Vertebral Column & Back Flashcards
What are the 5 functions of the vertebral column?
- Carries + protects spinal cord + nerves
- Provides support to thoracic/rib cage
- Transfers weight from upper body to lower limbs
- Shock absorbing
- Muscle attachment point
In order from top to bottom, list the vertebral regions.
7x cervical (C1-C7) 12x thoracic (T1-T12) 5/6x lumbar (L1-L5/6) 5x sacral (S1-S5) Coccyx
How many cervical spine nerves are there?
8
What is unique about the sacral vertebral bodies?
They are fused together
What muscle is attached to the coccyx? What can therefore happen if you damage your coccyx?
Leviator ani so if you damage the coccyx, defecation + coughing for e.g. will become painful due to this muscles involvement in these processes
What structures make up the neural arch?
Pedicle Transverse process Lamina Spinous process Vertebral canal Articular facets (synovial joint attachment)
What does the vertebral canal of the neural arch house?
Spinal cord (enters L1-2) Spinal nerves
What is the function of the C1 vertebrae?
AKA atlas
Carries the weight of cranium
Joins to occipital condyle on base of skull + permits movement i.e. flexion + extension (nodding)
What in unique about the C1 vertebrae?
It has no body as C2 steals it in development
What part of C1 can you palpate in your neck?
Transverse process/lateral mass of axis via lateral neck deep to sternocleidomastoid
What is a Jefferson fracture? What can cause it?
Express compression can shatter the ring of atlas i.e. C1 vertebrae
Causes:
- Diving into shallow water + landing on head
- Jumping from height + landing on feet as force transmits up
How does the C2 (axis) provide rotation movement of the head and neck?
Odontoid process/peg (used to be the body of C1 in development) forms pivot joint with C1 (atlas) allowing axial rotation of head
Where in the spine could you attain a displacement fracture that was fatal? Below which level would you survive?
C1 is lethal as respiratory centre is at C3, 4 + 5
So below C6, you would survive
What can happen to the odontoid process of C2 in trauma i.e. car crash?
Can become fractured + impinge on the spinal cord as a result of rapid flexion/extension snapping it
What is whiplash? If its particularly bad what can happen?
Rapid hyperextension + flexion of neck e.g. in car crash causing ligamentous injury mostly
Hangman’s fracture if particularly bad
What are the typical structures features of cervical vertebrae?
Small bodies + holes/foramens (foramen transversarium) in short transverse processes where arteries pass up into cranial cavity to supply top of spinal cord, brain stem + lower part of brain
What do cervical vertebrae have small bodies?
Less weight at top of vertebral column
What would happen if the vertebral artery of the foramen transversarium of cervical vertebrae got compressed?
Transient loss of consciousness (could last longer) due to deficit in brainstem blood supply so would cause stroke-associated symptoms
What are the structural features of the thoracic vertebrae?
Progressively increase in size
Possess articulations for ribs i.e. articular facet + transverse process (synovial joint attachment)
Heart-shaped body
Spinous processes go from backwards pointing -> downwards pointing -> stumpy/square shape
Why do the bodies of the vertebrae increase in size when moving inferiorly?
More weight + force being applied to vertebral column as you move inferiorly
What are the holes called at every level of the vertebral column where spinal nerves escape?
Intervertebral foramen
What are the functions of the lumbar vertebrae?
Articulations aligned to prevent rotational movements so facet joints can balance mobility with stability (< mobility = > stability)
Allows them to cope with large forces + lots of weight
What are the structural features of the lumbar vertebrae?
Big kidney-shaped bodies
Spines squat + square
What is the function of the sacral vertebrae?
Transmit weight to pelvic girdle into hips, lower limbs + then the floor so there is more weight transmission at top than bottom
What are the structural features of the sacrum?
Wedge-shaped so its pushed between hip bones
Fused bodies decreasing in size inferiorly
Where do the ventral and dorsal rami exit the vertebral column?
Ventral rami of sacral nerves exit via anterior sacral foramen
Dorsal rami of sacral nerves exit via posterior sacral foramen
What is a ramus?
Branch of spinal nerves that is mixed sensory + motor that comes off of the ventral or dorsal roots
What can the sacral hiatus be used for?
A sacral epidural can be performed through this foramen
What can spinous processes be used for?
Palpated, counted + used to landmark key structures
What spinous process landmarks the apex of the lung? What must you be careful of here?
C7
In surgery/needle insertion, do not go too far forward at this level due to risk of pneumothorax
What spinous processes indicate the level of the transpyloric plane?
T12/L1
How is the vertebral column inherently stable with little muscle activity?
Connections of ligaments + joints
What is the function of intervertebral discs?
Resit compression + form a mobile joint
What are intervertebral discs? Where are they?
Secondary cartilaginous joints sitting between vertebral bodies present from beneath C2
Cartilage end plate on bone
Increase in thickness distally due to increased weight/force
What are the 2 parts of the intervertebral discs?
Annulus fibrosus (AF): layers of fibrocartilage
Nucleus pulposus (NP): rubbery central core (GAG) with high water content
What are zygapophyseal joints?
Simple synovial plane joints located between articular facets of adjacent vertebrae
Change orientation from superior -> inferior to decrease rotation available
What can go wrong with the zygapophyseal joints?
Dislocation displacing the vertebral bodies
What happens to the intervertebral discs if force is applied towards the back of the vertebral column?
Increased NP pressure which increases AF tension -> limits movement between vertebral bodies -> NP can rupture through AP = disc herniation posteriorly due to ligaments supporting the disc
Why is the invertebral discs clever at dealing with loads?
If you correctly list a heavy load in the correct position, the NP changes shape pushing the AF too allowing the vertebral bodies to move closer together stabilising the vertebral column
What is the function of the ligamentum flavum?
Helps vertebral column to return to upright position after being flexed
Where are the supraspinous and interspinous ligaments?
Supraspinous: on top of vertebral body
Interspinous: between vertebral bodies
What is the ligamentum nuchae useful for?
It can be palpated in the midline posterior to neck + used for surgery as it is a avascular + aneural plane
What are the 3 ligaments that support the vertebral column?
- Anterior longitudinal
- Posterior longitudinal
- Ligamentum flavum
Why is the posterior longitudinal ligament less supportive than the anterior one?
Relatively incomplete nature i.e. it has deficits + is narrow
Where are disc herniations most common in the vertebral column?
Posterior (posterior-lateral) because the posterior longitudinal ligament is not fully supportive of the discs
What can the ligamentum flavum be used for?
Pierced during lumbar puncture
Where is the ligamentum flavum?
Elastic ligament joining the adjacent lamina
What are the 2 types of spinal curvatures? Where do they occur along the spines?
- Lordosis (front): cervical (C) + lumbar (L)
2. Kyphosis (back): thoracic (T) + sacrum (S)
What happens to the spines curvature as you age and why?
Curve (more specifically lumbar lordosis) starts to occur as babies hold their head up -> fully developed in adulthood -> disc degeneration as you age leads to loss of curvatures
What occurs in the spine during pregnancy? Why?
Lumbar hyperlordosis because weight on ventral side of column has increased so curve becomes greater so that centre of gravity allows you to stand upright (reversible)
What are some problems that may occur with the spinal curvature?
Age-related kyphosis
Hyperloidosis
Scoliosis
Disease IV disc degeneration
What can happen if a patient lands too heavily on their feet?
Wedge compression fracture around T12-L1 as the shock cannot be absorbed by the vertebral column at this level
What is spondylolysis? What can be seen in an X-ray?
Fracture in region of articular facets without displacement perhaps due to stress on bone
Scotty dog sign: lower back pain but no other problems
Scotty dog sign wearing collar: bad sign
What is spondylolisthesis? What can cause it?
Lumbar vertebrae body slips + moves anteriorly (often accompanies spondylolysis)
Causes: traumatic, degenerative + dysplastic
The overall vertebral column movement equates to?
Sum of many small movements i.e. movement between 2 vertebral body’s adds up allowing the structure to be mobile + dynamic
What do the superficial vertebral column muscles do? What is their innervation?
Act on limbs
Supplied by brachial plexus + CN XI
What do the deep vertebral column muscles do? What is their innervation?
Includes splenius capiitis (acts on head), intrinsic erector spinae muscles + quadratus lumborum
Act on vertebrae + head to keep you upright
Dorsal rami of spinal nerves innervate it at each level
What is the nerve supply of the erector spinae muscles of the back?
Dorsal ramus given off by every spinal nerve supplies the muscle at the level closest to it
What is the sub-occipital triangle? What is its clinical relevance?
Sits under occiput on upper neck adjacent to splenius capitis
Entrapment of C2 + C3 dorsal rami nerves can cause posterior headache/sub-occipital neuralgia (transient or permanent)
How do the vertebral column muscles contract? Give a few examples.
Unilaterally or bilaterally
E.G. psoas major that help to support + move column
What does the psoas major do? What is the clinical relevance of this?
Attaches to + flexes femur
Hip flexion can exacerbate mechanical back pain
Other than the vertebral column muscles, what other muscles also aid in moving and supporting the vertebral column?
Abdominal wall muscles e.g. rectus abdominis, external oblique, internal oblique + transversus abdominis
Provide pneumatic support to vertebral column
What problems are weight lifters at increased risk of when increasing their intra-abdominal pressure?
Valsalva manoeuvre increases intra-abdominal pressure helping to maintain posture by putting air in front of vertebral column = good
If used too much, hernias will pop out from any weakness in abdominal wall (defecation/micturition/rectal prolapse a risk too)
