There is a single muscle in the posterior compartment of the arm, which is the triceps muscle. The triceps originates from the infraglenoid tubercle of the scapula and posterior surface of the humerus. It inserts into the olecranon process of the ulna and fascia of the forearm. The triceps acts to extend the elbow joint and is innervated by the radial nerve with its blood supply coming from branches of the deep brachial artery.

1. Posterior Arm

2. There is only one muscle in the
posterior compartment of the arm…

3. There is only one muscle in the
posterior compartment of the arm…
Hoorah !!!

4. Elbow Full Flexion
The Triceps

5. Triceps
Origin Long head: infraglenoid
tubercle of scapula;
Lateral head: posterior surface
of humerus, superior to radial
groove
Medial head: posterior surface
of humerus, inferior to radial
groove
Insertion Olecranon process of ulna,
fascia of forearm
Action Extends elbow joint
Nerve Supply Radial nerve (C6, C7 and C8)
Blood Supply Branches of deep brachial
artery - Profunda Brachii
Posterior Arm

6. Triceps
Origin Long head: infraglenoid
tubercle of scapula;
Lateral head: posterior surface
of humerus, superior to radial
groove
Medial head: posterior surface
of humerus, inferior to radial
groove
Insertion Olecranon process of ulna,
fascia of forearm
Action Extends elbow joint
Nerve Supply Radial nerve (C6, C7 and C8)
Blood Supply Branches of deep brachial
artery - Profunda Brachii
Posterior Arm