Chapter 13: Spinal Cord And Spinal Nerves Flashcards
Vertebral Column
Vertebrae provide a sturdy shelter for the enclosed spinal cord.
The vertebral ligaments, meninges, cerebrospinal fluid provide additional protection.
Meninges
Singular: meninx
3 protective, connective tissue coverings that encircle the spinal cord and the brain.
Superficial to deep:
Dura mater
Arachnoid mater
Pia mater
Spinal Meninges
Surround the spinal cord. Are continuous with the cranial meninges.
Cranial Meninges
Encircle the brain.
Epidural Space
A space between the dura mater and the wall of the vertebral canal. Contains a cushion of fat and CT that protect the spinal cord.
Dura Mater
Most superficial layer of the 3 meninges.
Thick strong layer composed of dense irregular CT.
Arachnoid Mater
The middle layer of the meningeal membranes.
A thin, a vascular covering comprised of cells and thin, loosely arranged collagen and elastic fibers.
Subdural Space
Space between the dura mater and arachnoid mater, contains interstitial fluid.
Pia Mater
The innermost meninx is a thin transparent CT layer that adheres to the surface of the spinal cord and brain.
Contains thin squamous to cuboidal cells within interlacing bundles of collagen fiber and some fine elastic fibers.
Contains many blood vessels that supply O2 and nutrients to the spinal cord.
Denticulate Ligaments
Extensions in pia mater.
Thickenings , project laterally and fuse with the arachnoid mater and inner surface of the dura mater between the anterior and posterior nerve roots of spinal nerves on either side.
Subarachnoid Space
Space between the arachnoid mater and pia mater. Contains shock absorbing cerebrospinal fluid.
Spinal Cord
Is a roughly oval shape, being flattened slightly anteriorly and posteriorly.
Anatomy of Spinal Cord/Nerves
Spinal cord extends from the medulla oblong at the base of the brain to the superior boarder of the second lumbar vertebra.
Cervical Plexus C1-C5
Brachial Plexus C5-T1
Lumbar Plexus L1-L4
Sacral Plexus L4-S4
Cervical Plexus C1-C5
Formed by the roots of C1-C4 with contributions from C5.
There is one on each side of neck along the first 4 cervical vertebrae.
Supplies: skin and muscles of the head, neck and superior part of shoulder, chestnut and diaphragm.
Nerves:
Lesser Occipital Nerve
Greater Auricular
Ansa Cervicalis
Transverse Cervical nerve
Supraclaviculat nerve
Phrenic nerve
Brachial Plexus C5-T1
Roots of spinal nerves C5-C8 - T1. Extends inferiorly and laterally on either side of the last 4 cervical and 1st thoracic vertebra. Passes above the 1st rib to the clavicle and enters axilla. Provides entire nerve supply to shoulders and upper limbs.
Nerves:
Musculocutaneous Nerve
Axillary nerve
Median nerve
Radial nerve
Ulnar nerve
Intercostal nerves
Subcostal nerve
Second lumbar vertebra
Lumbar Plexus L1-L4
Roots of spinal nerves L1-L4. There is minimal intermingling of fibers in the lumbar plexus.
Supplies: anterolateral abd wall, external genitals and parts of lower limbs.
Nerves:
Lliphypogastric Nerve
Llioingunial nerve
Genitofemeral nerve
Lateral femoral cutaneous nerve
Femoral nerve
Obturator nerve
Sacral Plexus L4-S4
Roots of spinal nerves L4-L5 and S1-S4.
Situated largely anterior to the sacrum.
Supplies: buttocks, perineum and lower limbs.
Nerves:
Superior gluteal nerve
Inferior gluteal nerve
Sciatic nerve: largest nerve in body
Posterior cutaneous nerve of height
Pudendeal nerve
Cervical Enlargement
Superior enlargement, extends from the fourth cervical vertebra C4 to the first thoracic vertebra T1. Nerves to and from the upper limbs arise in this enlargement.
Lumbar Enlgargement
Inferior enlargement, extends from the 9th -12th thoracic vertebra. Nerves to and from the lower limbs arise from the lumbar enlargement.
Conus Medullaris
Where the spinal cord terminates as a tapering, conical structure.
Inferior to the lumbar enlargement
Filum Terminale
Arises from the conus medullaris. An extension of the pia mater that extends interiorly, fused with arachnoid mater and dura mater.
Anchors the spinal cord to the coccyx.
Spinal Nerves
Path of communication between the spinal cord and specific regions of the body.
31 pairs
Roots
Two bundles of axons that connect each spinal nerve to a segment of the cord by smaller bundles of axons.
Rootlets
Smaller bundle of axons.
Contains sensory axons.
Posterior Root
Only contain sensory axons. Conduct nerve impulses from sensory receptors in the skin, muslces and internal organs.
Posterior Root Ganglion
Contained in posterior root. Swelling which contains the cell bodies of sensory neurons.
Anterior Root
Contains axons of motor neurons which conduct nerve impulses from the CNS to effectors.
White Matter of Spinal Cord
Consists of bundles of myelinated axons of neurons.
Divided grooves into right and left sides.
Anterior Median Fissure
Is a wide groove on there anterior (ventral) side.