Most common nerve injured in fracture humerus is
**Core Concept**
The most common nerve injured in a fracture of the humerus is due to its anatomical proximity to the bone and its susceptibility to compression or laceration during the fracture process. The radial nerve, in particular, is at risk due to its course through the radial groove of the humerus.
**Why the Correct Answer is Right**
The radial nerve is the most commonly injured nerve in humeral fractures because of its close relationship with the humerus. It runs through the radial groove on the posterior aspect of the humerus, making it vulnerable to injury during a fracture. The nerve may be compressed or lacerated by bone fragments or swelling, leading to radial nerve palsy. This condition is characterized by weakness or paralysis of the extensor muscles of the wrist and fingers, resulting in wrist drop.
**Why Each Wrong Option is Incorrect**
**Option A:** The median nerve is not typically injured in humeral fractures, as it is located on the anterior aspect of the humerus and is not as closely associated with the bone.
**Option B:** The ulnar nerve is also not commonly injured in humeral fractures, as it is located on the medial aspect of the humerus and is not as susceptible to compression or laceration during a fracture.
**Option C:** The axillary nerve is not typically injured in humeral fractures, as it is located higher up in the shoulder region and is not as closely associated with the humerus.
**Clinical Pearl / High-Yield Fact**
When evaluating a patient with a humeral fracture, it is essential to assess for radial nerve function, including wrist extension and finger extension. A decrease in these functions may indicate radial nerve injury, which requires prompt recognition and treatment to prevent long-term sequelae.
**Correct Answer: C. Radial nerve.**