Lumbar Spine, Hip and Knee LO1

1. Understand the organization of the lumbar portion of the vertebral column.

There are 5 lumbar vertebrae, and these are considerably more robust than the cervical or thoracic types. L5 articulates with the base of the sacrum; thus, the lumbar spinal column is attached to the pelvic girdle.

Between the bodies of the vertebrae are intervertebral discs (symphyses - cartilaginous joints). These discs are composed of an outer, fibrous ring (anulus fibrosus) and the deep nucleus pulposus. There are intervertebral discs between all the lumbar vertebrae and between L5 and S1. The nucleus pulposus is considerably thicker anteriorly than posteriorly.

The highest frequency of disc herniations/protrusions occur at the L4/L5 or L5/S1 levels, and occur in a posterolateral direction. Acute herniations may be comorbid with intervertebral foramina narrowing that can compress spinal nerves or roots.

Disc herniation and intervertebral foramina narrowing are among the many possible causes of lower back pain.

The sacro-iliac joints posterior joints of the hip girdle formed by the articulation of the auricular surfaces of the ilia and sacrum. This is a compound joint with both a synovial (anterior) component and a syndesmosis/fibrous (posterior) component. This is one of the strongest, weight-bearing joints of the body, which is supported by many strong ligaments and only allows a limited amount of movement.