February 10, 2015 Objective:

To describe the anatomy and physiology of the spinal cord

To list and describe the function of the protective coverings found around the spinal cord

Journal: What do you think the function of the spinal

cord is?

Spinal Cord

Spinal Cord

Neural information superhighway that runs inside your vertebral column to the foramen magnum

Runs from the the second lumbar vertebrae to the brain stem

Made up of 31 segments each with a pair of spinal nerves

Spinal Cord Nerve Names Named for their corresponding vertebrae

Cervical Nerves: C1 – C8 Thoracic Nerves: T1 – T12 Lumbar Nerves: L1 – L5 Sacral Nerves: S1 – S5 Coccygeal Nerve located at the coccyx

Spinal Cord External Anatomy Spinal cord ends at L2 at

the conus medullaris Hanging from the conus

medullaris is the cauda equina (“Horse Tail”), which is a bunch of spinal nerves that hang from the L2 spinal nerves to the coccygeal nerve in a bath of cerebrospinal fluid

Meninges Series of protective membranes within the

bone that cover the brain and spinal cord Help set up the layers of cushioning and

shock absorbers for the brain and spinal cord

Layers of Protection around the CNS

Vertebrae Epidural space Dura mater Subdural space Arachnoid mater Subarachnoid space Pia mater Spinal Cord

Epidural Space Found between the dura mater and vertebrae Filled with fat and blood vessels

Dura Mater Outer layer of the meninges, closest to the

bone Made of thick, fibrous tissue

Subdural Space found between the dura mater and the

arachnoid mater Filled with cerebrospinal fluid

Arachnoid Mater Middle meninge layer Made of a delicate

layer of collagen and elastic fibers surrounded by cerebrospinal fluid Acts as a shock

absorber Can transport

nutrients, dissolved gases, neurotransmitters and waste

Contain arachnoid villi

Subarachnoid Space Found between the arachnoid mater and the

pia mater Cerebrospinal fluid cushioning for the CNS

Pia mater Meninge layer fused to the neural tissue of the

CNS Contains blood vessels that supply blood to

the brain and spinal cord

Spinal Cord Internal Anatomy

Anterior Medial Fissure: deep groove on the CNS Posterior Median Sulcus: shallow groove on the

CNS

Gray Matter Horns Cell body regions that are unmyelinated Three Types:

Dorsal Horns: Involved in sensory functions Ventral Horns: Involved in motor functions Lateral Horns: Involved in autonomic functions

White Matter Columns Nerve tracts (similar to axons) that run up and

down the spinal cord, to and from the brain Like communication wires that transport

information

Spine Extending to Nerves

Central Canal: cavity in the center of the spinal cord that is filled with cerebrospinal fluid

Spinal Roots: project from the spinal cord in pairs and then fuse to form spinal nerves

Dorsal Root Ganglion: carries sensory information

Ventral Root Ganglion: carries motor information

Spinal Nerves: carries both sensory and motor information from the body to the spinal cord

Plexus

Complex branching patterns that extend from the spinal cord to peripheral structures

Types Nerves C1 to C4 supply the skin and muscles in the

neck, shoulders, and diaphragm Nerves C5 to C8 & T1 supplies the upper extremities Nerves T12, L1-L5, and S1-S4 supplies the skin and

muscles of the abdominal wall & lower extremities