Nerves Lower Body (MAle)

R Cauda Equina Base

At the base of the spinal column, near the first lumbar vertebra, is a collection of nerves called the cauda equina. They are called this because they resemble a horse’s tail. Just above the cauda equina, the spinal cord ends and it continues on as this collection of spinal nerves through the vertebral canal. The cauda equina has approximately 10 fiber pairs at its base. These consist of three to five lumbar fiber pairs, five sacral fiber pairs, and one coccygeal nerve. The primary function of the cauda equina is to send and receive messages between the lower limbs and the pelvic organs, which consist of the bladder, the rectum, and the internal genital organs. When these nerve roots become highly compressed, cauda equina syndrome may be diagnosed. This condition is considered serious, as the patient could permanently lose the functions of their bowel and bladder, and can lead to permanent paralysis of the legs. When cauda equina syndrome is diagnosed, surgery will generally be required to relieve the compression of the nerves. Source

R Lumbar Plexus

The lumbar plexus is a network of nerve fibres that supplies the skin and musculature of the lower limb. It is located in the lumbar region, within the substance of the psoas major muscle and anterior to the transverse processes of the lumbar vertebrae. The plexus is formed by the anterior rami (divisions) of the lumbar spinal nerves L1, L2, L3 and L4. It also receives contributions from thoracic spinal nerve 12. In this article, we shall look at the anatomy of the lumbar plexus – its formation and major branches. Source

R Iliohypogastric Nerve

The iliohypogastric nerve is a nerve that originates from the lumbar plexus that supplies sensation to skin over the lateral gluteal region and motor to the internal and transverse abdominal muscles.

R Ilioinguinal Nerve

The ilioinguinal nerve branches off the first lumbar nerve, which is near the lower back. It branches down the body through the second and third abdominal muscles and communicates with the iliohypogastric nerve, whose main function is to regulate the diaphragm (a muscle that helps with breathing) and the areas around it. The ilioinguinal nerve moves further down the body, eventually branching out into the upper part of the thigh muscles. It also reaches the mons pubis and labia majora, both parts of the groin. The nerve provides sensation to these areas. During certain abdominal operations, such as hernia surgery, the ilioinguinal nerve must be carefully avoided, as severing this nerve will lead to pain in the thighs and labia majora and a weakening of the local muscle fibers, which can lead to a direct inguinal hernia. An inguinal hernia is a bulging of soft tissue through weakened abdominal muscle walls into the lowest part of the abdomen or the groin. This condition is far more common in men than in women. Source

R Sacral Plexus

A network of intersecting nerves is referred to as a nerve plexus. Nerves that serve the same part of the body merge into one large nerve or group of nerves via a plexus. The sacral plexus provides motor and sensory nerves for the pelvis, buttocks, genitals, thighs, calves, and feet. Source

R Genitofemoral Nerve

The genitofemoral nerve is a branch of the lumbar plexus, one of three components of the larger lumbosacral plexus (a network of intersecting nerves in the lower vertebral column). Running from this source, it pierces the front surface of the psoas major — the muscle stabilizing the spine that controls rotation of the hips. At this point, it splits into its two eponymous branches (or rami): the genital ramus and the femoral ramus. In women, the genital ramus terminates in sensory branches that supply the labia majora (part of the external genital organs). In men, the branch constitutes part of the spermatic cord and acts additionally as a motor for the cremasteric reflex. The cremaster is a muscle that elevates and lowers the testes. Sensory fibers in the upper male thigh respond to gentle touch, stimulating the motor fibers of the genital branch of the genitofemoral nerve and causing the cremaster to contract, raising the testes on the same side. The function of the femoral branch of the genitofemoral nerve is exclusively for sensory perception in both genders. It connects to the area of skin below the inguinal ligament, which extends from the hip to the pubic bone in the groin. Source

R Superior Gluteal Nerve

The superior gluteal nerve is the term used to describe the nerve near the upper pelvis that comes straight out of both the fourth and fifth lumbar nerves (the back sections), as well as the first sacral nerve. The nerve is made up of the sacral plexus’ branches. The sacral plexus is responsible for muscle supply within the region. The nerve plexus also offers sensory and motor nerves for sections of the pelvis, the entirety of the foot, the back of the thigh, and the majority of the lower legs. The superior nerve starts out in the pelvis and supplies the tensor fasciae latae, the gluteus minimus, and the gluteus medius muscles. The nerve departs from the pelvis via the greater sciatic foramen, which is an important gap in the pelvic bones. The foramen is situated directly over the piriformis muscle of the lower limbs. The superior gluteal nerve, along with the vessels, goes over the piriformis muscle to get to the foramen, while the inferior gluteal nerves travel just under it. Source

R Inferior Gluteal Nerve

The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle. It is responsible for the movement of the gluteus maximus in activities requiring the hip to extend the thigh, such as climbing stairs. Injury to this nerve is rare but often occurs as a complication of posterior approach to the hip during hip replacement. When damaged, one would develop gluteus maximus lurch, which is a gait abnormality which causes the individual to ‘lurch’ backwards to compensate lack in hip extension.

R Pudendal Nerve

The pudendal nerve is found in the pelvis. It is the biggest division of the pudendal plexus (a network of nerves) and is located behind the sacrospinous ligament, near the tailbone. The nerve extends from the sacral plexus, through the pudendal canal, the perineum, and the gluteal area. These are structures located near the genital, rectal, and gluteal (buttock) regions. The condition known as pudendal neuralgia can cause both bladder and anal incontinence. Other symptoms include chronic constipation, rectal pain, and sexual dysfunction. Pudendal nerve entrapment is another form of pudendal neuralgia. This condition causes phantom pain (pain related to an area that isn’t actually part of the body) in the lower regions of the pelvis, penis and scrotum, vulva, anus, and perineum. Individuals diagnosed with pudendal nerve entrapment have described pain when sitting down. This pain decreases when standing or removing pressure. This condition may be diagnosed in two ways. Source

R Spinal Cord Dura Mater

In the central nervous system, there are three different layers that cover the spinal cord and brain. These are called the meninges, and their three levels consist of the pia, arachnoid, and dura mater. Bone is situated above these layers, followed by periosteum (a fibrous membrane that covers bone) and skin. The dura mater is the top layer of the meninges, lying beneath the bone tissue.

This material at times opens into sinus cavities (spaces) located around the skull. This is particularly notable with the dural venous sinuses. Here, liquids, like blood and cerebrospinal fluid, drain and collect into the internal jugular vein. Cerebrospinal fluid is a clear liquid that cushions the brain and spinal cord while also transporting nutrients, chemicals, and waste. Dura mater is also the home to meningeal veins. Many types of medical conditions involve the dura mater. The most common come in the form of hematomas. Arterial bleeding can result in an epidural hematoma, which is when blood collects between the dura mater and the skull. If blood collects between the dura and arachnoid mater, a subdural hematoma results. Also, there are some instances where the dura plays a major role in certain types of headaches. Source

L Lumbar Plexus

L Iliohypogastric Nerve

The iliohypogastric nerve is a nerve that originates from the lumbar plexus that supplies sensation to skin over the lateral gluteal region and motor to the internal and transverse abdominal muscles.