Vertebral Column Flashcards
How many vertebrae are there?
33 - 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused sacrum), 4 coccygeal (coccyx)
What does it mean to have primary curvature and what two regions do?
Same curvature as embryonic development, concave ventrally (anteriorly). The thoracic and sacral regions have this. Lumbar and cervical regions are the opposite (secondary curvature)
What is the vertebral body vs the vertebral arch?
Body - provides support and weight-loads of the body (discs are between)
Arch - rest of vertebrae, surrounds spinal cord and has muscle attachments
What are the pedicles and lamina of a vertebrae?
Pedicle - between vertebral body and transverse process
Lamina - between transverse and spinous processes.
They make up the vertebral arch and come in pairs. They also form the vertebral foramen
What do the alignment of all vertebral foramen of the cervical, thoracic, and lumbar vertebrae + sacral canal form?
vertebral / spinal canal
Where do the superior and inferior articular processes come from?
Superior - bony processes from the lamina above the transverse process
Inferior - bony processes from the lamina below the transverse process.
They form synovial joints. This is true for all spinal cord levels through the lumbar
What forms the intervertebral foramen?
The inferior vertebral notch at the pedicle level of the upper vertebrae, and the superior vertebral notch at the pedicle level of the lower vertebrae
What is the vertebrae prominens?
CV7, the largest spinous process. It is the only cervical vertebrae that can be palpated, and forms the first prominence felt at the back of your neck.
What is unique about all 7 cervical vertebrae?
They contain transverse cervical foramen next to their vertebral body, in the transverse processes. C1-C6 accommodate paired vertebral arteries. On C7, it accommodates the auxiliary vertebral vein.
What makes it possible for the neck to rotate about its axis (left or right), anterior flexion, posterior extension, and lateral flexion?
The relatively thick intervertebral discs between C2-C7.
What is the atlas? What does it lack?
Atlas = CV1. Lacks a vertebral body as well as a true spinous process (posterior tubercule instead). The transverse processes are connected by the anterior and posterior arches, which have the tubercules on them.
What allows for the nodding “yes” head motion?
The superior articular surface of the atlas (CV1) forms a synovial joint with the occipital condyle of the cranium, allows for anterior flexion and posterior extension.
What is the axis? What is its distinguishing feature?
CV2, has a prominent dens “tooth-like” process
What is the function of the dens?
It is on the top of CV2, attaches inferiorly to the anterior arch of the atlas. It is the pivot point for the “no” head movement”. Dens is anterior
What are the vertebral foramen and body like in thoracic vertebrae
“Heart-shaped” - vertebral body
Foramen - smaller than the cervical and lumbar regions
The spinous processes become shorter and more hatchet like down the spine
What are costal facets or demifacets?
They are articulation surfaces for synovial joints with ribs that will be on all thoracic vertebrae. The costal facets are on pedicle, demifacets are half-facets and form articulations with the neighboring vertebrae’s demifacet.
What is a transverse costal facet?
Only on TV1-TV10, they are articulations with the first 10 ribs via transverse processes, forming synovial joints.
How much movement does the thoracic level allow?
Anterior flexion and extension of the thorax, but less lateral rotation than the cervical region.
What shape characterizes lumbar vertebrae?
Kidney-shaped body. The superior and interior facets interlock to the lower levels, unlike cervical or thoracic vertebrae. Hatchet-shaped or quandrangular spinous processes.
What is the implication of the lumbar spinal cord level having interlocking articular facets?
You can still have flexion and extension but no LATERAL rotation.
What is the function of the fused sacral vertebrae?
Fuses during development, gives strength and stability to pelvis in pelvic girdle via sacroiliac joint. The bodies actually decrease in mass from SV1 to SV5.
What is the sacral canal?
Formed by the fusin of the vertebral canal from SV1-SV3, opens at SV4 level posteriorly at the sacral hiatus
What makes the sacral hiatus?
Incomplete closure of the lamina of SV4 and SV5. It is easily palpated by the presence of two lateral bony ridges called sacral horns at the SV5 level
How does SV1 interlock with LV5?
Superior articular facet interlocks with inferior articulating process of LV5.
What forms the sacroiliac joint?
The articular surfaces lateral on the posterior side of the sacrum.
What are the ala and promontory?
Promontory - name for the vertebral “body” of the sacrum at the top of SV1 which tapers
Ala - Wing-like structures of sacrum located laterally to the promontory
What makes up the intervertebral discs and how many are they?
23 discs, located inferiorly from CV2 to LV5. They have a central gelatinous portion (nucleus pulposus), and a ring of fibrous tissue (anulus fibrosus). Discs are ossified in sacral levels and absent in coccyx
How is an intervertebral disc held in position
Anulus fibrosus fuses with the annular epiphysis on either side of the vertebral bodies (superior and inferior)
What is the embryological remnant of a tail?
The 4 fused coccyx vertebrae
What is the anterior longitudinal ligament?
Originates at the anterior rim of foramen magnum (occipital bone) and anterior tubercule of CV2, running down anterior surface of CV2 to SV1 vertebral bodies. Broadens as it descends.
Where does the posterior longitudinal ligament run?
Posterior surface of the vertebral bodies from CV2 to SV1, merges with tectorial membrane!!! at top of CV2 level. It narrows as it descends.
What is the supraspinous ligament?
Ligament extending from spinous process of CV7 to SV3, continuous with free border of ligamentum nuchae superiorly
What is the ligamentum nuchae?
Free border - Continuous with supraspinous ligament, extends from external occipital protuberance to spinous process of CV7
Superior border - attaches to the occipital bone along the external occipital crest to the base of the foramen magnum
Attach border - attachment to spinous processes from CV2-CV7, as well as base of foramen magnum and posterior tubercule of CV1
What are interspinous ligaments?
Ligaments that attach between the adjacent spinous processes between CV2 and SV1
What is ligamentum flavum?
Pairs of elastic membranes that attach lamina between CV1 and SV1, but do not meet in the midline.
What is the posterior atlantooccipital membrane? Anterior?
fibrous, non-elastic membrane that replaces the ligamentum flavum between the cranium occipital bone and CV1. Stretches to posterior arch on both sides.
Anterior stretches from cranium to anterior arch on both sides
What is the function of the cruciate ligament?
Prevents posterior displacement of dens process into spinal canal, located beneath tectorial membrane and holds atlantoaxial joint
What is the function of the alar ligament?
Paired ligaments, Attach to dens and insert at 100 degrees angle to eachother to the base of the occipital bone. Prevents over-rotation of the head
Where are the iliolumbar ligaments?
Arise from transverse processes of LV4-5, insert on anterior surface of iliac crest
What are the sacroiliac ligaments?
Provide support for the synovial joint between the sacrum and the ilium at the anterior and posterior surface of SV1-SV4 levels
What is a zygapophyseal joint?
Synovial joint between interior articular process of superior vertebrae, and superior articular process of neighboring inferior vertebrae
What are the atlantooccipital joints?
Paired synovial joints between occipital condyles and superior articular processes of CV1 (the atlas)
What is the atlantoaxial joint?
The synovial joint between dens process of axis and anterior arch of atlas (strength provided by cruciate ligament)
What are the three meninges layers?
Dura mater (outer), arachnoid mater (middle), and pia mater (innermost)
Where does the spinal dura mater extend to? What accompanies it?
Continuous with dura mater of brain, extends from foramen magnum to SV2. Also exits spinal nerves to form epineurium
Accompanied by arachnoid mater, which ends at same point
What forms the subarachnoid space and what’s in it?
Between the arachnoid mater and the pia mater, there is cerebrospinal fluid
What is the pia mater?
Innermost layer of three meninges, firmly attached to spinal cord and its nerve rootlets
What are the denticulate ligaments?
Ligaments that come from pia mater (20 or so per side) and pierce arachnoid mater, anchoring into dura mater. They hold the central positioning of the spinal cord within the subarachnoid space
What is the filum terminale?
A ligament of the pia mater, it is a fiber that originates at terminal end of the spinal cord (conus medullaris) and attaches to the base of the dural sac at SV2 level.
What is the coccygeal ligament?
The extension of the filum terminale after it acquires an outer layer of dura. Attaches to the tip of the coccyx
What is the function of the anterior and posterior sacral foramina?
Passage of spinal nerves SN1-SN4 (Ventral and dorsal rami)
How many pairs of spinal nerves are there?
- There are 8 cervical, but only 1 coccygeal
What is the conus medullaris?
The conical tapering region of the spinal cord. It ends around LV1-LV2
What is the relationship between vertebrae and exiting of spinal cord levels?
C1 to C7 exit superior to the corresponding vertebrae
C8 exits inferior to C7 and superior to T1
All remaining nerves exit inferior to corresponding vertebrae
What are the spinal cord enlargements?
Areas in the cervical and lumbar / sacral regions are enlarged to form the brachial plexus / plexus for the legs
What is the lumbar cistern?
It is a reservoir starting at the conus medullaris and ending at SV2. It is lined by the arachnoid mater and retains CSF. Contains the filum terminale (pia mater) as well as the group of nerves known as the cauda equina. Safe site to obtain CSF
What is the cauda equina?
The dorsal and ventral rootlets for the lower lumbar, sacral, and coccygeal nerves contained in the lumbar cistern.
What supplies blood to the cervical region?
The vertebral arteries, the ascending cervical and deep cervical arteries.
How is blood to the spinal cord generally supplied?
Regionally. Vessels run in subarachnoid space
What supplies blood to the thoracic region?
intercostal arteries, and the medullary / radicular arteries.
What is the great medullary artery?
Also known as the artery of Adamkiewicz, it is formed from the left subcostal artery at the TV12-LV1 level. Supplies most of the blood to the lumbar / sacral region.
Where is secondary blood supply to the lumbar region provided by?
Most come from great medullary artery. Secondary comes from lumbar or lateral sacral arteries
What are the numbers of the spinal arteries?
Region blood supply. Anterior there is one located medially. Posteriorly there are a pair of spinal arteries
Where do the vertebral arteries arise from and where do they go?
They are the first branch off the subclavian artery at the C7 level, and ascend through the transverse cervical foramen. They make a sharp turn at posterior arch of CV1, pierce the posterior atlantooccipital membrane, the dura, and arachnoid mater. They pass into the foramen magnum and combine to form the basilar artery in the subarachnoid space.
What is kyphosis?
Hunchback - increased curvature of thoracic vertebrae due to erosion anteriorly. Common in elderly
What is lordosis?
Swayback - results from abnormal increase in lumbar curvature. This pushes the pelvic gurdle posteriorly
L - LUMBAR
What is scoliosis?
Any lateral curvature of vertebral column, usually hereditary and 7 times more common in women. Manifests during pubery
What is spina bifida?
Lamina do not fully fuse, creating an opening in the vertebral canal
What is spondylolisthesis?
Most common around LV5 displaced relative to SV1, it is a dorsal or ventral displacement of the body that does not allow articular facets to touch between the vertebrae. Can lead to herniated disc, pinched nerve, etc even though the longitudinal ligaments can stay in place.
What is a herniated disc? “slipped disc” even though the disc cannot actually split
Uneven compression on anterior half of disc causes nucleus polposus to be displaced posteriorly, and annulus fibrosus pushes posteriorly into the spinal cord, causing localized pain and possible loss of motor function. Most often spinal rootlets (laterally) rather than the cord since it is protected by the posterior longitudinal ligament
What is special about herniated discs in the lower thoracic and lumbar regions?
If you have a herniated disc between LV4 and LV5, your L4 can superiorly to the herniated disc and not be affected. However, the next nerve (L5) will have to cross this disc and be compressed against its lamina. Can affect multiple lower nerves.
Where do you normally do a lumbar cisternal puncture?
Between LV3-LV4 or LV4-LV5, into the lumbar cistern. Because the ligamentum flavum is not found in the midline (it is between the lamina, anteriorly / deep to the puncture), it will not be punctured. The tap is stabilized by supraspinous and interspinous ligaments
How is epidural anesthesia given?
Palpate between the sacral horns (cornua) and the spinous process of SV4 to find the sacral hiatus. Anesthesia injected into this hiatus will let the drug diffuse into the exiting spinal nerves (cauda equina) without piercing the dural (lumbar cisternal) sac
