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

 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