The shoulder girdle consists of three key bones:
Clavicle
Scapula
Humerus
Important features of the proximal humerus:
Greater Tubercle (Tuberosity): Lateral projection providing attachment for rotator cuff muscles.
Lesser Tubercle (Tuberosity): Smaller, anterior projection for muscle attachment.
Intertubular Groove (Bicipital Groove): Located between the tubercles; allows passage of the biceps tendon.
Head: Rounded end of the humerus fitting into the glenoid cavity of the scapula.
Anatomic Neck: Constriction below the head, not typically a site of fracture.
Surgical Neck: Common site for humeral fractures.
Deltoid Tuberosity: Roughened area on the lateral surface for attachment of the deltoid muscle.
Body (Shaft): Long midsection of the humerus.
Acromial Extremity: Lateral end of clavicle, articulates with acromion of scapula.
Sternal Extremity: Medial end, articulates with the manubrium of the sternum.
Joints Involved:
Acromioclavicular Joint: Between the acromion and clavicle.
Sternoclavicular Joint: Between the sternum and clavicle.
Three major borders:
Superior Border
Medial (Vertebral) Border
Lateral (Axillary) Border
Scapulohumeral (Glenohumeral) Joint: Joint formed by the scapula and humerus.
Anterior View:
Key features include:
Coracoid process
Glenoid cavity
Subscapular fossa
Posterior View:
Includes:
Supraspinous fossa
Infraspinous fossa
Acromion
Lateral View:
Important for understanding relationships between acromion and coracoid processes.
Types of Joints:
Sternoclavicular Joint: Plane or gliding joint.
Acromioclavicular Joint: Also a plane or gliding joint.
Scapulohumeral Joint: Spheroidal or ball-and-socket joint, allows for greater range of motion.
Scapulohumeral Joint: Greater freedom of movement due to its structure.
Sternoclavicular & Acromioclavicular Joints: Allow slight gliding movements.
AP Proximal Humerus (External Rotation):
Shows the greater tubercle in lateral profile, lesser tubercle anteriorly.
Lateral Proximal Humerus (Internal Rotation):
Displays greater tubercle anteriorly, lesser tubercle medially.
Oblique Proximal Humerus (Neutral Rotation):
Positioned at a 45° angle to the image receptor; not showing tubercles clearly.
For each projection, ensure:
Entire humerus is included in the image.
Tubercle positioning is correct (greater tubercle lateral for external rotation, etc.).
Epicondyles are in appropriate alignment relative to the film/cassette.
Inferosuperior Axial Projection (Lawrence Method):
CR angled 25° to 30° toward the axilla.
PA Transaxillary Projection (Hobbs Modification):
Used for non-traumatic imaging of the shoulder.
Neer Method: Outlet view of the shoulder, emphasizes the supraspinatus outlet to assess rotator cuff pathology.
AP Clavicle:
CR perpendicular to midclavicle.
For AP axial, angles between 15° to 30°.
Verify entire clavicle is shown, optimal exposure factors are met, correct markers visible, and collimation is appropriate.
Scapula AP: Breathing technique may be optional; CR directed to mid-scapula.
Scapular Y Lateral: 2 inches below the top of the shoulder.
Which of the following humeral structures is most distal?
Answer: Surgical neck
What is another term for the mid area of the costal surface of the scapula?
Answer: Subscapular fossa
Which projection demonstrates the Hill-Sachs defect best?
Answer: Inferosuperior axial projection with exaggerated external rotation.
Ensure understanding of body rotations necessary for oblique projections (e.g., Grashey 35° to 45°).
Use shielding for radiosensitive areas and employ collimation to limit exposure.
Recommended technical factors for shoulder girdle include kVp range, grid requirements, and short exposure times for optimal imaging results.
Shoulder Girdle Anatomy and Projections
AP Proximal Humerus (External Rotation):
Lateral Proximal Humerus (Internal Rotation):
Oblique Proximal Humerus (Neutral Rotation):