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Interspinous Bursa

bursa interspinalis

Interspinous bursae develop between adjacent lumbar spinous processes, particularly at L3-L4 and L4-L5, in response to repetitive contact between opposing spinous processes. They represent acquired adventitial bursae that are not present at birth and develop over decades of spinal loading. Their presence indicates spinous process contact from loss of disc height and hyperlordosis.

Region: Lower Back

Clinical Relevance

Clinical Notes

Interspinous bursitis (Baastrup disease, kissing spine syndrome) produces midline low back pain at the spinous process level, reproduced by lumbar extension and direct palpation of the interspinous space. Plain lateral radiograph shows approximation of spinous processes; MRI demonstrates bursal fluid between them with adjacent bone marrow oedema. Corticosteroid injection into the interspinous bursa provides good short-term relief. Surgical resection of the impinging spinous processes (interspinous process decompression) is reserved for refractory cases.

Pathology

Common Injuries & Conditions

Baastrup Disease at Lumbar Interspinous Bursa

Approximation and contact of adjacent lumbar spinous processes from disc height loss and hyperlordosis causes interspinous bursal inflammation producing central low back pain reproduced by extension and direct spinous process palpation; lateral radiograph confirms spinous contact and MRI demonstrates bursal fluid and adjacent bone oedema, managed by interspinous injection.