Radiographic Anatomy of Shoulder Joint

Radiographic Anatomy of Shoulder Joint:

Fig: Shoulder AP and Axial views

Clavicle: The clavicle is a long bone having a shaft, and two ends. The shaft shows gentle S-shaped curve.

The lateral or acromial end of the clavicle bears a smooth facet which articulates with the acromion of the scapula to form the acromion-clavicular joint.

The medial or sternal end of the clavicle articulates with the manibrium sterni, and also with the first costal cartilage.

Conoid tubercle: This prominence lies near the acromial end of the clavicle.

Scapula: The greater part of the scapula consists of a flat triangular plate of bone called the body. The upper part of the body is broad, representing the base of the triangle. The inferior end is pointed and represents the apex. The body has anterior (or costal)) and posterior (or dorsal) surfaces.

Spine of Scapula: The upper part of the posterior surface gives off a large projection called the spine. The part of the posterior surface above the spine forms the supraspinous fossa, and the area below the spine forms the infraspinous fossa.

Humerus: It is a long bone. It has a cylindrical central part called the shaft, and enlarged upper and lower ends.

Humeral head: It is rounded and forms the shoulder joint along with the glenoid cavity of scapula.

Anatomic neck: The slightly constricted area directly below and lateral to the head is the anatomic neck which appears as a line of demarcation between the rounded head and the adjoining greater and lesser tubercles.

Lesser tubercle: It is the process or the prominence directly below the anatomic neck on the anterior surface.

Greater tubercle: The larger lateral process is the greater tubercle, to which the pectoralis major and supraspinatus muscles attach.

Intertubercular (bicipital) groove: It is the deep groove between these two tubercles (tuberosities).

Surgical neck: It is the tapered area below the head and tubercles, and distal to the surgical neck is the long body (shaft) of the humerus.

Deltoid tuberosity: It is the roughened raised triangular elevation along the anterolateral surface of the body (shaft) to which the deltoid muscle is attached.

Shoulder joint: This ball and socket joint is formed by the glenoid cavity of the scapula and the head of the humerus.

Glenoid cavity: It is a shallow, concave, oval fossa, directed anterolaterally and slightly superiorly- that is considerably smaller than the ball (head of the humerus) for which it serves as a socket.

Coracoid process: It is a beak-like process, superior to the glenoid cavity and projects anterolaterally.