The lumbar spine is the third an ar of the vertebral column, located in the lower ago between the thoracic and also sacral vertebral segments.

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It is made up of five distinctive vertebrae, which space the biggest of the vertebral column. This support the lumbar spine in its main role as a weight bearing structure.

This write-up will look in ~ the osteology the the lumbar vertebrae, assessing their characteristic features, joints and also their clinical correlations.

 


Characteristic Features

Although the lumbar vertebrae absence some of the much more distinctive features of other vertebrae, there room several attributes that aid to differentiate them.

The vertebral bodies are huge and kidney-shaped. They room deeper anteriorly than posteriorly, producing the lumbosacral edge (the angle between the lengthy axis the the lumbar an ar and that of the sacrum). The vertebral foramen is triangle in shape.

Other attributes of a common lumbar vertebrae:

Transverse processes space long and slender.Articular processes have virtually vertical facets.Spinous processes room short and broad.Accessory processes can be uncovered on the posterior element of the base of each transverse process. They act as sites of attachment for deep earlier muscles.Mammillary processes can be discovered on the posterior surface ar of each exceptional articular process. They act as sites of attachment because that deep ago muscles.

The 5th lumbar vertebrae, L5, has actually some distinctive features of that own. It has actually a notably large vertebral body and also transverse procedures as the carries the weight of the whole upper body.


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Fig 1.1 – premium view of a lumbar vertebrae, mirroring its characteristic features.


Joints

There space two types of share in the lumbar spine. Both of these articulations space not unique to the lumbar vertebrae, and also are current throughout the vertebral column.

Between vertebral arches – developed by the articulation of superior and also inferior articular procedures from adjacent vertebrae. It is a synovial form joint.

Ligaments

The joints that the lumbar vertebrae room supported by numerous ligaments. They can be separated into two groups; those current throughout the vertebral column, and also those unique to the lumbar spine.

Present throughout Vertebral Column

Anterior and posterior longitudinal ligaments: lengthy ligaments that operation the size of the vertebral column, spanning the vertebral bodies and also intervertebral discs.Ligamentum flavum: Connects the laminae of adjacent vertebrae.Interspinous ligament: Connects the spinous procedures of adjacent vertebrae.Supraspinous ligament: connects the tips of adjacent spinous processes.

(Note: In the cervical spine, the interspinous and also supraspinous ligaments thicken and combine to type the nuchal ligament).

Unique come Lumbar Spine

The lumbosacral share (between L5 and also S1 vertebrae) is strengthened by the iliolumbar ligaments. These room fan-like ligaments radiating from the transverse procedures of the L5 vertebra to the ilia of the pelvis


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Fig 1.2 – Ligaments of the lumbar vertebrae


Anatomical Relationships

Throughout the vertebral column, the spinal cord travels with the vertebral canal (made increase by the foramina of every vertebrae). At around the level of L1, the spinal cord terminates and the cauda equina begins. This is a bundle that lumbar, sacral and coccygeal nerve roots.

Spinal nerves leave the vertebral canal v the intervertebral foramina.


Clinical Relevance: Abnormalities the the Lumbar Spine

Lumbar Spinal Stenosis

Thought to be hereditary, lumbar spinal stenosis results in a stenotic (narrow) vertebral foramen in one or number of lumbar vertebrae. This deserve to cause compression that the spinal cord and exiting nerves.


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Fig 1.3 – excessive lumbar lordosis.


This problem can it is in worsened by age-related degenerative changes, such together bulging the the intervertebral discs.

Lumbar spinal stenosis can sometimes be cure surgically through a decompressive laminectomy.

Excessive Lumbar Lordosis

This is an abnormal anterior curvature that the vertebral obelisk in the lumbar region, characterised by anterior tilting that the pelvis.

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Women construct temporary too much lumbar lordosis in late pregnancy, but this resolves ~ childbirth. In either sex, weight problems can an in similar way cause lordosis due to the increased weight the the abdomen. Both examples can cause back pain, and occur as a an outcome of an altered line that gravity.