Spine

Question 1

about what axis does the synovial atlanto-occipital joint rotate?

Answer 1

yes joint

Question 2

about what axis does the synovial atlanto-axial joint rotate?

Answer 2

no joint

Question 3

where does the first cervical spinal nerve emerge from the vertebral column?

Answer 3

lateral foramen

Question 4

where does the second cervical spinal nerve emerge from the vertebral column?

Answer 4

between atlas and axis

Question 5

what is different about the lateral alar notch in ungulates?

Answer 5

it is enclosed as a complete foramen

Question 6

what passes through the lateral alar notch?

Answer 6

continuation of the vertebral artery (into the vertebral canal via the lateral foramen)

Question 7

where did the atlas’ centrum and neural spine go?

Answer 7

incorporated into the axis of the dens and cranial neural spine respectively

Question 8

what “straps” the dens down on the vertebral canal of the atlas? and where do these things pass?

Answer 8

• transverse ligament
• variety of apical ligaments
• passing from dens to the floor of the atlas

Question 9

give two reasons why the canine axis neural spine is so large

Answer 9

• receive insertion of nuchal ligament
• provide origin for the head rotating muscles

Question 10

what runs in the transverse canal?

Answer 10

• vertebral artery
• left vertebral artery passes through transverse foramina of C6-1
• enters vertebral canal to form ventral spinal and basilar arteries

Question 11

how do the costotransverse processes of C6 differ from the rest?

Answer 11

they have additional “ventral laminae” - large flaps of bone which divert the pull of the longus colli muscle (neck flexor)

Question 12

how does C7 differ from the rest?

Question 13

of the supraspinous and nuchal ligaments, one part is elastic and one less so – which is which and why?

Question 14

where does the nuchal ligament insert in the dog, unlike that of the horse? and where in the horse?

Answer 14

• large neural spine of C2 (dog)
• funicular part attaches to skull (horse)

Question 15

the nuchal ligament has two portions in horse and ox – what are they?

Question 16

what is the common name for large neural spines of the thoracic vertebrae that act as the origin for the nuchal
ligament?

Question 17

which species forms synovial joints between transverse processes, where and why?

Answer 17

• horse
• between transverse processes of sacrum and caudal lumbar vertebrae
• perhaps an adaptation for rearing up on hindlimbs

Question 18

which vertebra is very commonly fractured in the rabbit, and how?

Answer 18

• most caudal lumbar vertebrae and tibia
• if picked up by scruff without supporting the hock, they may kick

Question 19

in which mammalian taxa are they best developed (hanging in the zoology museum)?

Answer 19

cetacean

Question 20

spondylosis

Answer 20

• degenerative condition causing the fusion of vertebrae
• arches of bone between successive centra
• may cause further issues by narrowing vertebral canal or intervertebral foramina

Question 21

in which species are the neural spines more distinct?

Answer 21

horse

Question 22

the sacroiliac joint is mixed symphysis/diarthrosis – what does this mean?

Question 23

what two parts make up a disc? what do each do?

Answer 23

• outer annulus fibrosus (resists tension and torsion)
• inner nucleus pulposus (resists compression)

Question 24

why are different surgeries carried out to treat cervical and thoracolumbar lesions?

Answer 24

minimise destruction of tissues during surgical approach

Question 25

how would you define a vertebra as ‘thoracic’? why?

Answer 25

- large neural spines (point of attachments for epaxial muscles and nuchal ligament) - small transverse processes (mainly act as articulation with ribs) - small articular facets (less mobile in thoracic region)

Question 26

how and why does the orientation of the neural spines change around this vertebra?

Answer 26

- neural spines change from pointing caudally (thoracic) to cranially (lumbar) - orientation also changes at C-T and L-S junctions as they point cranially in the neck and caudally in the tail

Question 27

out of interest, how does the orientation change at the C-T and L-S junctions?

Question 28

how and why does the orientation of the articular facets change in the region of the anticlinal vertebra?

Answer 28

- articular facets are horizontal for frontal plane flexion in thoracic region - abrupt transition at anticlinical vertebra to vertical facets for sagittal flexion

Question 29

in some species there is external evidence of the anticlinal vertebra – what is it?

Answer 29

dip in profile of the back at the anticlinical vertebra

Question 30

which is the diaphragmatic vertebra? how can you tell?

Answer 30

- usually T10 - horizontal cranial facets - vertical caudal facets

Question 31

which is the anticlinal vertebra? how can you tell?

Answer 31

- usually T11 - vertical neural spine - has vertical cranial and caudal articular facets

Question 32

what structure is present only in the cervical vertebrae? which cervical vertebrae are they present in? what are they for?

Answer 32

- transverse foramina - C1-C6 - vertebral artery passes through them (from thorax, through neck, to brain)

Question 33

at which point is there a change in direction of the neural spine? which directions do the neural spines point either side of this point? why?

Answer 33

- anticlinal vertebra (vertical neural spine) - vertebrae cranial to anticlinal vertebra have their neural spines pointing caudally (away from forelimbs) - vertebrae caudal to anticlinal vertebra have their neural spines pointing cranially (away from hindlimbs) - could this potentially be so that cranial and caudal muscles pull towards the centre of the body for sagittal flexion?

Question 34

which parts of the spine have horizontally facing articular facets?

Answer 34

- cervical - most of thoracic (cranial to diaphragmatic vertebra)

Question 35

which parts of the spine have vertically facing articular facets?

Answer 35

- last few thoracic (caudal to diaphragmatic vertebra) - lumbar - caudal

Question 36

which sections of the spine are used for which motions?

Answer 36

- thoracic - frontal flexion - lumbar - sagittal flexion which is used for axial rotation??

Question 37

why aren't the thoracic vertebrae used in sagittal flexion?

Answer 37

ribs are in the way of sagittal flexion

Question 38

what are the motions of the spine?

Answer 38

- sagittal flexion + extension - frontal flexion - axial rotation

Question 39

how can you identify thoracic vertebrae?

Answer 39

they will have the tuberculum and capitulum where the costovertebral and costotransverse joints are (where the head and tubercle of the rib articulate respectively) CHECK THIS

Question 40

where do vertebrae derive from?

Answer 40

- medial part of somite - sclerotome

Question 41

three primary centres in most vertebrae

Answer 41

- x1 interstitial (inside cartilage model of centrum) - cranial and caudal epiphyses - x2 appositional around model of the laminae

Question 42

order the regions of the spine from most to least mobile

Answer 42

- caudal + cervical - lumbar - thoracic - sacrum

Question 43

where does sagittal plane flexion and extension occur?

Answer 43

lumbar vertebrae

Question 44

where does frontal plane flexion occur?

Answer 44

thoracic vertebrae

Question 45

spinal formulae of: - dogs + cats - ruminants - pigs - horses - donkeys - rabbits

Answer 45

C, T, L, S, Cd dogs + cats: 7, 13, 7, 3±, ?20 ruminants: 7, 13, 6, 5± pigs: 7, 14/5, 7/6, 4± horses: 7, 18/19. 6, 5± donkeys: 7, 18/19, 5, 5± rabbits: 7, 12/13, 7/6, 3