Dorsal rami are branches of spinal nerves that supply the posterior aspect of the body. Specifically, the dorsal rami provide motor innervation to the deep (a.k.a. intrinsic or true) muscles of the back, and sensory innervation to the skin of the posterior portion of the head, neck and back.
In simpler terms, think of spinal nerves as roads with exits. After a spinal nerve exits the spinal cord, it splits into two main branches: a ventral ramus and a dorsal ramus. The dorsal ramus is the smaller of the two and heads posteriorly (towards the back).
Functions of Dorsal Rami
The dorsal rami have two primary functions:
- Motor Innervation: They control the deep muscles of the back. These muscles are responsible for maintaining posture and controlling movements of the vertebral column.
- Sensory Innervation: They transmit sensory information from the skin of the back, head, and neck to the central nervous system. This includes touch, temperature, pain, and pressure sensations.
Summary Table
| Feature | Description |
|---|---|
| Origin | Spinal nerves |
| Destination | Posterior aspect of the body (back, head, neck) |
| Motor Function | Innervates deep (intrinsic) muscles of the back |
| Sensory Function | Provides sensory innervation to the skin of the posterior head, neck, and back |
