Cervical biomechanics Flashcards
Cervical spine is the most mobile region for
vision, hearing, smell, equilibrium
normal lordosis of the neck
30- 35° extension
Upper cervical spine motion
very little flexion extension
Atlanto axial joint
large amount of rotation
Greatest segmental motion and most common sites of DJD
C4 5
C5 6
C6 7
type one mechanics
rotation and sidebend occurring opposite directions
Upper cervical spine
type two mechanics
Rotation side bent occurred to the same side
Lower cervical spine
type three mechanics
Motion in one plane reduces motion and all the remaining planes
Fully flex the lower cervical spine, then rotate the head. This allows assessment of primarily C1 C2 rotation.
OA joint surfaces
occiput has convex occipital condyles
Atlas has concave articular facets
OA arthrokinematics flexion and extension
Flexion- occipital condyles role anterior and glide posterior
Extension- occipital condyles role posterior and glide anterior
AA joint movment
Atlas and transverse ligament twist around the dens
shaking or no joint
full rotation provides stretch to vertebral arteries
Limits to movement, alar ligaments apophyseal joint, tension, muscles
Upper cervical ligaments
Alar
Transverse
Tectorial membrane
alar ligament
stabilizes occiput- atlas with rotation
transverse ligament
Prevents anterior migration of C1 on C2
Lhermittes sign
tectorial membrane
Proximal extension of the posterior longitudinal ligament
The vertebral artery enters intervertebral foramen at
C6
And travel superiorly
And angles at C2 which is accentuated by cervical rotation
Internal carotid artery
less affected by movement but can still influence head and neck symptoms
lower cervical spine extension
Inferior articular facet of the superior vertebrae slides on inferior superior articular facet
maximizes the contact of the facets
Close Packed position
lower cervical spine flexion
The inferior articular facet of the superior vertebrae slides anterior and superior
opening
Maximizes volume in space of the vertebral canal for the spinal cord
protraction
Flexes the lower cervical
Extends the upper cervical spine
Retraction
flexion of the upper cervical spine
Extension of the lower cervical spine
Protraction causes a strain in
trapezius
cervical extensors
and a weakness in the deep cervical flexors
rotation of the lower cervical (R)
Right facets slide posterior and inferiorly closing
left facets slide anterior and superior opening
lateral flexion of the lower cervical R
closing of the ipsilateral side posterior, inferior gliding
Opening on the contralateral side superior anterior gliding
Muscles shortened with bad posture
upper cervical muscles
Sub occipital triangle
Upper traps
Splenius capitis cervicis
semispinalis cervicis
SCM
pec
lat
scalenes
weak muscles due to posture
deep neck flexors stabilizers
longus capitis
longus coli
thoracic extendors
