Posterior Neck - LO4
4. What is the ‘big picture’ structure of a single spinal nerve, and what are the various functions of the parts of a spinal nerve?
4. What is the ‘big picture’ structure of a single spinal nerve, and what are the various functions of the parts of a spinal nerve?
Spinal nerves exit the spinal cord at regular intervals as dorsal and ventral rootlets, which coalesce into dorsal and ventral roots, which join to form the trunk of the spinal nerve. The dorsal root is most obvious as it is associated with a mass of cell bodies known as the dorsal root ganglion (DRG). Dorsal roots (and rootlets) are entirely afferent (sensory), whereas ventral roots (and rootlets) are efferent (motor). The trunk of the spinal nerve exits the vertebral canal laterally via an intervertebral foramen and almost immediately bifurcates into a dorsal primary ramus (DPR) and a ventral primary ramus (VPR). These rami may further bifurcate along their courses.
