PECTORAL GIRDLE

PECTORAL GIRDLE

1. clavicle

   • "collar bone"
     • most frequently broken bone in body 
     • functions: braces the shoulders(keeps arms away from midline), transfers force from arm to axial body region. S-shaped
       • Sternal end (medial): articulates with the manubrium of the sternum- sternoclavicular joint
       • Acromial end (lateral): articulates with the acromial region of the scapula- acromioclavicular joint

2. Scapula

   • "shoulder bone"
     • only direct attachment to thoracic is by muscles
     • Triangular plate overlies ribs 2-7
       • Has 3 sides:
         • Superior Border
           • horizontal edge of scapula
           • Suprascapular notch: nerve passage way
         • Medial Border
           • "vertebral" lies close to vertebra
         • Lateral Border
           • "Axillary" lies close to axilla (armpit)
       • Has 3 angles
         • Superior
         • Inferior
         • Lateral
           • most complex region
           • Acromion
             • Articulates with the clavicle. The only attachment of the appendicular skeleton to the axial skeleton. Transfers force from one arm to axial body region. Plate like extension of the scapular spine
           • Coracoid process
             • Shaped like a bent finger. Projects anteriorly. Provides attachment site for muscles.
           • Glenoid cavity
             • Shallow socket. Articulates with the head of the humerus - glenohumeral joint
   • Anterior surface: Subscapular fossa- broad anterior surface, slightly concave
   • Posterior surface:
     • Spine: shelf-like ridge
     • Supraspinous fossa: deep indention superior to spine
     • Infraspinous fossa: broad surface inferior to spine