The teres minor is a narrow, intrinsic muscle of the shoulder that's part of the rotator cuff. It extends from the lateral border of the scapula to the greater tubercle of the humerus and helps stabilize the shoulder joint.
Detailed Explanation
The teres minor plays a crucial role in shoulder function. Here's a breakdown:
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Location: The teres minor is located on the posterior aspect of the shoulder, running from the scapula (shoulder blade) to the humerus (upper arm bone).
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Origin: It originates from the lateral border of the scapula.
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Insertion: It inserts onto the greater tubercle (also known as greater tuberosity) of the humerus.
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Function: The primary functions of the teres minor are:
- External Rotation: Rotating the arm outward.
- Adduction: Bringing the arm closer to the body.
- Stabilization: Along with the other rotator cuff muscles, it helps stabilize the glenohumeral joint (shoulder joint), preventing dislocation.
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Rotator Cuff: The teres minor is one of the four muscles that make up the rotator cuff (the others being the supraspinatus, infraspinatus, and subscapularis). The rotator cuff muscles and their tendons surround the shoulder joint, providing stability and a wide range of motion.
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Innervation: The teres minor is innervated by the axillary nerve.
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Clinical Significance: The teres minor can be injured through overuse, trauma, or age-related degeneration. Injuries can cause pain, weakness, and limited range of motion in the shoulder. Rotator cuff tears often involve one or more of the rotator cuff muscles, including the teres minor.
Summary
In summary, the teres minor muscle is a small but important rotator cuff muscle that contributes to the stability and external rotation of the shoulder joint. Understanding its anatomy and function is crucial for diagnosing and treating shoulder problems.
