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2011-09-22 11:42:31
Shoulder gross anatomy

shoulder gross anatomy
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  1. Intrinsic Muscles of the Shoulder
    • Deltoid
    • Teres Major
    • Rotator Cuff Muscles (SITS)
    • Supraspinatus
    • Infraspinatus
    • Teres Minor
    • Subscapularis
  2. Glenohumeral Joint
    • 1. synovial, ball & socket Joint
    • 2. flexion, extension, abduction,
    • adduction, med & lat rotation,
    • circumduction
    • 3. reinforced by rotator cuff ms.
    • 4. weak inferiorly, often dislocated
  3. Sternoclavicular ( SC ) Joint
    • 1. synovial, saddle-type Joint (functions as ball & socket)
    • 2. has articular disk and 2 separate joint cavities
    • 3. very strong, dislocation rare
    • 4. significantly mobile to allow movements of pectoral girdle
    • 5. only joint between pectoral girdle & axial skeleton
  4. Acromioclavicular ( AC ) Joint
    • 1. synovial, plane-type
    • 2. gliding movements
    • 3. site of "shoulder separation" injury
  5. The Scapular Anastomoses
    • A. Branches Involved:
    • 1. branches of the 1st part of the subclavian a.
    • a. transverse cervical a. (from thyrocervical tr.)
    • b. suprascapular a. (from thyrocervical tr.)
    • c. dorsal scapular a.
    • 2. branches of the 3rd part of the axillary a.
    • a. subscapular a & its branches
    • 3. intercostal as.
    • B. Demonstrates the principle of colateral circulation around joints
  6. pectoralis major
    • Extrinsic Anterior Shoulder
    • attach: sternum, costal cartilages 1-6, clavicle
    • bicipital groove of the humerus.
    • nerve: medial & lateral pectoral nerves
    • action: adducts & medially rotates humerus;
    • clavicular head (acting alone) flexes humerus;
    • sternocostal head (acting alone) extends humerus from flexed position
  7. pectoralis minor
    • Extrinsic Anterior Shoulder
    • attach: scapula (coracoid process); ribs 3-5.
    • nerve: medial pectoral nerve
    • action: stabilizes & protracts scapula
  8. serratus anterior
    • attach: ribs 1-9 , medial border of the scapula
    • nerve: long thoracic (C5-7)
    • action: protracts scapula; raises ribs when scapula is fixed; stabilizes scapula
    • extrinsic Anterior Shoulder
  9. subclavius
    • attach: 1st rib; clavicle
    • nerve: nerve to subclavius
    • action: draws clavicle inferiorly & anteriorly, protects deeper structures
    • extrinsic Anterior Shoulder
  10. deltoid
    • attach: clavicle (lateral 1/3), acromion & spine of scapula
    • deltoid tuberosity of humerus
    • nerve: axillary n.
    • action: anterior fibers: flexes & medially rotates arm
    • middle fibers: abducts arm
    • posterior fibers: extends & laterally rotates arm
    • intrinsic shoulder
  11. teres major
    • attach: scapula (lat. border near inf. angle)
    • bicipital groove of humerus
    • nerve: lower subscapular n.
    • action: adduction & medial rotation of arm
    • intrinsic shoulder
  12. supraspinatus
    • attach: supraspinous fossa of scapula
    • greater tubercle of humerus
    • nerve: suprascapular n.
    • action: abduction of arm
    • intrinsic shoulder, rotator cuff
  13. infraspinatus
    • attach: infraspinous fossa of scapula
    • greater tubercle of humerus
    • nerve: suprascapular n.
    • action: lateral rotation of arm
    • intrinsic shoulder, rotator cuff
  14. teres minor
    • attach: lateral border of scapula
    • greater tubercle of humerus
    • nerve: axillary n.
    • action: lateral rotation of arm
    • intrinsic shoulder, rotator cuff
  15. subscapularis
    • attach: subscapular fossa of scapula
    • lesser tubercle of humerus
    • nerve: upper and lower subscapular ns.
    • action: medial rotation & adduction of arm
    • intrinsic shoulder, rotator cuff
  16. Scapulohumeral Rhythm
    • refers to the integrated movement of the scapula and humerus together
    • there is a simultaneous movement of the humerus at the glenohumeral joint accompanied by rotation of the scapula.
    • For every 2� of abduction at the glenohumeral joint, there is 1� of scapular rotation.
    • Thus, when the arm is abducted 90�, 60� occurs at the glenohumeral joint, 30� occurs from scapular rotation.
  17. Critical Zone (shoulder)
    • area of vascular anastomoses within the rotator cuff.
    • This anastomoses is alternately ischemic or hyperemic depending on whether there is tension on the cuff.
    • This zone is often the site of degeneration, calcium deposits, and tears.
  18. Glenoid Labrum
    • fibrocartilagenous ring that surrounds the glenoid fossa and helps deepen the socket of the shoulder joint.
    • Note that the fibrous joint capsule attaches to the labrum, so any injury of the joint capsule can potentially involve the labrum.
  19. Suprahumeral �Joint� Space
    • not a true joint, the space between the head of the humerus and the acromion and coracoacromial ligament.
    • This space contains the biceps long head tendon, rotator cuff tendons (e.g., supraspinatus tendon), subacromial/subdeltoid bursa, and the gleno-humeral joint capsule.
    • Inflammation in this space can affect these structures.
  20. Subacromial/Subdeltoid Bursa
    • synovial-lined sac that has two parts. The part of the bursa deep to the acromion is called the subacromial bursa. That part deep to the deltoid is called the subdeltoid bursa. Both these parts may be fused or may be separated.
    • The bursa lies between the supraspinatus tendon and deltoid muscle in the suprahumeral �joint� space. It reduces friction during abduction and if inflamed can cause pain during this movement.
  21. Quadrangular Space
    an anatomical space containing the axillary nerve and posterior circumflex humeral artery. Its borders are: the long head of the triceps, lateral head of triceps, teres minor, & teres major.
  22. Intrinsic Shoulder Muscles
  23. Neurovascular Shoulder diagram
  24. Quadrangle Space