Learning Objectives

Identify the characteristic features of the lumbar vertebrae. Distinguish between the two types of spinal joints. Memorize the ligaments unique to the lumbar region. Understand spinal stenosis and excessive lordosis.

Overview & Development

The lumbar spine consists of five vertebrae (L1-L5). They are the largest in the column because they serve as a primary weight-bearing structure. The vertebral bodies are large and kidney-shaped, while the vertebral foramen is triangular.

Characteristic Features

• Transverse processes: Long and slender.
• Spinous processes: Short and broad.
• Accessory and Mammillary processes: Key sites of attachment for deep back muscles.
• L5 Vertebra: Has a notably large body and transverse processes as it carries the weight of the entire upper body.

Joints of the Lumbar Spine

• Intervertebral Discs: Located between vertebral bodies; these are cartilaginous joints (symphyses).
• Facet Joints: Formed by the superior and inferior articular processes; these are synovial joints.

Ligaments

General Ligaments: Anterior/Posterior longitudinal, Ligamentum flavum, and interspinous/supraspinous ligaments.

Unique to Lumbar: The Iliolumbar ligaments radiate from the transverse processes of L5 to the ilia to strengthen the lumbosacral joint.

Anatomical Relationships

• The spinal cord ends at L1, where the cauda equina begins.
• Spinal nerves exit the column through the intervertebral foramina.

Clinical Relevance: Abnormalities

• Lumbar Spinal Stenosis: A narrowing of the vertebral foramen that causes compression of nerve roots.
• Excessive Lumbar Lordosis: An abnormal anterior curvature of the spine, often caused by pregnancy or obesity.

Activity