What muscles are involved in shoulder flexion?

Under normal circumstances, the muscles responsible for shoulder flexion include the anterior deltoid, biceps brachii, triceps brachii, subclavius, teres major, teres minor, and levator scapulae. A detailed analysis is as follows:

1. Anterior Deltoid

Located above the scapula, this muscle enables forward elevation of the shoulder and arm, playing a crucial role in shoulder flexion.

2. Biceps Brachii

Situated on the anterior side of the upper arm, this muscle primarily contributes to elbow flexion and shoulder flexion, and also assists in lifting the arm forward.

3. Triceps Brachii

Located on the posterior side of the upper arm, this muscle mainly participates in elbow extension and also helps stabilize the arm during shoulder flexion by controlling its downward movement.

4. Subclavius

Positioned along the inferior border of the clavicle, it stabilizes the clavicle and aids in depressing the shoulder, providing support for forward arm elevation.

5. Teres Major

Located on the posterior aspect of the scapula, it assists in upward abduction and external rotation of the arm, supporting forward arm lifting movements.

6. Teres Minor

Also located on the posterior side of the scapula, it primarily contributes to external rotation and downward rotation of the arm.

7. Levator Scapulae

Situated at the superior portion of the scapula, it elevates and externally rotates the scapula, thereby assisting in forward elevation of the arm.

In summary, these muscles work together synergistically to accomplish shoulder flexion. If any discomfort or symptoms arise, prompt medical evaluation and treatment are recommended to prevent delay in diagnosis and management.