Peripheral Nervous System

These flashcards cover the key concepts and terms related to the peripheral nervous system, specifically focusing on spinal nerves, their functions, and their anatomical relationships.

Spinal Nerves

31 pairs of mixed nerves that emerge from the spinal cord, supplying all body parts except the head and part of the neck.

Cervical Nerves

8 pairs of spinal nerves (C1–C8) that emerge from the cervical region of the spinal cord.

Brachial Plexus

A network formed by the ventral rami of C5–C8 and T1, which gives rise to nerves of the upper limb.

Dorsal Roots

Contain sensory (afferent) fibers that conduct impulses from peripheral receptors to the spinal cord.

Ventral Roots

Contain motor (efferent) fibers from spinal cord to skeletal muscles and are involved in motor signaling.

Cauda Equina

A bundle of spinal nerves and rootlets that resembles a horse's tail; it extends below the termination of the spinal cord.

Phrenic Nerve

Major motor and sensory nerve of the diaphragm, important for breathing; it receives fibers from C3 to C5.

Median Nerve

Innervates skin and most flexor muscles of the forearm; commonly affected in carpal tunnel syndrome.

Sciatic Nerve

The longest and thickest nerve of the body that innervates the hamstring muscles and most leg and foot muscles.

Dermatome

An area of skin innervated by cutaneous branches of a single spinal nerve; useful for assessing spinal cord injuries.