The sacrococcygeal symphysis is an amphiahrodial (slightly mobile) joint, formed between the oval surface at the apex of the sacrum, and the base of the coccyx.The movements which take place between the sacrum and coccyx, and between the different pieces of the latter bone, are forward and backward; they are very limited. Their extent increases during pregnancy.A zygapophyseal joint (or facet joint) is a veebral joint between the superior aicular process of one veebra and the inferior aicular process of the one adjacent. It is of plane synol variety. In fact, all the joints of veebra are plane synol Except the median one- which is a symphysis (as expected *).*All midline joints tend to be symphysis, only very few Exceptions are there. E.g., spheno-occipital joint, which is a synchondrosisInterveebral discs (or interveebral fibrocailage) lie between adjacent veebrae in the spine. Each disc forms a secondary cailaginous (symphysis) joint to allow slight movement of the veebrae, and acts as a ligament to hold the veebrae together.Discs consist of an outer annulus fibrosus, which surrounds the inner nucleus pulposus. The annulus fibrosus consists of several layers of fibrocailage. The strong annular fibers contain the nucleus pulposus and distribute pressure evenly across the disc. The nucleus pulposus contains loose fibers suspended in a mucoprotein gel the consistency of jelly. The nucleus of the disc acts as a shock absorber, absorbing the impact of the body&;s daily activities and keeping the two veebrae separated.The disc can be likened to a doughnut: whereby the annulus fibrosis is similar to the dough and the nucleus pulposis is the jelly. If one presses down on the front of the doughnut the jelly moves posteriorly or to the back. When one develops a prolapsed disc the jelly/ nucleus pulposis is forced out of the doughnut/ disc and may put pressure on the nerve located near the disc. This will give one the symptoms of sciatica if the disc herniation is at lumbosacral region.There is one disc between each pair of veebrae, Except for the first cervical segment, the atlas. There are a total of twenty-three discs in the spine.When the annulus fibrosus tears due to an injury or the aging process, the nucleus pulposus can begin to extrude through the tear, most commonly postero-lateral. This is called disc herniation. Near the posterior side of each disc, all along the spine, major spinal nerves extend out to different organs, tissues, extremities etc. It is very common for the herniated disc to press against these nerves (pinched nerve) causing radiating pain, numbness, tingling, and diminished strength and/or range of motion. In addition, the contact of the inner nuclear gel, which contains inflammatory proteins, with a nerve can also cause significant pain and muscle spasm. Nerve-related pain is called radicular pain.