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Lumbar Plexus
The lumbar plexus is a web of nerves (a nerve plexus) in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the divisions of the first four lumbar nerves (L1–L4) and from contributions of the subcostal nerve (T12), which is the last thoracic nerve. Additionally, the ventral rami of the fourth lumbar nerve pass communicating branches, the lumbosacral trunk, to the sacral plexus. The nerves of the lumbar plexus pass in front of the hip joint and mainly support the anterior part of the thigh.''Thieme Atlas of anatomy'' (2006), pp 470-471 The plexus is formed lateral to the intervertebral foramina and passes through psoas major. Its smaller motor branches are distributed directly to psoas major, while the larger branches leave the muscle at various sites to run obliquely down through the pelvis to leave under the inguinal ligament with the exception of the obturator nerve which exits the pelvis through the obturator foramen. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumbosacral Trunk
The lumbosacral trunk is nervous tissue that connects the lumbar plexus with the sacral plexus. It is formed by the union of parts of the fourth and fifth lumbar nerves and descends to join the sacral plexus. Anatomy The lumbosacral trunk is formed by the union of the entire anterior ramus of lumbar nerve L5 . L4 first issues its branches to the lumbar plexus, then emerges from the medial border of the psoas muscle to unite with the anterior ramus of L5 just superior to the pelvic brim to form the thick, cord-like trunk which crosses the pelvic brim (medial to the obturator nerve) to descend upon the anterior surface of the ala of sacrum before joining the sacral plexus. Like the sacral nerves, the lumbosacral trunks splits into an anterior division and a posterior division before recombining to form nerves for the flexor and extensor compartments of the lower limb. Clinical significance The lumbosacral trunk may be compressed by the fetal head during the second stage of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilioinguinal Nerve
The ilioinguinal nerve is a branch of the first lumbar nerve (L1). It separates from the first lumbar nerve along with the larger iliohypogastric nerve. It emerges from the lateral border of the psoas major just inferior to the iliohypogastric, and passes obliquely across the quadratus lumborum and iliacus. The ilioinguinal nerve then perforates the transversus abdominis near the anterior part of the iliac crest, and communicates with the iliohypogastric nerve between the transversus and the internal oblique muscle. It then pierces the internal oblique muscle, distributing filaments to it, and then accompanies the spermatic cord (in males) or the round ligament of uterus (in females) through the superficial inguinal ring. Its fibres are then distributed to the skin of the upper and medial part of the thigh, and to the following locations in the male and female: * In the male (" anterior scrotal nerve"): to the skin over the root of the penis and upper part of the scrotum. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve Plexus
A nerve plexus is a plexus (branching network) of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve plexuses, except in the thoracic region, as well as other forms of autonomic nervous system, autonomic plexuses, many of which are a part of the enteric nervous system. The nerves that arise from the plexuses have both sensory and motor functions. These functions include muscle contraction, the maintenance of body coordination and control, and the reaction to sensations such as heat, cold, pain, and pressure. There are several plexuses in the body, including: *Spinal plexuses **Cervical plexusserves the head, neck and shoulders **Brachial plexusserves the chest, shoulders, arms and hands **Lumbosacral plexus ***Lumbar plexusserves the back, abdomen, groin, thighs, knees, and calves ****Subsartorial plexusbelow the sartorius muscle of thigh *** ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genitofemoral Nerve
The genitofemoral nerve is a mixed branch of the lumbar plexus derived from anterior rami of lumbar nerves L1–L2. It splits into a genital branch and a femoral branch. It provides sensory innervation to the upper anterior thigh, as well as the skin of the anterior scrotum in males and mons pubis in females. It also provides motor innervation to the cremaster muscle (via its genital branch). Structure Origin The genitofemoral nerve is a branch of the lumbar plexus. It is derived from the anterior rami of lumbar nerves L1–L2. It coalesces within the substances of the psoas major muscle. Course It passes downwards, pierces the psoas major and emerges from its anterior surface. The nerve divides into two branches, the genital branch and the lumboinguinal nerve also known as the femoral branch, both of which then continue downwards and medially to the inguinal and femoral canal respectively. Branches Genital branch The genital branch continues downward on the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iliohypogastric Nerve
The iliohypogastric nerve is a nerve that originates from the lumbar plexus that supplies sensation to skin over the lateral gluteal and hypogastric regions and motor to the internal oblique muscles and transverse abdominal muscles. Structure Origin The iliohypogastric nerve originates from the superior branch of the anterior ramus of spinal nerve L1. It also receives fibers from T12 via the subcostal nerve. The branch below it is the ilioinguinal nerve. Course It emerges from the upper lateral border of the psoas major. It then crosses in front of the quadratus lumborum muscle to an area superior to the iliac crest. It runs behind the kidneys. Just superior to the iliac crest, it pierces the posterior part of the transversus abdominis muscle and continues anteriorly in the abdominal wall between the transversus abdominis and internal oblique muscles. It divides into a lateral cutaneous branch and an anterior cutaneous branch between the transversus abdominis muscle a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obturator Nerve
The obturator nerve in human anatomy arises from the ventral divisions of the second, third, and fourth lumbar nerves in the lumbar plexus; the branch from the third is the largest, while that from the second is often very small. Structure The obturator nerve originates from the anterior divisions of the L2, L3, and L4 spinal nerve roots. It descends through the fibers of the psoas major, and emerges from its medial border near the brim of the pelvis. It then passes behind the common iliac arteries, and on the lateral side of the internal iliac artery and vein, and runs along the lateral wall of the lesser pelvis, above and in front of the obturator vessels, to the upper part of the obturator foramen. Here it enters the thigh, through the obturator canal, and divides into an anterior and a posterior branch, which are separated at first by some of the fibers of the obturator externus, and lower down by the adductor brevis. An accessory obturator nerve may be present in ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abdominal External Oblique Muscle
The abdominal external oblique muscle (also external oblique muscle or exterior oblique) is the largest and outermost of the three flat Abdomen#Muscles, abdominal muscles of the lateral anterior abdomen. Structure The external oblique is situated on the lateral and anterior parts of the abdomen. It is broad, thin, and irregularly quadrilateral, its muscular portion occupying the side, its aponeurosis the anterior wall of the abdomen. In most humans, the oblique is not visible, due to subcutaneous adipose, fat deposits and the small size of the muscle. It arises from eight fleshy digitations, each from the external surfaces and inferior borders of the fifth to twelfth ribs (lower eight ribs). These digitations are arranged in an oblique line which runs inferiorly and anteriorly, with the upper digitations being attached close to the cartilages of the corresponding ribs, the lowest to the apex of the cartilage of the last rib, the intermediate ones to the ribs at some distance fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
External Inguinal Ring
The inguinal canal is a passage in the anterior abdominal wall on each side of the body (one on each side of the midline), which in males, convey the spermatic cords and in females, the round ligament of the uterus. The inguinal canals are larger and more prominent in males. Structure The inguinal canals are situated just above the medial half of the inguinal ligament. The canals are approximately 4 to 6 cm long, angled anteroinferiorly and medially. In males, its diameter is normally 2 cm (±1 cm in standard deviation) at the deep inguinal ring.The diameter has been estimated to be ±2.2cm ±1.08cm in Africans, and 2.1 cm ±0.41cm in Europeans. A first-order approximation is to visualize each canal as a cylinder. Walls To help define the boundaries, these canals are often further approximated as boxes with six sides. Not including the two rings, the remaining four sides are usually called the "anterior wall", "inferior wall ("floor")", "superior wall ("roof")", and "poster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypogastrium
The hypogastrium (also called the hypogastric region or suprapubic region) is a region of the abdomen located below the umbilical region. Etymology The roots of the word ''hypogastrium'' mean "below the stomach"; the roots of ''suprapubic'' mean "above the pubic bone". Boundaries The upper limit is the umbilicus while the pubis bone constitutes its lower limit. The lateral boundaries are formed are drawing straight lines through the midway between the anterior superior iliac spine The anterior superior iliac spine (ASIS) is a bony projection of the iliac bone, and an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis. It provides attachment for the inguinal ligament, ... and symphisis pubis. References External links * Abdomen {{Anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thoracic Nerves
A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column. These are grouped into the corresponding cervical, thoracic, lumbar, sacral and coccygeal regions of the spine. There are eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves. The spinal nerves are part of the peripheral nervous system. Structure Each spinal nerve is a mixed nerve, formed from the combination of nerve root fibers from its dorsal and ventral roots. The dorsal root is the afferent sensory root and carries sensory information to the brain. The ventral root is the efferent motor root and carries motor information from the brain. The spinal nerve emerges from the spinal column through an opening (intervertebral foramen) between adjacent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Cutaneous Branch Of Iliohypogastric Nerve
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, ''Terminologia Anato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abdominal Internal Oblique Muscle
The abdominal internal oblique muscle, also internal oblique muscle or interior oblique, is an abdominal muscle in the abdominal wall that lies below the external oblique muscle and just above the transverse abdominal muscle. Structure Its fibers run perpendicular to the external oblique muscle, beginning in the thoracolumbar fascia of the lower back, the anterior 2/3 of the iliac crest (upper part of hip bone) and the lateral half of the inguinal ligament. The muscle fibers run from these points superomedially (up and towards midline) to the muscle's insertions on the inferior borders of the 10th through 12th ribs and the linea alba. In males, the cremaster muscle is also attached to the internal oblique. Nerve supply The internal oblique is supplied by the lower intercostal nerves, as well as the iliohypogastric nerve and the ilioinguinal nerve. Function The internal oblique performs two major functions. Firstly as an accessory muscle of respiration, it acts as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
