**Question:** Sensory supply to diaphragm is through -

A. Intercostal nerves
B. Phrenic nerves
C. Cranial nerves
D. Intercostal arteries

**Core Concept:**
The diaphragm is a crucial muscle involved in respiration, separating the thoracic and abdominal cavities. It receives both motor and sensory innervation, allowing it to contract and relax, as well as perceive stimuli from the surrounding environment. Sensory supply to the diaphragm is essential for proprioception (body awareness) during breathing.

**Why the Correct Answer is Right:**
The correct answer, **B. Phrenic nerves**, is responsible for providing sensory supply to the diaphragm. Phrenic nerves are cranial nerves (CN) that originate from the brainstem, specifically the cervical spinal cord segments C3, C4, C5, and C6. These nerves travel through the neck, pass under the scalene muscles, and reach the diaphragm to convey sensory information.

**Why Each Wrong Option is Incorrect:**

A. Intercostal nerves (Option A): These nerves are responsible for motor innervation of the intercostal muscles, which are involved in rib expansion and contraction during respiration. They do not provide sensory supply to the diaphragm.

B. Intercostal arteries (Option D): Arteries are blood vessels that carry oxygenated blood, and their primary function is to supply blood to the diaphragm, not sensory supply.

C. Cranial nerves (Option C): While some cranial nerves do supply sensory information, the specific cranial nerves (CN) responsible for sensory supply to the diaphragm are the phrenic nerves (CN V2), not the general category of cranial nerves.

**Clinical Pearl:**
Understanding the sensory supply to the diaphragm helps in appreciating the role of the diaphragm in respiration and its integration with the central nervous system. The phrenic nerves convey sensory information from the diaphragm to the brainstem, allowing awareness of diaphragmatic position and effort during breathing. This knowledge is crucial for diagnosing and treating respiratory disorders, such as in cases of diaphragmatic paralysis or injury affecting the phrenic nerves.