Anatomy of the Shoulder Girdle

Shoulder Girdle Overview

• Shoulder girdle = incomplete bony ring (clavicle & scapula).

• Joins to body at sternum via sternoclavicular joint.

• Connects upper limb to axial skeleton via glenohumeral joint.

• Allows greater range of motion than hip joint.

Clavicle (Collarbone)

• S-shaped long bone, palpable along its length.

• Composed of three parts: sternoproximal end, body, acromial end.

• Functions as attachment site for muscles and ligaments.

  • Proximal end (sternal): articulates with sternum (manubrium).

  • Distal end (acromial): articulates with scapula (acromion).

• Landmarks:

  • Sternal facet (articulation with sternum).

  • Costal tuberosity (attachment for costoclavicular ligament).

  • Conoid tubercle (conoid ligament attachment).

  • Trapezoid line (trapezoid ligament attachment).

  • Subclavian groove (for subclavius muscle).

  • Acromial facet (articulation with acromion).

Scapula (Shoulder Blade)

• Triangular flat bone, lies on posterolateral thorax.

• Articulates with humerus (glenohumeral joint) & clavicle (acromioclavicular joint).

• Held in place by muscles, allows movement across thorax (scapulothoracic joint).

• Borders:

  • Superior (thinnest), medial (vertebral), lateral (axillary, thickest).

• Angles:

  • Lateral (glenoid cavity for humerus head).

  • Superior (attachment for levator scapulae).

  • Inferior (between medial and lateral borders).

Glenoid Cavity

• Shallow socket for humerus head, smaller than ball-humerus head.

• Tubercle landmarks:

  • Supraglenoid tubercle (biceps muscle attachment).

  • Infraglenoid tubercle (triceps muscle attachment).

Surfaces of Scapula

• Anterior: smooth costal surface, subscapular fossa.

• Posterior: convex, spine separates into supraspinous/infraspinous fossa (muscle origins).

• Processes:

  • Coracoid process (attachment for pec minor, coracobrachialis, biceps).

  • Acromion process (articulates with clavicle, variant shapes affect rotator cuff injuries).