Vertebral Column and Spinal Cord Flashcards
Joints of vertebral column
Craniovertebral Joints
1. Atlanto-occipital: between C1 and occipital
2. Atlanto-axial: C1 + C2
Joints of Articular Processes
3. Zygapophysial
Joints of Vertebral Bodies
4. Unconvertebral
5. Intervertebral
Intervertebral Joints
Between Intervertebral discs and the vertebral body
What is the intervertebral disc composed of?
-Annulus Fibrosus
-Nucleus pulposus
What is a herniation, and where is it most common?
When a portion of the nucleus pulposus is pushed through a weakened portion of the annulus fibrosis
-Herniation is most common posteriolaterally at L4-L5 and L5-S1, no PLL or ALL
Ligamenta Flava
Def: connects adjacent laminae of vertebrae
a. Limits flexion
b. Clinically significant (epidural)
Anterior Longitudinal Ligament (ALL)
anterior bodies and IV discs from skull to sacrum
a.Prevents hyperextension
(bigger one)
Posterior Longitudinal Ligament (PLL)
posterior bodies and IV disc from C2 to sacrum within spinal canal
a.Prevents hyperflexion
(smaller one)
Nuchal Ligament
provides attachment site for cervical muscles
a.Resists flexion
Supraspinous Ligament
connects tips of spinous processes
a.Limits hyperflexion
Intraspinous Ligament
connects adjacent spinous processes
a.Limits hyperflexion
“Whiplash” Injury
oA strain or muscle injury of the neck due to sudden hyperextension and possible hyperflexion as head rebounds
oPossible stretching or even tearing of anterior longitudinal ligament (ALL)
oPossible “facet jumping” or locking of cervical vertebrae due to arch dislocation
Neck Injuries
oIllegal face blocking causes hyperextension and will likely injure posterior portions of the vertebrae
oT11/T12 most common non-cervical break
Order of Spinal Cord Meninges
-Epidural space, dura mater, subdural space, arachnoid mater, subarachnoid space, pia mater
Epidural space
o Between dura mater and inner walls of the vertebra
o Contains far and blood vessels
Dura Mater
o Most external of the meninges
o Fuses with epineurium that surround that spinal nerves
Subdural space
o Separates the dura mater from the arachnoid mater
o This is a potential space
Arachnoid mater
o Located deep to the dura mater and subdural space
Subarachnoid space
o REAL space
o Filled with CSF
Pia Mater
o Adheres directly to the spinal cord
o Forms lateral extensions called denticulate ligaments
Suspend and anchor the spinal cord laterally to the dura mater
Spinal Cord
-Protected by vertebrae, ligaments, and muscles, spinal meninges, and CSF
-Continuation of the medulla oblongata
-Extends from foramen magnum to approx. T12-L3 in adults (Avg: L1)
-31 pairs of spinal nerves:
o Cervical (C1-C8)
o Thoracic (T1-T12)
o Lumbar (L1-L5)
o Sacral (S1-S5)
o Coccygeal (Co1)
-Cervical (C4-T1) and Lumbar (L1-S3) enlargement (significant number of motor neurons exiting
Sclerotome Resegmentation
8 cervical sclerotomes–> 7 cervical vertebrae, 8 cervical spinal nerve pairs
Anterior (ventral) root
contains only motor axons
Posterior (dorsal) root
contains only sensory axons
Dorsal Root Ganglion
contains cell body for sensory neurons
Spinal nerve
The anterior and posterior roots unite within intervertebral foramen to become a spinal nerve
Posterior (dorsal) ramus
a.Inn: Intrinsic (deep) muscles of the back
b.Carries sensory from the skin of the back
Anterior (ventral) ramus
a.Inn: anterior and lateral portions of the trunk (intercostal nn.) upper and lower limbs
b.Carries sensory from the associated skin
c.Larger than posterior
Arterial supply of spinal cord
-Vertebral and ascending cervical arteries (aa.)
-Major segmental aa:
oPosterior intercostal aa. In the thorax
oSubcostal and lumbar aa. In the abdomen
oIliolumbar, lateral and medial sacral aa. in pelvis
-Spinal arteries pass through the intervertebral foramina then divide into anterior and posterior branches
Venous drainage of spinal cord
-3 anterior and 3 posterior veins (vv.) run longitudinally: drains into internal vertebral plexus in epidural space
-Spinal veins (vv.) form internal and external venous plexus
-Plexuses communicate through the intervertebral foramina
-Spinal cord and vertebral venous plexus drain into intervertebral vein which drains to:
oVertebral veins in the neck
oSegmental veins in the trunk (posterior intercostal, lumbar, and sacral)
Conus medullaris
tapering inferior end of the spinal cord
Cauda equina
bundle of nerve roots running inferior to the spinal cord
Filum terminale
thin strand of pia mater that helps anchor the conus medullaris to the coccyx
Lumbar puncture
to obtain CSF
oDrawn from subarachnoid space, constantly being produced, L4/L5 (posterior iliac spines- PSIS as landmarks for lumbar puncture)
oNo agent in here- if put in will be gone ASAP as it will be pumped out quickly
Epidural
injection of anesthetic agent into the epidural space, where there is direct effect on the spinal nerve roots and cauda equina
oEpidural space is fat filled and includes spinal nerve segments, able to keep a drug present for awhile
Laminectomy
-Option to relieve spinal stenosis
-Relieves pressure within intervertebral column
-Most common cause of narrowed vertebral column is bony outgrowths
