Spinal Nerves and Plexuses Diagram

All 17 parts on the diagram

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Nerve groups and plexuses 9

Brachial plexus A web of nerves C5 to T1; it supplies the upper limb.
Lumbar plexus A web of nerves L1 to L4 in the lower back.
Sacral plexus A web of nerves L4 to S4 in the pelvis.
Cervical plexus A web of nerves C1 to C4 in the neck.
Cervical nerves Eight pairs, C1 to C8, in the neck.
Thoracic nerves Twelve pairs, T1 to T12, in the chest region.
Lumbar nerves Five pairs, L1 to L5, in the lower back.
Sacral nerves Five pairs, S1 to S5; they leave through the sacrum.
Coccygeal nerve One pair, Co1: the last of the 31 pairs.

Named nerves 8

Sciatic nerve From the sacral plexus down the thigh's back.
Femoral nerve From the lumbar plexus to the front of the thigh.
Ulnar nerve From the brachial plexus to the little-finger side of the hand.
Median nerve From the brachial plexus to the forearm and hand.
Radial nerve From the brachial plexus; it supplies the back of the arm.
Intercostal nerves Thoracic nerves T1 to T11, running between the ribs.
Phrenic nerve From C3 to C5 in the neck down to the diaphragm.
Obturator nerve From the lumbar plexus to the inner side of the thigh.

How this list was compiled: Every name and detail line was checked on 2026-09-30 against TeachMeAnatomy, The Cervical Plexus, The Brachial Plexus, The Lumbar Plexus and The Sacral Plexus, https://teachmeanatomy.info/; Kenhub, Spinal nerves, https://www.kenhub.com/en/library/anatomy/spinal-nerves; the US National Cancer Institute SEER Training Modules, The Peripheral Nervous System, https://training.seer.cancer.gov/anatomy/nervous/organization/pns.html; and Wikipedia, Spinal nerve and the article on each plexus and nerve, text only. Hints and detail lines are in our own words. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry. Own original drawing; nothing traced or copied. Licence: own work

How it works

This spinal nerves and plexuses diagram shows a body from behind in two views. The first has the 31 pairs of spinal nerves in five groups and the four plexuses. The second has the main nerves that leave each plexus.

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Nerve groups and plexuses

The spinal nerves are named for the part of the column they leave: cervical, thoracic, lumbar, sacral and coccygeal. In a plexus the nerves of neighboring levels cross and join. The cervical plexus lies in the neck, the brachial plexus runs to the armpit, the lumbar plexus lies in the lower back and the sacral plexus in the pelvis.

The nerves that leave them

The phrenic nerve runs from the neck to the diaphragm. The radial, median and ulnar nerves leave the brachial plexus for the arm. The femoral and obturator nerves leave the lumbar plexus, and the sciatic nerve leaves the sacral plexus. The thoracic nerves form no plexus: they run between the ribs as the intercostal nerves.

There are eight cervical nerves but only seven cervical vertebrae: the eighth pair leaves below the seventh vertebra.
The body is drawn as if transparent, so nerves that run on the front, such as the femoral nerve, show through.

Questions and answers

How many spinal nerves are there?

Thirty-one pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal. Each pair is named for the part of the vertebral column where it leaves.

What are the four nerve plexuses?

The cervical plexus (C1 to C4), the brachial plexus (C5 to T1), the lumbar plexus (L1 to L4) and the sacral plexus (L4 to S4). A much smaller coccygeal plexus is sometimes counted as a fifth.

Why do the thoracic nerves have no plexus?

Their front branches stay separate. Each one runs round the chest between two ribs as an intercostal nerve, without crossing and joining its neighbors the way the nerves of the limbs do.

Is this the answer key to “correctly identify and label the spinal nerves and their plexuses”?

That sentence is a publisher’s labeling activity. This page shows the same nerve groups and plexuses on a drawing of our own, so the layout differs, but the names are the standard ones.