**Core Concept:** Cervical radiculopathy is a condition caused by compression or irritation of a cervical nerve root, typically resulting in sensory or motor deficits in the dermatome or myotome innervated by the affected root. In this case, the symptoms and examination findings are suggestive of a cervical radiculopathy involving C4 and C5 nerve roots.

**Why the Correct Answer is Right:** The correct answer is C. Cervical radiculopathy, also known as brachialgia, is the result of compression or irritation of the cervical nerve roots (C5, C6, C7, C8, and T1). In this scenario, the patient presents with numbness over the neck and decreased pain and temperature sensation in the distribution of C4 and C5 dermatomes. The other options are incorrect for the following reasons:

A. Sensory deficits are not exclusive to the scalp, and motor deficits are not present in this case.
B. Bladder and bowel sphincter control are normal, ruling out peripheral neuropathy or spinal cord compression.
D. The patient does not show any signs of spinal cord compression or involvement of other spinal cord segments.

**Why Each Wrong Option is Incorrect:**

A. Sensory deficits are not limited to the scalp, and motor deficits are absent in this case.
B. Bladder and bowel sphincter control are normal, ruling out peripheral neuropathy or spinal cord compression.
D. The patient does not demonstrate any signs of spinal cord compression or involvement of other spinal cord segments.

**Clinical Pearl:** Cervical radiculopathies are commonly caused by herniated cervical discs, spinal stenosis, or trauma. Early recognition and treatment can prevent further neurological damage and improve patient outcomes.

**Correct Answer:** Cervical radiculopathy, specifically affecting C4 and C5 dermatomes, is the correct diagnosis for this patient presenting with numbness over the neck and decreased pain and temperature sensation in the distribution of C4 and C5 dermatomes. This condition is typically due to compression or irritation of the cervical nerve roots (C5, C6, C7, C8, and T1). Correct diagnosis is important as it guides treatment options and ensures appropriate management for the patient's neurological recovery and prevention of further damage.