**Core Concept:**
The radial nerve is a large peripheral nerve that arises from the ventrolateral cord of the cervical spinal cord and supplies motor and sensory functions to various regions of the upper limb. In humans, it is divided into two branches: the superficial radial nerve and the deep radial nerve.

**Why the Correct Answer is Right:**
The radial nerve divides into two branches: the superficial radial nerve and the deep radial nerve, both of which play essential roles in the upper limb's motor and sensory functions. The division occurs at the level of the forearm, specifically at the level of the spiral groove of the radius bone or Guyon's canal.

**Why Each Wrong Option is Incorrect:**
A. Division of radial nerve at the level of the cervical cord is incorrect as the radial nerve originates from the ventrolateral cord of the cervical spinal cord and does not divide there.
B. Division of radial nerve at the level of the axilla is wrong as the division happens at the forearm level, not in the axilla.
C. Division of radial nerve at the level of the elbow joint is not correct, as the division occurs at the forearm level, not at the elbow joint.

**Clinical Pearl / High-Yield Fact:**
Guyon's canal is a crucial anatomical landmark for surgeons and anesthesiologists when performing radial nerve blocks, as it helps to avoid damaging the sensory innervation of the radial aspect of the thumb, index, and middle finger.

**Correct Answer:**
D. Division of radial nerve at the level of the spiral groove of the radius bone or Guyon's canal.