Vertebral Column/Canal Flashcards
Vertebral Column and Canal Contents
Four Functions of the Vertebral Column
Protection
Support of Body’s Weight
Movement/Locomotion
Posture
List vertebral types, number, and curvature
C7 Cervical Concave Posteriorly (lordoses)
T12 Thoracic Concave Anteriorly (kyphoses)
L5 Lumbar Concave Posteriorly (lordoses)
S5 Sacral (Fused)-Concave Anteriorly (kyphoses)
C4 Coccyx (Fused)
Describe what makes C1 and C2 unique?
C1 (Atlas) has no body or spinous process, lateral masses are weight bearing, grooves for the vertebral artery, facet for dens of C2
C1 structure allows for flexion and extension of the head
C2 (Axis) has a dens (the inherited body of C1) and facet for atlas
C2 structure allows for rotation of the head
Describe the difference between the cervical, thoracic, and lumbar vert.
Cervical vert
bifid process, transverse foramen for vertebral artery, uncinate process(lipping)
Thoracic Vert.
Spinous process, larger vert. body, transverse process facets, articulated facets for ribs (full or demi)
Lumbar Vert.
Larger vert. body, mammillary processes, larger vert overall
Function of the intervertebral foramen
Allows structures to enter and exit the vertebral canal
there is space posteriorly between the vertebral arches in lumbar vert.
no space between thoracic vert. sit on top of each other tightly
Structure of the Sacrum and Coccyx
Sacral has 5 fused vert.
Coccyx has 4 fused vert.
Describe Pars interarticularis, Spondylolysis, and Spondylolithesis
Pars interarticularis is the column of bone connecting the superior and inferior articular processes of vert.
Spondylolysis is a defect or fracture in the pars interarticularis
Spondylolithesis is a dislocation between adjacent vertebrae following Spondylolysis
Spinal Stenosis
Spinal Stenosis is the narrowing of the vertebral foramen
Extreme cases may cause extreme pain or numbness as the spinal cord becomes pinch
Joints of the Vertebral Bodies
Intervertebral and Uncovertebral joints
Intervertebral Joint or symphysis joints are connected by the intervertebral discs and ligaments
Uncovertebral joints are located between the uncinate process of C3/4 to C6/7
A common site for osteophyte(spur formation)
Describe Disc Herniations
A disc herniation is a protrusion of the nucleus pulposus into or through the annulus fibrosus
They usually extend posterolaterally where annulus fibrosus is relatively thin
They tend to cause nerve compression
Joints of the Vertebral Arches
Facet (Zygapophysial) Joints
Facet joints are a plane synovial joint that determines the movement of the body
In cervical region allows flexion and extension
In thoracic region facilitates rotation
In lumbar region they limit range of motion
Important Ligaments of the Vertebral Column
Anterior Longitudinal
Posterior Longitudinal (tectorial membrane)
Interspinous
Supraspinous
Nuchal
Intertransverse
Ligamentum flava
Anterior Longitudinal maintains the stability of IV joints and limits extension
Posterior Longitudinal prevent hyperflexion of the neck
Interspinous and supraspinous limit flexion
Nuchal is an attachment site for many muscles
Intertransverse limits lateral flexion
Ligamentum flava prevents abrupt flexion and damage to vert.
Atlanto-occipital and Atlanto-axial Joints
Atlanto-occipital is a condyloid synovial joint bet atlas and occipital bone
Atlanto-axial Joints is a plane or pivot synovial joint bet atlas and axis vert.
Cruciate and Alar ligaments of the craniovert. joints
Cruciate ligament holds the dens of C2 in position
Alar ligament limits excessive rotation of the head
Both ligaments maintain the stability of the head and prevent injury due to excessive movement
What does each of these become?
Posterior longitudinal ligament
Anterior longitudinal ligament
Ligamentum Flavum
Posterior longitudinal ligament becomes the tectorial membrane
Anterior longitudinal ligament becomes the anterior atlanto-axial membrane and the anterior atlanto-occipital membrane
Ligamentum Flavum becomes the posterior atlanto-occipital membrane
What is the difference between Kyphoses and Lordoses?
Kyphoses indicates an anterior concave of the spine
Lordoses indicates a posterior concave of the spine
Cervical and Lumbar have secondary or lordoses curvature (concave posteriorly)
The thoracic and sacral region have primary or Kyphoses curvature (concave anteriorly)
Venous Drainage of the Vertebral Column
Basivertebral and Intervertebral veins
Spinal veins form internal and external venous plexuses
Basivertebral veins form within the vertebral bodies and drain into the internal venous plexus
Intervertebral veins receive drainage from the spinal cord veins and vertebral venous plexuses and drain themselves into the vertebral veins of the neck and segmental veins of the trunk
What are the components of the vertebral canal?
Spinal cord
Spinal meninges
Spinal vasculature
Spinal nerve roots
Spinal Cord Function
The spinal cord is the major reflex center and conduction pathway between the body and brain
Spinal cord grey vs white matter
The gray matter is the central region of the spinal cord that consists of interneurons and motor neurons
The white matter is the surrounding region of the spinal cord that consists mainly of myelinated axons that connect the grey matter and carry nerve impulses.
What are areas of the spinal cord enlarged and why?
Cervical enlargement at C4/5-T1
Lumbosacral enlargement at L1/2-S3
Enlargement of the grey matter occurs in these areas to accommodate the neural machinery necessary to operate the limbs
Define the function:
Conus medullaris
Filum terminale internum/externum
Cauda equina
Conus medullaris is the most distal end of the spinal cord (terminates around L1/2)
Filum terminale provides longitudinal support of the spinal cord
– Internum consists of neural tissue, connective tissue, and neuroglial tissue covered by pia mater.
– Externum closely adheres to the dura mater and attaches to the coccyx
Cauda equina is a bundle of spinal nerves and spinal nerve rootlets (horsetail resemblance)
T1 vs T2 Weighted MRIs
In T1 the CSF is dark (hypointense)
In T2 the CSF is light (hyperintense)
Spinal Meninges
List the Superficial to Deep Meninges
Surround, support, and protect the spinal cord and nerve roots, contains CSF
Superficial to Deep:
Dura mater
Arachnoid mater
Pia mater
Dura Mater
The tough outer covering of the spinal cord or the membrane that envelops the arachnoid mater
Spinal dural sac surrounds the spinal cord and the cauda equina. It contains CSF which provides nutrients and buoyancy to the spinal cord
Dural root sheaths are an extension of the dura mater that surrounds the spinal nerves roots (extend laterally)
Arachnoid Mater
The delicate, avascular membrane lining of the dural sacs and dural root sheaths.
It encloses CSF-filled subarachnoid space
Arachnoid trabeculae
the delicate strands of connective tissue spanning the subarachnoid space connecting the spinal arachnoid and pia matter
Pia Mater
Denticulate ligaments
Thin, transparent innermost membrane of the meninges enveloping the brain and spinal cord
Denticulate ligaments (pia mater) that anchors the spinal cord in the center of the vertebral canal
Spinal Cord Spaces
Epidural
Dural-arachnoid
Subarachnoid space
Epidural Space
Located between the bone and dural sac and filled with internal vertebral venous plexus and fat
Dural-arachnoid space
potential space in injured patients when dural and arachnoid membranes separate (not present in healthy patients)
Subarachnoid space
Located between arachnoid and pia mater and filled with CSF
Myelogram
Uses contrast to visualize specific spinal structures
Lumbar Puncture Procedure
Procedure to withdraw CSF from spinal canal
Patient is asked to flex back (curl spine forward)
Needle inserted into dural sac (lumbar cistern) usually between L3 and L4 in adults
(L4 is about level with inter-illiac crest line)
At or below L4 in children
Adult vs Newborn Spinal Cord Location
Longitudinal growth of the spinal cord lags behind that of the vertebral column during development
conus medullaris (distal end of the spinal cord) ends around L3 in a child, L1/2 in adults
Spinal Cord Arterial Supply
Anterior spinal artery
Located in anterior median fissure, branches off from the vertebral artery and gives rise to sucul arteries
Posterior spinal arteries
Located in posterolateral sulci, branches off of either vertebral or posterior inferior cerebellar artery
By themselves, the anterior and posterior spinal arteries supply only the short superior part of the spinal cord
Segmental spinal arteries
Arise from ascending cervical, deep cervical, vertebral, posterior intercostal, and lumbar arteries just depending on their location
Enter vertebral canal via intervertebral foramina
Anterior and posterior radicular arteries
Anterior and posterior segmental medullary arteries
radicular arteries supply blood to spinal nerve roots
segmental medullary arteries supply blood to the cervical and lumbosacral enlargements areas of the spinal cord
Great anterior segmental medullary artery
Reinforces circulation to 2/3 of the spinal cord
If this artery is narrowed or obstructed, the patient may lose all sensation and voluntary movement inferior to the level of impairment
Spinal Cord Venous Drainage
Internal vertebral venous plexus
Internal vertebral venous plexus are valve-less veins are located in epidural space
They communicate with intracranial veins and dural venous sinuses
clinically importance of internal vertebral venous plexus
a potential route on infection
Spinal Nerves
C1-C7 emerges superior to vert.
C8 spinal nerve emerges inferior to C7 vert.
Thoracic, Lumbar, Sacral spinal nerves emerge inferior to its corresponding vert.
Disc Herniation Rule of Thumb for PLL
Cervical and lumbosacral disc herniations involve the nerve root that corresponds to the lower adjacent vertebrae
Three Types of Disc Herniation
Posterolateral
Most common due to posterior longitudinal ligament
Far lateral
Impingement of next higher nerve root
Central
At the level of cauda equine can impinge on nerve roots lower than the level of herniation
Structure and Function of
Anterior rootlets and root
Posterior rootlets and root
Posterior (dorsal) root ganglion (DRG)
Anterior (Ventral) ramus
Posterior (Dorsal) ramus
Anterior (ventral) rootlets and root
motor signals
Posterior (dorsal) rootlets and root
sensory signals
Posterior (dorsal) root ganglion (DRG)
House sensory neuron cell bodies
Anterior (Ventral) ramus
mixed signals from the anterior portion of body
Posterior (Dorsal) ramus
mixed signals from the posterior portion of body
Recurrent Meningeal Nerves
Each spinal nerve gives rise to 2-4 small recurrent meningeal (sinuvertebral) nerves
They reenter the intervertebral foramen to supply the dura, ligaments, intervertebral discs, and blood vessels with innervation
Cutaneous innervation
skin areas innervated by particular peripheral nerves
issue with a spinal nerve will affect its corresponding cutaneous innervation
Dermatomes
bandlike areas of skin innervated by sensory fibers from a single spinal nerve
issue with the spinal cord will affect the corresponding dermatome
Effect of Cervical Cord Lesion
C1–C3
C4–C5
C6–C8
C1–C3
no function below head level, unable to maintain respiration
C4–C5
quadriplegia, able to respiration
C6–C8
loss of lower limb function combined with upper limb function
Effects of Thoracic/Lumbar Cord Lesion
T1–T9
T10–L1
L2–L3
T1–T9
paraplegia
T10–L1
some thigh muscle function
L2–L3
retention of most leg muscle function
Laminectomy
Removal of one or more spinous processes and the adjacent supporting laminae to gain access to vertebral contents
used to relieve pressure on the spinal cord or nerve roots caused by a tumor, herniated IV disc, or bony hypertrophy
