Coronary Bypass
    A coronary artery bypass graft (CABG), also called "the cabbage procedure," offers a surgical approach for revascularization. Veins or arteries from elsewhere in the patient's body are grafted to the coronary arteries to improve blood supply. In a saphenous vein graft, a portion of the great saphenous vein is harvested from the patient's lower limb; other alternatives are the internal thoracic artery graft and the radial artery graft.
  91. Myocardial Infarction
    Myocardial infarction (MI) is a major cause of death. Coronary artery atherosclerosis and thrombosis, the major causes of MI, precipitate local ischemia and necrosis of a defined myocardial area. Necrosis usually occurs approximately 20 to 30 minutes after coronary artery occlusion. Usually MI begins in the subendocardium. This is because the subendocardial region is the most poorly perfused part of the ventricular wall.
  92. Auricle of Right Atrium
    Pouchlike appendage of atrium; embryonic heart tube derivative
  93. Pectinate muscles of Right Atrium
    Ridges of myocardium inside auricle
  94. Crista terminalis of Right Atrium
    Ridge that runs from the inferior vena cava (IVC) to superior vena cava (SVC) openings; its superior extent marks the site of the SA node
  95. Fossa ovalis of Right Atrium
    Depression in interatrial septum; former site of foramen ovale
  96. Atrial openings of Right Atrium
    One each for SVC, IVC, and coronary sinus (venous return from cardiac veins)
  97. Trabeculae carneae of Right Ventricle
    Irregular ridges of ventricular myocardium
  98. Papillary muscles of Right Ventricle
    Anterior, posterior, and septal projections of myocardium extending into ventricular cavity; prevent valve leaflet prolapse
  99. Chordae tendineae of Right Ventricle
    Fibrous cords that connect papillary muscles to valve leaflets
  100. Moderator band of Right Ventricle
    Muscular band that conveys AV bundle from septum to base of ventricle at site of anterior papillary muscle
  101. Ventricular openings of Right Ventricle
    One to pulmonary trunk through pulmonary valve; one to receive blood from right atrium through tricuspid valve
  102. Auricle of Left Atrium
    Small appendage representing primitive embryonic atrium whose wall has pectinate muscle
  103. Atrial wall of Left Atrium
    Wall slightly thicker than thin-walled right atrium
  104. Atrial openings of Left Atrium
    Usually four openings for four pulmonary veins
  105. Papillary muscles of Left Ventricle
    Anterior and posterior muscles, larger than those of right ventricle
  106. Chordae tendineae of Left Ventricle
    Fibrous cords that connect papillary muscles to valve leaflets
  107. Ventricular wall of Left Ventricle
    Wall much thicker than that of right ventricle
  108. Membranous septum of Left Ventricle
    Very thin superior portion of IVS and site of most ventricular septal defects (VSDs)
  109. Ventricular openings of Left Ventricle
    One to aorta through aortic valve; one to receive blood from left atrium through mitral valve
  110. First sound (S1):
    results from the closing of the mitral and tricuspid valves
  111. Second sound (S2):
    results from the closing of the aortic and pulmonary valves
  112. Tricuspid
    (Right AV) Between right atrium and ventricle; has three cusps
  113. Pulmonary
    (Semilunar) Between the right ventricle and pulmonary trunk; has three semilunar cusps (leaflets)
  114. Mitral
    (Bicuspid) Between left atrium and ventricle; has two cusps
  115. Aortic
    (Semilunar) Between left ventricle and aorta; has three semilunar cusps
  116. SA (sinoatrial) node:
    the "pacemaker" of the heart, where initiation of action potential occurs; located at the superior end of the crista terminalis near the superior vena cava (SVC) opening
  117. AV (atrioventricular) node:
    the area of the heart that receives impulses from the SA node and conveys them to the common atrioventricular bundle (of His); located between the opening of the coronary sinus and the origin of the septal cusp of the tricuspid valve
  118. Common AV bundle and bundle branches:
    a collection of specialized heart muscle cells; divides into right and left bundle branches, which course down the interventricular septum
  119. Subendocardial (Purkinje) system:
    the ramification of bundle branches in the ventricles of the heart's conduction system; distributes into a subendocardial network of conduction cells that supply the ventricular walls and papillary muscles
  120. Parasympathetic fibers
    • from the vagus nerve (CN X) course as preganglionic nerves that synapse on postganglionic neurons in the cardiac plexus or within the heart wall itself. Parasympathetic stimulation does the following:
    • Decreases heart rate
    • Decreases the force of contraction
    • Vasodilates coronary resistance vessels (however, most vagus effects are restricted directly to the SA nodal region)
  121. Sympathetic fibers
    • arise from the upper thoracic cord levels (intermediolateral cell column of T1-T4/T5) and enter the sympathetic trunk. These preganglionic fibers synapse in the upper cervical and thoracic sympathetic chain ganglia, and then postganglionic fibers pass to the cardiac plexus. Sympathetic stimulation does the following:
    • Increases the heart rate
    • Increases the force of contraction
    • Vasoconstricts the coronary resistance vessels (via alpha adrenoceptors), but this is masked by a powerful and very important metabolic coronary vasodilation (mediated by adenosine release from myocytes); important because coronary arteries must dilate to supply blood to the heart as it increases its workload
  122. Visceral afferents for pain
    are conveyed back to the upper thoracic spinal cord via the sympathetic fiber pathways
  123. Visceral afferents mediating cardiopulmonary reflexes
    (stretch receptors, baroreflexes, and chemoreflexes) are conveyed back to the brainstem via the vagus nerve.
  124. Cardiac Pacemakers
    Cardiac pacemakers consist of a pulse generator and one or two endocardial leads with an electrode (passive or active fixation lead). The lead is threaded through the subclavian vein, brachiocephalic vein, SVC, and right atrium and is either embedded there or threaded in the trabeculae carnae of the right ventricular wall. Depending on the device and its programming, the lead may sense as well as pace the cardiac chamber in which it is embedded. In pacing, the electrode impulses generated by the pulse generator depolarize the myocardium and initiate contractions at a prescribed rate.
  125. Cardiac Defibrillators
    An implantable cardioverter defibrillator is used for survivors of sudden cardiac death, patients with sustained ventricular tachycardia (a dysrhythmia originating from a ventricular focus with a heart rate typically greater than 120 beats/minute), those at high risk for developing ventricular arrhythmias (ischemic dilated cardiomyopathy), and other indications. In addition to sensing arrhythmias and providing defibrillation to stop them, the device can function as a pacemaker for postdefibrillation bradycardia or atrioventricular dissociation.
  126. Anterior mediastinum:
    the region posterior to the body of the sternum and anterior to the pericardium (substernal region); contains a variable amount of fat
  127. Middle mediastinum:
    the region containing the pericardium and heart
  128. Posterior mediastinum:
    the region posterior to the heart and anterior to the bodies of the thoracic vertebrae; contains the esophagus and its nerve plexus, thoracic aorta, azygos system of veins, sympathetic trunks, lymphatics, and thoracic duct
  129. Pericardial arteries:
    small arteries that branch from the thoracic aorta and supply the posterior pericardium; variable in number (arises from thoracic aorta)
  130. Bronchial arteries:
    arteries that supply blood to the lungs; usually one artery to the right and two to the left, but variable in number (arises from thoracic aorta)
  131. Esophageal arteries:
    arteries that supply the esophagus; variable in number (arises from thoracic aorta)
  132. Mediastinal arteries:
    small branches of the internal thoracic artery that supply the lymph nodes, nerves, and connective tissue of the posterior mediastinum
  133. Posterior intercostal arteries:
    paired arteries that supply blood to the lower nine intercostal spaces (arises from thoracic aorta)
  134. Superior phrenic arteries:
    small arteries to the superior surface of the diaphragm; anastomose with the musculophrenic and pericardiacophrenic arteries (which arise from the internal thoracic artery)
  135. Subcostal arteries:
    paired arteries that lie below the inferior margin of the last rib; anastomose with superior epigastric, lower intercostal, and lumbar arteries (arises from thoracic aorta)
  136. azygos venous system
    drains the posterior thorax and forms an important venous conduit between the IVC and SVC. This system represents the deep venous drainage characteristic of veins throughout the body. Its branches, although variable, largely drain the same regions supplied by the thoracic aorta's branches. The key veins include the azygos vein, with its right ascending lumbar, subcostal, and intercostal tributaries (sometimes the azygos vein also arises from the IVC before the ascending lumbar and subcostal tributaries join it), the hemiazygos vein, and the accessory hemiazygos vein. (If present, it usually begins at the fourth intercostal space.) Ultimately, these veins drain into the azygos vein, which ascends right of the midline to empty into the SVC.
  137. cisterna chyli
    start of the thoracic lymphatic duct in the abdomen, ascends through the posterior mediastinum posterior to the esophagus, crosses to the left of the median plane at approximately the T5-T6 vertebrae, and empties into the venous system at the junction of the left internal jugular and left subclavian veins
  138. laryngotracheal diverticulum
    formed from the ventral foregut, just inferior to the last pair of pharyngeal pouches
  139. left and right lung (bronchial) buds
    formed by the division of the laryngotracheal diverticulum, each with a primary bronchus, further divide to form the definitive lobes of the lungs (three lobes in the right lung, and two lobes in the left lung). Formation of segmental bronchi and 10 bronchopulmonary segments in each lung (by weeks 6 to 7).
  140. Vitelline veins:
    drain blood from yolk sac; will become the portal system draining the gastrointestinal tract through the liver
  141. Cardinal veins:
    form SVC and IVC (and azygos system of veins) and their tributaries; will become the caval system of venous return
  142. Aortic Arch 1 Derivative
    Largely disappears (part of maxillary artery in head)
  143. Aortic Arch 2 Derivative
    Largely disappears
  144. Aortic Arch 3 Derivative
    Common and internal carotid arteries
  145. Aortic Arch 4 Derivative
    Right subclavian artery and aortic arch (on left side)
  146. Aortic Arch 5 Derivative
  147. Aortic Arch 6 Derivative
    Ductus arteriosus and proximal part of pulmonary arteries
  148. heart tube
    • receives blood from the embryonic body, which passes through its heart tube segments in the following sequence:
    • Sinus venosus: receives all the venous return from the embryonic body to the heart tube
    • Atrium: receives blood from the sinus venosus and passes it to the ventricle
    • Ventricle: receives atrial blood and passes it to the bulbus cordis
    • Bulbus cordis: receives ventricular blood and passes it to the truncus arteriosus
    • Truncus arteriosus: receives blood and passes it to the aortic arch system for distribution to the body
  149. Adult Heart Derivatives of the Truncus arteriosus
    • Aorta
    • Pulmonary trunk
  150. Adult Heart Derivatives of the Bulbus cordis
    • Smooth part of right ventricle (conus arteriosus)
    • Smooth part of left ventricle (aortic vestibule)
  151. Adult Heart Derivatives of the Primitive ventricle
    • Pectinated part of right ventricle
    • Pectinated part of left ventricle
  152. Adult Heart Derivatives of the Primitive atrium
    • Pectinate wall of right atrium
    • Pectinate wall of left atrium
  153. Adult Heart Derivatives of the Sinus venosus
    • Smooth part of right atrium (sinus venarum)
    • Coronary sinus
    • Oblique vein of left atrium
    • (The smooth part of the left atrium is formed by incorporation of parts of the pulmonary veins into the atrial wall. The junction of the trabeculated and smooth parts of the right atrium is called the crista terminalis.)
  154. foramen ovale
    blood in the right atrium passes directly to the left atrium via this small opening in the interatrial septum
  155. interatrial septum
    formed by the fusion of a septum primum and a septum secundum (develops on the right atrial side of the septum primum). This fusion occurs after birth when the left atrial pressure exceeds that of the right atrium (blood now passes into the lungs and returns to the left atrium, raising the pressure on the left side) and pushes the two septae together, thus forming the fossa ovalis of the postnatal heart.
  156. ventricular septum
    forms from the superior growth of the muscular interventricular septum from the base of the heart toward the downward growth of a thin membranous septum from the endocardial cushion.
  157. bulbus cordis and truncus arteriosus
    form the outflow tracts of the ventricles, pulmonary artery, and aorta.
  158. Ventricular Septal Defect
    Ventricular septal defect (VSD) is the most common congenital heart defect, representing about 30% of all heart defects. Approximately 80% of cases are perimembranous (occur where the muscular septum and membranous septum of the endocardial cushion should fuse). This results in a left-to-right shunt, which may precipitate congestive heart failure.
  159. Atrial Septal Defect
    Atrial septal defects make up approximately 10% to 15% of congenital cardiac anomalies. Repair of these defects (other than fossa ovalis defects) can be achieved surgically by using a relatively new transcatheter approach through the IVC and into the atria, where a septal occluder is deployed and secured. By threading the catheter through the IVC, it is positioned perfectly to pass directly into the defect, which mimics the direction of flow of the fetal blood passing from the IVC through the foramen ovale and into the left atrium.
  160. Patent Ductus Arteriosus
    Patent ductus arteriosus (PDA) is failure of the ductus arteriosus to close shortly after birth. This results in a shunt of blood from the aorta into the pulmonary trunk, which may lead to congestive heart failure. PDA accounts for approximately 10% of congenital heart defects and can be treated medically (or surgically if necessary). The latter treatment is by direct surgical ligation or via a less invasive catheter-based device that is threaded through the vasculature and positioned to occlude the PDA. Often, children with a PDA may be fine until they become more active and then experience trouble breathing when exercising and demonstrate a failure to thrive. A continuous murmur usually is evident over the left sternal border to just below the clavicle
  161. Rectus sheath:
    a fascial sheath containing the rectus abdominis muscle, which runs from the pubic symphysis and crests to the xiphoid process and fifth to seventh costal cartilages
  162. Linea alba:
    literally the "white line"; a relatively avascular midline subcutaneous band of fibrous tissue where the fascial aponeuroses of the rectus sheath from each side interdigitate in the midline
  163. Semilunar line:
    the lateral border of the rectus abdominis muscle in the rectus sheath
  164. Tendinous intersections:
    transverse skin grooves that demarcate transverse fibrous attachment points of the rectus sheath to the underlying rectus abdominis muscle
  165. Umbilicus:
    the site that marks the T10 dermatome, lying at the level of the intervertebral disc between L3 and L4; the former attachment site of the umbilical cord
  166. Iliac crest:
    the rim of the ilium, which lies at about the level of the L4 vertebra
  167. Inguinal ligament:
    a ligament composed of the aponeurotic fibers of the external abdominal oblique muscle, which lies deep to a skin crease that marks the division between the lower abdominal wall and thigh of the lower limb
  168. Skin layer of abdominal wall:
    epidermis and dermis
  169. Superficial fascia (subcutaneous tissue) layer of abdominal wall: below the umbilicus, this single layer divides into a more superficial fatty layer (Camper's fascia) and a deeper membranous layer (Scarpa's fascia) (see Fig. 4-11)
  170. Investing fascia layer of abdominal wall:
    tissue that covers the muscle layers
  171. Abdominal muscles layer of abdominal wall:
    three flat layers, similar to the thoracic wall musculature, except in the anterior mid-region where the vertically oriented rectus abdominis muscle lies in the rectus sheath
  172. Endoabdominal fascia layer of abdominal wall:
    tissue that is unremarkable except for a thicker portion called the transversalis fascia, which commonly lines the inner aspect of the transversus abdominis muscle
  173. Extraperitoneal fat layer of abdominal wall:
    connective tissue that is variable in thickness
  174. Peritoneum layer of abdominal wall:
    thin serous membrane that lines the inner aspect of the abdominal wall (parietal peritoneum) and occasionally reflects off the walls as a mesentery to partially or completely invest various visceral structures (visceral peritoneum)
  175. External oblique
    • External surfaces of 5th to 12th ribs to Linea alba, pubic tubercle, and anterior half of iliac crest
    • Innervated by Inferior six thoracic nerves and subcostal nerve
    • Compresses and supports abdominal viscera; flexes and rotates trunk
  176. Internal oblique
    • Thoracolumbar fascia, anterior two thirds of iliac crest, and lateral half of inguinal ligament to Inferior borders of 10th to 12th ribs, linea alba, and pubis via conjoint tendon
    • Innervated by Ventral rami of inferior six thoracic nerves and first lumbar nerve
    • Compresses and supports abdominal viscera; flexes and rotates trunk
  177. Transversus abdominis
    • Internal surfaces of 7-12 costal cartilages, thoracolumbar fascia, iliac crest, and lateral third of inguinal ligament to Linea alba with aponeurosis of internal oblique, pubic crest, and pecten pubis via conjoint tendon
    • Innervated by Ventral rami of inferior six thoracic nerves and first lumbar nerve
    • Compresses and supports abdominal viscera
  178. Rectus abdominis
    • Pubic symphysis and pubic crest to Xiphoid process and costal cartilages 5-7
    • Innervated by Ventral rami of inferior six thoracic nerves
    • Compresses abdominal viscera and flexes trunk
  179. Anterior lamina above arcuate line
    Formed by fused aponeuroses of external and internal abdominal oblique muscles
  180. Posterior lamina above arcuate line
    Formed by fused aponeuroses of internal abdominal oblique and transversus abdominis muscles
  181. Aponeuroses and Layers Forming the Rectus Sheath Below arcuate line
    All three muscle aponeuroses fuse to form anterior lamina, with rectus abdominis in contact only with transversalis fascia posteriorly
  182. rectus sheath
    encloses the vertically running rectus abdominis muscle (and inconsistent pyramidalis), the superior and inferior epigastric vessels, the lymphatics, and the ventral rami of T7-L1 nerves, which enter the sheath along its lateral margins. The superior three-quarters of the rectus abdominis is completely enveloped within the rectus sheath, while the inferior one-quarter is supported posteriorly only by the transversalis fascia, extraperitoneal fat, and the peritoneum; the site of this transition is called the arcuate line
  183. Musculophrenic artery:
    a terminal branch of the internal thoracic artery; it courses along the costal margin
  184. Superior epigastric artery:
    arises from the terminal end of the internal thoracic artery and anastomoses with the inferior epigastric artery at the level of the umbilicus
  185. Inferior epigastric artery:
    arises from the external iliac artery and anastomoses with the superior epigastric artery
  186. Superficial circumflex iliac artery:
    arises from the femoral artery and anastomoses with the deep circumflex iliac artery
  187. Superficial epigastric artery:
    arises from the femoral artery and courses toward the umbilicus
  188. External pudendal artery:
    arises from the femoral artery and courses toward the pubis
  189. Superficial epigastric vein
    Drains into femoral vein
  190. Superficial circumflex iliac vein
    Drains into femoral vein and parallels inguinal ligament
  191. Inferior epigastric vein
    Drains into external iliac vein
  192. Superior epigastric vein
    Drains into internal thoracic vein
  193. Thoracoepigastric vein
    Anastomoses between superficial epigastric and lateral thoracic
  194. Lateral thoracic vein
    Drains into axillary vein
  195. Axillary nodes:
    superficial drainage above the umbilicus
  196. Superficial inguinal nodes:
    superficial drainage below the umbilicus
  197. Parasternal nodes:
    deep drainage along the internal thoracic vessels
  198. Lumbar nodes:
    deep drainage internally to the nodes along the abdominal aorta
  199. External iliac nodes:
    deep drainage along the external iliac vessels
  200. processus vaginalis
    a peritoneal pouch (for the descending gonads in males) extends through the various layers of the anterior abdominal wall and acquires a covering from each layer except for the transversus abdominis muscle, because the pouch passes beneath this muscle layer.
  201. fetal inguinal canal
    formed by the processus vaginalis and its coverings,it's a tunnel or passageway through the anterior abdominal wall.
  202. gubernaculum in females
    In the female, the ovaries are attached to the gubernaculum, whose other end terminates in the labioscrotal swellings (which will form the labia majora in females or the scrotum in males). The ovaries descend into the pelvis, where they remain, tethered between the lateral pelvic wall and the uterus medially (by the ovarian ligament, a derivative of the gubernaculum). The gubernaculum then reflects off the uterus as the uterine ligament, passes through the inguinal canal, and ends as a fibrofatty mass in the future labia majora.
  203. gubernaculum in males
    The gubernaculum terminates in the scrotum and anchors the testis to the floor of the scrotum. A small pouch of the processus vaginalis, called the tunica vaginalis, persists and partially envelops the testis.
  204. Cryptorchidism
    undescended testes
  205. contents of the spermatic cord
    • Ductus (vas) deferens
    • Testicular artery, artery of the ductus deferens, and cremasteric artery
    • Pampiniform plexus of veins
    • Autonomic nerve fibers (efferent and visceral afferents) coursing on the arteries and ductus deferens
    • Genital branch of the genitofemoral nerve (innervates cremaster muscle)
    • Lymphatics
  206. Layers of the spermatic cord
    • External spermatic fascia: derived from the external abdominal oblique aponeurosis
    • Cremasteric (middle spermatic) fascia: derived from the internal abdominal oblique muscle
    • Internal spermatic fascia: derived from the transversalis fascia
  207. Superficial ring of the Inguinal Canal
    Medial opening in external abdominal oblique aponeurosis
  208. Deep ring of the Inguinal Canal
    Outpouching in transversalis fascia lateral to inferior epigastric vessels
  209. Inguinal Canal
    Tunnel extending from deep to superficial ring, paralleling inguinal ligament (transmits spermatic cord or round ligament of uterus)
  210. Anterior wall of the Inguinal Canal
    Aponeuroses of external and internal abdominal oblique muscles
  211. Posterior wall of the Inguinal Canal
    Transversalis fascia (medially includes conjoint tendon)
  212. Roof of the Inguinal Canal
    Arching muscle fibers of internal abdominal oblique and transversalis abdominal muscles
  213. Floor of the Inguinal Canal
    Inguinal ligament (and medially by lacunar ligament, an expanded extension of the ligament)
  214. Inguinal ligament
    Ligament extending between anterior superior iliac spine and pubic tubercle (folded inferior border of external abdominal oblique aponeurosis)
  215. Indirect (congenital) Inguinal hernia:
    75% of inguinal hernias occur lateral to the inferior epigastric vessels, pass through the deep inguinal ring and inguinal canal as a protrusion along the spermatic cord, and lie within the internal spermatic fascia
  216. Direct (acquired) Inguinal hernia:
    occurs medial to the inferior epigastric vessels, passes directly through the posterior wall of the inguinal canal, and is separate from the spermatic cord and its coverings derived from the abdominal wall
  217. Hydrocele
    The most common cause of scrotal enlargement is hydrocele, an excessive accumulation of serous fluid within the tunica vaginalis (usually a potential space). It is a small sack of peritoneum originally derived from the processus vaginalis that covers about two thirds of the testis. An infection (in the testis or epididymis), trauma, or a tumor may lead to a hydrocele, or it may be idiopathic.
  218. Varicocele
    Varicocele is an abnormal dilation and tortuosity of the pampiniform venous plexus within the spermatic cord. Almost all varicoceles are on the left side, perhaps because the left testicular vein drains into the left renal vein rather than the larger inferior vena cava, as the right testicular vein does. A varicocele is evident at physical examination when a patient stands, but it often resolves when the patient is recumbent.
  219. ascites
    abnormal accumulation of fluid in the abdomen
  220. Greater omentum
    "Apron" of peritoneum hanging from the greater curvature of the stomach, folding back on itself to attach to the transverse colon
  221. Lesser omentum
    Double layer of peritoneum extending from the lesser curvature of the stomach and proximal duodenum to the liver
  222. Mesenteries
    Double fold of peritoneum suspending parts of bowel and conveying vessels, lymphatics, and nerves of bowel (mesoappendix, transverse mesocolon, and sigmoid mesocolon)
  223. Peritoneal ligaments
    Double layer of peritoneum attaching viscera to walls or to other viscera
  224. Gastrocolic ligament
    Portion of greater omentum that extends from the greater curvature of the stomach to the transverse colon
  225. Gastrosplenic ligament
    Left part of greater omentum that extends from the hilum of the spleen to the greater curvature of the stomach
  226. Splenorenal ligament
    Connects the spleen and left kidney
  227. Gastrophrenic ligament
    Portion of greater omentum that extends from fundus to the diaphragm
  228. Phrenocolic ligament
    Extends from the left colic flexure to the diaphragm
  229. Hepatorenal ligament
    Connects the liver to the right kidney
  230. Hepatogastric ligament
    Portion of lesser omentum that extends from the liver to the lesser curvature of the stomach
  231. Hepatoduodenal ligament
    Portion of lesser omentum that extends from the liver to the first part of the duodenum
  232. Falciform ligament
    Extends from the liver to the anterior abdominal wall
  233. Ligamentum teres hepatis
    Obliterated left umbilical vein in the free margin of the falciform ligament
  234. Coronary ligaments
    Reflections of peritoneum from the superior aspect of the liver to the diaphragm
  235. Ligamentum venosum
    Fibrous remnant of the obliterated ductus venosus
  236. Suspensory ligament of the ovary
    Extends from the lateral pelvic wall to the ovary
  237. Ovarian ligament
    Connects the ovary to the uterus (part of gubernaculum)
  238. Round ligament of the uterus
    Extends from the uterus to the deep inguinal ring (part of gubernaculum)
  239. stomach
    • a dilated, saclike portion of the GI tract that exhibits significant variation in size and configuration, and terminates at the thick smooth muscle sphincter (pyloric sphincter) by joining the first portion of the duodenum. It is tethered superiorly by the lesser omentum (gastrohepatic ligament portion) extending from its lesser curvature and is attached along its greater curvature to the greater omentum and the gastrosplenic ligament. Generally, the J-shaped stomach is divided into the following regions:
    • Cardiac region
    • Fundus
    • Body
    • Pyloric region (antrum and canal)
  240. Lesser curvature of the Stomach
    Right border of stomach; lesser omentum attaches here and extends to liver
  241. Greater curvature of the Stomach
    Convex border with greater omentum suspended from its margin
  242. Cardiac part of the Stomach
    Area of stomach that communicates with esophagus superiorly
  243. Fundus of the Stomach
    Superior part just under the left dome of the diaphragm
  244. Body of the Stomach
    Main part between the fundus and the pyloric antrum
  245. Pyloric part of the Stomach
    Portion that is divided into proximal antrum and distal canal
  246. Pylorus of the Stomach
    Site of pyloric sphincter muscle; joins first part of duodenum
  247. Gastroesophageal Reflux Disease (GERD)
    The terminal end of the esophagus possesses a lower esophageal sphincter (specialized smooth muscle that is pharmacologically different from the smooth muscle lining the lower esophagus). It prevents the reflux of gastric contents into the lower esophagus. However, it can become compromised, usually by a loss of muscle tone or a sliding hiatal hernia, leading to GERD and inflammation of the esophageal lining. GERD often presents with upper abdominal pain, dyspepsia, gas, heartburn, dysphagia, bronchospasm (15% to 20%), or asthma (15% to 20%).
  248. Hiatal Hernia
    • Herniation of the diaphragm that involves the stomach is referred to as a hiatal hernia. A widening of the space between the muscular right crus forming the esophageal hiatus allows protrusion of part of the stomach superiorly into the posterior mediastinum of the thorax. The two anatomical types are the following:
    • Sliding, rolling, or axial hernia (95% of hiatal hernias): appears as a bell-shaped protrusion
    • Paraesophageal, or nonaxial hernia: usually involves the gastric fundus
  249. Bariatric Surgery
    • In some cases of morbid obesity, bariatric surgery may offer a viable alternative to failed dieting. The following three approaches may be considered:
    • Gastric stapling (vertical banded gastroplasty) involves creating a small stomach pouch in conjunction with stomach stapling and banding; this approach is performed less frequently in preference to other options.
    • Gastric bypass (Roux-en-Y) spares a small region of the fundus and attaches it to the proximal jejunum; the main portion of the stomach is stapled off, and the duodenum is reattached to a more distal section of jejunum, allowing for the mixture of digestive juices from the liver and pancreas.
    • Adjustable gastric banding restricts the size of the proximal stomach, limiting the amount of food that can enter; the band can be tightened or relaxed via a subcutaneous access port if circumstances warrant.
  250. Rugae
    The interior of the unstretched stomach is lined with prominent longitudinal mucosal gastric folds called rugae, which become more evident as they approach the pyloric region.
  251. Duodenum:
    about 25 cm long and largely retroperitoneal. The duodenum is the first portion of the small intestine and descriptively is divided into four parts. Most of the C-shaped duodenum is retroperitoneal and ends at the duodenojejunal flexure, where it is tethered by a musculoperitoneal fold called the suspensory ligament of the duodenum (ligament of Treitz)
  252. Superior of the Duodenum
    First part; attachment site for hepatoduodenal ligament of lesser omentum
  253. Descending of the Duodenum
    Second part; site where bile and pancreatic ducts empty
  254. Inferior of the Duodenum
    Third part; part that crosses inferior vena cava (IVC) and aorta and is crossed anteriorly by mesenteric vessels
  255. Ascending of the Duodenum
    Fourth part; portion tethered by suspensory ligament at duodenojejunal flexure
  256. Jejunum and Ileum:
    • Jejunum is about 2.5 meters long
    • Ileum is about 3.5 meters long
    • Both suspended by a mesentery
    • Compared to the ileum, the jejunum:
    • occupies the left upper quadrant of the abdomen.
    • is larger in diameter.
    • walls are thicker.
    • mesentery contains less fat.
    • has arterial branches with fewer arcades and longer vasa recta.
    • internally it has mucosal folds that are higher and more numerous, which increases the surface area for absorption.
  257. Peptic Ulcer Disease
    Peptic ulcers are GI lesions that extend through the muscularis mucosae and are remitting, relapsing lesions. (Erosions, on the other hand, affect only the superficial epithelium.) Acute lesions are small and shallow, whereas chronic ulcers may erode into the muscularis externa or perforate the serosa. Although they may occur in the stomach, most occur in the first part of the duodenum, which is referred to by clinicians as the duodenal cap.
  258. Crohn Disease
    • Crohn disease is an idiopathic inflammatory bowel disease that can affect any segment of the GI tract but usually involves the small intestine (terminal ileum) and colon. Young adults of northern European ancestry are more commonly affected. Transmural edema, follicular lymphocytic infiltrates, epithelioid cell granulomas, and fistulation characterize this disease. Signs and symptoms include the following:
    • Diffuse abdominal pain (paraumbilical and lower-right quadrant)
    • Diarrhea
    • Fever
    • Dyspareunia (pain during sexual intercourse)
    • Urinary tract infection (UTI)
    • Malabsorption
  259. large intestine
    • about 1.5 meters long and extends from the cecum to the anal canal. It includes the following segments:
    • Cecum
    • Appendix
    • Ascending colon
    • Transverse colon
    • Descending colon
    • Sigmoid colon
    • Rectum and anal canal
  260. Cecum:
    a pouch that is connected to the ascending colon and the ileum; it extends below the ileocecal junction, although it is not suspended by a mesentery
  261. Appendix:
    a narrow tube of variable length (usually about 7 to 10 cm) that contains numerous lymphoid nodules and is suspended by mesentery called the mesoappendix
  262. Ascending colon:
    is retroperitoneal and ascends on the right flank to reach the liver, where it bends into the right colic (hepatic) flexure
  263. Transverse colon:
    is suspended by a mesentery, the transverse mesocolon, and runs transversely from the right hypochondrium to the left, where is bends to form the left colic (splenic) flexure
  264. Descending colon:
    is retroperitoneal and descends along the left flank to join the sigmoid colon in the left groin region
  265. Sigmoid colon:
    is suspended by a mesentery, the sigmoid mesocolon, and forms a variable loop of bowel that runs medially to join the midline rectum in the pelvis
  266. Rectum and anal canal:
    are retroperitoneal and extend from the middle sacrum to the anus
  267. Taeniae coli:
    three longitudinal bands of smooth muscle that are visible on the cecum and colon's surface and assist in peristalsis
  268. Haustra:
    sacculations of the colon created by the contracting taeniae coli
  269. Omental appendices:
    small fat accumulations that are covered by visceral peritoneum and hang from the colon
  270. Greater luminal diameter:
    the large intestine has a larger luminal diameter than the small intestine
  271. Acute Appendicitis
    Appendicitis is a fairly common inflammation of the appendix, often caused by bacterial infection. Initially, diffuse pain is felt in the periumbilical region. However, as the appendix becomes more inflamed and irritates the parietal peritoneum, the pain becomes well localized to the right lower quadrant (circumscribed tenderness to palpation). Surgical resection is the treatment of choice to prevent more serious life-threatening complications (abscesses and peritonitis).
  272. Ulcerative Colitis
    an idiopathic inflammatory bowel disease that begins in the rectum and extends proximally. Usually the inflammation is limited to the mucosal and submucosal layers of the bowel.
  273. Diverticulosis
    Diverticulosis is a herniation of colonic mucosa and submucosa through the muscular wall, with a diverticular expansion in the adventitia of the bowel visible on its external surface. Common sites of development occur where neurovascular bundles penetrate the muscular wall of the bowel.
  274. Colorectal Cancer
    Colorectal cancer is second only to lung cancer in site-specific mortality and accounts for almost 15% of cancer-related deaths in the United States. The cancer appears as polypoid and ulcerating, and spreads by infiltration through the colonic wall, by regional lymph nodes, and to the liver through portal venous tributaries.
  275. Volvulus
    Volvulus is the twisting of a bowel loop that may cause bowel obstruction and constriction of its vascular supply, which may lead to infarction. Volvulus affects the small intestine more often than the large, and the sigmoid colon is the most common site in the large intestine; the mesenteric mobility of these portions of the bowel account for this higher occurrence at these sites. Volvulus is associated with dietary habits, perhaps a bulky vegetable diet that results in an increased fecal load.
  276. Intussusception
    Intussusception is the invagination, or telescoping, of one bowel segment into a contiguous distal segment. In children, the cause may be linked to excessive peristalsis. In adults, an intraluminal mass, such as a tumor, may become trapped during a peristaltic wave and pull its attachment site forward into the more distal segment. Intestinal obstruction and infarction may occur.
  277. liver
    • receives the venous drainage from the GI tract, its accessory organs, and the spleen via the portal vein
    • the largest solid organ in the body and anatomically is divided into four lobes:
    • Right lobe (largest lobe)
    • Left lobe
    • Quadrate lobe (lies between the gallbladder and the round ligament of the liver)
    • Caudate lobe (lies between the IVC, ligamentum venosum, and porta hepatis)
  278. Important functions of the liver
    • Storage of energy sources (glycogen, fat, protein, and vitamins)
    • Production of cellular fuels (glucose, fatty acids, and keto acids)
    • Production of plasma proteins and clotting factors
    • Metabolism of toxins and drugs
    • Modification of many hormones
    • Production of bile acids
    • Excretion of substances (bilirubin)
    • Storage of iron and many vitamins
    • Phagocytosis of foreign materials that enter the portal circulation from the bowel
  279. Lobes of the Liver
    Divisions, in functional terms, into right and left lobes, with anatomical subdivisions into quadrate and caudate lobes
  280. Round ligament of the Liver
    Ligament that contains obliterated umbilical vein
  281. Falciform ligament of the Liver
    Peritoneal reflection off anterior abdominal wall with round ligament in its margin
  282. Ligamentum venosum of the Liver
    Ligamentous remnant of fetal ductus venosus, allowing fetal blood from placenta to bypass liver
  283. Coronary ligaments of the Liver
    Reflections of peritoneum from liver to diaphragm
  284. Bare area of the Liver
    Area of liver pressed against diaphragm that lacks visceral peritoneum
  285. Porta hepatis of the Liver
    Site at which vessels, ducts, lymphatics, and nerves enter or leave liver
  286. gallbladder
    • composed of a fundus, body, and neck. Its function is to receive, store, and concentrate bile. Bile, which is secreted by the hepatocytes of the liver, passes through the extrahepatic duct system in the following way:
    • Collects in the right and left hepatic ducts after draining the right and left liver lobes
    • Enters the common hepatic duct
    • Enters the cystic duct and is stored and concentrated in the gallbladder
    • Upon stimulation (largely by vagal efferents and cholecystokinin [CCK]), leaves the gallbladder and enters the cystic duct
    • Passes inferiorly down the common bile duct
    • Enters the hepatopancreatic ampulla (of Vater)
    • Empties into the second part of the duodenum (major duodenal papilla)
  287. Gallstones (Cholelithiasis)
    Cholelithiasis results from stone formation in the gallbladder and extrahepatic ducts. Acute pain (biliary colic) can be referred to several sites. Common sites include the back just below the right scapula (T6-T9 dermatomes) or even the right shoulder region, if an inflamed gallbladder (cholecystitis) irritates the diaphragm. Obstruction of bile flow (bile stasis) can lead to numerous complications and jaundice (yellow discoloration of the skin and sclera that is caused by bilirubin accumulation in the blood plasma).
  288. pancreas
    • an exocrine and endocrine organ that lies posterior to the stomach in the floor of the lesser sac. It is a retroperitoneal organ, except for the distal tail, which is in contact with the spleen. The anatomical parts of the pancreas include the following:
    • Head: nestled within the C-shaped curve of the duodenum, with its uncinate process lying posterior to the superior mesenteric vessels
    • Neck: lies anterior to the mesenteric vessels, deep to the pyloris of the stomach
    • Body: extends above the duodenojejunal flexure and across the superior part of the left kidney
    • Tail: terminates at the hilum of the spleen in the splenorenal ligament
  289. Pancreatic secretion
    is under neural (vagus nerve) and hormonal (secretin and CCK) control, and the exocrine secretions empty primarily into the main pancreatic duct, which joins the common bile duct at the hepatopancreatic ampulla (of Vater). A smaller accessory pancreatic duct also empties into the second part of the duodenum above the major duodenal papilla.
  290. Pancreatic Cancer
    Carcinoma of the pancreas is the fifth leading cause of cancer death in the United States. Pancreatic carcinomas, which are mostly adenocarcinomas, arise from the exocrine part of the organ (cells of the duct system); 60% of cancers are found in the pancreatic head (these often cause obstructive jaundice). Islet tumors of the endocrine pancreas are less common. Because of the anatomical position of the pancreas, adjacent anatomical sites may be directly involved (duodenum, stomach, liver, colon, spleen), and pancreatic metastases via the lymphatic network are common and extensive.
  291. spleen
    • is slightly larger than a clenched fist and weighs about 180 to 250 grams. It lies in the upper left quadrant of the abdomen and is tucked posterolateral to the stomach under the protection of the lower-left rib cage and diaphragm (Figs. 4-20 and 4-21). Simplistically, it is a large lymph node (and can become quite large during infections), although functionally it is much more and is involved in the following functions:
    • Lymphocyte proliferation (B and T cells)
    • Immune surveillance and response
    • Blood filtration
    • Destruction of old or damaged red blood cells (RBCs)
    • Destruction of damaged platelets
    • Recycling iron and globin
    • Providing a reservoir for blood
    • Providing a source of RBCs in early fetal life
  292. spleen is tethered
    between the stomach by the gastrosplenic ligament and the left kidney by the splenorenal ligament. Vessels, nerves, and lymphatics enter or leave the spleen at the hilum
  293. Rupture of the Spleen
    Trauma to the left upper quadrant can lead to splenic rupture. The adventitial capsule of the spleen is very thin, making traumatic rupture a medical emergency, as the spleen receives a rich vascular supply and can bleed profusely.
  294. Foregut:
    gives rise to the abdominal esophagus, stomach, proximal half of the duodenum, liver, gallbladder, and pancreas
  295. Midgut:
    gives rise to distal half of the duodenum, jejunum, ileum, cecum, appendix, ascending colon, and proximal two-thirds of the transverse colon
  296. Hindgut:
    gives rise to distal third of the transverse colon, descending colon, sigmoid colon, rectum, and proximal anal canal
  297. Celiac trunk (artery):
    arises from the anterior aspect of the abdominal aorta immediately inferior to the diaphragm and supplies foregut derivatives and the spleen
  298. Common hepatic branch:
    branch of celiac trunk (artery) that supplies the liver, gallbladder, stomach, duodenum, and pancreas (head and neck)
  299. Left gastric branch:
    branch of celiac trunk (artery) the smallest branch; supplies the stomach and esophagus
  300. Splenic branch:
    branch of celiac trunk (artery) the largest branch; takes a tortuous course along the superior margin of the pancreas, and supplies the spleen, stomach, and pancreas (neck, body, and tail)
  301. Superior mesenteric artery (SMA):
    arises from the anterior aspect of the abdominal aorta about one finger's breadth inferior to the celiac trunk and supplies midgut derivatives
  302. Inferior pancreaticoduodenal artery branch:
    branch of SMA, supplies the head of the pancreas and duodenum
  303. Jejunal and ileal branches:
    branch of SMA, give rise to 15 to 18 intestinal branches; run in the mesentery tethering the jejunum and ileum
  304. Middle colic artery branch:
    branch of SMA, runs in the transverse mesocolon; supplies the transverse colon
  305. Right colic artery branch:
    branch of SMA, courses retroperitoneally to the right side; supplies the ascending colon
  306. Ileocolic artery branch:
    branch of SMA, passes to the right iliac fossa and supplies the ileum, cecum, appendix, and proximal ascending colon; terminal branch of the SMA
  307. Inferior mesenteric artery (IMA):
    arises from the anterior aspect of the abdominal aorta at about the level of the L3 vertebra and supplies hindgut derivatives
  308. Left colic artery branch:
    branch of IMA, courses to the left and ascends retroperitoneally; supplies the distal transverse colon (by an ascending branch that enters the transverse mesocolon) and the descending colon
  309. Sigmoid arteries branch:
    branch of IMA, a variable number of arteries (2 to 4) that enter the sigmoid mesocolon; supply the sigmoid colon
  310. Superior rectal artery branch:
    branch of IMA, a small terminal branch; supplies the distal sigmoid colon and proximal rectum
  311. hepatic portal system
    drains the abdominal GI tract, pancreas, gallbladder, and spleen and ultimately drains into the liver and its sinusoids. A portal system, by definition, implies that arterial blood flows into a capillary system (in this case the bowel and its accessory organs), then into larger veins (portal tributaries), and then again into another capillary (or sinusoids) system (the liver), before ultimately being collected into larger veins (hepatic veins and the IVC) that return the blood to the heart.
  312. portal vein
    ascends from behind the pancreas (superior neck) and courses superiorly in the hepatoduodenal ligament (which also contains the common bile duct and proper hepatic artery) to the hilum of the liver; it is formed by the Superior mesenteric and Splenic veins
  313. Superior mesenteric vein (SMV):
    large vein that lies to the right of the SMA and drains portions of the foregut and all of the midgut derivatives
  314. Splenic vein:
    large vein that lies inferior to the splenic artery, parallels its course, and drains the spleen, pancreas, foregut, and, usually, hindgut derivatives (via the inferior mesenteric vein)
  315. Cirrhosis of the Liver
    • Cirrhosis is a largely irreversible disease characterized by diffuse fibrosis, parenchymal nodular regeneration, and disturbed hepatic architecture. Progressive fibrosis disrupts the portal blood flow, leading to portal hypertension. Major causes of cirrhosis include the following:
    • Alcoholic liver disease (60% to 70%)
    • Viral hepatitis (10%)
    • Biliary diseases (5% to 10%)
    • Genetic hemochromatosis (5%)
    • Cryptogenic cirrhosis (10% to 15%)
    • Portal hypertension can lead to esophageal and rectal varices (tortuous enlargement of the esophageal and rectal veins) as the portal venous blood is shunted into the caval system using portacaval anastomoses. Additionally, the engorgement of the superficial venous channels in the subcutaneous tissues of the abdominal wall can appear as a caput medusae (tortuous subcutaneous varices that resemble the snakes of Medusa's head).
  316. Portal Hypertension
    • If the portal vein becomes occluded or its blood cannot pass through the hepatic sinusoids, a significant increase in portal venous pressure will ensue, resulting in portal hypertension. Normal portal venous pressure is about 3 to 6 mm Hg, but it can exceed 12 mm Hg (portal hypertension), resulting in dilated, tortuous veins (varices) and variceal rupture. The following three major mechanisms are defined:
    • Prehepatic: obstructed blood flow to the liver
    • Posthepatic: obstructed blood flow from the liver to the heart
    • Intrahepatic: cirrhosis or another liver disease, affecting hepatic sinusoidal blood flow
  317. Clinical consequences of portal hypertension include:
    • Ascites, usually detectable when 500 mL of fluid accumulates in the abdomen
    • Formation of portacaval shunts via anastomotic channels
    • Congestive splenomegaly (becomes engorged with venous blood backing up from the splenic vein)
    • Hepatic encephalopathy (neurological problems due to the inadequate removal of toxins in the blood by the diseased liver)
  318. sympathetic innervation of the viscera
    • derived from the following nerves:
    • Thoracic splanchnic nerves: greater (T5-T9), lesser (T10-T11), and least (T12) splanchnic nerves (the nerve branches from the thoracic ganglia from which these nerves arise is variable) that convey preganglionic axons to the prevertebral ganglia to innervate the foregut and midgut derivatives
    • Lumbar splanchnic nerves: usually several lumbar splanchnic nerves (L1-L2 or L3) that convey preganglionic axons to the prevertebral ganglia and plexus to innervate the hindgut derivatives
    • Vasoconstriction to shunt blood to other parts of the body, thus inhibiting digestion
    • Reduced bowel motility
    • Reduced bowel secretion
  319. parasympathetic innervation of the viscera
    • derived from the following:
    • Vagus nerves: anterior and posterior vagal trunks enter the abdomen on the esophagus and send preganglionic axons directly to postganglionic neurons in the walls of the viscera derived from the foregut and midgut
    • Pelvic splanchnic nerves: preganglionic axons from S2-S4 travel via these splanchnic nerves to the prevertebral plexus and distribute to the postganglionic neurons of the hindgut derivatives. (Note: pelvic splanchnic nerves are not part of the sympathetic trunk; only sympathetic neurons and axons reside in the sympathetic trunk and chain ganglia.)
    • Increased bowel motility
    • Increased secretion
  320. Visceral afferent fibers
    • travel with the ANS components and can be summarized as follows:
    • Pain afferents: include the pain of distension and ischemia, which is conveyed to the CNS largely by the sympathetic components to the spinal dorsal root ganglia associated with the T5-L2 spinal cord levels
    • Reflex afferents: include information from chemoreceptors, osmoreceptors, and mechanoreceptors, which are conveyed to autonomic centers in the medulla oblongata via the vagus nerves
  321. Psoas fascia:
    covers the psoas major muscle and is thickened superiorly, forming the medial arcuate ligament
  322. Thoracolumbar fascia:
    anterior layer covers the quadratus lumborum muscle and is thickened superiorly, forming the lateral arcuate ligament; middle and posterior layers envelop the erector spinae muscles of the back
  323. Psoas major muscle
    • Transverse processes of lumbar vertebrae; sides of bodies of T12-L5 vertebrae, and intervening intervertebral discs to Lesser trochanter of femur
    • Innervated by Lumbar plexus via ventral branches of L2-L4 nerves
    • Acting superiorly with iliacus, flexes hip; acting inferiorly, flexes vertebral column laterally; used to balance trunk in sitting position; acting inferiorly with iliacus, flexes trunk
  324. Iliacus muscle
    • Superior two thirds of iliac fossa, ala of sacrum, and anterior sacroiliac ligaments to Lesser trochanter of femur and shaft inferior to it, and to psoas major tendon
    • Innervated by Femoral nerve
    • Flexes hip and stabilizes hip joint; acts with psoas major
  325. Quadratus lumborum muscle
    • Medial half of inferior border of 12th rib and tips of lumbar transverse processes to Iliolumbar ligament and internal lip of iliac crest
    • Innvervated by Ventral branches of T12 and L1-L4 nerves
    • Extends and laterally flexes vertebral column; fixes 12th rib during inspiration
  326. Diaphragm
    • Thoracic outlet: xiphoid, lower six costal cartilages, L1-L3 vertebrae to Converge into central tendon
    • Innervated by Phrenic nerve
    • Draws central tendon down and forward during inspiration
  327. Renal capsule:
    covers each kidney; a thick fibroconnective tissue capsule
  328. Perirenal (perinephric) fat:
    directly surrounds the kidney (and adrenal glands) and cushions it
  329. Renal fascia:
    surrounds the kidney (and adrenal glands) and perirenal fat; superiorly it is continuous with the fascia covering the diaphragm; inferiorly it may blend with the transversalis fascia
  330. Pararenal (paranephric) fat:
    an outer layer of fat that is variable in thickness and is continuous with the extraperitoneal (retroperitoneal) fat
  331. Renal capsule:
    a fibroconnective tissue capsule that surrounds the renal cortex
  332. Renal cortex:
    outer layer that surrounds the renal medulla and contains nephrons (units of filtration) and renal tubules
  333. Renal medulla:
    inner layer (usually appears darker in color) that contains renal tubules and collecting ducts that convey filtrate to minor calices; the renal cortex extends as renal columns in between the medulla, demarcating the distinctive "renal pyramids" whose apex (renal papilla) terminates with a minor calyx
  334. Minor calyx:
    structure that receives urine from the collecting ducts of the renal pyramids
  335. Major calyx:
    site at which several minor calices drain
  336. Renal pelvis:
    point at which several major calices unite; conveys urine to the proximal ureter
  337. Hilum of kidney:
    medial aspect of each kidney, where the renal pelvis emerges from the kidney and where vessels, nerves, and lymphatics enter or leave the kidney
  338. adrenal (suprarenal) glands
    right adrenal (suprarenal) gland often is pyramidal in shape, whereas the left gland is semilunar. Each adrenal gland "caps" the superior pole of the kidney and is surrounded by perirenal fat and renal fascia. The right adrenal gland is in close proximity to the IVC and liver, whereas the stomach, pancreas, and even the spleen can lie anterior to the left adrenal gland.
  339. Renal Stones (Calculi)
    Renal stones may form in the kidney and remain there or, more commonly, pass down the ureters to the bladder. When the stones traverse the ureter, they cause significant pain (renal colic) that typically distributes on the side of the insult radiating from "loin to groin." The ureters narrow at three points along their course to the bladder. This is a common location for renal stones to become lodged and cause pain. This pain distribution reflects the pathway of visceral pain afferents (pain is from distension of the ureter) that course to the spinal cord levels T11-L1 via the sympathetic splanchnic nerves. Complications of renal stones include obstruction to the flow of urine, infection, and destruction of the renal parenchyma.
  340. Obstructive Uropathy
    Obstruction to the normal flow of urine, which may occur anywhere from the level of the renal nephrons to the urethral opening, can precipitate pathological changes that coupled with an infection can lead to serious uropathies. This composite figure shows a number of obstructive possibilities and highlights important aspects of the adjacent anatomy one sees along the extent of the urinary tract.
  341. Malignant Tumors of the Kidney
    Of the malignant kidney tumors, 80% to 90% are adenocarcinomas that arise from the tubular epithelium. They account for about 2% of all adult cancers, often occur after 50 years of age, and occur twice as often in men as in women. Wilms tumor is the third most common solid tumor in young children (<10 years of age) and is associated with congenital malformations related to chromosome 11.
  342. Spinal Cord Levels for Visceral Referred Pain of the Stomach
    • T5-T9
    • Epigastric or left hypochondrium
  343. Spinal Cord Levels for Visceral Referred Pain of the Spleen
    • T6-T8
    • Left hypochondrium
  344. Spinal Cord Levels for Visceral Referred Pain of the Duodenum
    • T5-T8
    • Epigastric or right hypochondrium
  345. Spinal Cord Levels for Visceral Referred Pain of the Pancreas
    • T7-T9
    • Inferior part of epigastric
  346. Spinal Cord Levels for Visceral Referred Pain of the Liver or gallbladder
    • T6-T9
    • Epigastric or right hypochondrium
  347. Spinal Cord Levels for Visceral Referred Pain of the Jejunum
    • T6-T10
    • Umbilical
  348. Spinal Cord Levels for Visceral Referred Pain of the Ileum
    • T7-T10
    • Umbilical
  349. Spinal Cord Levels for Visceral Referred Pain of the Cecum
    • T10-T11
    • Umbilical or right lumbar or right lower quadrant
  350. Spinal Cord Levels for Visceral Referred Pain of the Appendix
    • T10-T11
    • Umbilical or right inguinal or right lower quadrant
  351. Spinal Cord Levels for Visceral Referred Pain of the Ascending colon
    • T10-T12
    • Umbilical or right lumbar
  352. Spinal Cord Levels for Visceral Referred Pain of the Sigmoid colon
    L1-L2 Left lumbar or left lower quadrant
  353. Spinal Cord Levels for Visceral Referred Pain of the Kidney
    • T10-L1
    • Lower hypochondrium or lumbar
  354. Spinal Cord Levels for Visceral Referred Pain of the Ureter
    • T11-L1
    • Lumbar to inguinal (loin to groin)
  355. Somatic nerves of the posterior abdominal wall
    derived from the lumbar plexus, which is composed of the ventral rami of L1-L4 (sometimes with a small contribution from T12)
  356. Subcostal (T12) Branch of the Lumbar Plexus
    Last thoracic nerve; courses inferior to the 12th rib
  357. Iliohypogastric (L1) Branch of the Lumbar Plexus
    Motor and sensory (above pubis and posterolateral buttocks)
  358. Ilioinguinal (L1) Branch of the Lumbar Plexus
    Motor and sensory (sensory to inguinal region)
  359. Genitofemoral (L1-L2) Branch of the Lumbar Plexus
    Genital branch to cremaster muscle, femoral branch to femoral triangle
  360. Lateral cutaneous nerve of thigh (L2-L3) Branch of the Lumbar Plexus
    Sensory to anterolateral thigh
  361. Femoral (L2-L4) Branch of the Lumbar Plexus
    Motor in pelvis (to iliacus) and anterior thigh muscles, sensory to thigh and medial leg
  362. Obturator (L2-L4) Branch of the Lumbar Plexus
    Motor to adductor muscles in thigh, sensory to medial thigh
  363. Accessory obturator Branch of the Lumbar Plexus
    Inconstant (10%); motor to pectineus muscle
  364. Meckel's Diverticulum
    • Meckel's diverticulum is the most common developmental anomaly of the bowel and occurs as a result of failure of the vitelline (yolk stalk) duct to involute once the gut loop has re-entered the abdominal cavity. It is often referred to as the "syndrome of twos" because of the following reasons:
    • It occurs in approximately 2% of the population.
    • It is about 2 inches long.
    • It is located about 2 feet from the ileocecal junction.
    • It often contains at least 2 types of mucosa.
  365. Congenital Megacolon
    Congenital megacolon results from the failure of neural crest cells to migrate distally along the colon (usually the sigmoid colon and rectum). This leads to an aganglionic segment that lacks both Meissner's submucosal and Auerbach's myenteric plexuses. Distention proximal to the aganglionic region may occur shortly after birth or may cause symptoms in early childhood. Surgical repair involves prolapse and eversion of the segment.
  366. Congenital Malrotation of the Colon
    Many congenital lesions of the GI tract cause intestinal obstruction, which commonly results from malrotation of the midgut, atresia, volvulus, meconium ileus, or imperforate anus. Vomiting, absence of stool, and abdominal distention characterize the clinical picture. Intestinal obstruction can be life threatening, requiring surgical intervention. The corrective procedure for congenital malrotation with volvulus of the midgut is illustrated.
  367. Renal Fusion
    The term renal fusion refers to various common defects in which the two kidneys fuse to become one. The horseshoe kidney, in which developing kidneys fuse (usually the lower lobes) anterior to the aorta, often lies low in the abdomen and is the most common kind of fusion. Fused kidneys are close to the midline, have multiple renal arteries, and are malrotated. Obstruction, stone formation, and infection are potential complications.
  368. Pheochromocytoma
    • Although pheochromocytomas are relatively rare neoplasms composed largely of adrenal medullary cells (which secrete excessive amounts of catecholamines), they can occur elsewhere throughout the body associated with the sympathetic chain or at other sites where neural crest cells typically migrate. Common clinical features include the following:
    • Vasoconstriction and elevated blood pressure
    • Headache, sweating, and flushing
    • Anxiety, nausea, tremor, and palpitations or chest pain