Chapter 2 - Shoulder Girdle 2

• Pectoral (shoulder) girdle


  Part of the upper limb anatomy

  
• Bones in the upper limb

  • Humerus
  • Ulna and radius (forearm and elbow)
  • 8 carpals in (carpus) wrist, 5 metacarpals in (metacarpus) palm, 14 phalanges (bones of the digits) in the hand

  
• Shoulder joint


  • Ball and socket joint that moves in all three planes
  • Most mobile and least stable joint

  
• Shoulder joint motions


  1. Flexion (0-180 degrees)

  2. Extension (return to anatomical position)

  3. Hyperextension (0-45 degrees back through the lateral plane)

  4. Abduction (0-180 degrees in the frontal plane)

  5. Adduction (0-180 degrees back to midline)

  6. Internal rotation (0-90 degrees into body in transverse plane)

  7. External rotation (0-90 degrees out from neutral in transverse plane)

  8. Horizontal abduction (120 degrees)

  9. Horizontal adduction (30 degrees)

  
• Shoulder landmarks


  • Glenoid labrum
  • Humerus head
  • Humerus shaft
  • Surgical neck
  • Anatomical neck
  • Greater tubercle/tuberosity
  • Lesser tubercle/tuberosity
  • Deltoid tuberosity
  • Bicipital groove

  
• Muscles that move the humerus

  • Pectoralis major
  • Latissmus dorsi
  • Deltoid
  • Subscapularis
  • Supraspinatus
  • Infraspinatus
  • Teres major
  • Teres minor
  • Coracobrachialis
• Pectoralis major


  Adducts and medially rotates the arm
• Latissimus dorsi


  Extends, adducts, and medially rotates the arm
• Deltoid


  Lateral fibers abduct arm, anterior fibers flex and medially rotate arm, posterior fibers extend and laterally rotate arm

  
• Subscapularis


  Medially rotates the arm
• Supraspinatus


  Assists deltoid in abducting the arm
• Infraspinatus


  Laterally rotates and adducts the arm
• Teres major


  Extends, adducts, and medially rotates the arm
• Teres minor


  Laterally rotates, extends, and adducts the shoulder joint

  
• Coracobrachialis


  Flexes and adducts the arm
• Rotator cuff muscles


  • Supraspinatus
  • Infraspinatus
  • Teres minor
  • Subscapularis
• Rotator cuff


  Predominantly stabilize the glenohumeral joint<|>Compress the glenohumeral joint during arm elevation to allow the deltoid to further elevate the arm

  
• Without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa and the efficiency of the deltoid muscle would be much less
• Deltopectoral triangle


  Deep fascia separating deltoid and pectoralis muscles

  
• Walls/folds of the axilla

  • Anterior: pectoralis major & minor, subclavius, clavipectoral fascia
  • Posterior: latissimus dorsi, teres major, subscapularis
  • Lateral: humerus, tendon of long head of biceps brachii, tendon of coracobrachialis
  • Medial: rib 1-3 & intercostal muscles, serratus anterior (superior part)

  
• Contents of the axilla

  • Axillary artery & branches
  • Axillary vein and tributaries
  • Axillary lymph nodes
  • Brachial plexus