Which nerve innervates the erector spinae group?

Which nerve innervates the erector spinae group?

• A. Dorsal rami spinal nerve
• B. Ventral rami spinal nerve
• C. Cranial nerves IX and X
• D. Dorsal root ganglion only

Answer: (A)

The erector spinae are intrinsic back muscles that get their nerve supply from the dorsal rami (posterior primary rami) of the spinal nerves. These branches specifically innervate the deep back muscles and the overlying skin, providing the motor input needed for stabilizing and extending the spine. Ventral rami supply most trunk and limb muscles and the anterior and lateral walls, not these deep back muscles. Cranial nerves IX and X don’t relate to the intrinsic back muscles, and the dorsal root ganglion is a sensory structure, not a motor innervation source. So the correct innervation is the dorsal rami of the spinal nerves.

The erector spinae are intrinsic back muscles that get their nerve supply from the dorsal rami (posterior primary rami) of the spinal nerves. These branches specifically innervate the deep back muscles and the overlying skin, providing the motor input needed for stabilizing and extending the spine. Ventral rami supply most trunk and limb muscles and the anterior and lateral walls, not these deep back muscles. Cranial nerves IX and X don’t relate to the intrinsic back muscles, and the dorsal root ganglion is a sensory structure, not a motor innervation source. So the correct innervation is the dorsal rami of the spinal nerves.