Nerves are an important part of our body. They allow us to move, feel and understand. We have whole network of nerves branching throughout our bodies. If even a single nerve doesn’t function properly, it creates a huge problem.
One of the most important nerves of our body is the Sciatic nerve. It is one of the largest nerve which supplies large area of our body. It begins its course in the lower back and runs from the hip area and down to the lower limb. Sciatic nerve is the longest and widest single nerve present in the human body, going from the top of the leg to the foot and ending on its the posterior aspect.
The sciatic nerve gives both motor and sensory supply to the lower limb. It is derived from L4, L5, S1, S2, S3 segments of the spinal cord, which are the nerve roots originating from our spinal cord. It contains of fibers from both anterior and posterior trunks of lumbosacral plexus which is composed of lumbar and sacral segments of spinal cord. It supplies most of the muscles of legs, thighs and foot, making them able to move. It also gives sensory supply to leg and foot that helps us feel sensations like pain, temperature and touch etc.
The course of this nerve in body starts in front of piriform muscle which is a muscle of hip area where it is formed by union of fibers. It exits from sciatic notch which is present in our hip bone and runs anterior or deep to piriformis muscle. After that, it runs posterior or superficial to short external rotator muscles which include superior gemellus, inferior gemellus, and obturator internus muscles which are also the muscles of hip area. Then it runs down the posterior aspect of the leg where it divides into its three main branches approximately on the level of the mid-thigh. Its terminal branches include common peroneal nerve and tibial nerve. Hence, it starts from the hips and passes through various muscles in hips, thighs and legs ending in the foot by dividing into two final branches.
Both tibial and peroneal divisions have motor and sensory supplies of their assigned areas. The motor supply of tibial division goes to semi tendinous muscle, semi membranous muscle, long head of biceps femoris and gastrocnemius. This nerve doesn’t have any sensory supply. The motor supply of peroneal division goes to popliteus, soleus, tibialis posterior muscle, flexor digitorum longus, flexor hallucis longus, and many more muscles. The sensory supply is for knee joint through an articular branch followed by a sural nerve branch which runs towards distal end of limb with the small saphenous vein and forms anastomoses with a branch from the peroneal nerve. It then continues distal on lateral aspect of the Achilles tendon and ends as the lateral dorsal cutaneous nerve on the foot. There are many other sensory and motor branches of common peroneal, superficial peroneal and deep peroneal nerve.
As it is evident by above discussion, this nerves supplies a larger portion of our lower limb. Damage to any part of it can lead to severe pain along with motor and sensory deficit. While it is such an important nerve, its course in leg shows that it is quite vulnerable to damage and can get injured during accidents causing severe disabilities.
The most common diseases of sciatic nerve include iatrogenic injuries, sciatica, and nerve entrapment. These diseases not only cause disability but also cause pain and discomfort so proper treatment should be taken as soon as possible to avoid any further degeneration of the nerve fiber that can lead to permanent disabilities of lower limb.
The sciatic nerve is a collection of fibers from the anterior and posterior devisions of the lumbosacral plexus that emerge from the sacral part of the spinal cord. These fibers then unite and proceed to form the piriformis muscle. Further down the leg, this nerve then divides into two branches:
- The tibial nerve
This nerve travels down the posterior compartment of the leg towards and into the foot.
- The common peroneal nerve
This nerve travels down the anterior compartment of the leg towards and into the foot.
Function of the Sciatic Nerve
The sciatic nerve is mainly responsible for providing the skin of your legs and feet with the sensation to feel as well as the muscles of the back and thigh. Thus, if the nerve goes haywire, your legs ability to feel will become impaired. The sciatic nerve also helps with bladder control and the control of tiny muscles in the sole of your feet. Damaging this nerve can result in some serious consequences. A common condition associated with the irritation or compression of the sciatic nerve is known as Sciatica.
Damaging the Sciatic Nerve
Just like leaving any other condition untreated, Sciatica has some serious consequences on the long run.
IF THERE IS PERMANENT DAMAGE TO THE SCIATIC NERVE, THE FOLLOWING AFTER EFFECTS WILL OCCUR:
Pins and needles
If the sciatic nerve is damaged, the person will feel a tingling sensation in the legs or feet. This is because of nerve damage, the sciatic nerve helps with the “feel receptors” in the legs and feet of a person. Damaging this communication line can have the result of regular experience of pins and needles.
The pinching of the sciatic nerve will cause a sharp pain originating from the lower back, through the buttocks and down towards the calf and foot. This pain is normally increased after standing up from a seated position.
Numbness and Muscular Weakness
The pinching of the sciatic nerve may also cause numbness in the buttocks, leg, calf and foot. This can be a serious problem as it influences the body’s proprioception. The body’s proprioception is the awareness that the body has of its position in space. Proprioception helps the body to achieve balance and go about efficiently.
The pain and numbness caused by the pinched nerve will cause the person to alter his/her alignment as a means of protecting the leg from pain. This has the after effect of an adjusted posture and that may lead to a list of problems on its own.