The primary function of the coracoclavicular ligaments is to: Answers:
A-D A Limit excessive abduction of the glenohumeral joint.
B Prevent superior displacement of the clavicle.
C Assist in external rotation of the humerus.
D Connect the coracold process to the acromion.
The correct answer and explanation is:
Correct Answer: B. Prevent superior displacement of the clavicle.
The coracoclavicular ligaments are strong connective tissue structures that play a critical role in stabilizing the shoulder girdle. These ligaments consist of two parts: the conoid ligament and the trapezoid ligament. Both connect the coracoid process of the scapula to the underside of the clavicle, but they differ slightly in their anatomical orientation and function.
The primary role of the coracoclavicular ligaments is to prevent the clavicle from moving excessively upward relative to the scapula, especially during upward forces applied to the upper limb. In other words, they prevent superior displacement of the clavicle. This function is essential in maintaining the proper alignment between the clavicle and the scapula, which helps stabilize the acromioclavicular (AC) joint.
These ligaments are especially important because the AC joint itself is relatively weak and would be prone to dislocation without reinforcement. The coracoclavicular ligaments serve as the main stabilizers of the AC joint, anchoring the clavicle downward and securing it to the scapula. When these ligaments are torn or stretched, such as in a shoulder separation injury, the clavicle can be visibly displaced upward, indicating a disruption of this support system.
Other answer choices are incorrect for the following reasons:
- A (Limit excessive abduction of the glenohumeral joint): This function relates more to the glenohumeral ligaments, not the coracoclavicular ligaments.
- C (Assist in external rotation of the humerus): External rotation is controlled by muscles like the infraspinatus and teres minor, not ligaments connecting the clavicle to the scapula.
- D (Connect the coracoid process to the acromion): That describes the coracoacromial ligament, not the coracoclavicular ligaments.
Therefore, the correct and most accurate function is B.