Cervical and Thoracic Spine Arthrology

Vertebral column

Consists of 33 vertebrae
7 cervical and 12 thoracic
5 lumbar, 5 sacral and 4 coccygeal

Cervical region

3-6 are typical
1,2 and 7 are atypical

Cervical vertebrae

Small vertebral bodies
Large triangular neural canal
Bifid spinous process
Transverse foramen
Uncovertebral joints

Thoracic vertebrae

Heart shaped vertebral bodies
Long vertically-inclined spinous processes
Long transverse processes
Facets of articulation with ribs

Articular facets of cervical region

Superior, slightly convex facets are directed upwards, backwards and slightly medially
Inferior, slightly concave facets face downwards, forwards and slightly laterally
Facets become more vertical in the lower part of the region

Articular facets of thoracic region

Superior facets face backwards, slightly laterally and upwards
Inferior facets face forwards, slightly medially and downwards

Intervertebral disc

Fundamental part of the vertebral column that enable movement while maintaining stability, transferring weight and absorbing shock
Formed of three elements; central nucleus pulpous, peripheral annulus fibrous and superior and inferior vertebral end plates

Vertebral end plates

Layers of cartilage that cover top and bottom of discs, separating and attaching discs to vertebral bodies

Nucleus pulpous

Semi-liquid mass held within confines of annulus fibrous, it consists of cartilage, collagen fibres in a semi-fluid ground substance
It has a high level of internal friction which allows the disc to hold water - this means it can be deformed under pressure to absorb and transfer force

Annulus fibrous

Formed of organised collagen layers of 10-12 lamellae forming concentric rings around nucleus pulpous - thickest anteriorly and laterally, thinnest posterolaterally
Successive layers form an X arrangement providing strength

Functional spinal unit

Smallest individual unit of movement within the vertebral column
Made up of two vertebrae and the intervening joints
Anteriorly - a secondary cartilaginous joint (symphysis)
Posteriorly - two simple, synovial, plane joint - zygapophyseal/facet joints

Uncovertebral joints

Joints of Luschua
Simple, synovial, plane joint
Due to small size of IVDs in the cervical region compared to the size of vertebral bodies, there is often direct connection between vertebral bodies in the mid-cervical region
Helps minimise friction between vertebrae
Vertebral bodies overlap discs

Anterior longitudinal ligament

Attaches to anterior part of bodies and discs from anterior tubercle of atlas to pelvic surface of sacrum, widening as it descends

Posterior longitudinal ligament

Attaches to intervertebral discs and adjacent margins of vertebral bodies within the vertebral canal, extending from C2 to sacrum

Ligamentum flavum

Passes between both laminae and adjacent vertebrae from C1 to L5, attaching to the front of the lower border of the lamina above and back of the upper border of lamina below - medial borders meet at root of spine

Supraspinous ligament

Band of longitudinal fibres running over and connecting tips of spinous processes from C7 to sacrum and is continuous with the posterior edge of the interspinous ligament

Interspinous ligament

Thin membranous bands between adjacent vertebral spines

Intertransverse ligament

Pass between adjacent transverse processes - absent in cervical region

Ligamentum nuchae

In cervical region - supraspinous ligament is extended and developed into a new structure
Attaches between the external occipital protuberance, nuchal lines, spinous processes of cervical vertebrae 1-7
Performs the same functions of the supraspinous ligaments along with some additional features
Triangular midline septum between spine of C7 and external occipital protuberance

C7

Vertebral prominens
Transition between cervical region and thoracic region
Long, vertically inclined, non-bifid spinous process
Relatively large vertebral body
Relatively narrow neural canal

C1

Atlas
Most atypical vertebrae in the spine
No vertebral body or spinous process - instead anterior arch and posterior tubercle
Very large neural canal and large articular masses for communication of large CNA content, articulation with occiput and weightbearing

C2

Axis
Strongest vertebrae in cervical region
Stout vertebral body and spinous process
Tooth like projection - dens or odontoid peg for articulation with the anterior arch of atlas
Large articulation masses for articulation with atlas

Occipital bone

C0
Flat, cranial bone at base of skull
Characterised by - external occipital protuberance, nuchal line, foramen magnum and condyles for articulation with atlas

Atlanto-occipital joint

Synovial, simple, ellipsoid, biaxial
Between superior concave facets on lateral mass of atlas and convex facets on occipital condyles
Anterior and posterior atlano-occipital membranes run between anterior and posterior margins respectively of foramen magnum and arch of atlas
Flexion, extension and lateral flexion can occur here but only in small ranges of movement

Atlanto-axial joint - lateral

Synovial, plane, simple, multiaxial
Between inferior facet on lateral mass of atlas and superior facet on axis
Anterior longitudinal ligament
Posterior atlanto-axial membrane extending from lower border of posterior arches to upper edges of lamiae of axis
Rotation

Atlanto-axial joint - medial

Synovial, pivot, simple, uniaxial
Between dens of axis and ring formed by anterior arch of atlas and transverse ligament of atlas
Transverse ligament to hold dens in place - thick, strong band extending between tubercle on medial sides of lateral masses of atlas
Membrane tectora - broad sheet continuous with PLL extending from posterior aspect of body of C2 to anterior edge of foramen magnum
Alar ligament - extending from either side of the base of the dens to the medial side of occipital condyle
Apical ligament - extending from tip of dens to anterior margin of foramen magnum
Rotation

Movement

Limited in thoracic but free in cervical
Rotation most limited in lumbar
Movement at FSUs limited by summation of movement produces relatively free movements
Factors influencing - shape and direction of articular facets and size of disc relative to size of body (larger means more movement)

Tectorial membrane

Blends with posterior longitudinal ligament so limits flexion