**Core Concept**
The posterior interosseous nerve (PIN) is a branch of the radial nerve that supplies the muscles of the forearm and wrist, except for the flexor carpi radialis and palmaris longus. It is particularly vulnerable to injury due to its superficial location in the forearm.

**Why the Correct Answer is Right**
The PIN is at risk during surgical procedures such as the removal of the radial head or in cases of trauma, particularly when a fracture of the radius occurs. The nerve can also be compressed by ganglia or other soft tissue lesions. When the PIN is injured, patients typically present with weakness or paralysis of the extensor muscles of the wrist and fingers, leading to a characteristic "wrist drop."

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the question as it does not specify a known cause of PIN injury.
**Option B:** This option is not a common cause of PIN injury and is not directly related to the nerve's anatomy or function.
**Option C:** This option is not a direct cause of PIN injury and is not a well-known risk factor for nerve damage.

**Clinical Pearl / High-Yield Fact**
The PIN is often injured in conjunction with a fracture of the radial head, a common injury in the context of a fall on an outstretched hand.

**Correct Answer:** D. A fracture of the radius.