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How many bones does a typical adult have?
206. Varies with individual and age because some bones fuse together
Paired vs Unpaired bones
- Paired= 2 bones, same type on left and right side (86 paired bones)
- Unpaired= located in midline (34 unpaired)
Head of bone
Enlarged, often rounded end
Neck of Bone
Constriction between head and body
Margin or border of bone
Branch off body beyond angle
- Smooth rounded articular surface
- Smooth rounded end covered with articular cartilage
Small, flattened articular surface
Crest or crista
Terms for projections
- Tuberosity or tuber
- Prominent projection
- Usually ligament or tendon attached
- Small, rounded bump
- Usually ligament or tendon attached
knob; larger than tubercle
tuberosities on proximal femur
Upon a condyle
- Canal or meatus
- Sinus or labyrinth
- Usually occupied by something like nerves or blood vessels
Sinus or labyrinth
- Groove or sulcus
General term for a depression
Depression in margin of bone
Groove or sulcus
Deeper, narrow depression
- Upright axis of body, includes skull, auditory ossicles, hyoid one, vertebral column, and thoracic cage
- Protects brain, spinal cord, and vital organs in thorax
How many bones are in the skull?
- 22 bones
- 8 bone in brain case
- 14 facial bones
What 8 bones encase the brain?
- 2 parietal bone
- 2 temporal bone
- 1 Frontal bone
- 1 Occipital bone
- 1 Sphenoid bone
- 1 Ethmoid bone
What 14 bones make up the face?
- 2 maxilla
- 2 zygomatic bones
- 2 palatine bones
- 2 lacrimal bones
- 2 nasal bones
- 2 inferior nasal concha
- 1 mandible
- 1 vomer
What are the functions of the facial bones?
- Support organs of vision, smell, and taste
- Provide attachment points for muscles involved in mastication, facial expression and eye movement
Bones of the skull are pretty much a single unit. What is the 1 bone that moves freely from the rest?
Calvaria (skull cap)
Top of skull, usually cut off to reveal interior of skull
What sutures are associated with the parietal bones?
- 2 parietal bones joined at midline by sagittal suture
- Joined to frontal bone by coronal suture (anterior)
- Joined to occipital bone by lamboid suture (posterior)
- Joined to temporal bones by squamous suture (lateral)
Sutural or wormian bones
Extra small bones that sometimes form along lamboid suture
External Occipital Protuberance
- Base of head, palpable through scalp, size varies
- Site of attachment of ligamentum nuche (nape of neck)
Elastic ligament that extends down neck and helps keep head erect by pulling on occipital region of skull
Set of small ridges that extend laterally from external occipital protuberance. Pts of attachment for many neck muscles.
What bone contains the external auditory meatus or canal?
- Temporal bones
- Transmit sound waves to tempanic membranes
What process is posterior and inferior to the EACs?
- Mastoid process
- Not solid bone, filled with cavities called mastoid air cells that connect to inner ear. Muscles in neck involved in rotation of head attach to mastoid process
- Inferior and superior on lateral surface of parietal bones
- Attachment points for temporalis muscles involved in mastication
- One bone that extends across entire head (mostly internal)
- Greater wing of sphenoid bone is anterior to temporal bone
- Cheek bone
- Anterior to sphenoid bone and part of temporal bone
- Consists of joined processes from temporal and zygomatic bone, forms bridge across side of skull
- Easily palpable, muscles on each side palpable when jaw opens/closes
- Inferior to maxilla
- 2 parts: body and ramus, joins angle of mandible
- Mandibular condyle articulates with temporal bone to allow movement of mandible
Attachment pt of temporalis muscle to mandible
Sockets for attachment of teeth on maxillae and mandible.
- Protect eye and attachment pts for eye muscles
- Contains blood vessels, nerves, fat, eyeballs, and muscles
- Several openings between orbit and other cavities
Superior and inferior orbital fissures
Nerves and blood vessels pass
Optic nerve passes into cranial cavity
- Passes from orbit into nasal cavity
- Duct that takes tears from eye to nasal cavity
Divided into right and left halves by nasal septum
- Bony part of nasal septum: primarily the vomer inferiorly and perpindicular plate of ethmoid bone superiorly
- Anterior part of nasal septum is hyaline cartilage called septal cartilage
Deviated nasal septum
- Usually in median plane until about 7 yrs old and then deviates slightly to 1 side
- Can deviate significantly at birth or due to injury
- Surgically repaired
What does a "broken nose" typically involve?
Fracture of nasals, ethmoid, vomer, or maxillae
- Lateral of wall of nasal cavity
- Middle and superior nasal conchae are projections from ethmoid bone
- Inferior nasal conchae is a separate bone
What are the functions of the nasal conchae and septum?
Promotes moistening and warming of inhaled air and removal of particles from air by mucous membranes
- Decrease weight of skull and act as resonating chambers during voice production
- Frontal, maxillary, and sphenoidal sinuses
- Ethmoidal sinuses=ethmoidal labyrinth
- Most prominent foramen.
- Connects spinal cord and brain.
- Located in occipital bone.
Next to foramen magnum, connect skull and vertebral column
Blood carried to brain through internal carotid arteries and vertebral arteries (foramen magnum)
How does blood leave the brain?
- Through internal jugular veins
- Exit through jugular foramina, lateral to occipital condyles
Styloid processes (2)
- Long, pointed projections from inferior surface of temporal bone
- Muscles involved in movement of tongue, hyoid bone, and pharynx attached to each process
Where mandibular condyle articulates with skull, anterior to styloid process
Medial and lateral pterygoid plates
- Vertical bony plates of sphenoid bone
- Binds each side of posterior nasal cavity
Most of posterior portion of nasal septum
Hard or Bony Palate
- Forms floor of nasal cavity
- Formed by 4 bones
What 4 bones form the hard palate?
- 2 palatine processes of maxillae (2/3)
- Horizontal plates of 2 palatine bones (1/3)
Hard and soft palate function
Separates nasal cavity from mouth allowing humans to chew and breathe at the same time
Cleft lip and cleft palate
- Cleft lip: maxillae don't form normally or fuse
- Cleft palate: Palatine processes of maxillae don't fuse. Difficult to eat, drink, or speak distinctly because opening between oral and nasal cavities
Superior view of skull with calvaria removed
- 1) Anterior cranial fossa
- 2) Middle cranial fossa
- 3) Posterior cranial fossa
Crista galli of ethmoid bone (rooster's comb)
- Prominent ridge in anterior cranial fossa
- Attachment point for one of the meninges
- on each side of crista galli
- Olfactory nerves extend from cranial cavity into roof of nasal cavity through sievelike perforations in cribiform plate called olfactory foramina
Sella turcica (Turkish saddle)
Center of spehnoid bone, resembles saddle, houses pituitary gland
Petrous (rocky) part of temporal bone
- Thick, bony ridge lateral to foramen magnum
- Hollow, contains middle and inner ear (auditory ossicles in middle ear)
- Carotid canal runs anteromedially within petrous aprt of temporal bone
What allows people to hear their own heartbeat?
Thin plate of bone between carotid canal and middle ear
- Not part of adult skull, no direct bony attachment to skull
- "floats" in superior aspect of neck just inferior to mandible
- Attachment for some tongue and neck muscles that elevate larynx during speech/swallowing.
Function of Vertebral Column
- 1) Supports weight of head and trunk
- 2) Protects spinal cord
- 3) Allows spinal nerves to exit spinal cord
- 4) Site of attachment for muscles
- 5) Permits movement of head and trunk
How many bones and regionsare in the vertebral column?
- 26 bones
- 5 regions
- 7 cervical
- 12 thoracic
- 5 lumbar
- 1 sacral
- 1 coccygeal
Why does the developing embryo have 33-34 vertebrae?
5 sacral vertebrae fuse to form sacral bone and 4-5 coccygeal bones fuse
4 major curves in adult spine
- Concave anteriorly: Thoracic and sacral curve
- Convex anteriorly: Cervical and Lumbar
Which spinal curves form in the fetus?
Thoracic and sacral curves. C-shape curve of fetus
Which spinal curve forms when infant lifts head a few months after birth?
Which spinal curve forms when the infant learns how to sit and walk?
What are 3 types of abnormal spine curvature?
- Lordosis: Exaggeration of lumbar curve (swayback condition)
- Kyphosis: Exaggeration of thoracic curve (hunchback)
- Scoliosis: abnormal lateral and rotational curvature of spine
What is the weight bearing portion of the vertebrae?
Body of vertebrae
Projects posteriorly from vertebral foramen
Contains spinal cord and cauda equina
What 2 structures are attached to the vertebral body?
What two structures extend from transverse processes to spinous processes?
What structures serve as attachment points for the back muscles?
- Spinous processes
- Transverse processes
Extends laterally from each side of arch between lamina and pedicle
- At junction between 2 laminae
- Can be palpated down midline of back
- Support and movement of vertebral column between individual vertebrae.
- Each has a smooth articular facet allowing movement between processes.
How many articular processes does each vertebrae have?
- 4 articular processes: 2 superior and 2 inferior
- Superior articular process of one vertebrae articulates with inferior process of next superior vertebrae.
- Exit of spinal nerves between vertebrae.
- Formed by superior and inferior intervertebral notches.
- Vertebral laminae partially or completely fail to fuse during fetal development.
- Most common in lumbar region
- If severe, may interfere with normal nerve function below point of defect.
- Pads of fibrocartilage between bodies of adjacent vertebrae
- Shock absorbers and allow vertebral column to bend
What two components make up the intervertebral disks?
- Annulus fibrosus: external, fibrous
- Nucleus pulposus: internal, gelatinous
What happens to intervertebral disks with age?
Disks more compressed, decreased height, weakend annulus fibrosus, increase suceptibility for herniation.
Herniated or Ruptured Intervertebral Disks
- Brakage or ballooning of annulus fibrosus with partial or complete release of nucleus pulposus.
- Herniated portion can push on and compress spinal cord, cauda equina, or nerves, decreasing function and increasing pain.
- Most common in lumbar and cervical spines
Cervical vertebrae differences
- All have transverse foramen for vertebral arteries to go towards head
- Also small bodies, bifid spinous processes except C&
- No body, no spinous process
- Holds up head, large superior articular facets that articulate with occipital condyles on base of skull
- Nodding and tilting of head (side to side, front to back)
- Articulates with Atlas (C1) for "no" motion of head
- Dens or odontoid process (protrudes superiorly from body)
Only cervical vertebrae with non-bifid spinous process
Easily palpable between shoulders, usually spinous process of C7 sometimes C6 or T1
Thoracic Vertebrae Differences
- Have attachment sites for ribs
- T1-T10 have articular facets on their transverse processes to articulate with tubercles of ribs.
- Long, thin spinous processes directed inferiorly
Lumbar Vertebrae Differences
- Large, thick bodies and heavy, rectangular transverse and spinous processes
- Superior articular facets face mdially, inferior articular facets face laterally
- When superior articular surface of one vertebrae join inferior articular process of another, tends to "lock" adjacent vertebrae together increasing stability and decreasing rotation
Sacral Vertebrae Differences
- Margins of sacral body unite after 20 years.
- Transverse processes fuse to form lateral parts of sacrum, interior ossifies around midlife.
Wing shaped superior and lateral parts of sacrum (top corners)
Most of lateral surface of sacrum; joins sacrum to pelvic bone. Ear shaped
Median Sacral Crest
Partially fused spinous processes of S1-S4
- S5 spinous process doesn't form, exposes sacral canal
- Used to access sacral canal and administer anesthetics during child birth.
What landmark separates abdomen and pelvis?
- Sacral promontory
- Can be felt during pelvic exam
- 4 or more fused vertebrae into 1 bone
- No foramen or processes
- Easily broken in fall or during childbirth
T1-T12, ribs, associated costal cartilage and sternum
How many pairs of ribs do humans have?
- 12 pairs
- Articulate posteriorly with thoracic vertebrae
What is the role of costal cartilage?
Attach many ribs anteriorly with sternum
What is the difference between "true ribs" and "false ribs"?
- True ribs: attach to sternum (1-7)
- False ribs: don't attach to sternum directly, attach through common cartilage of rib 7 (8-10)
What are "floating ribs"?
Don't attach to sternum at all (11 and 12)
What are the 2 points of articulation of ribs with vertebrae?
- 1) Head: articulates with bodies of 2 adjacent vertebrae and intervetebral disk
- 2) Tubercle: articulates with transverse process of inferior vertabrae
What are the 3 main parts of the sternum?
- Like a sword
- 1) Manubrium (handle)
- 2) Body (blade)
- 3) Xiphoid process (tip)
B/w ends of clavicles whre the articulate with manubrium, base of the human neck. Depression easily visible.
- Slight ridge at junction of manubrium and body
- 2nd rib is lateral to it
- Angle of Louis
What are the components of the pectoral girdle?
- 2 scapulae and 2 clavicles
- Each humerus --> scapula --> Clavicle --> Sternum
Depression in scapula where humerus attaches
What are the 3 fossa of the scapula?
- Posterior surface: 1) Supraspinous 2)Infraspinous (separated by scapular spine)
- Anterior surface: 3) Subscapular fossa
- Extension of spine forming point of shoulder
- Protective cover for shoulder
- Attachment site for clavicle and some shoulder muscles
Curves below clavicle and is attachment point for arm and chest muscles
- Acromial (lateral end)
- Sternal (medial end), articulates with manubrium
Where does the humeral head articulate with the scapula?
What is the anatomical neck of the humerus?
Around the humeral head, attachment point for connective tissue for shoulder
What is the surgical neck of the humerus?
Common site of fracture requiring surgery
What are the functions of the greater and less tubercles of the humerus?
Sites for muscle attachment
What structure is between the greater and lesser tubercles? What is in this structure?
- Biceptal (Intertubercular) Groove
- Tendon of biceps brachii muscle
- Lateral surface of humerus
- 1/3 way down humerus
- Attachement point for deltoid muscle
What are the two condyles on the distal end of the humerus?
What bone does the trochlea articulate with?
What bone does the capitulum articulate with?
What are the two epicondyles on the humerus? What are their functions?
- Medial and lateral epicondyles
- Attachment points for forearm muscles
What are the two bone in the forearm?
- Radius (lateral side, thumb side)
- Ulna (Medial side, pinky side)
What is the trochlear or semilunar notch?
Fits over trochlea of humerus and forms most of elbow joint
What are the 2 processes in the elbow?
- Olecranon: posterior process (tip of elbow), site of attachment for posterior arm muscles
- Coronoid process: Anterior process, smaller
Head of radius
- Proximal end, concave, articulates with capitulum of humerus
- Lateral surface forms a smooth cylinder where radius rotates against radial notch of ulna
Radial and ulnar tuberosities
- Just distal of elbow
- Attachment point for arm muscles
Distal head of ulna
Small head, articulates with radius and carpal bones
What is the purpose of the ulnar and radial styloid processes?
Attachment points for wrist ligaments
What population is most at risk for radius fractures?
Which hand position is associated with a radius fracture?
Fall on outstretched hand, posterior displacement of hand.
What is a Colles fracture?
Complete, transverse fracture of radius 2.5 cm proximal to wrist. Often comminuted or impacted.
What are the 8 carpal bones in the wrist?
- Proximal row (thumb to pinky): Scaphoid, lunate, triquetrum, pisiform
- Distal row (thumb to pinky): Trapezium, Trapezoid, Capitate, Hamate
What is carpal tunnel syndrome?
- Bones and ligaments form "carpal tunnel" on anterior (ventral) side of wrist without much give
- Overuse or trauma can cause fluid and/or enlarged tendons to associated with inflammation to apply pressure to major nerve in carpal tunnel.
- Symptoms: numbness, tingling and burning in hand
How are the metacarpals numbered? What do their distal ends form?
- 1-5 (thumb to pinky)
What are the 2 phalanges in the thumb? 3 in fingers?
- Thumb: Proximal and distal phalanges
- Fingers: Proximal, middle, and distal phalanges
What are the distal interphalangeal (DIP), proximal interphalangeal (PIP), and metacarpophalangeal (MCP) joints?
- DIP: between distal and middle phalanges
- PIP: between middle and proximal phalanges
- MCP: between proximal phalanges and metacarpals
Where do the coxal bones join anteriorly and posteriorly?
- Anteriorly: Pubic symphysis
- Posteriorly: Sacrum
What are the components of the pelvis?
- 1)Right and left coxal bones
- 2) Sacrum
- 3) Coccyx bone
What are the 3 parts of each coxal bone?
- 1) Ilium (superior)
- 2) Ischium (inferior and posterior)
- 3) Pubis (Inferior and anterior)
What is the acetabulum?
- Fossa on lateral surface of each coxal bone
- Point of articulation with lower extremities
- Lunate surface: crescent shape, superior and leteral aspects of fossa (articular surface)
- Large, opening in ischium where nerves and blood vessels pass
- Mostly closed off by connective tissue that separates pelvic cavity and superficial structures.
- Only a few, small blood vessels and nerves pass.
- Superior part of ilium, easily palpable
- Ends anteriorly at anterior superior iliac spine and posteriorly at posterior superior iliac spine
Anterior superior iliac spine
Attachment point for anterior thigh muscles
Posterior inferior iliac spine
Attachment point for ligaments anchoring coxal bone to sacrum
- Attachment point for posterior thigh muscles
- Part of coxal bone where person sits
Auricular surface of Ilium
Joins auricular surface of sacrum to form sacroiliac joint
What passes through the greater and lesser sciatic notch?
Nerves and blood vessels
Bony boundary from sacral promontory to pubic crest
False or greater pelvis
Superior to pelvic brim and partially surrounded by bone on posterior and lateral sides.
Inferior to pelvic brim, completely surrounded by bone
Superior opening of true pelvis at pelvic brim
Inferior opening of true pelvis, bordered by inferior margin of pubis, ischial spines, tuberosities and coccyx.
Where does the femur articulate with the coxal bone?
Acetabulum of coxalbone
What are the greater and lesser trochanter of the femur?
- Attach muscles that fasten hip to leg
- Greater trochanter and ssociated muscles are wides part of hips
What are 3 other muscle attachment points on the femur?
- 1) Pectineal line
- 2) Gluteal tuberosity
- 3) Linea aspera
What are the major structures of the distal end of the femur?
- Medial and Lateral condyles
- Medial and lateral epicondyles
- Adductor tubercle
What is the role of the medial and lateral condyles?
Articulation with the tibia
What is the role of the meidal and lateral epicondyles?
What is the role of the patella?
- Articulation with femur in patellar groove
- Holds tendon away from distal end of femur and changes angle of tendon between quadriceps femoris muscle and tibia where tendon attaches
- Change in angle increases force with less muscle contraction because of more leverage
Where is the patella located?
Large, sesamoid bone within tendon of quadriceps femoris muscle group
What are the two bones of the lower leg?
Tibia (larger) and Fibula (smaller)
- Larger, weight bearing bone of leg
- Rounded condyles of femur rest on flat medial and lateral condyles on proximal end of tibia.
What is the function of the tibial tuberosity?
- Attachment point for quadriceps femoris, easily palpable just inferior to patella
- Convex anteriorly
What is the sharp edge of the shin called?
Anterior crest of tibia
What is the medial malleolus?
- Distal, enlarged end of Tibia
- Medial aspect of ankle
Does the fibula articulate with the femur?
NO! Articulates with tibia
What is the lateral malleolus?
Distal, slightly enlarged end of fibula
What is the thinnest, weakest point of the fibula?
Just proximal to lateral malleolus
How many bones are in the foot?
- 7 tarsal bones
- Proximal rows: Navicular, Talus, and Calcaneus
- Distal row: Medial, intermediate, and distal cuniforms and cuboid
What is the talus?
- Articulates with tibia and fibula to form ankle joint
- Unusual, no muscle attachments
- Attachment point for large calf muscles
Foot Eversion Injury
- Medial malleolus moves to ground, plantar surface outward
- Talus slides laterally forcing malleoli to separate.
- Ligament is stronger than bone in the ankle so medial malleolus breaks as talus slides laterally
- Can cause lateral malleolus to shear off or fracture the fibula (Pott's fracture)
Foot Inversion Injury
- Plantar surface inward
- Can fracture fibula just proximal to lateral malleolus
- Often ligament between medial malleolus and tarsal bones is weaker than bones and ligaments are damaged with no fracture=sprain
What forms the ball of the foot?
Distal ends of metatarsals
What are the 3 arches of the foot?
- Medial longitudinal arch
- Lateral longitudinal arch
- Transverrse arch
Medial longitudinal arch
- Calcaneus, talus, navicular, cuniforms, and 3 medial metatarsals
- Highest arch
Lateral longitudinal arch
Calcaneus, cuboid, 2 lateral metatarsals
Cuboid and cuniforms
Shifting of weight to different bones while walking
Tibula-fibula --> Talus --> Calcaneus --> Lateral arch system --> Ball of foot
Which types of joints allow more movement?
- Cartilagnous joints with smooth articulating surfaces
- Fibrous joints have much less movement
What are the 3 classes of joints?
- 1) Fibrous
- 2) Cartilaginous
- 3) Synovial
- 2 bones, united with fibrous connective tissue
- No joint cavity
- Little or no movement
What are the 3 types of fibrous joints?
1) Sutures 2) Syndesmoses 3) Gomphoses
- Fibrous joints between skull bones
- Dense, regular collagenous connective tissue
- Interlocking finger like process increases stability
- Margins of bone in suture: continuous intramembrane bone growth and many become ossified
Two bones fuse together across a joint to form a single bone (ie. Frontal bone)
- Joint where bones are farther apart than suture
- Joined by ligaments, some movement (ie. Radioulnar syndesmoses)
Pegs held in place within sockets by fibrous tissue (ie. Joints between teeth and alveoli of mandible and maxillae)
Fibrous connective tissue between teeth and sockets
What are cartilaginous joints?
Unite 2 bones with either hyaline or fibrocartilage
What are synchondroses?
- Hyaline cartilage with little to no movement
- Most are temporary with bone replacing cartilage to form synostosis
- Ie. Ilium, ischium, and pubis before fusion, ephyseal plates, and sternocostal synchondroses
- Fibrocartilage uniting 2 bones
- I.e. manubrium, sternum, invertertebral disks and symphysis pubis
What are synovial joints?
- Freely moveable, contain synovial fluid in a cavity surrounding ends of articulating bones
- Articular cartilage=hyaline cartilage
- Joint capsule surrounds ends of bones forming synovial joints forming a joint cavity
What are articular disks?
- Disks located between articular cartilage of bones
- Absorb and distribute forces between articular cartilage as bones move (TMJ, sternoclavicular, and AC joints)
What is the meniscus?
- Incomplete, crescent shaped fibrocartilage pad found in joints like knee and wrist.
- "articular disk with hole in the center"
Outer fibrous capsule
- Dense, irregular connective tissue, continuous with periosteum
- May thicken and collagen fibers may arrange to become ligaments
- Lines joint cavity except over articular cartilage and disks
- Thin, delicate membrane of modified connective tissue
- Produces synovial fluid
What is synovial fluid made of?
- Serum filtrate, polysaccharides, proteins, fats, and cells
- Major polysaccharide is hyaluronic acid (lubricant)
- Pocket or sac of synovial membrane that extends away from the rest of the joint cavity
- Provide cushioning between structures that would normally rub against each other like tendons and bones
Are bursa always associated with bones?
- No; some provide cushion between skin and underlying bone prominences like the subcutaneous olecranon bursae
- Others extend along tendons forming a tendon sheath
What are the 6 types of synovial joints?
- 1) Plane
- 2) Pivot
- 3) Hinge
- 4) Ball and socket
- 5) Elipsoid
- 6) Saddle
Plane (Gliding) Joints
2 opposed flat surfaces that can glide against each other (uniaxial)
- Cylindrical process rotates within a ring
- Uniaxial rotation
- Concave end of 1 bone and convex end of another bone
- Uniaxial bending
Ball and socket joints
- Head of one bone (ball) and a socket of another bone where the ball fits in
- Modified ball and socket joints, ellipsoid articular surfaces
- 2 saddle shaped articulating surfaces oriented perpendicular to each other
to bend or move in anterior direction
To straighten or move in posterior direction
Standing on tiptoes
Away from midline
axial skeleton to one side
Mandible away from midline (chewing)
Mandible back to neutral position
Temporomandibular Joint (TMJ)
- Mandibular condyle fits into mandibular fossa of temporal bone
- Fibrocartilage articular disk located between mandible and temporal bone separates joint into superior and inferior joint cavities
- Ellipsoid and plane joint (mainly ellipsoid)
Temporomandibular disorder (TMD)
- 2nd most common cause of orofacial pain after toothache
- 1) Muscle related TMD
- 2) Joint related TMD
Muscle related TMD
- More common, muscle hyperactivity like grinding of teeth during sleep and jaw clenching when stressed
- Radiographs may appear normal
Joint related TMD
- Caused by disk displacement, degeneration of joint, arthritis, infection etc
- Abnormal movement of disk causes popping or clicking sound, may make impossible to open mouth fully
Glenohumeral Joint (shoulder)
- Ball and socket joint, decreases stability for more mobility
- Flexion, extension, abduction, adduction, rotation, and circumduction
- Round head of humerus articulates with shallow glenoid cavity of scapula
- Rim of glenoid cavity built up by fibrocartilage ring where joint capsule attaches
- Subacromial bursa is outside joint cavity
- Maintains stability of glenohumeral joint
- Consists of 4 muscles and ligaments
Biceps brachii muscle tendon
- Also stabilizes glenohumeral joint with rotator cuff
- Attaches at supraglenoid tubercle, crosses over head of humerus within joint cavity and passes through the intertubercular groove and joins biceps brachii
What are the most common shoulder disorders?
- Dislocations and muscle or tendon tears
- Most commonly dislocated joint because major ligaments cross superior part but no ligaments across inferior side
In which direction is the glenohumeral joint most likely to dislocate?
- Dislocation of humerus most likely to occur inferiorly into axilla
- Can damage axillary nerve and blood vessels
- Humeroulnar and humeroradial joints
- Shape of trochlear notch and trochlea limit movement to flexion and extension
- Joint capsule reinforced by ligaments
- Olecranon bursa covers proximal and posterior surface of olecranon processes
What happens during pronation and supination?
Rounded radial head rotates in radial notch of ulna against capitulum of humerus to allow pronation and supination
What are two common elbow problems?
- 1) Olecranon bursitis (student's elbow)
- 2) Nursemaid's elbow
Olecranon bursitis (student's elbow)
Excessive rubbing of elbow against a hard surface
- Radial head subluxated from annular ligament of radius
- Can happen if child is lifted by one hand
Coxal Joint (Hip)
- Femoral head articulates with concave acetabulum of coxal bone
- Flexion, extension, abduction, adduction, rotation, and circumduction
- Acetabulum is deepened and strengthened by a lip of fibrocartilage called acetabular labrum
- Extremely strong joint capsule, reinforced by several ligaments, extends from rim of acetabulum to neck of femur
Which side of the knee is more likely to be injured?
- Medial side because MCL is weaker than LCL.
- Medial meniscus is tightly attached to MCL and is damaged 20x more than lateral meniscus (thinner and not attached to LCL)
Torn meniscus in knee
- Causes "clicking" sound during extension
- If severe damage, torn cartilage may move between articular surfaces causing knee to "lock" in partially flexed position
Torn ACL and PCL
- If knee is driven anteriorly, ACL maybe torn
- If flexed and driven posteriorly, PCL may be torn
Bursitis of subcutaneous prepatellar bursa "housemaid's knee" from prolonged work performed while on hands and knees
- Affects subcutaneous infrapatellar bursa
- From excessive kneeling
Softening of cartilage resulting in abnormal movement of patella within patellar groove
Fat Pad Syndrome
Accumulation of fluid in fat pad posterior to patella
- When hip is flexed and femur is driven posteriorly such as when a person is sitting in MVC
- Head of femur usually dislocates from posterior to acetabulum tearing accetabular labrum, fibrous capsule, and ligaments.
- Fracture of femur and coxal bones are usually associated
- Femur joins tibia and patella
- Fibula joins tibia
- Distal end of femur has 2 large, round condyles with a deep intercondylar fossa between them
- Femur articulates with tibia's proximal condyles that are flattened with a crest called the intercondylar eminence
Where is the patella located?
within tendons of quadriceps femoris
ACL and PCL
- ACL attaches anteriorly to intercondylar eminence on tibia
- PCL attaches posteriorly to intercondylar eminenc on tibia
- Prevent tibia sliding anteriorly or posteriorly on femur
MCL and LCL
- Strengthen medial and lateral sides of knee
- Prevent femur from tipping side to side on tibia
- Suprapatellar bursa
- Subcutaneous prepatellar bursa
- Deep infrapatellar bursa
- Largest, superior extension of joint capsule
- Allows movement of anterior thigh muscles over distal end of femur
Talocrural Joint (Ankle)
- Medial and lateral malleoli of tibia and fibula form sides
- Almost non-existent anterior and posterior margins
- Most of weight beared by tibia and talus
- Ligaments from lateral and medial malloli attach to trasal bones and stabilize joint
- Arches of foot supported by ligaments that distribute weight and return to normal position