GENERAL INFORMATION
The subscapularis is a muscle located in the shoulder region. It is one of the four muscles that make up the rotator cuff. The subscapularis muscle plays a vital role in stabilising as well as internally rotating the shoulder joint.
ORIGIN
This muscle originates from the subscapular fossa, which is a concave area on the anterior surface of the scapula (shoulder blade).
INSERTION POINT
The muscle inserts into the lesser tuberosity of the humerus (upper arm bone). It attaches to the bone via a tendon that blends with the joint capsule of the shoulder.
MAJOR ARTERIES
The subscapularis muscle receives its blood supply from branches of the subscapular artery.
NEURAL INNERVATION
This muscle is innervated by the upper and lower subscapular nerves, which arise from the posterior cord of the brachial plexus (C5-C6).
TRIGGER POINT
Trigger points can develop in the subscapularis muscle, causing localised pain and tenderness. These trigger points can be associated with muscle overuse, poor posture, or trauma.
CONCENTRIC FUNCTION
Contraction of the subscapularis muscle initiates and assists in the internal rotation of the arm. It helps to rotate the arm inward as well as stabilise the shoulder joint.
ECCENTRIC FUNCTION
The subscapularis muscle has a crucial eccentric function during controlled shoulder movements, particularly in managing the outward rotation of the arm.
ISOMETRIC FUNCTION
Isometric contraction of the subscapularis muscle provides stability and support to the shoulder joint, maintaining proper alignment as well as preventing excessive outward rotation.
RELATED MUSCLE SCIENTIFIC NAMES
- Subscapularis: This muscle is located on the anterior surface of the scapula and plays a key role in the internal rotation as well as stabilisation of the shoulder joint.
ANTAGONIST
- Infraspinatus: Located on the posterior aspect of the scapula, this muscle externally rotates the arm and works opposite to the subscapularis.
- Teres minor: Another muscle on the posterior scapula, it assists with external rotation of the arm and acts antagonistically to the subscapularis.
COMMON INJURIES
- Subscapularis tendonitis: Inflammation due to overuse or repetitive motions, leading to shoulder pain.
- Subscapularis tear: Partial or complete tear from trauma or chronic degeneration, resulting in weakness as well as pain.
- Impingement syndrome: Compression causing pain and limited range of motion in the shoulder.
EXERCISES
- Internal rotation with bands: Strengthen internal rotators, including subscapularis, using resistance bands.
- Internal rotation with dumbbells: Use dumbbells to perform internal rotation exercises, targeting the subscapularis.
- Scaption exercises: Raise the arm diagonally to engage the subscapularis and other shoulder muscles.
- Isometric internal rotation: Hold the arm in the internal rotation against resistance to strengthen the subscapularis.
- Shoulder stabilisation drills: Perform exercises that enhance shoulder joint stability involving the subscapularis.
STRETCHES
- Cross-body stretch: Bring the affected arm across the chest, gently pulling with the opposite hand.
- Wall stretches: Place the hand on a wall at shoulder height, leaning away to pull the subscapularis.
- Doorway stretch: Stand in a doorway, place your arms on the frame, and lean forward to stretch your shoulder muscles.
- Sleeper stretch: Lie on your side with the affected arm bent, as well as use the other hand to push the forearm down gently.
- Overhead stretch: Reach the affected arm overhead and bend the elbow, using the other hand to push the arm down gently.