lumbar spine

what curvature is foundat the lumbar spine

secondary lordosis

actions of lumbar spine

flexion, lateral flexion, no rotation

shape of VB

very large, kindney bean shaped

SP SHAPE

SHORT Broad rectangular

what makes up the verterbral forament

body+arch

does the lumbar vertebrae house the spinal cord

no it hosts the cauda equine

superior ap of lumbar spine face which way

medially, wider , and contain mamillary process

inferior ap whicway

laterally, narrower, and have no mamillary process

what creatses a saggitall orientation in facet joints in lumbar spin e

medial+lateral articulation

borders of intervertebral foramen poserolateral

part of the VB and IV DISC 

superior 

superiru vertebral notch 

where do spinal nerves exit 

the inferior border of numerically corresponding vertebra

where does l5 articulate

base of sacrum and superior ap of sacrum (ala of sacrum)

clinical applications- herniation of IVD L4/L5 posterolteral herniation

where does it herniate

which spinal nerve affected?

A posterolateral (paramedian) herniation occurs just lateral to the posterior longitudinal ligament, in the lateral recess of the vertebral canal.
This area is a common weak spot because the posterior longitudinal ligament is thinner laterally.

posterolateral L4/L5 disc herniation compresses the L5 spinal nerve root.

Why L5?

• The L4/L5 disc lies below the L4 vertebra, so a herniation here affects the nerve root exiting one level below the disc, which is L5.

• The L4 nerve root exits above the disc (through the L4/L5 intervertebral foramen), so it is usually spared.

clinical applications- herniation of IVD L4/L5 extraforminal herniatoin herniation

where does it herniate

which spinal nerve affected?

Where does it herniate?

Extraforaminal (far-lateral) herniation occurs:

• Lateral to the intervertebral foramen

• Beyond the boundaries of the spinal canal

• Often compressing structures as they exit the foramen

It protrudes directly lateral to the pedicle, sometimes called a far-lateral or foraminal-plus herniation.

Which spinal nerve is affected?

➡ The L4 spinal nerve root is affected.

Why?

• At the L4/L5 disc level, the L4 nerve root exits through the L4/L5 foramen.

• A far-lateral/extraforaminal herniation compresses the nerve root as it exits, so:

  • L4 nerve root is compressed

  • L5 nerve root is NOT typically affected (because L5 travels medial to this area)

This is the opposite of the more common posterolateral herniation, which affects L5.

spondylolysis

tress fracture or defect of the pars interarticularis (also called the isthmus), which is the bony bridge between the superior and inferior articular processes of a vertebra.

• Most commonly affects L5

spondyololithesis

Spondylolisthesis = forward slippage of one vertebral body over the one below it.

It most commonly occurs at L5 slipping over S1, often due to a defect in the pars interarticularis.

anterior displacement of a vertebra relative to the vertebra beneath it.
It often results from bilateral spondylolysis (pars fractures), but can also occur from degenerative changes, trauma, or congenital abnormalities.