Lumbar Vertebrae

Written by Tele Demetrious


Relevant Bony Anatomy

The lumbar vertebrae (of the lower back) are the largest vertebrae within the spine. This is necessary to provide a strong foundation to support the weight of our head, arms and trunk.

There are five lumbar vertebrae (namely L1 to L5, from top to bottom). The L1 vertebra articulates (forms a joint) with the 12th thoracic vertebra, whilst the L5 vertebra articulates with the sacrum (tail bone). Occasionally, a 6th lumbar vertebra is present as part of the sacrum. This is termed ‘lumbarisation of S1’ and is present from birth in a relatively low percentage of the population.

Typical lumbar vertebrae primarily comprise of a heart shaped body (at the front of the bone) and a vertebral arch (situated directly behind the body), which forms a hole known as the vertebral foramen. Since each lumbar vertebrae is situated directly above or below each other, their collective vertebral foramen line up forming the vertebral canal which houses and protects the spinal cord. In the lumbar spine, the vertebral foramen is relatively larger than the thoracic spine (upper back) as it has to accommodate the lumbar and sacral plexus’ (all the nerves to supply the lower limbs).

Each lumbar vertebra joins with adjacent lumbar vertebrae primarily at the facet joints (located at the back, and on each side, of the spine) and the discs of the lumbar spine (located centrally at the front of the spine) (figure 1). Movements between each adjacent vertebra are relatively small, but when summated over the entire vertebral column allow considerable mobility.

Anatomy of the Lumbar Vertebrae

Figure 1 – Anatomy of the Lumbar Vertebrae

In the lumbar spine the facet joints are orientated in the sagittal plane, which means the primary movement of the lumbar spine is flexion/extension (i.e. forward and backward bending of the spine), allowing only limited rotation or side flexion (side bending).

Each lumbar vertebra also has various bony prominences, such as the spinous processes (located at the back of the bone) and transverse processes (located at each side of the vertebra). These bony prominences provide attachment points to the ligaments and muscles of the lumbar spine. In the lumbar spine, the spinous processes are short, broad and thick. They need to be broad to create a strong attachment point for muscles, whilst they need to be short and horizontally orientated, to allow extension (arching backwards). The L5 vertebra has a slightly smaller spinous process than the L1-L4 vertebrae, to allow it to articulate with the sacrum.

There are several other distinguishing features of lumbar vertebrae. Unlike thoracic vertebrae, the lumbar vertebrae do not articulate with the ribs. The lumbar vertebrae are also bigger. This is especially apparent when comparing the size of the vertebral bodies. The vertebral bodies in the lumbar spine are larger and more oval shaped. This is necessary as the lumbar spine supports more weight than the cervical (neck) and thoracic (upper back) spines. The vertebral bodies are also slightly wedge shaped (thicker at the front and narrower at the back) to give us the natural curve of our lower back, known as the lumbar lordosis.

A commonly injured part of the lower back are the lumbar discs. These are located between the vertebral bodies of each lumbar vertebra. The disc (also known as intervertebral disc) is in fact a joint – a fibrocartilaginous joint. Its main role is to provide strength and shock absorption, but also to allow flexibility of the vertebral column (spine). It does this through its unique design. The outer part (wall) of the disc is constructed of supportive fibrous rings, known as the annulus fibrosis. These rings are aligned as cross bridges for added strength and support. The inner part of the disc is made of a jelly-like viscous fluid, called the nucleus pulposis, which helps absorb shock and weight bearing forces. When doing this, the fluid spreads outwards to meet the opposing resistance of the annulus fibrosis. Injuries to the lumbar disc typically involve damage to the annulus fibrosis and subsequent bulging of the nucleus pulposis. This is known as a lumbar disc bulge.

Interestingly, the disc is the largest avascular structure in the body. This means that it has no direct blood supply. Instead its nutrition relies on blood flow diffusing through the tiny arteries (capillary beds) found in the intervertebral bodies above and below. In regards to nerve supply, only the outer third of the annulus fibrosis has a nerve supply.


The five lumbar vertebrae are located at the bottom of the spine. The five lumbar vertebrae are numbered from the top to the bottom as L1 to L5.

Forms Joints With

Major Muscles of the Lumbar Spine

Trunk Muscles

Posterior Abdominal Wall Muscles

Posterior Vertebral Muscles – Superficial layer:

Intermediate Layer:

Deep Layer:

Deepest Layer:

Other Attachments

Related Injuries


  Related injuries

Relevant Physiotherapy Exercises



  Relevant Physiotherapy Exercises

Recommended Reading

  Recommended Reading

Find a Physio

  Find a Physio

Find a physiotherapist in your local area who can diagnose and treat sports and spinal injuries and provide education on the anatomy of the lumbar spine and lumbar vertebrae.

Link to this Page

Link to this Page

If you would like to link to this article on your website, simply copy the code below and add it to your page:

<a href="”>Lumbar Vertebrae –</a><br/>PhysioAdvisor provides detailed physiotherapy information on the human anatomy of the lumbar spine and lumbar vertebrae. Including location, joints, muscular attachments, relevant injuries and more...

Return to the top of Lumbar Vertebrae.