Attachment of Ligamentum flavum:
B/w anterior surface of one lamina and posterior surface of lamina below
Function of Ligamentum flavum:
limits flexion
Attachments of supraspinous and interspinous ligaments:
B/w adjacent spinous processes from C7 to sacrum
Fuction of supraspinous and interspinous ligaments:
limit flexion
Attachment of Intertransverse ligaments:
Between adjacent transverse processes
Function of Intertransverse ligaments:
Limits contralateral lateral flexion and forward flexion
Attachment of Anterior longitudinal ligament
B/w basilar part of occipital bone and entire length of anterior surfaces of all vertebral bodies, including sacrum
Function of Anterior longitudinal ligament
Limits extension or excessive lordosis in cervical and lumbar regions. Reinforces anterior sides of intervertebral discs (IVDs)
Attachment of Posterior longitudinal ligament
Throughout length of posterior surfaces of all vertebral bodies, b/w axis (C2) and sacrum
Function of Posterior longitudinal ligament
Limits flexion.
Reinforces posterior sides of IVDs
Attachment of Capsules of the apophyseal joints
Capsules of the apophyseal joints
Function of Capsules of the apophyseal joints
Strengthen apophyseal joints
Intervertebral junction has three functional components:
(1) transverse (TVP) and spinous processes (SP)
(2) apophyseal joints
(3) an interbody joint
What is primarily responsible for guiding intervertebral motion:
apophyseal joints
What increases mechanical leverage of muscles and ligaments?
SP and TVPs provide mechanical levers
Plane of movement of flexion and extension of axial skeleton
sagittal
Plane of movement of lateral flexion (right or left) of axial skeleton:
frontal
Plane of movement of axial rotation (right or left) of axial skeleton
horizontal
AOR axial rotation (right or left) of axial skeleton
vertical
AOR of flexion and extension of axial skeleton
medial-lateral
AOR of lateral flexion (right or left) of axial skeleton
anterior-posterior
What strongly influences kinematics at different regions across vertebral column?
orientation of plane of facet surfaces within each joint
Horizontal facet surfaces favor:
axial rotation
Vertical facet surfaces (either in sagittal or frontal planes) block:
axial rotation
Why is axial rotation is far greater in cervical region than lumbar region?
plane of facet surfaces
What is the orientation of each collagen fiber?
65 degrees from vertical
How are the collagen fibers arranged?
concentric layers with fibers in every other layer running in identical directions
-130 degrees relative to each other
ROM atlanto-occipital joint (C0-C1) flexion and extension:
Flexion: 5
Extension: 10
Total: 15
ROM atlanto-axial joint complex (C1-C2), flexion and extension:
Flexion: 5
Extension: 10
Total: 15
ROM intracervical region (C2-C7), flexion and extension:
Flexion: 35-40
Extension: 55-60
Total: 90-100
Total ROM across craniocervical region, flexion and extension:
Flexion: 45-50
Extension: 75-80
Total: 120-130
ROM atlanto-occipital joint (C0-C1) axial rotaiton
negligible
ROM atlanto-occipital joint (C0-C1), lateral flexion
about 5
ROM Atlanto-axial joint complex (C1-C2) axial rotation
35-40
Atlanto-axial joint complex (C1-C2) lateral flexion
negligible
ROM Intracervical region (C2-C7) axial rotation
30-35
ROM Intracervical region (C2-C7) lateral flexion
30-35
ROM Total across craniocervical region axial rotaiton
65-75
ROM Total across craniocervical region lateral flexion
35-40
Protraction of cranium, lower-to-mid cervical spine:
flexes as upper craniocervical region extends
Retraction of cranium, lower to mid cervical spine:
extends as upper cranicervical region flexes
Kinematics of craniocervical axial rotation C2-C7:
inferior facets slide posteriorly and slightly inferiorly on the same side as rotation and anteriorly and superiorly on the side opposite rotation.
What does the 45° inclination of articular facets of C2 to C7 dictate?
mechanical spinal coupling b/w movements in frontal and horizontal planes
Because upper vertebra follows plane of articular facet of lower vertebra:
lateral flexion and axial rotation occur simultaneously
Lateral flexion and axial rotation in mid-and-low cervical region area:
coupled in ipsilateral fashion
-lateral flexion to right occurs with slight axial rotation to right and vice versa
Approximate ROM for Thoracic Region, flexion and extension:
flexion: 30-40
extension: 20-25
total: 50-65
Approximate ROM for Thoracic Region axial rotation
30-35
Approximate ROM for Thoracic Region lateral flexion
25-30
Approximate ROM for Lumbar Region, flexion and extension:
flexion: 40-50
extension: 15-20
total: 55-70
Approximate ROM for Lumbar Region axial rotation
5-7
Approximate ROM for Lumbar Region lateral flexion
20
Total flexion between thoracic and lumbar regions:
85 degrees (35 thoracic, 50 of lumbar)
Total extension between thoracic and lumbar regions:
35-40 degrees (20-25 thoracic extension, 15 lumbar extension)
Total axial rotation between thoracic and lumbar region
-40 degree arc: sum of about 35° of thoracic rotation and 5° of lumbar rotation
Total lateral flexion of thoracic and lumbar region:
-45 degrees, sum of 25° of thoracic lateral flexion and 20° of lumbar lateral flexion
Large amount of motion in cervical spine and why:
large motion in all three planes, highest is axial rotation permitted at atlanto-axial joint
Thoracic spine permits:
constant amount of lateral flexion: reflects general frontal plane orientation of apophyseal joints combined w/stabilzing effect of ribs
Thoracolumbar spine, from crainial-to caudal direction permits:
increasing amounts of flexion and extension at expense of axial rotation
Orientation of apophyseal joints in cervical-thoracis junction:
horizontal and frontal planes
Orientation of apophyseal joints in lumbar region
near sagittal plane and vertical orientation
Prevailing near-sagittal plane and vertical orientation of lumbar region naturally favor :
flexion and extension but restrict axial rotation
Lumbar spine, in combination with flexion and extension of ribs:
forms primary pivot point for sagittal plane motion of entire trunk
SI joints mark transition between…
caudal end of axial skeleton and lower appendicular skeleton
What are the components of the pelvic ring?
sacrum, pair of SI joints, three bones of each hemipelvis (ilium, pubis and ischium) and pubic symphysis
What does the pelvic ring do?
transfers body weight bidirectionally b/w trunk and femurs
What does the strength of the pelvic ring depend on?
primarily on tight fit of sacrum wedged b/w two halves of pelvis
What are the movements at the SI joints?
nutation and countermutation
Nutation:
anterior sacral tilt
posterior iliac tilt
forward movement of sacral apex/anterior pelvic tilt
Countermutation:
posterior sacral tilt
anterior iliac tilt
Nutation is couped with
lumbar extension
Countermutation is coupled with
lumbar flexion
Mechanisms of injury for low back
trauma
fatigue
What are the orientations of the trabecular design within cancellous bone?
one vertical
two oblique
What compresses cancellous bone?
NP pressurizes & causes cartilaginous end plates of vertebra to bulge inward
What plays the role of shock absorbers?
vertebral bodies
How do end plates bulge into seemingly rigid bone?
design of cancellous bone
Vertebral cancellous bone structure dominated by system of columns of bone that run…
vertically from end plate to end plate
Vertical columns tied together with what?
smaller transverse trabeculae
Under axial compression, as end plates bulge into vertebral bodies….
these columns experience compression and appear to bend
Under extreme compressive load…
bending columns will buckle as smaller bony transverse trabeculae fracture
How much of cancellous bone can rebound back to original shape?
95% of original unloaded shape
What causes microdamage to trabeculae?
highly repetitive loads, even at low magnitudes
What is lost in osteoporotic vertebrae?
transverse trabeculae are far fewer in number and smaller in diameter then longitudinal trabeculae
When does osteporotic vertebrae begin to collapse?
gradually when exposed to excessive load, with serial buckling or failure of columns of bone
Transverse trabeculae were thick and dense from…
weightlifters
Schmori’s node:
local area of bone collapses under end plate to create a pit or crater that gradually forms
What injury is associated with spinal compression when spine is in neutral ROM?
schmori’s node/end plate fracture
What remains intact with end plate fracture?
AF of disc
In an end plate fracture, if there is substantial loss of nucleus from disc, what results?
immediate loss of disc height & compromise of nerve root
-mimics symptoms of true herniation
Why is end plate fracture misdiagnosed as a herniated or degnerated disc?
b/c in films loss of disc nucleus results in flattened interdiscal space
What has a shell of cortical bone?
posterior elements of vertebrae (pedicles, laminae, spinous processes and facet joints)
What can lead to spondylolisthesis?
failure of posterior elements in conjunction with facet damage
What appears to be somewhat flexible during flexion/extension movements?
neural arch in general (pedicles and lamina)
Damage to posterior elements mar be associated with what?
full ROM
Repeated, cyclic full spine flexion and extension leads to fatigue within arch (repeated stress reversals) can lead to what?
a pars fracture- spondylolisthesis
Patients with pars fractures do not do well with what?
therapeutic exercises that take spine through ROM, stability objective maybe better
During craniocervical extension, the atlanto-occipital joint demostrates a ______ roll and ______ slide, while atlanto-axial joint demonstrates a ______tilt.
posterior, anterior, posterior
During craniocervical flexion, the atlanto-occipital joint demostrates a ______ roll and ______ slide, while atlanto-axial joint demonstrates a ______tilt.
anterior, posterior, anterior
C2-C7 lateral flexion, inferior articular facets on side opposite side lateral flexion slide______ and; ________.
superior anteriorly