Herniated disc LWK 5/SWK 1 rightT2 sagittal MRIOne can see a large, cranially shifted, sequestered disc herniation at L5/S1 (right side). Because of the herniation of the disc into the spinal canal there is compression and irritiation of spinal nerves L5 and S1 right (see MRI). The spinal nerves L1-S5 form the lumbosacral plexus, source of the sciatic nerve, the longest and thickest nerve of man.The sciadic nerve has sensory and motor nerve fibers and divides above or behind the knee into the peroneal and tibial nerve, thus supplying the entire back of the leg and foot.A herniated disc often leads to pain in the area supplied by the nerve, to sensory disturbances (numbness, tingling) and paralysis (affecting the ability to stand on the heels or tiptoe). In rare cases the herniated disc can shift, leading to paraplegia and urinary and fecal incontinence, the so-called cauda equina syndrome.In this young patient (32 years old) the disc L5/S1 is narrower than the other discs and the signal in MRI is hypointense (darker). These are signs of increased wear. In healthy discs, the disc nucleus (nucleus pulposus) appears light and the fibrous cartilage ring (annulus fibrosus) dark in MRI.
