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How many pairs of cranial nerves and spinal nerves do humans have?

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Diagram of a human figure showing the full nervous system, including the brain, spinal cord, and branching peripheral nerves throughout the body, with labels for each part. — human nervous system The conduction of electrochemical stimuli from sensory receptors in the human nervous system occurs via organized groups of specialized cells, consisting largely of neurons, various neural support cells, and tracts of nerve fibers.

In the human nervous system, there are 12 pairs of cranial nerves and 31 pairs of spinal nerves.1

Cranial Nerves

The 12 pairs of cranial nerves connect the brain directly to the sense organs and muscles of the head and thoracic region. While these 12 pairs are standard, a 13th pair—known as the terminal nerve (CN 0)—is sometimes recognized, though its function remains unclear.21

Spinal Nerves

The 31 pairs of spinal nerves are attached to the spinal cord and are categorized by the region of the vertebral column from which they emerge:314

Cervical: 8 pairs (C1–C8)
Thoracic: 12 pairs (T1–T12)
Lumbar: 5 pairs (L1–L5)
Sacral: 5 pairs (S1–S5)
Coccygeal: 1 pair (Co1)

Each of these nerves connects the spinal cord to specific regions of the body, facilitating both sensory and motor functions.34