Glenoid cavity

Study entry

Description

Shallow, concave, oval fossa at the lateral angle (head) of the scapula, facing forward, outward and slightly upward; much smaller than the head of the humerus.

Relations

Articulates with the head of the humerus at the shoulder joint; the glenoid labrum deepens it.

Source: cap. 3, «Huesos del miembro superior: escápula»

Clinical correlation

Dislocation of the shoulder

Because it is very mobile and unstable, the shoulder dislocates often. The coracoacromial arch and the cuff prevent exit upward, so the head of the humerus comes out downward, but the dislocation is called anterior or posterior (rare) according to whether it descends in front of or behind the infraglenoid tubercle and the long head of the triceps. The anterior is the most common, in young adults and athletes, from excessive extension and lateral rotation: the capsule and the glenoid labrum may be torn from the front of the glenoid cavity. With the arm fully abducted, a blow drives the head onto the low, weak part of the capsule.

Injury to the glenoid labrum

The glenoid labrum (fibrocartilage) tears in throwers and in those with an unstable shoulder with subluxations, from a sudden contraction of the biceps or from the head of the humerus forcing the rim. It is usually in the anterosuperior part. It hurts on throwing, above all in acceleration, and may click on abducting and laterally rotating the arm.

Related clinical cases

• Dislocation of the shoulder
• Injury to the glenoid labrum

Other structures in this region

• Conoid tubercle
• Trapezoid line
• Scapular notch
• Supraglenoid tubercle
• Infraglenoid tubercle
• Subscapular fossa
• Supraspinous fossa
• Infraspinous fossa