UPPER BACK, SHOULDER, ELBOW, ARM OR HAND PAIN? ⠀ TRICEPS BRACHII MUSCLE ⠀ [ANATOMY, FUNCTION & PATHOLOGY] ⠀⠀ The triceps brachii is the muscle that runs down the back of the humerus and ends at the top of the ulna. The triceps brachii gets its name because it contains three muscle 'heads' or points of origin. These include the medial head, lateral head and long head. ⠀ Origin of long head: Infraglenoid tubercle of the scapula. Origin of lateral head: Lateral and posterior surfaces of the humerus above the radial groove and lateral intermuscular septum. Origin of medial head: Posterior surfaces of the humerus below the radial groove and from the medial intermuscular septum. ⠀ It inserts at the posterior surface of the olecranon process of the ulna, capsule of the elbow joint and antebrachial fascia. It helps in extension of the elbow joint and also act as an antagonist of the biceps and brachialis. The triceps brachii also helps to stabilize the shoulder by keeping the head of the humerus in its correct position in the shoulder joint. When the shoulder is internally rotated, the ability of the long head of the triceps brachii to extend and adduct the shoulder is diminished. The shoulder must be externally rotated in order for the long head of the triceps brachii to assist shoulder adduction. ⠀ The triceps brachii muscle is able to send pain to your shoulder, elbow, forearm and hand (Pic 3). ⠀ If your triceps contains trigger points (TPs), you might experience pain mainly in your upper back, shoulder and your arm, depending on the location of these points. Hence, it can be involved in the following conditions: Pain at the back of the shoulder, Pain at the tip of the elbow, Tennis elbow, Golfers elbow, Forearm pain. ⠀ TPs or a very tight triceps brachii muscle may hinder you from fully extending your arm or it might be painful to do so. Maybe you will not realize it because you unconsciously keep it flexed permanently and thus prevent the painful extension/straightening. Also any strong extension – pushing against something for example – of your elbow can be painful if you have TPs in this muscle.