Dorsal Disc Essay

The structure of intertebral disc is complex. Nucleus pulposus has a well organized matrix which is laid down by relatively few cells. Nucleus pulposus is a gelatinous structure present in the centre and is contained in the periphery by annulus which is collagenous and cartilaginous, and two cartilaginous endplates cephalad and caudad. Collagen fibers from annulus continue and attach to the surrounding tissues, tying into the vertebral body along its rim, cartilaginous endplates superiorly and inferiorly and anterior and posterior longitudinal ligaments. Bony endplate and cartilaginous endplates were connected by calcified cartilage. At birth, the disc has a direct blood supply in the annulus and endplates which disappears by the age of 1 year and from then on the disc

Nomenclature of intervertebral disc is such that it takes the name of the vertebra cephalad to it. The disc between L4 and 5 will be called L4 disc.

Dorsal root ganglion (DRG) is present at the level of the intervertebral foramina and it is in the confines of the foramina. Three branches arise distal to the DRG- Ventral ramus, Dorsal ramus and sinuvertebral nerve. The ventral ramus is the most prominent and most important branch and it supplies the structures ventral to the neural canal. Second branch is the sinuvertebral nerve is a small branch arising from the ventral ramus traverses medially over the posterior aspect of the disc, vertebral body and posterior longitudinal ligament and supplies these structures. Third branch, the dorsal ramus courses dorsally and pierces the intertransverse ligament near the pars interarticularis and divides into 3 branches which supply the structures dorsal to the neural canal. The lateral and intermediate branches supply the posterior musculature and skin while the medial branch divides into 3 branches and supplies the facet joints at and the adjacent