Cervical Biomechanics Flashcards
Function of the spine
- protects spinal cord and exiting spinal nerves
- serves as attachment for muscles/ligaments
- provides a structural base of support
- is vertical sustaining rod to support upright posture
- gives trunk mobility
- provides a link between the upper and lower extremities
- absorb shock for the entire body
Structure of spine (how many of each)
- 33 vertebrae
- 23 intervertebral discs
- 7 cervical
- 12 thoracic
- 5 lumbar
- 9 fused vertebrae
- -5 sacral
- -4 coccyx
primary spinal curves (where are they located, is it kyphotic or lordotic)
- kyphotic
- -thoracic spine
- -sacral region
secondary spinal curves (where are they located, is it kyphotic or lordotic)
lordotic
- -cervical spine
- -lumbar spine
what is the degree of curvature in each region
cervical-30-35 deg lordosis
thoracic-40 deg kyphosis
lumbar-45 deg lordosis
functions of the intervertebral disc
- bind vertebrae together
- contribute to shape of spinal curves
- absorb shock of vertical loading
- stabilize spinal segments
- facilitate movement in spine by acting as a spacer between the vertebrae
what is the nucleus pulpous and its function
- soft gel-like interior
- shock absorber
what is the annulus fibrosis and its function
- contains nucleus pulposus
- prevents herniation
ligaments and structures that limit flexion
- Ligamentum nuchae
- Interspinous ligament
- Supraspinous ligament
- Ligamentum flava
- Apophyseal joints
- Posterior annulus fibrosus
- Posterior longitudinal ligament
ligaments and structures that limit extension (beyond neutral)
- Apophyseal joints
- Cervical viscera
- Anterior annulus fibrosus
- Anterior longitudinal ligament
ligaments and structures that limit axial rotation
- Annulus fibrosus
- Apophyseal joints
- Alar ligament
ligaments and structures that limit lateral flexion
- Intertransverse ligaments
- Contralateral annulus fibrosus
- Apophyseal joints
what type of joint is the AO joint
synovial joint
AA joint: joint articulations (medial joint)
- two synovial cavities around the dens (anterior/posterior)
- transverse ligament of the axis
AA joint: joint articulations (lateral joint)
2 lateral joints
- superior zygapopyseal facets of the axis
- inferior zygapophyseal facets of the atlas
what motion does the AO joint allow for
nodding
what motion does he AA joint allow for
rotation of the head
what are each pair of vertebrae connected through (C3-7)
- 2 zygopophyseal joints
- 2 uncovertebral joints
- interbody joint with the intervertebral disc
describe type 1 coupling
Sidebending and rotation occur in OPPOSITE directions
describe type 2 coupling
Sidebending and rotation occur in SAME directions
where is the first cervical disc located
between C2 and C3
How is the nucleus pulposus contained in the cervical spine ?
by the posterior longitudinal ligament (PLL)
What is the function of the transverse ligament?
- Main stabilizer of the dens
* Limits the amount of flexion in the AA joint
What can compromise the transverse ligament?
Down syndrome and rheumatoid arthritis (RA)
what is the function of the alar ligament
• Limits rotation of the head
• Limits lateral flexion of the head to the opposite side
(From dens to medial side of occipital condyles)
How many degrees of freedom does the AO joint have? and what are they?
3 degrees
- sagittal: flexion/extension
- frontal: sidebending
- Transverse: rotation
How many degrees of freedom does the AA joint have? and what are they?
2 degrees
-transverse: rotation (primary movement)
-sagittal: flexion/extension
(convex on convex)
Capsular pattern/s for AO joint
- Extension = Side bending
* Flexion > Extension
Capsular pattern/s forAA joint
- rotation
arthokinematics for C3-C7 (closed, open and capsular pattern)
-Closed= full extension
-Open= Resting position midway between flexion and extension
-capsular pattern
• Side bending = Rotation
• Extension > Flexion
cervical flexion arthokinematics (at AO, AA and C2-7)
AO- anterior roll, posterior glide
AA- superior tilt
C2-7- anterior translation, anterior rotation
cervical extension arthokinematics (at AO, AA and C2-7)
AO- posterior roll, anterior glide
AA- inferior tilt
C2-7- posterior translation, posterior rotation
cervical retraction arthokinematics (at AO, AA and C2-7)
AO-anterior roll, posterior glide
AA- superior tilt
C2-7-posterior translation, posterior rotation
cervical protraction arthokinematics (at AO, AA and C2-7)
AO- posterior roll, anterior glide
AA- inferior
C2-7- anterior translation, anterior rotation
cervical rotation arthokinematics (at AO, AA and C2-7)
AO-negligible
AA- Ipsilateral posterior glide/medial
glide, Contralateral anterior/lateral glide
C2-7- Ipsilateral posterior/medial glide-contralateral anterior/lateral glide
cervical lateral flexion arthokinematics (at AO, AA and C2-7)
AO- ipsilateral roll, contralateral slide
AA- negligible
C2-7- ipsilateral posterior glide/approximation- contralateral anterior glide/gapping
What coupling is at AO and AA joint
Type 1- opposite side rotation
what coupling is at C2-7
Type 2- same side rotation
What is torticollis? and what is affected?
congenital muscular disorder
-unilateral contracture of the SCM
what is thoracic outlet syndrome (TOS)? what is affected?
- compression of the brachial plexus and/or subclavian vessels
- mimic ulnar n. entrapment (numbness and tingling)
what is cervical radiculopathy? what is affected?
- neurogenic pain in the distribution of cervical nerve root
- caused by herniation of cervical disc
- patient may present with decreased cervical lordosis and reduced ROM
