Anatomy of the vertebral column Flashcards
What does the back include? (7)
- Skin
- Subcutaneous tissue
- Vertebral column
- Spinal cord and meninges
- Ribs
- Nerves and vessels
- Muscles
How many cervical vertebrae are there?
7 (C1-C7)
How many thoracic vertebrae are there?
12 (T1-T12)
How many lumbar vertebrae are there?
5 (L1-L5)
How many sacral vertebrae are there?
5 (S1-S5)
How many bones are there in the coccygeal/coccyx region?
4 (small tightly fused bones)
Why do you become shorter when you are older?
-the intervertebral disks shrink as they become dehydrated
What is involved in the general structure of a vertebra? (5)
- body
- vertebral arch –> pedicles and laminae
- articular facets –> superior (x2) and inferior (x2)
- Processes - transverse (x2) and spinous
- vertebral foramen
What part of the vertebra is the weight bearing portion?
body
How many superior facets are there?
2
How many inferior facets are there?
2
How many transverse processes are there?
2
What runs through the vertebral foramen? (3)
- spinal cord
- meninges
- CSF
What is the vertebral arch made up of? (2)
- pedicles
2. Laminae
What are the 2 main types of processes in vertebra?
- transverse
2. spinous
What runs through the intervertebral foramen?
- spinal nerve
Where are the vertebral notches?
-superior and inferior to the pedicles
What forms the intervertebral foramen? (2)
- superior and inferior vertebral notches of adjacent vertebrae
- intervertebral disc
What is the body of a cervical vertebra like? (2)
- small
2. with elevated uncus
What are the transverse process and pedicles like in cervical vertebra?
- have tubercles anterior and posteriorly
What foramina are involved in cervical vertebrae?
- transverse foramina
What is the uncus of the body of the cervical vertebra?
- edges which unite vertebral bodies together
What is the spinous process of cervical vertebra like?
-BIFID (splits into 2)
Why is the body of cervical vertebra thin and small?
- for fine positioning and movement of the head
What passes through transverse foramina?
- vertebral arteries and veins
What is the cervical function of the foramina transversaria?
- allows passage of vertebral artery and vein to the brain
Which cervical level do the vertebral arteries and veins not pass through?
C7
Why is dislocation of the cervical vertebrae likely?
- as the articular facets are FLAT
- hence here is not much bony congruity
What is the varying severity of dislocation of cervical vertebra?
- Flexion sprain
- 25% subluxation
- 50% sublaxation
- Complete dislocation - facet jumping
What is complete dislocation also known as?
facet jumping
Why might sublaxation in cervical vertebra not compress the spinal cord?
as vertebral foramen is relatively wide
What are the 2 atypical cervical vertebrae?
- C1 - Atlas
- C2 - Axis
What does the atlas (C1) not have? (2)
- spinous process
2. Body
What arches does Atlas (C1) contain?
- anterior and posterior arches
What do the anterior and posterior arches on the atlas have?
- tubercle
- lateral mass
What is the tubercles on the medial surface of the lateral mass for?
- transverse ligament
What does the transverse ligament do?
- holds in place the dens of the axis
What does the atlas (C1) articulate with?
- the base of the skull
How many large surfaces does the axis (C2) have?
2
What does the atlas rotate upon on the axis?
- superior articular facets
What is the distinguishing feature of the axis?
dens
What is the dens also known as?
odontoid process
Why does the transverse ligament of the atlas hold the dens in place?
to prevent horizontal displacement of the atlas
What does the dens do?
- allows the atlas to act as pivot
- allows the atlas to attach the head and enable it to move from side to side
Why is the dens prone to fracture?
the bone of the dens is less dense
What causes fracture of the dens? (2)
- hyperextension
- hyperflexion
Why is the spinal cord not usually affected in the fracture of the dens?
- as the dens is held in place via the transverse ligament of the atlas
What percentage of dens fractures results in non-union?
30-50%
What is the treatment for non-union dens fractures?
- atlantoaxis arthrodesis
- using bone graft from iliac crest
What is the vertebral body of thoracic vertebra like? (2)
- heart shaped
- superior and inferior costal demi-facets
In thoracic vertebra what do the superior and inferior costal demi facets articulate with?
-head of rib
What is the spinous process of thoracic vertebra like?
- long
- extends postero-inferiorly
In thoracic vertebra what does the transverse process articulate with?
tubercle of the rib
How does the superior articular facet face in thoracic veterbra?
posteriorly
How does the inferior articular facet face in thoracic vertebra?
anteriorly
Explain the costovertebral joints (ribs and demifacets articulations)?
- head of rib articulates with the superior demi facet of the corresponding (same number) vertebra
- and articulates with the inferior dmeifacet of the vertebra above
What is the vertebral body like in the lumbar region?
-large
Which way do the superior articular facets face in the lumbar vertebrae?
medially
Which way does the inferior articular facets face in the lumbar vertebrae?
laterally
What is the spinous process like in the lumbar vertebrae?
short and sturdy
What are the transverse processes like in the lumbar region and why are they like that?
not big - as they don;t have to articulate with something like the rib
What is the vertebra of the sacrum like?
fused
What passes through foramina of the sacrum?
spinal nerves
Where do the foramina in the sacrum lie?
anteriorly and posteriorly
What is the vertebrae held together by? (3)
- zygapophysial joints
- intervertebral discs
- intervertebral ligaments
Where does the zygapophysial joints occur?
between superior and inferior articular processes of adjacent vertebrae
What is the movement like in zygapophysial joints and what does it allow to do?
- limited
- lateral extension and flexion
What does orientation of articular facets determine?
- types of movements that are possible
Where do the intervertebral discs lie?
between vertebral bodies
What is the intervertebral disc made up of? (2)
- annulus fibrosis
2. nucleus pulposus
What is the annulus fibrosis of the intervertebral disc?
- a fibrocartilage ring attached to epiphyseal rim of the vertebral body - very tough
- it is the outer ring
What is the nucleus pulposus of the intervertebral disc?
gelatinous substance that acts as shock absorber
What is the nucleus pulpous rich in and what does do and act as?
- water
- acts as a rubber bouncy board
- shock absorber
- enables the vertebra to tilt
- allows slight movement only
What does the thickness of the intervertebral disc determine?
flexibility of the veterbra
- the thicker the vertebral discs the more movement of the vertebra as more compression of the intervertebral disc is allowed.
What are the ligaments of the vertebral column? (6)
- ligamentum flavum
- Posterior longitudinal ligament
- Anterior longitudinal ligament
- Interspinous ligament
- Supraspinous ligament
- Intertransverse ligament
What do the ligaments of the vertebral column allow resistance to?
-hyperflexion and hyperextension of the vertebral column
What does the ligamentum flavum of the vertebral column bind to?
lamina of adjacent vertebra
What does the posterior longitudinal ligament bind to and what is it’s function in the vertebral column?
- C2 to sacrum
- prevents posterior herniation of IV discs
What does the anterior longitudinal ligament of the vertebral column attach to?
- occipital bone and C1 to sacrum
Which ligament is resistant to hyperextension of vertebral column? (1)
Anterior longitudinal ligament
Which ligaments are resistant to hyper flexion? (2)
all the others apart from anterior longitudinal ligament
What happens in whiplash?
hyperextension of the cervical neck
What is whiplash commonly caused by?
- rear end car crashes
- esp if the head rest is too low
Which ligament in whiplash is torn/ stretched?
anterior longitudinal ligament
What can happen in severe cases of whiplash?
- part of the vertebral body is avulsed
- hence vertebra can dislocate
- this may cause the compression of the spinal cord
What are the movements of the vertebral column?
- extension/flexion
- lateral flexion
- rotation
Why may movements vary in different regions of the vertebra?
- due to orientation of zygapophysial joints
- and thickness of intervertebral discs
What are the curvatures of the vertebral column?
- thoracic and sacral kyphosis
- cervical and lumbar lordosis
When are primary curvatures present?
since in foetus - never changes in life
Where are secondary curvatures present?
develop later - changes shape during life
What are the abnormal curvatures? (3)
- Excessive kyphosis (bent too forwards)
- Excessive lordosis (bend too backwards)
- Scoliosis (wonky)
What group of people is osteoporosis most common in?
- post menopausal women
- due to decreased oestrogen - which protects bones
What happens in osteoporosis?
- loss of trabecular in bones
What type of fracture happen as a result of osteoporosis in vertebral column?
- compression fracture
Why do surgeons sometimes leave ovaries in a hysterectomy?
- so that oestrogen is still produced to protect the bones
What are the effects of ageing on the vertebrae?
- loss of bone density leading to concave vertebral bodies
- osteophytes develop in response to increased for ce on the rims of the vertebrae
What may ageing do to the intervertebral discs?
- herniation of nucleus pulpous (slipped discs)
What direction does herniation nucleus pulposus usually happen in and between which vertebral levels?
- posterolateral
- between L4/5 or L5/S1
What can compression of spinal nerve roots caused by herniation of nucleus pulposus result in?
- lower back pain or sciatica
What can happen in severe cases of herniation of nucleus pulposus?
- compression of most of the caudal equine
- this is called caudal equine syndrome
What is sciatica?
- compression of the sciatic nerve due to nucleus pulposus/ slipped disc
- this results in numbness which runs til below the knee
Why does ageing cause herniation of nucleus pulposus?
- increase pressure on the vertebral column due to dehydration and loss in structure
