Teres minor

The primary function of the teres minor muscle is to assist in the external rotation of the arm at the shoulder joint. This movement is essential for activities such as throwing, swimming, and reaching overhead. Additionally, the teres minor plays a key role in stabilizing the shoulder joint, particularly during arm movements that involve lifting or pushing. By working in tandem with the supraspinatus and infraspinatus muscles, the teres minor helps to maintain proper alignment of the joints during movement, thereby reducing the risk of injury. In essence, the teres minor is vital for active shoulder function and overall upper limb mobility.

The teres minor is located in the posterior aspect of the shoulder. It originates from the lateral border of the scapula, specifically the dorsal surface, and extends to insert onto the greater tubercle of the humerus. This positioning places it just above the teres major muscle and below the infraspinatus muscle, thus forming part of the rotator cuff structure. The proximity of the teres minor to the scapula and humerus makes it crucial for shoulder mechanics, as it helps secure the head of the humerus within the shallow glenoid cavity of the scapula, allowing for a wide range of arm movements while maintaining joint integrity.

• Teres minor gets its name from its shape; 'teres' means 'round' or 'smooth' in Latin, describing its cylindrical appearance.
• In combination with the other rotator cuff muscles, teres minor enables a significant amount of shoulder movement, making it essential for athletes in overhead sports.
• Injury or degeneration of the teres minor can lead to shoulder instability and limitations in arm mobility.