Nervous System: Physiology

00:00 The nervous system is an important thing to consider when it comes to the pelvic region. The pelvis housed a lot of sympathetic, parasympathetic and motor plexus. You have your lumbar plexus from T12 to L4, you have your sacral plexus from L4 to S4, the sciatic nerve originates and passes through the pelvis and you have your coccygeal plexus also. So the sacral sympathetic trunks are extension of the lumbar sympathetic chain and they fuse over the coccyx to form the ganglion impar. The parasympathetic nerves of the pelvic splanchnics also arise from S2 to S4 and that goes and supplies parasympathetic innervation to the left colon and then to most of the organs within the pelvis. So the vagus nerve from cranial nerve X comes down and generally supplies parasympathetic innervation to most of the organs of the abdomen, the heart, lungs and most of the gut whereas the sympathetics are provided from the sympathetic chain and now the parasympathetics of the pelvis in the distal gut is provided from S2 to S4. So this is really important to distinguish where the parasympathetic innervation starts and also the different organs that are innervated by the sacral plexus as opposed to the vagal nerve. Additionally, you have the inferior hypogastric plexus. Both are parasympathetic and sympathetic fibers. There is a smaller plexus to the rectum, bladder and prostate, uterus and the vagina. The pelvis houses a lot of different viscera. As a container, it holds the GI system, the GU and also the reproductive organs. There are many different ligaments that help to support the structures within the pelvis. These ligaments help to carry vessels and nerves and helps to innervate these organs and so some important ones to be familiar with include the lateral ligament of the bladder, the cardinal ligament which becomes the base of the broad ligament and the uterosacral ligaments. You also have another view here where you could appreciate some of the additional ligaments including the median ligament of the bladder, uterosacral ligaments, the broad ligament which you cannot picture here but it actually connects to the cardinal ligament labeled as 4, the suspensory ligament of the ovary and the round the ligament. So, the pelvis plays a large role with respiration and circulation. The abdominal diaphragm and pelvic diaphragm kind of have to work together for breathing. So, when you have your abdominal diaphragm descends when you take a deep breathe in, the pelvic diaphragm also has to descend and then when you exhale and recoil the pelvis also comes up and so this sort of pumping motion if you imagine 2 different cylinders helps to drive motion and movement to improve circulation to improve lymphatic flow and movement throughout the abdomen. If the abdominal diaphragm is restricted or if the pelvic diaphragm is restricted, that is going to limit the amount of excursion the diaphragm has. So, pelvic motion and when it's free from restriction is important for optimal function for all the different organs that sit and reside above the pelvis and also for the motion available at the thoracic abdominal diaphragm.