Therefore, the range of motion of humeral head is larger. The joint capsule is thin and loose, especially the inferior wall, which is attached to the periphery of the glenoid. The supraglenoid tubercle is wrapped in the upper articular capsule and attached to the anatomical neck of the lower humerus.
Shoulder joint is the most flexible ball-and-socket joint in the whole body, which can flex, stretch, contract, unfold, rotate and turn around. Combined with the structural characteristics such as large area difference between joint head and joint fossa, thin and loose joint capsule, it embodies its flexible movement function. There are many muscles around the shoulder joint.
These muscles are of great significance for maintaining the stability of the shoulder joint, but there are few muscles in the front and lower parts of the joint, and the joint capsule is the most relaxed, so it is the weakest point of joint stability.
Extended data
The upper limb falls backwards during abduction and supination, and the palm or elbow touches the ground, which is easy to cause anterior dislocation of the shoulder joint. It consists of humeral head and glenoid of shoulder joint, and is characterized by large humeral head, small glenoid, thin and loose joint capsule and weak lower wall of joint capsule. It can bend, stretch, contract, unfold, rotate inward, rotate outward and rotate around.
The synovial layer of the joint capsule covers the tendon of the long head of the biceps brachii, protrudes the fibrous layer together with the tendon, and is located in the intertubercular groove, forming the tendon sheath of the long head of the biceps brachii. Ligaments around the shoulder joint are few and weak. Above the shoulder joint, there is a coracoid-brachial ligament between the coracoid process and the greater tubercle of the humeral head. The glenohumeral ligament is connected from the glenoid periphery to the humeral tubercle and the lower part of the anatomical neck.