Special form of gray matter found on the top of the posterior horn of the spinal cord. The tissue type looks transparent and difficult to colour, mainly because here the nerve cells are small, the glial cell presence is high and myelinated nerve fibers are almost completely missing.
The area is of particular interest because of its influence on the spread of pain signals from the spinal cord to the brain.
Within the upper part of the cervical spinal cord (segments C1 - C4), parts of the gelatinosa substantia are included in the nucleus of the fifth cranial nerve (nucleus spinalis nervi trigemini). This part influences the spread of pain from the face, including the mouth, nose and eye sockets, to the brain.