The supraglenoid tubercle of the scapula, a bony prominence located on the lateral margin of the scapula, plays a significant role in the anatomy of the shoulder region. Directly anterior to the tubercle lies the coracoid process, providing attachment for various muscles and ligaments. The glenoid cavity, positioned just distal to the tubercle, articulates with the head of the humerus, forming the glenohumeral joint. Superiorly, the supraglenoid tubercle is bounded by the supraspinatus fossa, which accommodates the supraspinatus muscle. These four anatomical entities, the coracoid process, glenoid cavity, supraspinatus fossa, and supraglenoid tubercle, are closely interconnected and pivotal for the proper functioning of the shoulder.
Supraglenoid Tubercle: Its Anatomy and Structure
The supraglenoid tubercle is a small, bony projection located on the lateral border of the scapula, just superior to the glenoid cavity. It serves as an attachment point for the tendon of the long head of the triceps brachii muscle.
Structure
The supraglenoid tubercle is composed of a base and a summit:
- Base: The base is broad and triangular in shape, with a roughened surface for ligamentous attachments.
- Summit: The summit is a small, rounded elevation that projects upward and laterally. It marks the insertion point for the long head of the triceps brachii tendon.
Attachments
In addition to the long head of the triceps brachii, the supraglenoid tubercle also serves as an attachment point for:
- Coracoacromial ligament
- Superior glenohumeral ligament
- Transverse humeral ligament
Clinical Significance
The supraglenoid tubercle is often involved in shoulder injuries, particularly those involving the rotator cuff muscles. Tears in the long head of the triceps brachii tendon, which inserts onto the supraglenoid tubercle, can cause pain, weakness, and difficulty extending the arm.
Additional Notes
- The supraglenoid tubercle is sometimes referred to as the “tubercle for the triceps muscle.”
- It is best visualized in the axial view of the scapula, where it appears as a small, triangular projection.
| Structure | Description |
|---|---|
| Base | Broad and triangular |
| Summit | Small and rounded |
| Attachments | Long head of triceps brachii, coracoacromial ligament, superior glenohumeral ligament, transverse humeral ligament |
Question 1:
What is the significance of the supraglenoid tubercle in the anatomy of the scapula?
Answer:
The supraglenoid tubercle is a significant anatomical feature of the scapula, located superior to the glenoid cavity. It serves as the origin for the long head of the triceps brachii muscle, which plays a crucial role in extending the elbow joint. Additionally, the supraglenoid tubercle provides attachment for the coracobrachialis muscle.
Question 2:
How does the supraglenoid tubercle contribute to the stability of the glenohumeral joint?
Answer:
The supraglenoid tubercle enhances the stability of the glenohumeral joint by serving as a site of attachment for the superior glenohumeral ligament. This ligament helps to prevent anterior dislocation of the humerus during shoulder extension.
Question 3:
What are the clinical implications of supraglenoid tubercle abnormalities?
Answer:
Abnormalities in the supraglenoid tubercle can have clinical consequences. An enlarged or deformed supraglenoid tubercle may impinge upon the long head of the biceps brachii tendon, causing pain and restricted shoulder movement. In cases of severe trauma, a fractured supraglenoid tubercle may disrupt the attachment of the aforementioned muscles, impairing their function.
And that’s all about the enigmatic supraglenoid tubercle. Thanks for taking the time to journey into the depths of the shoulder and discover this fascinating anatomical feature. Remember, the human body is a marvel of evolution, and there’s always something new to learn. So if you ever find yourself curious about another anatomical mystery, don’t hesitate to dive right in. And who knows, you might just uncover another hidden treasure lurking beneath the skin. Thanks again for reading, and be sure to swing by again soon for more enlightening anatomical adventures!