Final answer:
The three ligaments that stabilize the AC joint are the acromioclavicular ligaments, the coracoclavicular ligament, and the coracoacromial ligament, with the coracoclavicular ligament providing the most support.
Step-by-step explanation:
The three ligaments that stabilize the acromioclavicular (AC) joint are the acromioclavicular ligaments, the coracoclavicular ligaments (which consist of the conoid and trapezoid ligaments), and the coracoacromial ligament. The AC ligaments are relatively weak and can be injured by a hard fall onto an outstretched hand or elbow. However, the coracoclavicular ligament, which anchors the coracoid process of the scapula to the inferior surface of the clavicle, provides significant indirect support to the joint. Injury to this area, such as a shoulder separation, can result from strong impacts, like those occurring in contact sports. This injury implicates the rupturing of both the acromioclavicular and coracoclavicular ligaments.
Coracoclavicular ligament: This strong connective tissue band anchors the coracoid process of the scapula to the inferior surface of the acromial end of the clavicle, providing indirect support for the AC joint.
Acromioclavicular ligament: This ligament strengthens the anterior articular capsule of the shoulder joint and helps stabilize the AC joint.
Coracoacromial ligament: Although not directly involved in stabilizing the AC joint, it provides support to the acromion process of the scapula.