Intervertebral disk of first lumbar vertebra

Looks like

The pad between L1 and L2: a large, thick disc, taller at the front, giving the lower back its inward curve. A tough fibre ring surrounds a soft gel core.

What it does

Joins the two vertebrae, absorbs shock and lets this level bend and twist a little.

Keeping it well

A bulge at L1–L2 can pinch the L2 nerve, giving pain in the front of the upper thigh. Numb groin or bladder trouble is an emergency.

Related conditions

• Axial spondyloarthritis
• Bone metastases and spinal cord compression
• Gout
• Haemophilia & bleeding disorders
• Lyme disease
• Marfan syndrome & connective tissue disorders
• Osteoarthritis
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• Rheumatic fever & rheumatic heart disease
• Rheumatoid arthritis
• Scoliosis
• Spina bifida & neural tube defects
• Spinal cord injury
• Systemic lupus erythematosus
• Temporomandibular joint disorder