Which option best describes the somatic motor pathway?

Which option best describes the somatic motor pathway?

• A. Two-neuron chain with a preganglionic and postganglionic.
• B. Three neurons including a dorsal root ganglion.
• C. A single neuron with the cell body in the CNS and a peripheral axon to skeletal muscle.
• D. A network of interneurons in the brainstem.

Answer: (C)

The somatic motor pathway is a direct projection from the central nervous system to skeletal muscle, using a single motor neuron whose cell body sits in the CNS and whose axon travels peripherally to the muscle. This neuron reaches the neuromuscular junction and releases acetylcholine to trigger a muscle contraction, with no relay through a ganglion. That direct, single-neuron route to the skeletal muscle is the hallmark of the somatic motor system. The other descriptions point to different systems or structures: a two-neuron chain with a preganglionic and postganglionic neuron is characteristic of autonomic pathways; a dorsal root ganglion is associated with sensory neurons, not motor output; and a network of interneurons in the brainstem reflects central processing circuits rather than the final efferent limb to muscle.

The somatic motor pathway is a direct projection from the central nervous system to skeletal muscle, using a single motor neuron whose cell body sits in the CNS and whose axon travels peripherally to the muscle. This neuron reaches the neuromuscular junction and releases acetylcholine to trigger a muscle contraction, with no relay through a ganglion. That direct, single-neuron route to the skeletal muscle is the hallmark of the somatic motor system.

The other descriptions point to different systems or structures: a two-neuron chain with a preganglionic and postganglionic neuron is characteristic of autonomic pathways; a dorsal root ganglion is associated with sensory neurons, not motor output; and a network of interneurons in the brainstem reflects central processing circuits rather than the final efferent limb to muscle.