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Robotic Spine Universe

Structures · Vertebrae

L3 vertebra

Vertebra 3 of the lumbar (lower back) spine. This page uses the vertebral level system; the cord segments that lie opposite it have different names.

Show in the 3D spineSee what it connects to in the body

At a glance

Level system
L3 vertebra (vertebral level)
Cord segments opposite its body
None: below the end of the cord in this model; the canal holds the cauda equina hereModel mapping. Frostell et al. 2016; De Leener et al. 2018; Cadotte et al. 2014
Canal, front to back × side to side
13.6 × 30.2 mmMeasured on one model: the Visible Human male, imaged as a supine cadaver. Not a normal range
L2 nerve
The L2 nerve exits between the L2 vertebra and the L3 vertebra, below the L2 vertebra.Betts et al. 2022, §13.4
L3 nerve
The L3 nerve exits between the L3 vertebra and the L4 vertebra, below the L3 vertebra.Betts et al. 2022, §13.4

What the sources say

“The lower back contains the L1–L5 lumbar vertebrae.” Betts et al. 2022, §7.3
“Lumbar Vertebrae Lumbar vertebrae carry the greatest amount of body weight and are thus characterized by the large size and thickness of the vertebral body ( Figure 7.28 ).” Betts et al. 2022, §7.3

Connections to the rest of the body

  • Muscle attachments

    Segmental muscles join neighbouring vertebrae

    The smallest back muscles span a single joint, from one vertebra to the next.

    Betts et al. 2022, §11.3 · Show on the body

  • Muscle attachments

    The diaphragm anchors to the lumbar spine

    Behind, the breathing muscle takes origin from the lumbar vertebrae and the 12th ribs; in front, from the sternum and lower ribs.

    Betts et al. 2022, §11.4 · Show on the body

  • Arterial supply

    Lumbar arteries supply the lower back and the cord

    Four pairs of lumbar arteries leave the abdominal aorta beside the lumbar vertebrae; they are the lower counterparts of the intercostal arteries.

    Betts et al. 2022, §20.5 · Show on the body

For learning only. Levels and sizes vary between people; nothing here describes a particular person or gives medical advice. Sources: Betts et al. 2022, §7.3; Frostell et al. 2016; De Leener et al. 2018; Cadotte et al. 2014; Betts et al. 2022, §13.4; Betts et al. 2022, §11.3; Betts et al. 2022, §11.4; Betts et al. 2022, §20.5.