The MSK anatomy of trunk & hindlimb - XERTE Flashcards
what is the vertebral formula for dogs?
C7, T13, L7 S3
Cd5-23 (no. of caudals are breed variable)
How can you tell thoracic and lumbar vertebrae apart?
the thoracic vertebrae articulate with ribs and possess tall spinous processes
You can also appreciate the sudden alteration from caudodorsal to craniodorsal orientation of spinous processes
what are the two most cranial cervical vertebrae also called and why?
they are called the atlas and axis due to their specialised morphology which gives them different mobility to the rest of the spine
how do the ribs articulate with the vertebrae?
most ribs make two separate articulations with the vertebral column, there are several joint types involved
where are the cartilaginous parts of the axial skeleton?
the junction between the ribs and sternal elements - though these may ossify/fuse w/ some species and/or in older animals
what happens if the annulus fibrosus degenerates?
fragmentation of the annulus (ring) may allow the nucleus to escape, usually in the direction of the vertebral canal - in/directly may press on the cord
degenerative changes to the annulus fibrosus may affect what?
may affect any disk but the effects are naturally likely to be most severe when they involve the disks at the most mobile regions
which regions are the most mobile regions that are likely to be affected most severely due to the annulus fibrosus degenerating?
those of the neck, thoracolumbar junction and, in large animals especially - the lumbosacral junction are susceptible
in what region does degeneration of the annulus fibrosus rarely happen and why?
in the thoracic region
because the intercapital ligaments reinforce the disc dorsally
how many cervical vertebrae do mammals have?
7 cervical (neck) vertebrae
How do giraffes follow the rule of only having 7 neck vertebrae?
their extreme neck length is only achieved by elongation of the vertebrae
which two mammals break the rule of having seven cervical (neck) vertebrae?
three-toed sloths (8) and manatees (6)
where do epaxial muscles lie?
lie dorsal to the transverse processes of the vertebrae
where do hypaxial muscles lie?
lie ventral to the transverse processes of the vertebrae
what groups can the epaxial muscles be further grouped into?
a lateral column
a middle/intermediate column
a medial column
what system is the lateral column of epaxial muscles?
the ilicostalis system
what system is the intermediate/middle column of epaxial muscles?
the longissimus system
what system is the medial column of epaxial muscles?
the transversospinalis system
what do the hypaxial muscles technically include?
the muscles of the thoracic and abdominal walls
why is a good understanding of the muscles of the vertebral column important?
for specific surgeries e.g. dorsal laminectomy
which vertebral column muscles flex the spine (along with the rectus abdominis)?
HYPAXIAL
major psoas
minor psoas
iliacus
which vertebral column muscles extend the spine?
EPAXIAL
iliocostalis
longissimus
semispinalis
multifidi
rotatores
spinalis
spinialis capitus
intertransversarii
which epaxial muscles are found in the medial column?
semispinalis
multifidi
rotatores
which epaxial muscle is found in the most lateral column of the epaxial muscles?
iliocostalis
