applied anatomy biomechanics Flashcards
CxSp function
Support weight of head Position special senses for optimal function mobile & stable vertical & horizontal plane Protect spinal cord Protect Vertebral Arteries
blood supply
cervical arteries ascend within confines of cervical spine
foramen in TP of the vertebrae
from C6 up
bony canal for arteries
4 arteries form circle of willis in brain
neck pain - dizzy ?
hind brain experiencing lack of blood supply
vertebral foramen more lateral in atlas than in axis
blood vessel needs to turn
atlas on axis motion - pivot movement 40-45 degrees of rotation
osteology
Upper cervical spine C0-2
Mid-lower cervical spine C3-7
vertebral artery splits into ant and posterior - gutter
exiting nerve roots lie in a gutter - more likely to be compromised but also positive protective
ATLAS
atlas supporting the occiput missing a vertebral body anterior arch posterior arch TP - very wide support weight of the head
AXIS
dens - body of atlas attached on
SAF - articular with inferior of atlas
spinous process not always the same size
typical cervical vertebra
body to foramen - even
bifid spinous process in most C segments
ligaments
transverse ligament
help stabilise dens with alar ligaments help control ligament of dens and C2
transverse stops dens moving and compromising the SC
The ligaments in this region have become highly specialised to maintain stability without sacrificing mobility
Transverse ligament: stabilises the atlanto-axial segment and protects the spinal cord from the dens
Alar ligament: controls motion both at the C0/1 and C1/2 joints
Tectorial membrane: the thickened end of the posterior longitudinal ligament
ADI
Normal radiological Atlanto-Dens Interval (ADI):
In flexion, less than 3mm in children
IN flexion, less than 3.5mm in adults
Ant. shift of C1 on C2 of > 3-5 mm implies injury to transverse ligament
Ant. shift > 5 mm implies injury transverse & alar ligaments
Atlanto-occipital joints
Condyloid joint: convex, oval shaped occipital condyles fit into concave, elliptical shaped superior articular facets on atlas
Atlanta-axial joints
Atlanto-Axial joints (C1-2)
Plane joints: between lateral masses of atlas and inferior articular facets on atlas
Pivot joint: between Dens and anterior arch of atlas and Cruciform (transverse) ligament
rotary pivot - most important movement
cervical joints
facet
uncovertebral
interbody
Facet / Apophyseal joints – 45˚ plane Weight bearing Meniscoid inclusions C1-7 attached to capsule: protect articular cartilage Uncovertebral joints - joints / pseudoarthroses – C3-6 degenerate early in life – danger of osteophytes (compromise of nerve roots at that level likely) protect disc from shear Interbody joints = discs Small NP less distinct less H2O
cervical disc
Small
NP less
distinct
less H2O
exiting nerve roots
C3-C4 short nerve root
dorsal - facet joints supply
and ventral ramus
C4 - compromised nerve root at the level below
C5 inflamed and irritated nerve root leaving at that level
know dermatomal pattern
Dermatomes
C5 finished around the elbow
C6 radial side of forearms
C7 middle fingers
C8 - medial side of the hand
muscles
levator scapula
tight - common
upper mid lower traps
splenius wapitis
splenius carvicis
deep muscles
inferior oblique
superior oblique
rectus captious posterior major and minor
direct connections between dura matter and rectus captious posterior minor
foramen magnum
traps most superficial attachment
sub occipital muscles are deep
muscles torque
SCM working together - biggest torque producing flexion
scalene anterior working together second best
anterior middle scalene - flexion to the same side
flexion
test separately
upper and lower cervical spine
flexion - separation of spinous processes
atlas to axis - small tilt barely any slide
RESTRAINTS – Ligamentum nuchae Interspinous & supraspinous ligts Ligamentum flava Facet joint capsules Posterior AF PLL Transverse ligament
cervical extension
occiput on atlas posterior glide
slide of facet joints
restraint from stretching anterior longitudinal ligament
occipital condyles roll back on the atlas
as they glide forward
cervical extension
RESTRAINTS:
Oesophagus & trachea
Anterior AF
ALL
cervical movement
saggital plane movement
combination of flexion and extension
greatest at C5-6
highest incidence of degenerative change
matched of flexion and extension
more movement than other segments on the spine
C0/C1 more movement than C1/C2
protraction
retraction
position of head relative to thorax
flexion of lower C spine
extension of higher C Spine
some shortening sub occipital muscles
practice retraction mvmt
side flexion
facet joints slide closed
other side slide open
slide open easier to palpate
restraints to side flexion
RESTRAINTS: Intertransverse ligaments Contralateral AF Facet joint capsule Alar ligaments
cervical rotation restraints
AF
Facet joint capsule
Contralateral Alar ligaments (excessive rotn may damage)
lateral flexion vs rotation
lateral flexion less than rotation
significant C1/C2 rotation
most of lateral flexion occurring at occiput and Atlas
occiput and atlas
saggiato plane movement
C2-C7
motion - normative data
FLEXION - 50 degs
EXTENSION - 70 degs
LAT FLEXION - 40 degs
ROTATION - 90 degs
coupled movement
C0-2:
C0-1 (OA jt):
Literature confused
C1-2 (AA jt): variable
pattern
Consider C0-2 as
functional unit
(L) Rotn C1-2 causes (R) SF C0-1 CONTRALATERAL Coupling
C2-C7 ipsilateral - coupling (L) Rotn causes (L) Sideflexion at same segmental level
Due to Facet joints
