Anatomy Section 8

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Anatomy Section 8
2012-11-15 16:16:58
Shoulder Muscles

Shoulder Muscles section 8
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  1. Posterior muscles of shoulder joint
    • Trapezius
    • Latissimus dorsi
    • Levator scapulae
    • Rhomboid Minor
    • Rhomboid Major 
    • Deltoid
    • Supraspinatus
    • InfraSpinatus
    • Teres minor
    • Teres major
    • subscapularis
    • long head of triceps brachii
  2. Anterior Muscles of shoulder Joint
    • Serratus anterior
    • Long head of biceps brachii
    • Long head of triceps brachii
    • pectorial major
    • pectorial minor
    • coracobrachialis
    • Deltoid
  3. Muscles of Rotator Cuff
    • Supraspinatus
    • Infraspinatus
    • Teres Minor
    • Subscapularis
  4. Superficial Shoulder muscles
    • Trapezius
    • Latissimus dorsi
  5. Trapezius 
    • Origin:
    • Upper part: Occipital bone, nuchal ligament, T1 to T3 midline
    • Lower: T1to T4 midline
    • Insertion:
    • Upper part:Upper edge of spine of scapula, acromion and lateral 3rd of clavicle
    • Lower: lower edge of medial part of spine of scapula
    • Action: Whole: retraction  Upper:  elevation
    • innervation: cranial nerve 11
  6. Latissimus dorsi
    (medial rotation)
    • Origin: spinous process of T7 to sacrum & posterior illio crest; lower 4 ribs; occasionally tip of scapula
    • Insertion: posterior (medial) edge of bicipital groove
    • Action: adduction, extension, and medial rotation of humerus; raises body towards arms during climbing
    • Innervation: thoracodorsal nerve
  7. Muscles of the Medial border of Shoulder
    • Levator Scapulae
    • Rhomboid minor
    • Rhomboid major
    • Serratus anterior
  8. Levator scapulae
    • origin:  posterior tubrcles of first 4 cervicle vertebrae
    • Insertion: upper medial corner of scapula
    • action: elevation and tilts glenoid cavity infereiorly
    • Innervation: dorsal scapular nerve
  9. Rhomboid minor & major
    • Origin: C4 spinous process to C5 spinous process
    • Insertion: along the medial border of scapula
    • Action: retraction and tilts glenoid cavity infereiorly
    • Innervation: dorsal scapular nerve
  10. Serratus anterior
    • Origin: side of front of first 8 ribs
    • Insertion: medial border of scapula
    • Action: protraction
    • Innervation: long thoracic nerve
  11. Muscles of Dorsal surface of shoulder
    • Supraspinatus
    • infraspinatus
    • Teres minor
    • Teres major
  12. Supraspinatus
    • Origin: supraspinous fossa
    • insertion: Greater tubercle (superior aspect)
    • Action: initiates abduction of humerous
    • Innervation: suprascapular nerve
  13. Infraspinatus
    • Origin: upper part of infraspinous fossa
    • Insertion: back or greater tubercle; above teres minor
    • Action:  external(lateral) rotation of humerus
    • Innervation: suprascapular nerve
  14. Teres minor
    • Origin: lower border of scapula
    • Insertion: back of greater tubercle; below infraspinatus
    • Action: external rotation
    • Innervation: axillary nerve
  15. Teres Major
    • Origin: lower border of scapula
    • Insertion: Medial (posterior) crest of bicipital  groove
    • Action: adduction and medial (internal) rotation of arm
    • Innervation: lower subscapular nerve
  16. Subscapularis (Costal surface)
    • Origin: subscapular fossa
    • Insertion: lesser tubercle
    • Action: Alone: internal rotation and adduction of arm 
    • Together with 3 short muscles: holding humerus in socket
    • Innervation: upper and lower subscapular nerve
  17. Deltoid (spine of scapula)
    • Origin: spine of scapula; acromion; lateral 3rd of clavical
    • Insertion: deltoid tuberosity
    • Action: anterior part: flexion
    •            posterior part: extension
    •            lateral part: abduction
    • Innervation: axillary nerve
  18. Biceps brachii
    • Origin: long head: supraglenoid tubercle
    •            short head: coracoid process
    • Insertion: tuberosity of radius 
    • Action: flexion of elbow; supination of forearm; short head resist dislocation of shoulder
    • Innervation: musculocutaneous nerve
  19. Coracobrachialis
    • Origin: coracoid process
    • Insertion: medial surface of humerus 
    • Action: flexion and adduction of shoulder joint
    • Innervation: musculocutaneous nerve
  20. Pectoralis minor
    • Origin: 3rd to 5th rib
    • Insertion: coracoid process
    • Action: depression
    • Innervation: medial pectoral nerve
  21. Muscles of the Coracoid Process of shoulder
    • Biceps brachii
    • Coracobrachialis
    • Pectoralis minor
  22. Pectoralis Major (no attachment to scapula)
    • Origin: medial 3rd of clavicle; front of sternum; front of first 6 costal cartilages
    • Insertion: anterior edge of bicipital groove
    • Action: adduction and internal rotation  of humerus, flexion
    • Innervation: lateral and medial pectoral nerve
  23. Triceps brachii (posterior arm)
    • Origin: long head: infraglenoid tubercle
    •            lateral head: posterior surface
    •             Medial head: posterior surface
    • Insertion: olecranon of ulna
    • Action: extension of forearm; long head resists dislocation of shoulder joint
    • Innervation: radial nerve 
  24. Rotator Cuff
    • 4 short muscles converge on the humerous to form a continuous cuff, a flat supporting tendons. 
    • keep the head of the humerous from sliding from the glenoid cavity
  25. Narrowing Impingement Syndrome
    narrowing in the space below the acromion and an inflammatory swelling of the synovial bursa.
  26. Bursea around shoulder joint
    • Subacrimion
    • subdelta
    • Subscapula
  27. boundaries of Triangle of Auscultation
    • medial border of scapula
    • lateral border of trapezius
    • superior border of latissimus dorsi
  28. floor of Triangle of Auscultation
    7th rib, 6th and 7th intercostal spaces and rhomboid major
  29. clinical correlates of Triangle of Auscultation
    lung sounds can be better heard here with stethoscope
  30. Axillary nerve
    • terminal branch from posterior cord of brachial plexus
    • innervates with deltoid and teres minor
  31. Anterior boundary of the Axilla
    • pectoralis major
    • pectoralis minor
    • clavipectoral fascia 
  32. Posterior boundary of the Axilla 
    • subcapularis
    • teres major
    • latissimus dorsi
  33. Medially serratus anterior boundary of axilla
    upper 4 ribs
  34. Lateral boundary of Axilla
    intertubercular sulcus
  35. apex triangular boundary of Axilla
    • clavical anteriorly 
    • scapula posteriorly
  36. base of Axilla
    concave floor of armpit
  37. Axilla
    quadrangular space bound medially by long head of triceps, laterally by humerous, superiorly by teres minor, and inferiorly by teres major.
  38. contents of Axilla
    • axillary artery 
    • axillary comitantes
    • brachial plexus cords and branches
    • lymph nodes
    • fat and connective tissue
    • axillary tail of the breast 
  39. Axillary Artery 
    • a continuation of the subclavian artery beyond the outer edge of the thirst rib 
    • becomes brachial artery and has 3 parts 
  40. parts of the brachial artery
    • 1. superior thoracic artery
    • 2. lateral thoracic artery
    • 3. branches into 
    •        1. subscapular artery
    •         2. posterior circumflex humeral artery
    •         3.  anterior circumflex humeral artery
  41. Formation of the Brachial Plexus
    • formed by ventral rami of C5, C6, C7, C8, T1 passing between sclenus anterior and medius muscles in the neck forming 3 trunks 
    • trunks divide into anterior and posterior divisions behind clavicle
    • from cords main nerves of brachial plexus
  42. 3 trunks of brachial plexus
    • upper trunk from C5 and C6
    • middle trunk from C7
    • lower trunk from C8 and T1
  43. anterior and posterior divisions of trunks of brachial plexus
    • posterior from all posterior divisions
    • lateral from the anterior divisions of upper and middle trunks
    • medial from lower trunk anterior division 
  44. main nerves of brachial plexus from roots
    • dorsal scapular nerve
    •       long thoracic nerve
  45. main nerves of brachial plexus from trunk
    • subclavius nerve
    •      suprascapular nerve
  46. main nerves of brachial plexus from the lateral cord
    • Lateral pectoral nerve
    •  - musculocutaneous nerve
    •  - lateral root of median nerve
  47. main nerves of brachial plexus from medial cord
    • medial pectoral nerve 
    • -median cutaneous of arm
    • -median cutaneous of forearm
    •          - ulnar nerve 
    •          - medial root of median nerve
  48. main nerves of brachial plexus from posterior cord
    • upper an lower subscapular nerves
    •   - thoracodorsal nerve
    •   - axiallry nerve
    •   - radially nerve 
  49. injuries of brachial plexus 
    • Avulsion
    • rupture
    • neuroma
    • neuropraxia (stretch)
  50. Avulsion injury
    • most severe
    • nerve is torn from spine
  51. rupture injury
    nerve is torn but not at spinal attachment
  52. Neuroma injury
    nerve has tried to heal itself but scar tissue has grown around  putting pressure on nerve and prevents it from sending signals to muscle
  53. Neuropraxia (stretch)
    • nerve is damaged but not torn
    • most common type of injury to brachial plexus
  54. Saturday Night [crutch] palsy
    • patient unable to extend elbow and will have wrist drop
    • do to loss of extension by triceps 
  55. 5 groups of Nodes in the Axilla.
    • anterior under pectoralis minor
    • posterior near subscapularis
    • lateral along axillary vein
    • central in the middle of Axilla
    • apical[just infraclavicular]
  56. Lymph Drainage and breast cancer
    • lymph is a clear fluid that travels through arteries, circulates your tissues to cleanse them
    • lymph nodes are filters along the system that trap cancer, bacteria, viruses and unwanted substances and eliminate from the body
  57. Paralysis of Serratus Anterior 
    • due to injury in long thoracic nerve
    • causes it to move laterally and Post.  forming winged scapula
  58. injury of thoracodorsal Nerve
    • become unable to raise the trunk 
    • can't use axillary crutch because shoulder is pushed superiorly by it
  59. injury to the Dorsal Scapula Nerve
    • effects actions of the rhomboids 
    • causing scapula of that side to be located further from the midline
  60. Injury to the Axillary Nerve 
    • winds around the surgical neck of humerous 
    • injured in fracture of proximal end of of humerous and dislocation of shoulder joint
  61. Injury to the Radial Nerve
    • wraps around back of humerous shaft.  cause by improper use of crutches, mid-shaft fracture, or arm hanging on chair
    • decreases ability to extend arm at elbow and difficulty lifting wrist or fingers
  62. injury to Musculocutaneous Nerve
    • rare injury
    • isolated injury causes weakness of shoulder, elbow flexion& supination of forearm
  63. musculotendinous Rotator cuff injuries
    damage  produces instability of glenohumeral joint
  64. Degenerative tendonitis of rotator cuff 
    common in old people 
  65. supraspinous tendon of rotator cuff
    • most commonly torn part.
    • relatively avascular 
    • when torn acutely or eroded by chronic abrasion 2 associated bursea communicate
  66. Subacromial Bursitis
    when bursa is inflamed, abduction of the arm is extremely painful 
  67. Dislocation of Acromiovicular joint
    • AC joint is weak itself and easily injured
    • shoulder seperates from the clavicle because of weight of upper limb 
  68. dislocation of Glenohumeral Joint
    • commonly dislocated by direct or indirect injury 
    • b/c presence of coracoacromial arch and support of rotator cuff, most dislocations of the humeral head occur in the downward direction