Chapter_14_-_Spinal_Cord_and_Nerves_Student

Spinal Cord

A cylindrical structure that extends from the brainstem and runs down the vertebral column, responsible for transmitting signals between the brain and the rest of the body.

Dura mater

The tough, outer layer of the spinal meninges that protects the spinal cord and contains the epidural space.

Arachnoid mater

The middle layer of the spinal meninges, situated between the dura mater and pia mater, containing the subarachnoid space filled with cerebrospinal fluid.

Pia mater

The delicate, inner layer of the spinal meninges that closely adheres to the surface of the spinal cord.

Gray matter

The region of the spinal cord that contains neuronal cell bodies and unmyelinated axons, organized into horns.

White matter

The area of the spinal cord that contains myelinated axons, organized into columns (funiculi) and responsible for transmitting information.

Central canal

A fluid-filled space in the center of the spinal cord that contains cerebrospinal fluid.

Spinal nerves

31 pairs of nerves that emerge from the spinal cord, carrying sensory and motor information to and from the body.

Dermatome

An area of skin that is mainly supplied by a single spinal nerve root, often used in clinical examinations.

Cervical plexus

A network of nerves in the neck, responsible for supplying muscles and skin in that area.

Brachial plexus

A network of nerves that innervates the shoulder, arm, and hand, derived from the anterior rami of spinal nerves C5-T1.

Lumbar plexus

A network of nerves that provides innervation to the lower back and parts of the lower limbs, formed mainly from L1-L4 spinal nerves.

Sacral plexus

A network of nerves that supplies the pelvis and lower limbs, formed from L4-S4 spinal nerves.

Decussation

The crossing of nerve fibers from one side of the nervous system to the other, commonly observed in many neural tracts.

Paraplegia

Paralysis of both lower limbs due to lesions affecting spinal cord segments T1 to L1.

Quadriplegia

Paralysis of all four limbs due to lesions affecting spinal cord segments above C5, often requiring ventilatory support.

Hemiplegia

Paralysis on one side of the body, commonly caused by strokes or lesions in the brain.