**Core Concept:** The radial nerve is a mixed sensory and motor nerve that originates from the cervical spinal cord and supplies the muscles of the forearm and the skin territories. Distal radial nerve injury refers to damage to the nerve distal to the elbow joint.

**Why the Correct Answer is Right:** Distal radial nerve injuries typically involve damage to the radial nerve beyond the elbow joint. The injury may be caused by trauma, compression, or ischemia, leading to a loss of function in the muscles and sensory loss in the corresponding skin territories. The correct answer, **D**, highlights the absence of sensory loss in the thumb, index, and middle fingers, which is a key feature of distal radial nerve injury.

**Why Each Wrong Option is Incorrect:**

A. **Option A:** Sensory loss in the thumb, index, and middle fingers is typically seen in injuries to the ulnar nerve, which is responsible for sensation in these areas. This is not seen in a distal radial nerve injury.

B. **Option B:** Motor deficits in the thumb and index finger are present in ulnar nerve lesions, not radial nerve lesions.

C. **Option C:** The absence of sensory loss in the radial side of the wrist and forearm is not specific to distal radial nerve injury. This could also be seen in lesions of the median nerve or brachial plexus.

**Clinical Pearl:** In clinical practice, understanding the sensory distribution of peripheral nerves is essential for diagnosing nerve injuries accurately. Recognizing specific deficits helps differentiate between different nerve lesions, leading to appropriate management and prognosis.