S2 - Back Flashcards
structure of vertebral column
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 4 coccygeal
functions of vertebral column
- protects spinal cord and spinal nerves
- support body weight
- provides a partly rigid and flexible axis for the body and a pivot for the head
- posture and movement
what are A, B, C, D?
- A = pedicle
- B = vertebral foramen
- C = articular processes
- D = spinous process
what are E, F, G, H?
- E = lamina
- F = transverse process
- G = vertebral arch
- H = vertebral body
explain the articulations of vertebrae
- 1) superior articular processes of one vertebra articulate w/ the inferior articular processes of the next (facet), allows for ROTATION
- 2) vertebral body articulates w/ the next vertebral body via intervertebral disc
how are cervical vertebrae arranged?
- C1 - atlas
- C2 - axis
- C3-6 (typical)
- C7 - vertebra prominens (long, slender spine)
structure of C1 (atlas)
- vertebral body
- spinous process
- foramen
- vertebral arches
- superior articulation
- atypical b/c lack of vertebral body and spinous process
- largest vertebral foramen
- contains TWO vertebral arches (A/P - each contains an A/P tubercle), other vertebrae have one
- articulates superiorly w/ occipital condyle of cranium
structure of C2 (axis)
- ANTERIOR tooth-like/odontoid process (dens) which projects superiorly and articulates w/ articular facets of atlas
what ligaments bind to the dens?
- cruciform (vertical and transverse ligaments): provide stability and prevent posterior displacement
- transverse ligament specifically binds the dens to the anterior arch of atlas
- apical: no functional significance but points tip of dens anteriorly
4 reference lines in the spine
what does a frontal X-ray with the patient’s mouth open show?
- the dens (odontoid) process of the axis (C2)
- therefore called odontoid view
structure of C3-C7
- vertebral body
- vertebral foramen
- transverse processes
- articular processes
- spinous process
- body: small, oval-shaped
- foramen: large, triangular
- transverse processes: contain transverse foramina
- articular processes: oblique and horizontal orientation
- spinous processes: short and bifid (except C7 - vertebra prominens)
structure of thoracic vertebra
- vertebral body
- vertebral foramen
- transverse processes
- articular processes
- spinous process
- body: large, heart-shaped
- foramen: small, circular
- transverse processes: long and contain facets for ribs (T1-T8 have superior and inferior costal facets, T9-T12 have only one costal facet)
- articular processes: almost coronal
- spinous processes: long, point inferiorly
structure of lumbar vertebrae
- vertebral body
- vertebral foramen
- transverse processes
- articular processes
- spinous process
- body: largest (since bear most weight), kidney-shaped
- foramen: triangular, larger than thoracic but smaller than cervical
- transverse processes: long, slender
- articular processes: almost sagittal
- spinous processes: short, sturdy
what type of vertebra is this?
cervical
what type of vertebra is this?
thoracic
what type of vertebra is this?
lumbar
structure of sacrum
- 5 bones fused into one wedge-shaped, immobile bone
- fusing finished by age 25-30
- provides strength + stability to pelvis and transmits weight of body to pelvic girdle via sacroiliac joint
- rough surface dorsally, smooth concave surface ventrally
what are A, B, C, D?
- A = sacral hiatus
- B = medial sacral crest
- C = auricular surface (forms sacroiliac joint)
- D = sacral canal
what are E, F, G?
- E = superior articular process (articulates w/ inferior articular process of L5)
- F = sacral foramina
- G = base
what are H, I, J?
- H = sacral ala (anterosuperior)
- I = transverse ridges/lines
- J = apex
structure of coccyx
- vestigal tail w/ 3-5 fused segments (very variable)
- has 2 horns which articulate w/ sacrum
- apex points anteriorly in males and inferiorly in females
spina bifida + types
- failure of vertebral lamina to unite during development, can be caused by folate deficiency
- mildest: spina bifida occulta (vertebral arch of L5 and S1 do not form completely, skin usually covers this but marked by tuft of hair or dimple, causes back pain and limb weakness)
- more severe: meningocele (fluid filled sac, no nerve damage but minor disability
- most severe: meningomyocele (spinal cord and nerves protrude thru > paralysis or weakness of limbs + bladder/bowel dysfunction)
curves of the vertebral column and how do they form?
- cervical (2˚) - lordosis
- thoracic (1˚) - kyphosis
- lumbar (2˚) - lordosis
- sacral (1˚) - kyphosis
- primary/kyphotic curves form during foetal development
- secondary/lordotic curves develop during childhood due to lifting head and upright sitting
3 types of vertebral column disorders
- kyphosis
- lordosis
- scoliosis
kyphosis + causes
- exaggerated thoracic curve (posterior)
- causes: osteoporosis, neuromuscular disorders,
lordosis + causes
- excessive anterior curve of lumbar region
- causes: obesity, pregnancy, abdominal muscle weakness
scoliosis + causes
- lateral curvature of column
- causes: unilateral muscular paralysis
how is the female lumbar spine different from males?
- during pregnancy, centre of gravity shifts anteriorly = disrupt posture and walking
- therefore more flexible to cope w/ carrying baby while standing on 2 feet
structure and function of intervertebral discs
- fibrous hyaline cartilage between vertebrae
- nucleus pulposus (avascular): soft, gelatinous inner sphere made of water - shock absorption + flexibility
- annulus fibrosus: outer collar of ligaments and fibrocartilage - resist compressive stress + provide protection
2 types of joints in the vertebral column
- vertebral body joints (where the discs are)
- facet joints (plane - b/n facets of vertebrae) - (zygapophyseal, allow for rotation)