Kinesiology - Vertebral column

Motion segment

Two vertebral bodies and the disc in between

Ligaments supporting the spine

ALL, PLL, ligamentum flavum, supraspinous ligament, interspinous ligament

Common site of disc injury

L5/S1

Anterior lumbar ligament

Intersegmental ligament

Limits disc motion in extension and side-bending

Compressed in flexion, stretched in extension

Ligamentum flavum

Intrasegmental ligament

Increases pressure on intervertebral discs to make them stiffer in neutral

Stretched during flexion but provides constant tension in neutral

Creep

The tendency of a stretched object to NOT return to original length

Can lead to increased ROM, decreased stability

Hysteresis

When an object is unloaded its stiffness is different than before

Axial compression

Force acting through the long axis of the spine at a right angle to the disc

Spinal Bending

Compression and tension of spine structures. Can cause creep

Spinal torsion

Force created during axial rotation

Spinal shear

Translational forces acting int he transverse plane

Autofusion

Under certain conditions, the body will fuse its own vertebra together

Trabecular pattern

Lines of reinforced bone found in the spine. Designed to resist compressive load

Par interarticularis

The portion of lamina between the superior and inferior articulating surfaces

Posterior longitudinal ligament

Intersegmental ligament

Runs within vertebral canal along posterior vertebral bodies

Stretched ini flexion, compressed in extension

Interspinous ligament

Intrasegmental ligament

Well developed in lumbar spine

Runs between base of spinous processes

Supraspinous ligament

Intersegmental ligament

Runs along spinous processes

Becomes ligamentum nuchae in cervical spine

Stretched during flexion

Intertransverse ligament

Intrasegmental ligament

Only well developed in lumbar area

Supports spine in side-bending

Function of cervical spine

Support and stabilize head

Position head

Protect neurovascular structures

Lever arms for muscles and ligaments