Anatomy 2 Flashcards
function of the back?
maintenance of posture
movement of limbs and trunk
bony landmarks of the back?
T1 spinous process (sometimes the first one you can feel) spine of scapula spinous processes iliac crests skin dimples (PSIS) sacrum coccyx intergluteal cleft
muscle landmarks of the back?
trapezius - superior (descending fibres) - middle (transverse fibres) - inferior (ascending fibres) teres major latissimus dorsi erector spinae
extrinsic back muscles function?
attach outside of the back
attach the back to the pectoral girdle
move the upper limb
what are the 4 extrinsic back muscles?
levator scapulae
rhomboids
trapezius
latissimus dorsi
what innervates extrinsic back muscles?
anterior rami of cervical spinal nerves
trapezius = spinal accessory
function of intrinsic back muscles?
maintain back posture
move spine
what are the 2 intrinsic spine muscles?
erector spinae (superficial) transversospinalis (deep)
attachments of erector spinae?
inferior = common tendon attaches to sacrum and iliac crest
superior = individual muscle fibres attach via tendon to either
- rib
- transverse process of a vertebra
- spinous process of vertebra
most low back pain is due to what muscle?
erector spinae strain
how many parks of erector spinae?
3
where is transversospinalis located?
within grooves between transverse and spinous processes
individual muscle fibres of transversospinalis attach between what?
vertebra and skull
vertebra and rib
vertebra and another vertebra
sacrum and vertebra
innervation of intrinsic muscles?
posterior rami branches of
- cervical/thoracic/lumbar depending on level (segmental nerve supply as per the dermatome/myotome)
what can cause referred back pain?
visceral disease
- AAA
- renal disease
- GI disease
- pelvic disease
functions of erector spinae and transversospinalis?
always engaged to maintain upright stance
maintain posture
support spine
extend the spine if contracted bilaterally
lateral flexion if contracted unilaterally
how does vertebral size change down spine?
get bigger as you go down as supporting more weight
become smaller again once weight has been transferred to the hip bones and lower limb
function of spine?
support head and trunk
protect spinal cord/nerves
allow movements of head on neck and movement of trunk
degrees of curvature in adult?
cervical lordosis = 2ndary
thoracic kyphosis = primary
lumbar lordosis = 2ndary (new)
sacral kyphosis = primary (same as fetus)
components of vertebral arch?
2 pedicles either side
2 lamina which join in the middle
transverse processes only present in what vertebrae?
thoracic
- facets for rib articulations
IV foramen?
forms between adjacent vertebrae
spinal nerves found here
facet joint?
between articular processes of adjacent vertebrae
commonly affected by arthritis
IV discs?
between bodies of adjacent vertebrae
strong attachment
can herniate
IV discs are between all vertebrae appart from which?
C1-C2
fused sacrum and coccyx
IV discs make up how much of length of spine?
20-25%
parts of IV disc?
outer annulus fibrosis (strong bond)
inner nucleus pulsosus (mainly water, flexibility and protection)
function of IV discs?
each disc only allows small amount of movement (stretch and one side and compressed at one side)
summation of movement at many discs produces larger movement
what are the 3 ligaments of the spine?
ligamentum flavum (short, connects adjacent laminae posterior to spinal cord) posterior longitudinal ligament (weak, narrow so less support for disc, prevents over-flexion of spine) anterior longitudinal ligament (broad, strong, stronger support for disc, prevents over-extension of spine) supraspinous (connects tips of spinous processes) interspinous ligament (connects superior and inferior surfaces of adjacent spinous processes)
where are transverse foramen found and what do they do?
cervical vertebrae
allow passage of vertebral arteries
(doesn’t accommodate vertebral arteries in C7, sometimes not even present)
in which direction is a disc most likely to herniate and why?
posterior
posterior longitudinal ligament is weaker
identifying features of cervical vertebrae?
transverse foramen
bifid transverse process
triangular vertebral foramen
abnormal cervical foramen?
C1 (atlas)
- no body or spinous process, anterior and posterior arch instead
C2 (axis)
- has an odontoid process projecting from body
C7
- vertebrae prominens, first palpable spinous process in most people
describe the atlanto-occipital joints
between occipital condyles and superior articular facets of the atlas
synovial joints with loose capsule
allows flexion/extension of the neck and little lateral flexion and rotation
describe atlanto-axial joints
3 synovial articulations
2 between the inferior articular facets of atlas and superior articular facets of axis
1 between anterior arch of atlas and odontoid process of axis
main movement = rotation
why might the spinal cord be spared in a slight dislocation of the cervical spine?
the vertebral canal is wider
stages of cervical vertebrae dislocation?
stage I = flexion sprain
stage II = anterior subluxation, 25% translation
stage III = 50% translation
stage IV = complete dislocation
no vertebral foramen in the sacrum, what is there instead?
sacral canal flows into sacral hiatus
anterior and posterior sacral foraminae for exit of spinal nerves
caudal anaesthesia?
local anaesthetic injected into the sacral hiatus to anaesthatise the sacral spinal nerve roots of the cauda equina
where does the spinal cord start and end?
foramen magnum at C1 segment
ends at vertebral level L1/L2 (conus medullaris)
what is the cauda equina?
all of the spinal nerve roots from L2 - C0 that have to descend to their numbered vertebrae where their spinal nerve is located in IV foramen
called nerve roots not spinal nerves as they have not yet entered the IV foramen
what surrounds the spinal cord?
3 layers of meninges surrounded by epidural fat (containing epidural venous plexuses)
how is an epidural anaesthetic administered?
inserted into space where subarachnoid space surrounds the cauda equina (not the spinal cord)
usually around L3/4 spinal cord segment (not the same as vertebral level)
how is a lumbar puncture performed?
same area but further in trough the dura mater and arachnoid mater into the CSF
what is a laminectomy and why is it performed?
removal of one or more spinous processes and the adjacent lamina
used to access the spinal canal, posterior exposure of the spinal cord and/or spinal roots or to relieve pressure on spinal cord or nerve roots
what layers must be cut through to perform a laminectomy?
skin
superficial fascia
aponeurotic origin of trapezius/thoracolumbar fascia of latissimus dorsi
intrinsic muscles
ligaments (ligamentum flavum, supraspinous, interspinous)
lamina
spinous process
