Anatomy - spine 2 Flashcards
the occiput-c1 joint provides most of what ROM? how much?
flexion. 50%
c1-c2 joint provides most of what ROM? how much?
rotation. 50%
surface land marks:C2-3C3C4-5
C2-3: mandibleC3: hyoidC4-5: thyroid cartilage
surface landmarks:C6C7T3
C6: cricoid cartilageC7: vertebral prominensT3: scapular spine
surface landmarks:T4T7L4-5
T4: nipples (variable)T7: distal tip of scapulaL4-5: iliac crest
what is a motion segment? what is it also called?
smallest segment of spine that shows biomech characteristics of the entire spinei.e. 2 adjacent vertebrae and intervening ligamentous tissuesAKA functional spinal unit
what spinal vertebrae have bifid spinous processes?
C2-6
at what level is the spinal cord largest in the c-spine?
c2
what shape is the vertebral body in the t-spine?
heart
L-spine vert bodies are what shape?
kidney
mamillary processes occur in what spinal region?from what structure do they project from?
L-spinefrom superior articular process
how many sacral foramina are there?
4 pairs dorsal and ventral
how many vertebrae fused embryologically to form the coccyx?
usually 4
most common site of disc herniation?second most common?
L5/S1 first, L4/5 second
transverse ligament of the c-spine occurs where?
posterior to Dens, stabilizes a-a joint and keeps dens up against anterior arch of c1
alar ligaments joint what to what?embryologically they are remnants of what?
from occiput to tip of densremnant of notochord
cruciform ligament of atlas is made of what?
includes the transverse ligamentplus inferior and superior longitudinal bands
annulus fibrosus is mostly what type of collagen?
type I
nucleus pulposis is mostly what collagen type?
type II
in the saggital and coronal planes, c-spine facet joints are oriented how?
saggital: 45 degcoronal 0 degi.e. roof shingles angled posteriorly at 45 deg
T-spine facet joints are oriented how in the sagg and coronal planes?
saggital 60 degcoronal 20 degi.e. similar to roof shingles but tilted 20 deg towards being saggital
L-spine facet joints are oriented how in the saggital and coronal planes?
saggital: 90 degcoronal: 45 degi.e. straight up and down plane of joint, but tilted out 45 deg
amount of “intoeing” for pedicle screws is greatest where? least where?
greatest at T1 and L5least at T12decreases from T1 and L5 towards T12L1 approximately 5-10 degincreases ~5 deg per level from L1 down to sacrum
T-spine pedicle screw start point
intersection of middle of TP and middle of inferior articular facet
lumbar pedicle screw start point?
midpoint of TPmidpoint of superior articular processnb: pars lines up with medial aspect of pedicle
upper spine largest pedicle?L-spine largest pedicle?
T1L5
smallest pedicle?smallest within L-spine?
T4L1
post-halo: what nerve injuries can occur?
basically supraorbital nerve, CN 4,6,10,11,12CN VI - abducens ncan hit it at petrosphenoidal junction. get eyes that look down and inGlossopharyngeal (4) + vagus (10) + hypoglossal (12)dysphagia, loss of palatal/pharyngeal reflexes, weakness of tonguefrom penetration of jugular foramenCN elevenaccessory nsupraorbital nerve - from anterior pins too medial
describe pin placement for halo
anterolateral pins: just below head equator, 1cm above orbit, in lateral 2/3 of orbit (avoid supraorbital nerve)posterior pins - avoid temporalis muscle. Usually place just directly above ear pinna
list the fixation options for c1-2 fusion
transarticular screwwiringlateral mass screw (c1) and pars screw (c2)clamp
list the c2 fixation options
transarticular screw (with c1)pars screwpedicle screwtranslaminar screwclampwiring
what is pelvic incidence?
fixed parameter describing the tilt of the S1 endplate relative to the centre of the acetabulumon lateral view, make line from middle of S1 endplate to centre of acetabulummake another line perpendicular to S1 endplateangle between these lines is pelvic incidenceGeometrically ends up being equal to pelvic tilt + sacral slopepelvic tilt=angle between vertical and line joining middle of S1 endplate to centre of acetabulumsacral slope=angle between s1 endplate and horizontal
describe the spinal cord blood supply - only immediately around the cord
single anterior spinal arterytwo posterior spinal arteriesthey have branches that form an anastmosis/plexus around the cord - vaso corona
what arteries feed the spinal arteries in c-spine?
vertebral aPICAsegmental branches
what arteries feed the spinal arteries in the T-L spine?
radicular arteries
what is the artery of adamkiewicz?
principle arterial suply of lower 2/3 of spinal cord - feeds the anterior and posterior spinal arteriesusually occurs on left side at T10 (between T9-11)can be between T7 and L4AKA arteria radicularis magnait is a large segmental radicular arteryenters through intervertebral foramen
extension of ALL from C1 to skull is called what?
anterior atlanto-occipital membrane
extension of PLL from C1 to skull is called what?
tectorial membrane
what is ligamentum nuchae?
c-spine supraspinous ligament
vertebral foramina occur in what vertebrae?through which does the vertebral artery pass?
C1-7artery exists in c1-6
continuation of ligamentum flavum from C1 to skull is called what?
posterior atlanto-occipital membrane
what are:basionopisthion
basion: anterior point on the foramen magnumopisthion: posterior point on the foramen magnum
anterior cord syndromepresentationprognosis?
loss of spinothalamic and corticospinal tractsloss of pain/temp, motorworse prognosis (10% recover)
posterior cord syndrome: presentation?
loss of dorsal white columnsloss of proprioception, fine touchrare
central cord syndrome: presentation, prognosis?
UE weaker than LEpreserved perianal sensation75% recover
brown-sequard syndrome: presentation, prognosis?
hemi-cord loss.lose contralateral pain and temp 2 levels below and ipsilateral motor90% recovery. best prognosis
explain the ASIA scale ABCDE
A - complete loss below levelB: incomplete - sensory intact, but no motor below level at allc: incomplete - motor function exists below level but most are d - incomplete - motor exists below level and most have 3/5 or moree: normal neuro exam
what is the definition of neurological level?
lowest (most caudal) level with intact motor AND sensory
where is the watershed region of the spinal cord?
T4-9. narrowest spinal canal and poorest blood supply.
Smith-robinson approach: from left or right side? Which is better and why?
left is betterreasons:predictable clourse of recurrent laryngeal n (around aortic arch, runs between trachea and esophagus. Problem: most ppl right handedc.f. right side: loops around subclavian a and crosses field from lateral to medial to run next to trachea. can be abberant at thyroid level
name the 3 fascial layers you pass through in the smith robinson approach, from superficial to deep
deep cervical fasciapretracheal fasciaprevertebral fascia
name 2 major anatomical structures superficial to deep cervical fascia (not skin and fat)
external jug vplatysma
Describe the smith robinson approach, and identifiy the important intervals.
transverse incisionsplit fibres of platysma (vertical) - CN VII facial ngo through deep cervical fasciago between SCM (CN XI accessory) and strap muscles (omohyoid, sternothyroid, sternohyoid, thyrohyoid - all ansa cervicalis innervation)go through pretrachial fascia anterior to carotid sheath (contains IJV, vagus n, common carotid a)go between left and right longus colli (segmental n)go thorugh prevertebral fascia
dangers of smith robinson approach
carotid sheath (vagus n, common coarotid a, IJV)thyroid arteriestracheaesopahgusrecurent laryngeal nstellate ganglion/sympathetic chainvertebral a
explain posterolateral approach to spineAKA costotransversectomy
incision adjacent to spinous processes over ribsplit trapezeus fibressubperiosteal dissection around ribwatch for intercostal bundleremove rib up to TPoperate via retroperitoneal space
interval of wiltse approach (modern variant)
between multifidus and longissimus
