Medial head of triceps brachii
Arms
Deep muscle — it lies under other muscles. X-ray makes the muscles over it see-through.
- Origin
- Back of the humerus below the radial groove
- Insertion
- Olecranon of the ulna
- Action
- Extends the elbow
- Nerve supply
- Radial nerve (C6–C8)
The deepest triceps head, lying mostly under the other two and covering the lower back of the humerus. Like the lateral head, it acts only at the elbow.