Cervical Spine Bones and Spinal Cord

how many bones make up the spine?

33

how many moveable bones are in the spine?

24

how many regions of the spine are there?

5 regions

What are the regions of the spine?

• cervical

• thoracic

• lumbar

• sacrum

• coccyx

how many vertebrae make up the cervical spine?

7

how many vertebrae make up the thoracic spine?

12

how many vertebrae make up the lumbar spine?

5

how many vertebrae make up the sacrum?

5 fused vertebrae

how many vertebrae make up the coccyx?

4 fused vertebrae

general information of the spine

• 24 cervical, thoracic, and lumbar vertebrae articulate to form intervetebral joints

• considerable flexibility

  • decent range of motion

  • 3-5 degrees of motion in each segment

• overall small movement in each section

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intervetebral bodies (bones) contribute _____ of the length of the vertebral column

3/4

intervetebral discs contribute _____ to length

1/4

how many curvatures of the spine are there?

4 curvatures

what are the four curvatures of the spine?

• cervical

• thoracic

• lumbar

• sacrococcygeal

cervical curve and lumbar curve

concave posteriorly

thoracic curve and sacroccygeal curve

concave anteriorly

componenets of the cervical vertebrae

• body

• spinous process

• foramen transversarium

• transverse process

• posterior arch

• anterior arch

• facets

typical cervical vertebrae

• 3, 4, 5, 6

• body small and longer from side to side than AP

• superior surface is concave; inferior surface convex

• vertebral foramen large and triangular

• is a transversarium in transverse process for vertebral vessels

• superior facets of articular processes are directed superior posteriorly; inferior facets directed inferoposteriorly

• short and bifid spinous processes

atypical cervical vertebrae

• atlas (C1)

• axis (C2)

• C7

Atlas

• atypical cervical vertebrae C1

• ringlike

• kideney-shaped

• lacks spinous process or body

• consists of 2 lateral masses connected by AP arches

• superior facets are concave receive occipital condyles

• carries the skull

Axis

• atypical cervical vertebrae C2

• Peg-like dens (odontoid process)

• projects superiorly from its body

C7

• atypical cervical vertebrae

• vertebrae promens

• long spinous process not bifid

• transverse processes (“wings”) are large

• formina in them are small; do not transmit the vertebral arteries

spinal cord

• major reflex center and conduction pathway between body and brain

• cylindrical structure

• slightly flattened anteriorly and posteriorly

• begins as a continuation of the medulla oblongata

• in adults extends from foramen magnum to IV disc betwen L1 and L2 (may terminate at T12 or L3)

what protects the spinal cord?

• vertebrae

• associated ligaments and muscles

• spinal meninges

• cerebrospinal fluid

the spinal cord occupies only superior _______ of the vertebral column

2/3

the spinal cord is englarged in 2 regions for limb innervation

• cervical enlargement

• lumbosacral enlargement

cervical enlargement

C4-T1 brachial plexus

lumbosacral enlargement

T11-L1 lumbar and sacral plexus

spinal meninges

• three different laters:

  • dura

  • arachnoid

  • Pia

• membranes and CSF that surround, support, and protect the spinal cord and cauda equina

cauda equina

• sacral and coccygeal nerves

• “horse tail”

what are the three layers of the meninges?

• dura mater

• arachnoid mater

• pia mater

dura mater

• first layer, most dense

• composed of tough, fibrous elastic tissue is the outermost covering

• forms external layer of dural sacs

• adheres to the margin of the foramen magnum of the skull where it is continuous with cranial dura mater

• anchored inferiorly to coccyx by filum terminale

• separated from periosteum by vertebrae by extradural or epidural space

• extends into the intervertebral foramina and along the dorsal and ventral nerve roots and spinal ganglia to form dural root sleeves

• those sleeves adhere to the periosteum lining the interveterbral foramina and end by blending with the lining of the spinal nerves

dural sac

• spinal cord to the L3

• long tubular sheath that is free within the vertebral canal

arachnoid mater

• second layer

• Delicate, avascular membrane composed of fibrous and elastic tissue that lines the dural sacs

• separated from the dura mater by a “potential” (if there are blood or extra fluid) space called the subdural space

• covers the spinal nerve roots and spinal ganglia and blends with sheath of spinal nerves

• separated from the pia mater by the subarachnoid space, but the two laters are connected by the arachnoid trabeculae

pia mater

• innermost covering membrane of spinal cord

• composed of two fused layers of loose connective tissue that adhere closely the the surface of the spinal cord

• covers the roots of spinal nerves and spinal blood vessels and unsheathes the anterior spinal artery

• inferiorly continues as the filum terminale and attaches to the coccyx

denticulate ligament

• spinal cord suspended in the dural sac by a saw-toothed ligament on each side

• consists of pia mater attached by 21 toothlike processes and extend from the foramen magnum to an area between T12 and L1 nerve roots

subarachnoid space

• located between arachnoid and pia mater

• contrains cerebrospinal fluid

• space is largest in the ingerior part of the vertebral canal where CSF forms lumbar cistern that surround the NR comprising the caude equina and filum terminale