Vertebral Column, Spinal Cord & Nerves George Salter, PH Vertebral Column, Spinal Cord & Nerves George Salter, PH.D Dental and Optometry--2009

The nervous system consists of the CNS- brain and spinal cord & The PNS which is = to everything else Lumbar Plexus

Body Pedicle Lamina Processes: Transverse (2) Articular (4) Spinous (1) Pedicle Lamina

Boundaries of vertebral foramen Lamina

Spina Bifida

Typical intervertebral joints 3 between adjacent vertebrae 2 facet joints 1 symphysis (disc) 3 between adjacent vertebrae Superior articular process Facet joint (zygapophysis) Intervertebral disc Inferior articular process Intervertebral foramen

CERVICAL VERTEBRAE Transverse Process: With Foramen & Tubercles Bifid Spinous Process

Uncinate Process

Of Luschka -

Ligaments Ligamentum Flavum Interspinous & Supraspinous & Ligamentum Nuchae Anterior Longitudinal Posterior Longitudinal Atlanto-occipital

supraspinous ligament Interspinous Lig supraspinous ligament Ligamentum Flavum

nuchal ligament C7

Anterior Longitudinal Ligament (ALL) Posterior (PLL)

PLL Pedicle

AOM PAO LIG. FLAVUM ALL

SPINAL CORD & NERVES

31 PAIR OF SPINAL NERVES: 8 CERVICAL; 12 THORACIC 5 LUMBAR 5 SACRAL 1 COCCYGEAL Spinal cord segment definintion Spinal Cord segments correspond to vertebral column segments

Lumbosacral enlargement (cord segments L2 – S3) 1st cervical n. (C1) exits above C1 vertebra Base of skull Cervical enlargement (cord segments C4 – T1) 8th cervical n. exits below C7 vertebra Cervical nerves Thoracic nerves Thoracic nerves Lumbar nerves Sacral & coccygeal nerves Lumbosacral enlargement (cord segments L2 – S3) Conus medullaris (termination of cord) 1. The spinal cord extends from the f. magnum at the base of the skull (where it is continuous w/the medulla of the brain) to the LV1/LV2 level. 2. There are 31 prs. of spinal nerves (8C., 12T,5L,5S, & 1Co). The part of the cord to which a pair of spinal nerves attaches is a spinal cord segment (hence there are also 31 spinal cord segments). 3. CN1-CN7 emerge superior to their respective vertebrae (ie, CN1 exits above CV1 and below skull). CN8 emerges between C7 & T1 vertebrae. Beginning w/T1 spinal nerve, spinal nerves emerge inferior to their respective vertebrae. 4. Since the cord ends at LV1/LV2, the roots of the spinal nerves become increasingly longer and more oblique as they descend to exit their respective foramina. Hence the formation of the cauda equina. 5. The spinal cord shows two enlargements (cervical and lumbosacral) for the origin of the nerves innervating the upper and lower limbs. 6. The tapered terminal part of the spinal cord is the conus medullaris. Distal to the conus the cord is prolonged as a nonnervous strand of tissue (pia mater) termed the internal filum terminale. 7. Also note that the dural sac surrounding the cord ends at SV2. Cauda equina Internal filum terminale of pia mater Termination of dural sac

Spinal Cord is shorter than vertebral column

The nervous system consists of the CNS- brain and spinal cord & The PNS which is = to everything else Lumbar Plexus

Additional terms: Cutaneous Brs. & sympathetic trunk & its communicating branches (rami communicantes)

Boundaries of intervertebral foramen

MENINGES: Dura Mater Arachnoid Mater Pia Mater

Dura Mater Arachnoid Mater and Pia Mater Dura Mater=Pachymenix Arachnoid and Pia =Leptomeninges

“MENINGEAL SPACES” Epidural---between vertebra and dura mater and contains fat and epidural (internal) vertebral plexus Subdural---only a potential space Subarachnoid---contains a web-like connective tissue plexus AND cerebrospinal fluid (CSF) plus vessels and spinal nerve rootlets

Subarachnoid Subdural & Epidural SPACES

Spinal Cord ends at one level & meninges at another 1st cervical n. (C1) exits above C1 vertebra Base of skull Cervical enlargement (cord segments C4 – T1) 8th cervical n. exits below C7 vertebra Cervical nerves Thoracic nerves Thoracic nerves Lumbar nerves Sacral & coccygeal nerves Lumbosacral enlargement (cord segments L2 – S3) Conus medullaris (termination of cord) 1. The spinal cord extends from the f. magnum at the base of the skull (where it is continuous w/the medulla of the brain) to the LV1/LV2 level. 2. There are 31 prs. of spinal nerves (8C., 12T,5L,5S, & 1Co). The part of the cord to which a pair of spinal nerves attaches is a spinal cord segment (hence there are also 31 spinal cord segments). 3. CN1-CN7 emerge superior to their respective vertebrae (ie, CN1 exits above CV1 and below skull). CN8 emerges between C7 & T1 vertebrae. Beginning w/T1 spinal nerve, spinal nerves emerge inferior to their respective vertebrae. 4. Since the cord ends at LV1/LV2, the roots of the spinal nerves become increasingly longer and more oblique as they descend to exit their respective foramina. Hence the formation of the cauda equina. 5. The spinal cord shows two enlargements (cervical and lumbosacral) for the origin of the nerves innervating the upper and lower limbs. 6. The tapered terminal part of the spinal cord is the conus medullaris. Distal to the conus the cord is prolonged as a nonnervous strand of tissue (pia mater) termed the internal filum terminale. 7. Also note that the dural sac surrounding the cord ends at SV2. Cauda equina Internal filum terminale of pia mater Spinal Cord ends at one level & meninges at another Termination of dural sac

WHAT ELSE PASSES THROUGH INTER- VERTEBRAL FORAMEN?

Intervertebral discs

Position of Spinal nerve in interver- tebral foramen

DERMATOME- STRIP OF SKIN SUPPLIED BY A PAIR OF DORSAL ROOTS

S1

A Typical Spinal Nerve

FUNCTIONAL COMPONENTS OF SPINAL NERVES

All Spinal nerves have ______ functional components. All are general All Spinal nerves have ______ functional components? All are general. When talking about the cranial nerves and their functional components, one has to take all the possible spinal nerve functional components and add the possibility of three more. NOW REMEMBER, all spinal nerves have both sensory and motor fibers in them, but some of the cranial nerves are, indeed mixed, but some are totally sensory and some totally motor. The additional 3 functional components are designated special instead of general.

Back Muscles Superficial: Trapezius Latissimus Dorsi, Levator Scapulae, Rhomboids, Serratus Muscles Native (or Deep) : Splenius Erector Spinae Transversospinalis Other: interspinalis, intertransversarium, levator costarum, suboccipital muscles

VA

Greater Occipital Nerve Suboccipital Nerve

VA

THE END