Some osseous and soft tissue causes of human intervertebral canal (foramen) stenosis.

Much attention has been paid to the causes of vertebral canal stenosis in humans but relatively little has been documented with regard to intervertebral canal (intervertebral "foramen," lateral spinal canal, nerve root canal) stenosis. As the dural sleeve ends at the outer opening of the intervertebral canal, a false "normal" myelogram is possible when a space occupying lesion occurs beyond the subarachnoid space. Also, if stenosis affects only vascular structures, compression of these structures cannot be noted during myelography, so venous stasis may be overlooked. Our cadaveric study investigates some causes of intervertebral canal stenosis due to encroachment by bony and soft tissue structures, and low magnification photomicrographs are used to illustrate some causes of stenosis.