Spine Lecture Questions Flashcards
What are the functions of the spine?
-Support the body’s weight
-Transmit forces
-Carry & positioning of the head
-Brace & help maneuver the upper limbs
What are the primary curvatures of the spine? What kind of curvature is it? When do they develop?
-Thoracic curvature: kyphosis
-Sacral/coccygeal curvature: kyphosis
-Present at birth
What are the secondary curvatures of the spine? What kind of curvature is it? When do they develop?
-Cervical curvature: lordosis
-Lumbar curvature: lordosis
-Cervical develops when babies start lifting their head
-Lumbar develops upon walking and sitting up
Why do we need secondary curvatures?
-After birth, we need secondary curvatures to counteract the primary ones so that we are able to stand up straight
-They bring the center of gravity into a vertical line so we can be bipedal
What do extrinsic back muscles do?
Move the upper limbs & ribs
What do intrinsic back muscles do?
Maintain posture & move vertebral column (flexion, extension, lateral flexion, rotation)
What does the spine protect?
-The CNS (brain and spinal cord)
-The PNS (cranial and spinal nerves)
How many cervical vertebrae are there?
7
How many thoracic vertebrae are there?
12
How many lumbar vertebrae are there?
5
How many sacral vertebrae are there?
5, but they are fused
How many coccygeal vertebrae are there?
3-4, but they are fused
What is the function of the body of the vertebrae?
Receives weight & provides mobility
What does the vertebral arch form? What does it do?
-It forms the vertebral canal
-It restricts some movement
What are the facet joints? What do they do?
-The articulation between two vertebrae
-They restrict and guide movement
What is a symphysis?
-A major joint between vertebrae
-Each symphysis includes an intervertebral disc
What makes up an intervertebral disc?
-Annulus fibrous, which is a ligament like structure that surrounds the nucleus pulposus and holds it together
-Nucleus polposus, which is a gellatenous like structure that helps the spine resist compression
What happens when the annulus fibrous degenerates?
Discs can be very easily herniated w/ degeneration of the annulus fibrous, because it can no longer properly hold the nucleus polposus in place
What are the extrinsic back muscles innervated by?
Anterior rami of spinal nerves
What are the intrinsic back muscles innervated by?
Posterior rami of spinal nerves
Where is the cerebrospinal fluid (CSF) located?
In the subarachnoid space
How many pairs of spinal nerves are there?
31 total
-8 cervical
-12 thoracic
-5 lumbar
-5 sacral
-1 coccygeal
What is the difference between rami and roots?
-Rami have both motor & sensory components, while roots do NOT
Why is the cervical vertebral foramen larger than the thoracic & lumbar?
Because the cervical vertebrae houses the cervical & brachial plexuses
What level does the spinal cord stop at? Why does it not go all the way down?
-The spinal cord stops at L1, but could be as high as T12, or as low as L2
-This occurs because the spinal cord grows a lot slower than the vertebrae
What is the cauda equina?
Formed by lumbar and sacral nerve roots
Where do the spinal nerves exit the vertebral column?
Through the intervertebral foramen that is formed by adjacent vertebral arches
How much movement can occur in the cervical vertebrae?
-60 degrees of flexion
-75 degrees of extension
-45 degrees of lateral flexion
-80 degrees of rotation
What is the incidence of cervical pain?
-25-70% of people will experience neck pain
-30% will develop chronic pain
What are the general characteristics of the cervical spine?
-Small size
-Spinal process is short and bifid (except C1 and C7)
-Presence of foramen in each transverse process (foramen transversarium)
Why is there a foramen in the transverse processes of the cervical vertebrae?
Because they house the vertebral artery
What level does the vertebral artery enter the vertebral column? How much blood does the vertebral artery supply to the brain?
-Enters at C6 and exits at C1 to go into the skull
-Supplies 15% of blood to the brain
What happens if someone’s vertebral artery enters the vertebral column at C7?
-It is more taught/tight, so it can cause headaches, dizziness, ataxic gait
What portions of the brain does the vertebral artery supply?
-Upper spinal cord
-Cerebellum
-Posterior part of brain
Where does the vertebral artery branch off of?
Subclavian artery
What are the 2 parts of the cervical vertebrae?
-Upper cervical/cranio-vertebral region (occipital condyles, C1 & C2)
-Lower cervical region (C3-C7)
Where does 50% of rotation occur?
Upper cervical region (C1 & C2)
What joint allows us to nod our heads?
OA joint (occipital-atlanto joint)
What are unique characteristics of C1 (Atlas)?
-Shaped like a ring
-Has no vertebral body or spinous process
-Has 2 large lateral masses that have a vertical alignment under each occipital condyle
What are the lateral masses in C1 connected by?
The lateral masses are connected by an anterior & posterior arch that form the ring structure and creates large transverse processes for muscle attachments
What is the function of C1?
-Transfers weight of head to segments below
-Knodding bone (“yes” bone)
Why is there slack in the vertebral artery where it exits at C1?
To allow for rotation
What is the primary function of C2
-Provides motion for axial rotation (“no” bone)
-Transmits the combined load of head & atlas
What are the unique characteristics of C2 (Axis)?
-The anterior portion of the body extends inferiorly & a vertical projection (dens) arises from the superior surface of the body
-Has the dens
What is the dens?
-Odontoid process of C2
-Has an anterior facet for articulation with the anterior arch of the atlas & a posterior groove for articulation w/ transverse ligament
What is the posterior groove of the dens for?
For attachment of the transverse ligament
What is the alar ligament? What motion does it limit?
-It attaches the axis, from the superior region of the dens, to the border of the foramen magnum
-It limits head rotation
What happens to head rotation if the alar ligament is injured?
Head rotation will increase by 30% if the alar ligament is injured
What is the transverse ligament? What movement does it prevent?
-Ligament that attaches to the both sides of the inside of C1
-Keeps dens from sliding forward into the spinal cord/vertebral canal
What types of surfaces are found at the atlanto-occipital joint? What movement does it allow?
-Atlas has superior concave facets
-Occipital condyles are convex
-The shape of these two surfaces allows for nodding of the head
What are the craniovertebral ligaments?
-Posterior antlanto-occipital membrane
-Posterior atlantoaxial ligament
-Nuchal ligament
-Alar ligament
-Transverse ligament (cruciate)
-Superior longitudinal band (cruciate)
-Inferior logintudinal band (cruciate)
What ligaments keep the transverse ligament in place?
-Superior longitudinal band
-Inferior longitudinal band
What are the attachments of the superior longitudinal band?
-Transverse ligament
-Occipital bone
What are the attachments of the inferior longitudinal band?
-Transverse ligament
-Body of C2
What is the tectorial membrane? Where does it attach?
-Continuation of the posterior longitudinal ligament
-Covers the dens & cruciate ligament
-Inserts at the anterior rim of the foramen magnum
What percentage of axis fractures are dens fractures? Why does fracture of the dens occur more often than a tear of the transverse ligament?
-40% of axis fractures are fractures of the dens
-The dens is fractures more often then the transverse ligament is torn because it is stronger than the dens
Why does a fracture higher up on the dens cause necrosis while a fracture lower on the dens, closer to the body, not?
-A fracture higher on the dens will be covered by the transverse ligament which would cut off the blood supply
-A fracture lower down would heal since the blood supply could get to it
Is a fracture of the dens or rupture of the transverse ligament more dangerous?
-Rupture of the transverse ligament is more dangerous because it keeps the dens from moving forward into the spinal cord
-If the dens is fractured, it is still held in place by the transverse ligament
What happens to the transverse ligament in some people with Down Syndrome?
20% of people with down syndrome have laxity in their transverse ligament
What is atlantoaxial instability (AAI) in individuals with Down Syndrome?
-Affects 10-20%
-Condition is mostly asymptomatic
-Lower cervical lordosis
-Causes by laxity in transverse ligament
What are normal anterior atlanto-odontoid distances?
-Males is ≤ 3mm
-Females is ≤ 2.5mm
How do ruptures of the alar ligament occur? What will be an objective sign of alar ligament rupture?
-Combined flexion and rotation of the head may tear one of the alar ligaments
-A rupture of the alar ligament will increase ROM by 30%
What population are alar ligament ruptures the most common in?
American football players
What is a unique joint of cervical vertebrae? What is the function?
-They have uncinate processes
-The uncinate processes help provide stability and guide movement
-Prevents segments from sliding anteriorly or laterally
-Limits sidebending
What are some other unique characteristics of the cervical vertebrae?
-Foramen transversarium (foramen in the transverse processes for vertebral artery)
-Anterior & posterior tubercles on the transverse process
What is the anterior tubercle on C6 called?
Carotid tubercle
What is C7 also called and why?
Also know as the “vertebral prominens” because it has the most prominent spinous process of the cervical vertebrae
How common is an extra rib? Where does it attach to?
-6% of people have an extra pair of ribs
-It is attached to C7
What are the main function of the sub-occipital muscles?
Extend and rotate the head at the atlantoaxial joint
What nerve is the posterior ramus of C1 nerve root?
Suboccipital nerve
What is the vascular supply of the suboccipital muscles?
Branches of vertebral and occipital arteries
What makes up the sub-occipital triangle?
-Medial border: rectus capitis posterior major
-Lateral border: obliquus capitis superior
-Inferior border: obliquus capitis inferior
What muscle of the suboccipital muscles is not part of the suboccipital triangle?
Rectus capitis posterior minor
What structures pass through the suboccipital triangle?
-Vertebral artery
-Suboccipital nerve
What muscle is attached to the dura mater? What happens if this muscle is tight?
-Rectus capitis posterior minor
-If it is tight, it can cause a disruption to the normal CSF fluctuations
-CSF will always be flowing into the brain, which can cause extra pressure in the brain causing headaches
What are the main functions of the thoracic region?
-Provides a stable basis for muscles to control the craniocervical region
-Protection of intrathoracic organs
-Mechanical allows for breathing, helps create pressure differences
What is unique about the thoracic vertebrae?
It has costal facets for the ribs to attach
How many joints are there in the spine?
364 joints
How many articular facets do thoracic vertebrae have?
10 each
Where does the ribs also attach to on the thoracic vertebrae?
As they curve posteriorly, they attach to the transverse process
What are the atypical thoracic vertebrae? Why are they atypical?
-T1, T11, and T12
-They are atypical because only articulate with 1 rib instead of 2
What is different about T10?
It only have a superior articular facet for a rib and no inferior
What connects the ribs to the sternum?
Costal cartilage
Does T1 articulate with rib 2?
-Yes, but barely
-It has a partial costal facet for rib 2
How prominent is the T1 spinous process?
Just as prominent as C7
What is unique about ribs 11 and 12?
They do not form articulations with the transverse processes
Which of the thoracic vertebrae are very similar to the lumbar spine?
T11 and T12
What are the joints in the thoracic cage?
-Costovertebral joints
-Costotransverse joints
What do the costovertebral joints allow the ribs to do?
-Rotate around their longitudinal axis
-Elevate and depress relative to the vertebral column
Why are the lower ribs able to elevate and depress more than the upper ribs?
Because there is more costal cartilage, which allows the ribs more space to move
What is the intraarticular ligament?
The ligament that connects the head of the rib to the intervertebral disc & separates into two different synovial compartments
How are the costotransverse joints stabilized?
-Costotransverse ligaments (medial)
-Lateral costotransverse ligament (lateral)
What does the costotransverse ligament do?
It connects the transverse processes to the rib below
What muscles are in the superficial group of back muscles?
-Trapezius
-Latissimus dorsi
-Rhomboids
-Levator scapulae
What muscles are in the intermediate group of back muscles?
-Serratus posterior superior
-Serratus posterior inferior
What is the blood supply to the serratus posterior superior/inferior?
Intercostal arteries
What muscles are involved in forced respiration during high intensity exercise?
Serratus posterior superior/inferior
What muscles are in the deep group of back muscles?
-Multifidi
-Rotatores
-Intrinsic muscles
What is one of the most distinct characteristics of the lumbar spine?
They have large vertebral bodies
In largest to smallest, what are the sizes of the vertebral foramens of the cervical, thoracic, and lumbar spine?
-Cervical
-Lumbar
-Thoracic
What direction are the facet joints in the lumbar spine?
-Vertical
-Inferior facets directed anterolaterally
What is the pars interarticularis?
-A region of the lamina located between the facet joints
Which lumbar vertebrae are typical?
L1-L4
What is unique about the lumbar vertebrae?
-They have accessory processes that come off the transverse process
-Mamillary processes
What is the function of the accessory processes on the lumbar vertebrae?
Provide attachments for the intertransversarii laterales muscles
What is the function of the mammillary processes on the lumbar vertebrae?
Provide attachment for the multifidi & intertransversarii mediales muscles
Why is L5 vertebrae atypical?
-It has a taller body anteriorly
-The taller body is responsible for the lumbosacral angle (LSA) between the axis of the lumbar vertebrae and the sacrum
What are the major nerves in the lumbar plexus?
-Iliohypogastric
-Ilioinguinal
-Genitofemoral
-Femoral
-Obturator
-Inferior gluteal
-Superior gluteal
What is the anterior longitudinal ligament? What is its function?
-Ligament that is anterior to the vertebral bodies
-Limits extension
What is the posterior longitudinal ligament? What is its function?
-Ligament that is posterior to the vertebral bodies
-Limits flexion
What is the ligamentum flava? What is its function?
-Ligament that is on each side of the inside surface of the lamina
-Guides the joints
-Suspends the column to help maintain upright w/ minimal energy needded
What is the most elastic ligament in the body?
Ligamentum flava
What is the supraspinous ligament? What is its function?
-Ligament on the spinous processes from C7-coccyx (continuation of ligamentum nuchae)
-Limits flexion
What is the intertransverse ligament? What is its function?
-Connects the transverse processes from C1-S1
-Limits side bending
What are the iliolumbar and lumbosacral ligaments? What is their function?
-2 bands that extend from the tip & border of the L5 transverse process to connect the lumbar spine to the sacrum & ilium
-Function is to stabilize L5 (resist flexion, extension, rotation, and side bending)
What is spondylolisthesis? Where does it often occur? How is it classified?
-It is when there is a stress fracture at the pars interarticularis and forward sliding of the vertebrae
-Often occurs in the lumbar spine since it takes heavier loads than other regions of the spine
-Grade I: 25% slippage
-Grade II: 25-50% slippage
-Grade III: 50-75% slippage
-Grade IV: 75-100% slippage
What are the causes/risk factors of spondylolisthesis?
-Usually occurs in adults over 50
-Abnormal wear and tear of the cartilage (arthritis)
-Common in L4/L5 and L5/S1
-Fractures in the parts interarticularis (can happen in weightlifting, gymnastics, and football)
What are common causes of abnormal spinal curvatures?
-Developmental anomalies
-Pathological processes such as osteoporosis
What are common abnormal spinal curvatures?
-Excessive thoracic kyphosis
-Excessive lumbar lordosis
-Scoliosis
What is excessive thoracic kyphosis typically associated with? What is the average degrees of normal kyphosis?
-Osteoporosis
-42 degrees
What can excessive thoracic kyphosis cause?
Significant reduction in pulmonary capacity
What is excessive lumbar lordosis typically associated with?
-Weakened anterolateral abdominal muscles
-Obesity
What are common causes of scoliosis? What population is it more common in?
-80% of structural scoliosis is idiopathic, and occurs without any other health conditions
-More common in females aged 10-15
What is a laminectomy? What is the objective of it?
-Surgical excision of one or more spinous processes
-Objective is to gain access to the vertebral canal and posterior spinal cord
What are common clinical indications of laminectomy?
-To relieve pressure on the spinal cord and nerve roots
-Pressure could be caused by tumor, herniated disc, or bony hypertrophy
