Vertebral Column 2 Flashcards
what are the regions of the vertebral column
- cervical
- thoracic
- lumbar
- sacral
- caudal or coccygeal
what is the vertebral formula of the dog
C7 T13 L7 S3 CC variable
what boundary does the thoracic region form
the dorsal boundary of the thoracic cavity
what boundary does the lumbar region form
dorsal boundary of the abdominal cavity
what boundary does the sacral region form
dorsal boundary of the pelvic cavity
what are species exceptions to 7 cervical vertebrae
2 toed sloth = 6 cervical vertebrae
manatee = 6 cervical vertebrae
3 toed sloth = 9 cervical vertebrae
what is the functions of the cervical region
- support of the head
- movement of the head
- protection of ventral neck structures
- muscle attachment
what are the features of cervical vertebrae
- dorsal spinous and transverse processes short
- transverse processes have ventral projection –> attachment of ventral neck muscles (hypaxial muscles)
- transverse foramen –> passage of vertebral A & V
why do cervical vertebra have short dorsal spinous and trasnverse processes
to allow large range of movement
what features of cervical vertebrae allow for large amount of mobility
no large projections
articular facets are relatively flat which allows for greater movement at the synovial joints between the vertebrae
all except 1st and 2nd cervical vertebrae
what is the first cervical vertebra called
atlas –> bears weight of the head
how does C1 differ from other cervical vertebra
vertebral arch but doesn’t have a vertical body
no dorsal spinous process
2 large transverse processes called wings (palpable)
how does C1 develop
the cranial section of the sclerotome remains assocaited with the caudal section rather than separating –> C1 develops from only caudal section of sclerotome (no vertebral body, but arch)
what is the second cervical vertebra called
axis
how is C2 different
- C2 has 2 vertebral bodies –> produces boney projection at cranial aspect called dens
- small transverse processes
- prominant dorsal spinous process (palpable and visible on radiograph)
how does the dens of C2 develop
develops from 2 cranial sections and 1 caudal sections of sclerotome
dens represents vertebral body of C1 that is associated with C2 instead
what vertebrae is this
C1
what vertebrae is this
cervical
what vertebrae is this
C2
what does the number of thoracic vertebrae correspond with
number of pairs of ribs
dog = 13
horse = 18
what are the functions of the thoracic vertebrae (4)
- articulates with ribs (little lateral movement –> only flexion and extension)
- forms dorsal boundary of thoracic cavity
- protection of thoracic cavity
- muscle attachement (vertebral columnn, body wall and extrinsic forelimb muscles)
what vertebrae is this
thoracic
what are the typical features of thoracic vertebrae
- short vertebral body
- long dorsal spinous processes (large and caudally arranged –> attachment of the epaxial muscles)
- small/short transverse processes to accomodate space for ribs
- costal fovea –> presence of ribs
what are the costal fovae of the thoracic vertebrae
flattened areas located on each side of vertebral bodiy at the cranial and caudal notches
provide smooth surface that articulates with the head of corresponding rib
how many costal fovea are there per thoracic vertebrae
4 present
1 right cranial
1 left cranial
1 right caudal
1 left caudal
name the structures
- vertebral body
- dorsal spinous process
- transverse process
- costal fovea
how do ribs 1-10 articulate
cranial costal fovea of the thoracic vertebra of the same number and the caudal costal fovea of the thoracic vertebra cranial to it
(head of rib 5 articulates with cranial costal fovea of the 5th thoracic vertebra and the caudal costal fovea of the 4th thoracic vertebra)
what are the structures
* head of rib
arrow: tuberculum
what does the tuberculum of the rib articulate with
small transverse process of the thoracic vertebra of the same #
what do ribs 11-13 articulate with
head and tuberculum articulate only with corresponding vertebra
how do rib 1 articulate
articulates with T1 and C7
why do ribs 11-13 articulate differently
to allow more movement between adjacent vertebra towards the caudal part of the thoracic region and the thoracolumbar junction
what are the anticlinal vertebra and where is it located in horses and dogs
the dorsal spinous processes become shorter in length until –> vertical dorsal spinous process –> anticlinal vertebra
located at T11 in dog and T16 in horse
what is the function of the anticlinal vertebra
- prevents overcrowding of dorsal spinous processes during extension
- marks transition from low movement thoracic to higher movement lumbar region
what are the typical features of lumbar vertebra
- long vertebral body
- long transverse processes (abdominal wall muscle attachment, support of abdominal contents)
- short and uniform in length dorsal spinous processes (slight cranial orientation)
what vertebrae are these
lumbar
- vertebral body
- transverse processes
- dorsal spinous processes
what are the functions of the lumbar vertebrae
- protection of abdominal contents
- attachment of abdominal wall muscles (associated with vert column, abdominal wall muscles –> support weight of abdominal contents)
- support of abdominal contents
- movement of trunk
what are the features of the sacral vertebrae
- fused to form sacrum
- no intervertebral disc space present
- no movement between components (single unit)
what are the functions of the sacral vertebrae
- protection of intra-pelvic structures
- locomotion
what are the joints of the sacral region
- S1 lumbo-sacral joint –> flexion/extension
- cranial portion of sacrum corresponds with location of the 1st sacral vertebra or S1 –> articulates with wing of ilium to form sacro-iliac joint –> transfer of forces
what are the structures shown
* S1
arrow: lumbo-sacral joint
circle: sacro-iliac joint
what are the functions of the coccygeal region vertebrae
- no spinal cord at this level to protect
- large range of movement –> expression, balance, removing flies
what vertebrae is this
coccygeal
