bio-mechanics trunk and spine

• Occipital-atlantal (OA) joint - condyloid - roll glide opposite (closed chain)
• Atlantal-Axis joint (AA) - pivot - spin
• C2-L5 - plane - just glide

Joint capsule - resists all extremes ecept extension when the arthokinamtics is only gliding.

Transverse ligament (or cruxiform lig) - prevents postior translation of the dens, which because C1 has no body this prevents it from pushing on the spin.

Ligamentum nuchae - (which becomes the supraspinous ligament in the thoracic and lumbar regions of the spine) - it restrics flexion of the spine

interspinous ligament - thin and membranous, connect adjoining spinous processes and extend from the root to the apex of each process.

Anterior and posterior Atlanto-occipital membranes -

Tectorial membrane of the OA joint which becomes posterior longitudinal ligament - restricts flexion.

Alar ligament of the AA joint - restricts rotation

Interransverse ligament - restricts contralateral side bending.

Anterior longitudinal ligament - restricts extension

Posterior longitudinal ligament - restricts flexion

Ligamentus flavum - restricts flexion

Annulus fibrosus - restrics axial rotation

anterior annulus fibrous - restricts extension

Posterior annulus fibrous - restrics flexion

Left side of the annulus fibrisus - restricts right side bending and vica versa

Cercixal viscera - (esophagus and trachea - restrict extension)

• Proper ligaments -
• Composed of Type I collagen fibers
• Oriented in direction of the movement that they limit

• False ligaments
• Collagen fibers are arranged randomly, which limit their strength

Transverse and spinous processes - acts as levers for muscle and ligament attachment.

Apophyseal -formed between adjacent superior and inferior articular facet.

interbody joints - acts as a shock absorber and stabilizer of the vertebral colum. Site of axis of rotation.

Vertebral body -

Verebral endplates

• Vertebral disc - has two part the
• which resist distraction, shear and torsion

Annulus fibrosis - deforms outward against annulus, and the back pressure from the annulus pushes on nucleus - reinforcing the entire disc and passes load to next vetebra. Diversion takes time and reduces loading and by sharing the load reduced wear.

Nucleus pulposis - is the pulp-like gel which functions as a hydraulic shock absorber. Moves in relation to spinal movements due to increased pressure.

Nucleus pulposus pushes against neural tissue.

Typically is in a posterior or posterior lateral direction.

May or may not breakthrough the annulus fibrosus.

Pain may be mechanical or neurogenic in nature.

• Flexion/ Extension
• Lateral flexion
• Rotation

right/left direction is determined by looking at which way the anterior surface of the superior vertebra is facing.

T7-8 right rotation: point on anterior body of T7 rotates right while spinous process goes left.

• Cranio-cervical -
• Occipital-atlantal - C1
• Atlanto-axial - C2

Intracervical apophyseal joints (C2-7)

• Thoracic
• Lumbar
• Pelvis

Flexion (nodding) - anterior roll and posterior glide on atlas.

Extension - posterior roll and anterior glide on atlas

• AA joint
• Flexion - pivot forward

Extension - pivot backward

Flexion - facets slide up - superior glide of superior vertenra on inferior vertebra.

Extension – “facets slide down” - Posterior, inferior glide of superior vertebra on inferior vertebra

Costotransverse and costovertebral joint