The Teres Minor muscle is a cord-like muscle that originates from a flattened area of the scapula immediately adjacent to its lateral border below the infraglenoid tubercle. Its tendon inserts on the inferior facet of the greater tubercle of the humerus. The teres minor laterally rotates the humerus and is a component of the rotator cuff.

Teres Minor

Origin

This narrow elongated muscle originates from posterior aspect of the lateral border of the scapula.

Insertion

The fibres run upwards and laterally through the shoulder joint to be inserted on to the lower facet of the greater tubercle of the humerus.

Nerve Supply

Teres minor is supplied by a branch of the axillary nerve (C5 and C6). The nerve to teres minor possesses a pseudoganglion.

Actions

Teres minor acts as a lateral rotator and weak adductor of the humerus.

Teres Major

Origin

This thick flat muscle originates from the oval area on the dorsal surface of the inferior angle and adjoining lateral border of the scapula.

Insertion

The fibres run upwards and laterally, and end in a flat tendon, that is inserted on to the medial lip of the intertubercular sulcus of the humerus.

Nerve Supply

Teres major is supplied by the lower subscapular nerve (C5, C6, and C7).

Action

Teres major acts as a medial rotator of the arm.