Spine Flashcards
the occiput-c1 (Atlas) joint provides most of what ROM? How much?
flexion/extension. 50%
c1-c2 joint (Axis) provides most of what ROM? how much?
Rotation. 50%
surface land marks:
C2-3
C3
C4-5
C2-3: mandible
C3: hyoid
C4-5: thyroid cartilage
surface landmarks:
C6
C7
T3
C6: cricoid cartilage
C7: vertebral prominens
T3: scapular spine
surface landmarks:
T4
T7
L2
L4
L4-5
T4: nipples (variable)
T7: distal tip of scapula
L2: Renal Arteries
L4: Aortic Bifurcation
L4-5: iliac crest (L4 spinous process is at the level of the iliac crest)
what spinal vertebrae have bifid spinous processes?
C2-6
At what level is the spinal cord largest in the c-spine?
C2
L-spine vert bodies are what shape?
T Spine?
L spine - kidney
T spine - heart
mamillary processes occur in what spinal region?
from what structure do they project from?
L-spine
from superior articular process
allow for attachment of the multifidis muscles.
How many sacral foramina are there?
4 pairs dorsal and ventral
The dorsal and ventral primary rami exit respectively
how many vertebrae fused embryologically to form the coccyx?
usually 4 sometimes 5
most common site of disc herniation?
second most common?
L5/S1 first, L4/5 second
What is the Tectorial membrane?
the extension of the PLL from C1 to the skull
Where does the transverse ligament of the c-spine live?
Posterior to Dens, stabilizes a-a joint and keeps dens up against anterior arch of c1
Part of the cruciate ligament which lies anterior to the tectorial membrane, behind the odontoid process
- The transverse atlantal ligament is the strongest component, connecting the posterior odontoid to the anterior atlas arch, inserting laterally on bony tubercles
- Vertical bands extend from the transverse ligament to the foramen magnum and body of the axis.
What is the Anterior Atlanto-Occipital membrane?
an extension of the ALL from C1 to the skull.
alar ligaments joint what to what?
embryologically they are remnants of what?
from occiput to tip of dens
remnant of notochord
cruciform ligament of atlas is made of what?
includes the transverse ligament
plus inferior and superior longitudinal bands
What are the two layers of the intervertebral discs and which layer contains nerve endings?
annulus fibrosis and nucleus pulposus
The AF contains nerve fibers.
What type of fibers compose the annulus fibrosis and how are they oriented?
type I collagen fibers oriented obliquely.
nucleus pulposis is mostly what collagen type?
type II
What is the orientation of the facet joints as your progress down the spine?
Sagittal Coronal
C 45° 0°
T 60° 20°
L 90° 45°
Describe the amount of pedicle screw “intoeing” you need as you go from T1-L5
Thoracic spine:
DECREASES at you go down from T1-T12
In males, goes from ~40 deg to ~15 deg
Therefore greatest at T1
Lumbar spine:
INCREASES as you go down from L1-L5
L1 approximately 5-10 deg
increases ~5 deg per level from L1 down to sacrum
What are the landmarks for the T-spine pedicle screw start point?
Superior ridge of TP
Midpoint of inferior articular facet
What is the landmarks for a lumbar pedicle screw start point?
midpoint of TP
midpoint of superior articular process
nb: pars lines up with medial aspect of pedicle
upper spine largest pedicle?
L-spine largest pedicle?
T1
L5
What is the smallest pedicle in T spine?
What is the smallest within L-spine?
T4
L1
What are some what nerve injuries can occur with appication of Halo traction?
Supraorbital nerve most common - avoid by
Cranial nerve injuries have also been described. CN 4,6,10,11,12
CN VI - abducens n
can hit it at petrosphenoidal junction. get eyes that look down and in
Glossopharyngeal (4) + vagus (10) + hypoglossal (12)
dysphagia, loss of palatal/pharyngeal reflexes, weakness of tongue
from penetration of jugular foramen
CN eleven accessory n
supraorbital 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)
place anterior pins lateral enough to avoid injury to the frontal sinus, supratrochlear and supraorbital nerves
place pins anterior enough to avoid the temporalis muscle
pinsposterior pins. Usually place just directly above ear pinna
list the fixation options for c1-2 fusion
transarticular screw
wiring
lateral mass screw (c1) and pars screw (c2)
clamp
list the c2 fixation options
transarticular screw (with c1)
pars screw
pedicle screw
translaminar screw
clamp
wiring
What are 3 contraindications to C1-C2 transarticular screws?
What about contraindications to C1-2 wiring?
Screws:
- abberant vertebral artery (medial or high riding)
- subluxation of C1-2
- cervicothoracic kyphosis precludes screw placement
Wiring:
•Need Intact Posterior Elements
- Decompression
- Trauma
- Tumour
What is pelvic incidence?
fixed parameter describing the tilt of the S1 endplate relative to the centre of the acetabulum
On lateral view, make line from middle of S1 endplate to centre of acetabulum (center of femoral head)
make another line perpendicular to S1 endplate
angle between these lines is pelvic incidence
Geometrically ends up being equal to pelvic tilt + sacral slope
pelvic tilt=angle between vertical and line joining middle of S1 endplate to centre of acetabulum
sacral slope=angle between s1 endplate and horizontal
Describe the spinal cord blood supply - only immediately around the cord
single anterior spinal artery
two posterior spinal arteries
they have branches that form an anastmosis/plexus around the cord - vaso corona
What arteries feed the spinal arteries in c-spine?
Vertebral aa
PICA
segmental 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 - anastomosis with the anterior spinal artery, supplying arterial blood to the spinal cord from T8 to the conus medullaris
usually occurs on left side at T9-12
can be between T7 and L4
AKA arteria radicularis magna
It arises from the radiculomedullary branch of the posterior branch of the intercostal or lumbar artery, which arise from the thoracic or abdominal aorta respectively 1. It has a diameter of ~1 mm (range 0.8-1.3 mm)
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
The supraspinous ligament only runs from C7 to sacrum
vertebral foramina occur in what vertebrae?
through which does the vertebral artery pass?
C1-7
artery exists in c1-6
continuation of ligamentum flavum from C1 to skull is called what?
posterior atlanto-occipital membrane
What are the Basion and Opisthion?
basion: anterior point on the foramen magnum
opisthion: posterior point on the foramen magnum