Spinal Cord and Nerve Roots Flashcards Preview

DPT 736 Neuroanatomy > Spinal Cord and Nerve Roots > Flashcards

Flashcards in Spinal Cord and Nerve Roots Deck (14)
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-consists of cranial nerves and spinal nerves, which link CNS to peripheral tissues
-neurons contributing to PNS are partly contained in CNS
-12 cranial nerves
-31 pairs spinal nerves


Spinal Cord Characteristics

-extends from foramen magnum to level of disc between L1 and L2
-distal end is conus medularis
-filum terminale tethers it down
-2 enlargements: cervical C5-T1 and lumbar L1-S3


Features of Spinal Cord

-anterior median fissure: anterior surface
-posterior median sulcus: posterior surface
-posterolateral sulcus: each side of posterior surface where posterior rootlets of spinal cord enter cord
-central canal surrounded by gray matter and white matter


Spinal Cord Arteries

-longitudinal arteries: anterior spinal and 2 posterior spinal arteries
-segmental spinal arteries: anterior and posterior radicular arteries supply anterior and posterior roots and segmental medullary arteries reinforce longitudinal vessels


Spinal Cord Veins

-2 pairs of veins on each side of posterior and anterior roots to cord
-anterior spinal vein: parallels anterior median fissure
-posterior spinal vein: parallels posterior median sulcus
-internal vertebral plexus


Spinal Cord Meninges

-epidural space separates vertebral canal from spinal dural mater
-spinal dura mater is outermost layer
-arachnoid matter ends at S2 and is below dura mater
-subarachnoid space is between arachnoid and pia mater, contains CSF, and ends at St
-pia mater is firmly attached to spinal cord and is a denticulate ligament


Arrangement of Structures in the Vertebral Canal

-anteriorly: bodies of vertebrae, IVDs, posterior longitudinal ligament
-laterally: pedicles, intervertebral foramina
-posteriorly: laminae, ligamentum flavum


Spinal Nerves

-posterior (dorsal) root
-anterior (ventral) root
-branches: posterior dorsal ramus-innervate only intrinsic back muscles; anterior ventral ramus-innervate most other skeletal muscles and areas of the skin and forms all major plexuses
-so the nerve consists of sensory, motor, and autonomic signals between the cord and the body
-the roots carry only sensory or motor messages
-the rami carry both sensory and motor messages
-the dorsal root ganglion is a group of cell bodies that...
-dorsal ramus is smaller than ventral
-have 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal


Conus Medullaris Syndrome

-deficits occur as result of lesion in sacral region
-compression/trauma at level of conus medullaris


Cauda Equina Syndrome

-impaired function in multiple nerve roots below L1 and L2
-compression at cauda equina roots


Naming the Spinal Nerve

-cervical region the spinal nerves come out above the named vertebrae
-in every other region (thoracic, lumbar, sacral, coccygeal) they come out below the named vertebrae



-one spinal nerve innervates the dermatome, myotome, and sclerotome (bone) from one somite
-so a dermatome is the area of skin innervated by a particular spinal nerve
-sharp lines on diagrams give false impression of boundaries
-sensory terminals overlap considerably



-herpes zoster
-virus remains in primary sensory neurons (usually in 1 dermatome on one side) dormant but viable
-virus may revive decades later wreaking havoc with somatosensory system
-agonizing pain for months or years
-constant burning, sometimes stabbing
-skin becomes inflamed and blistered, then scaly (very sensitive to stimuli)
-usually reactivates only in one DRG



-group of skeletal muscles innervated by a particular spinal nerve
-usually functionally related