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Humeral shaft fracture and radial nerve palsy
Most humeral shaft fractures heal well in a functional brace thanks to the wide range of shoulder motion; radial nerve palsy, shown as wrist drop, is the common nerve complication, and in a closed fracture it usually recovers on its own, so it is observed.
Why it matters in the exam
The typical stem describes a patient after a fall or accident with a fracture in the middle or distal third of the humerus who cannot extend the wrist and fingers and has numbness on the back of the hand between the thumb and index finger. The radial nerve runs in the spiral groove close to the bone, so it is injured in about 10% of humeral shaft fractures, mainly in a spiral fracture of the distal third (the Holstein-Lewis fracture). Questions test two decisions. The first: how to treat the fracture. Because the shoulder and elbow compensate for deformity, up to 20 degrees of anterior angulation, up to 30 degrees of varus and up to 3 cm of shortening are accepted, and treatment is a functional brace (Sarmiento). Indications for surgery are an open fracture, vascular injury, bilateral fractures or a floating elbow (fractures of the humerus and forearm in the same limb), multiple injuries, a pathological fracture and inability to keep acceptable alignment. The second: what to do about the nerve palsy. In a closed fracture most injuries are neurapraxia or axonotmesis that recover on their own, so a wrist splint is given, passive range of motion is kept, and electrical studies are done if there is no improvement; surgical exploration is considered if there is no recovery after 3–6 months. In contrast, in an open fracture with nerve palsy the nerve is explored during debridement, because it may be divided.
Key points
- Most humeral shaft fractures are treated in a functional brace.
- Up to 20 degrees anterior angulation, 30 degrees varus and 3 cm shortening are accepted.
- Radial palsy in about 10% of fractures, mainly in the distal third.
- Closed fracture with palsy — observe; open — explore.
- Explore if there is no recovery after 3–6 months.
Summary table
| Situation | Finding | Treatment |
|---|---|---|
| Closed fracture with acceptable alignment | Up to 20 degrees anterior angulation, 30 degrees varus, 3 cm shortening | Functional brace and radiographic follow-up |
| Fracture with an indication for surgery | Open, vascular injury, floating elbow, multiple injuries, pathological | Plate or nail fixation |
| Radial palsy with a closed fracture | Wrist drop, numbness on the back of the hand | Wrist splint and observation; EMG if no improvement |
| Radial palsy with an open fracture | Wrist drop with a wound | Explore the nerve during debridement |
| No nerve recovery | No clinical or electrical signs of recovery | Exploration after 3–6 months; tendon transfers later |
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Sources
- Rockwood and Green's Fractures in Adults, 9th ed. (2019) — Humeral Shaft Fractures
- Sarmiento A et al., J Bone Joint Surg Am (2000) — Functional bracing for the treatment of fractures of the humeral diaphysis
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.