teres minor and major

3 min read 14-03-2025

The teres minor and major muscles, located in the rotator cuff and posterior shoulder, play crucial roles in shoulder stability and movement. Understanding their anatomy, function, and potential injuries is vital for athletes, fitness enthusiasts, and healthcare professionals alike. This article will delve into the specifics of each muscle, highlighting their differences and interconnected roles.

Teres Minor Muscle: Anatomy and Function

The teres minor is a small, flat muscle situated below the infraspinatus muscle. It originates from the lateral border of the scapula (shoulder blade) and inserts into the greater tubercle of the humerus (upper arm bone).

Key Actions of the Teres Minor:

External rotation of the shoulder: This is its primary function, helping to rotate the arm away from the body.
Shoulder joint stabilization: The teres minor contributes to the overall stability of the shoulder joint, particularly during arm movements.
Horizontal abduction: Assists in moving the arm away from the midline of the body while keeping it level.

Teres Minor Injuries:

Tears in the teres minor are less common than those in the other rotator cuff muscles. However, injuries can occur from overuse, trauma, or sudden forceful movements. Symptoms might include pain in the posterior shoulder, weakness, and limited range of motion. Diagnosis often involves physical examination, imaging (MRI or ultrasound), and sometimes electromyography (EMG).

Teres Major Muscle: Anatomy and Function

The teres major, larger than its counterpart, is located inferiorly to the teres minor. It originates from the inferior angle of the scapula and inserts into the intertubercular sulcus of the humerus.

Key Actions of the Teres Major:

Internal rotation of the shoulder: This is its primary action, rotating the arm towards the body.
Shoulder extension: Helps to extend the arm backward.
Shoulder adduction: Assists in bringing the arm towards the body.

Teres Major Injuries:

Similar to the teres minor, injuries are possible though less frequent than rotator cuff tears. Overuse, sudden strain, or direct trauma can lead to tears or strains. Symptoms may overlap with those of teres minor injuries, including pain, weakness, and limited movement. Accurate diagnosis often requires a comprehensive physical examination and imaging studies.

The Teres Minor and Major: Synergistic Relationship

While the teres minor and major have opposing primary actions (external vs. internal rotation), they work synergistically to control shoulder movement. Their coordinated activity ensures smooth, controlled shoulder rotation and stability. Weakness or injury in either muscle can impact the overall function and stability of the shoulder joint.

How to Strengthen Teres Minor and Major Muscles

Strengthening both muscles can improve shoulder stability, reduce injury risk, and enhance athletic performance. Here are some exercises that target these muscles:

External Rotation Exercises (Teres Minor): These can include resistance band external rotations, cable external rotations, and dumbbell external rotations.
Internal Rotation Exercises (Teres Major): Consider exercises like resistance band internal rotations, cable internal rotations, and dumbbell internal rotations.
Scapular Retractions: These strengthen the muscles around the shoulder blade, which are crucial for supporting teres minor and major function.

Frequently Asked Questions (FAQs)

Q: What is the difference between teres minor and teres major?

A: The key difference lies in their primary actions. The teres minor externally rotates the shoulder, while the teres major internally rotates it. They also differ in size and location on the scapula.

Q: How are teres minor and major injuries diagnosed?

A: Diagnosis usually involves a physical exam, assessing range of motion and strength. Imaging techniques such as MRI or ultrasound can confirm the diagnosis and reveal the extent of any injury.

Q: How are teres minor and major injuries treated?

A: Treatment depends on the severity of the injury and can range from conservative measures like rest, ice, physical therapy, and anti-inflammatory medication to surgical intervention in cases of severe tears.

By understanding the anatomy, function, and potential injuries of the teres minor and major muscles, individuals can take steps to prevent injuries and promote optimal shoulder health. Remember to consult with a healthcare professional for any concerns regarding shoulder pain or dysfunction.