Trauma · Interactive 3D

Humerus & radial nerve

The right humerus from behind with the radial nerve winding obliquely down the spiral groove on the back of the shaft.

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AI-assisted model. Labels checked against standard anatomy references; specialist review pending.

What to look at

1The radial nerve (posterior cord, C5–T1) passes behind the humerus with the profunda brachii artery, in the spiral groove between the medial and lateral heads of triceps.
2It runs from proximal and medial to distal and lateral across the back of the middle third of the shaft.
3In the distal third it pierces the lateral intermuscular septum to the front of the arm, where it is tethered — the reason distal-third (Holstein–Lewis) fractures can trap it.
4Injury in the groove usually spares triceps, whose branches arise higher, but gives wrist drop and sensory loss over the first web space.

Hotspots

1Humeral head — Seen from behind; the axillary nerve winds round the surgical neck below it.
2Radial nerve in the spiral groove — With the profunda brachii artery, between the lateral and medial heads of triceps.
3Radial nerve, distal third — Pierces the lateral intermuscular septum about 10 cm above the lateral epicondyle.
4Olecranon fossa — Receives the olecranon in full extension.

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