What type of joint is the acromioclavicular (AC) joint?

The AC joint is a plane-type synovial joint. It is formed by the articulation between the lateral end of the clavicle and the medial margin of the acromion process of the scapula.

What are the main ligaments of the acromioclavicular joint?

The main ligaments are the acromioclavicular ligament, which reinforces the joint superiorly, and the coracoclavicular ligament, a key stabilizer consisting of the conoid and trapezoid ligaments.

What movements does the acromioclavicular joint allow?

It allows rotation of the acromion on the clavicle. This occurs in coordination with scapular movements like elevation, rotation, and protraction.

Why is the coracoclavicular ligament important?

It is the strongest ligament of the upper limb and a key stabilizer, suspending the scapula and upper limb from the clavicle to maintain joint integrity.

What structures articulate to form the acromioclavicular joint?

It is formed by the articulation between the lateral end of the clavicle and the medial margin of the acromion process of the scapula.

How is the acromioclavicular joint related to shoulder movement?

It facilitates scapular movements by allowing acromion rotation on the clavicle, coordinating with the scapulothoracic linkage during actions like shoulder elevation.

Acromioclavicular Joint Anatomy – Ligaments & Stability