L5–S1 intervertebral disc

At a glance

Level system

L5-S1 disc (vertebral level)

Between

L5 vertebra and Sacrum

In the model

Drawn schematically (filled between the endplates)Schematic

L5 nerve

Leaves through the foramen at this level. The L5 nerve exits between the L5 vertebra and the sacrum, below the L5 vertebra.Betts et al. 2022, §13.4

What the sources say

“Intervertebral Disc An intervertebral disc is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies (see Figure 7.24 ).” Betts et al. 2022, §7.3

“The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus.” Betts et al. 2022, §7.3

“Because of this, intervertebral discs are thin in the cervical region and thickest in the lumbar region, which carries the most body weight.” Betts et al. 2022, §7.3

“The most common sites for disc herniation are the L4/L5 or L5/S1 intervertebral discs, which can cause sciatica, a widespread pain that radiates from the lower back down the thigh and into the leg.” Betts et al. 2022, §7.3

Read more

• Sagittal alignment

  How the spine's side-view curves and the pelvis work together to keep the trunk balanced over the hips. Pelvic incidence, tilt and slope, the C7 plumb line, and how the body compensates when alignment is lost.

• The intervertebral disc

  The fibrocartilage pad between two vertebral bodies: a tough outer ring around a gel-like core. How it bears weight and lets the spine bend, how it changes with age, and what a herniated disc is.

• The sacrum and coccyx

  The fused bones at the base of the column. The sacrum carries the weight of the trunk into the pelvis and lets the sacral nerves out through its foramina; the coccyx is the tailbone.