Vertebral Column 1 Flashcards
what is the main function of the vertbral column (5)
- internal support for body
- protection of spinal cord
- support and protection of local structures
- muscle attachment (extrinsic muscles of limbs)
- locomotion - transfer of propulsive motion from hindlimbs
what are irrefular bones
located in the axial skeleton
what are the outer and centre layer of irregular bones
outer: compact bone
centre: cancellous bone
what are the structures shown
- compact bone
- cancellous bone
what are the features of the vertebral body
massive region of bone
roughly cylindrical
what is the convex cranial surface and concave caudal surface called
convex cranial surface = cranial endplate
concave caudal surface = caudal endplate
what is the invertebral disc space
space between adjacent vertebral bodies when aligned to form vertebral column
what is the invertebral disc space occupied by
soft tissue structure called invertebral disc
where is the vertebral arch located
arch of bone located dorsal to the vertebral body
what is the vertebral arch composed of
left and right vertical wall = pedicles
right and left laminae that come together to form the roof
how does the vertebral foramen form
combination of the vertebral arch dorsally and the vertebral body ventrally –> forms vertebral foramen
what is the function of the vertebral foramen
route for the spinal cord to run through the bone
how does the vertebral canal form
when the vertebral align the vertebral foraminae aligns to form a hollow channel running the length of the vertebral column = vertebral canal
what does the vertebral canal contain
contains the spinal cord allowing it to run the length of the body while being protected by the boney tube formed between the vertebral bodies and the vertebral arches
what structures are shown
vertebral foramen
what structure is shwon
vertebral canal
what are on the lateral aspect of the vertebra
there is a notch present at the cranial and caudal aspects of each pedicle –> cranial and caudal notches
how many notches are there
the vertebrae are the same on both left and right side –> total of 4 notches per vertebrae
what forms the invertebral foramen
when the vertebrae align to form the vertebral column –> notches line up with each other to form a series of gaps or spaces = intervertebral foramen
what is the function of intervertebral foramen
allows passage of spinal nerves and blood vessels from the spinal cord out of the vertebral canal to supply the body
what is this structure
intervertebral foramen
what are articular facets
each vertebra has articular facets that allow it to articulate with the vertebrae cranial and caudal to it
where are the articular facets located
at junction between the pedicle and the lamina at the cranial and caudal aspects of the vertebra
present on left and right sides of vertebra
how many articular facets are there per vertebra
located on left and right sides of vertebra so there are 4/vertebra
where do the articular facets articulate
with facets on adjacent vertebrae to form synovial joints (cranial and caudal)
the orientation depends on how much movement between vertebrae is permitted in each region
what are these structures
articular facets
what are the spinous processes
bony projections –> increase surface area for muscle attachment
length and inclination vary with region
what is the dorsal spinous process
single boney projection located on the dorsal aspect of the vertebral arch at the point where the laminae meet in midline
what is the transverse processes
2 boney projections located on the lateral aspect of the vertebral arising where the pedicle meets the vertebral body
what structures are shown
- dorsal spinous process
- transverse processes
what are the typical features of vertebra (6)
- vertebral body
- intervertebral disc spaces
- vertebral arch –> pedicles/laminae, vertebral foramen (vertebral canal)
- cranial and caudal notches –> intervertebral foramen
- articular facets
- spinous processes –> dorsal and transverse
how does the axial skeleton develop
paraxial mesoderm –> somites –> dermatone –> skin
somites –> myotome –> muscle
somites –> sclerotome –> axial skeleton
how does each side of vertebra develop
what does the paraxial mesoderm form from
more than 40 pairs of somites
these each split into 3 parts
what does the sclerotome form
develop a diffuse cranial section and dense caudal section –> on the left side of the neural tube combines with the diffuse cranial section of the adjacent sclerotome to form the left half of the same vertebra
same process occurs on the right side of the neural tube
how does the sclerotome split
into cranial and caudal sections
the caudal section combines with the cranial section of the adjacent slcerotome to form a hemivertebra
what occurs to the hemivertebra
the left and right hemivertebra come together and fuse to form complete vertebra
what encloses the neural tube and what forms in the process
the neural arch which is formed from the caudal sections of the sclerotome –> encloses neural tube and fuses dorsally –> forming vertebral foramen and canal
what occurs to the notochord q
when the vertebral body arises from the cranial section of the sclerotome it obliterates the notochord
but does still remain in the spaces between the adjacent vertebral bodies
in the space that the notochord occupied, what now occupies it
occupied by the intervertebral disc and these remnants of the notochord are incorperated into the invertebral disc as the nucleus pulposus (chusioning and shock absorption between adjacent vertebrae)
how many centres of ossification do the body of vertebrae develop from
3 centres
- body
- cranial endplate
- caudal endplate
what can be seen on radiographs in young animals
physes or growth plates between these centres of ossification are visible on radiographs
what is an example of abnormal development of vertebrae
block vertebrae –> 2 fused together with no disc space
what structures are shown
- body
- cranial endplate
- caudal endplate
what is transitional vertebrae
located at the boundary between different regions of the vertebral column and get confused in which region they belong to
in this ex. the last lumbar vertebra that is missing a transverse process
other ex. include the 1st lumbar vertebrae with a rib or the last thoracic vertebra without one
what is hemivertebra
wedge/butterfly vertebrae
the vertebral body fails to form properly
instead of being normal cylindrical shape –> its triangular instead
can cause devation of the column
