A nerve plexus is a

plexus In neuroanatomy, a plexus (from the Latin term for "braid") is a branching network of vessels or nerves. The vessels may be blood vessels (veins, capillaries) or lymphatic vessels. The nerves are typically axons outside the central nervous sy ...

(branching network) of intersecting

nerve A nerve is an enclosed, cable-like bundle of nerve fibers (called axons) in the peripheral nervous system. A nerve transmits electrical impulses. It is the basic unit of the peripheral nervous system. A nerve provides a common pathway for the ...

s. 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 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 plexus - serves the head, neck and shoulders **

Brachial plexus The brachial plexus is a network () of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve ( C5, C6, C7, C8, and T1). This plexus extends from the spinal cord, through the cervicoaxillary canal in th ...

- serves the chest, shoulders, arms and hands ** Lumbosacral plexus *** Lumbar plexus - serves the back, abdomen, groin, thighs, knees, and calves **** Subsartorial plexus - below the sartorius muscle of thigh *** Sacral plexus - serves the pelvis, buttocks, genitals, thighs, calves, and feet *** Pudendal plexus ** Coccygeal plexus - serves a small region over the coccyx *Autonomic Plexuses ** Celiac plexus (solar plexus) - serves internal organs **

Auerbach's plexus The myenteric plexus (or Auerbach's plexus) provides motor innervation to both layers of the muscular layer of the gut, having both parasympathetic and sympathetic input (although present ganglion cell bodies belong to parasympathetic innervatio ...

(myenteric plexus) - serves the gastrointestinal tract **

Meissner's plexus The submucosal plexus (Meissner's plexus, plexus of the submucosa, plexus submucosus) lies in the submucosa of the intestinal wall. The nerves of this plexus are derived from the myenteric plexus The myenteric plexus (or Auerbach's plexus) prov ...

(submucosal plexus) - serves the gastrointestinal tract ** Pharyngeal plexus of vagus nerve - serves the palate and pharynx ** Cardiac plexus - serves the heart

Spinal plexuses

The following table shows the nerves that arise from each spinal plexus as well as the spinal level each plexus arises from.

Cervical plexus

The Cervical plexus is formed by the ventral rami of the upper four cervical nerves and the upper part of fifth cervical ventral ramus. The network of rami is located deep to the sternocleidomastoid within the neck. The cervical plexus innervates muscles of the neck and areas of skin on the head, neck and chest. The deep branches innervate muscles, while the superficial branches supply areas of skin. A long branch (primarily of fibers of C4 and with contributions of fibers from C3 and C5;

nervus phrenicus The phrenic nerve is a mixed motor/sensory nerve which originates from the C3-C5 spinal nerves in the neck. The nerve is important for breathing because it provides exclusive motor control of the diaphragm, the primary muscle of respiration. In ...

) innervates muscles of the

diaphragm Diaphragm may refer to: Anatomy * Thoracic diaphragm, a thin sheet of muscle between the thorax and the abdomen * Pelvic diaphragm or pelvic floor, a pelvic structure * Urogenital diaphragm or triangular ligament, a pelvic structure Other * Diap ...

. The cervical plexus also communicates with the

cranial nerve Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...

vagus nerve The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and rig ...

and hypoglossal nerve.

Brachial plexus

The

is formed by the ventral rami of C5-C8-T1 spinal nerves, and lower and upper halves of C4 and T2 spinal nerves. The plexus extends toward the armpit. The ventral rami of C5 and C6 form upper trunk, the ventral ramus of C7 forms the middle trunk, and the ventral rami of C8 and T1 join to form the lower trunk of the brachial plexus. Under the clavicle, the trunks reorganize to form cords ''(fasciculi)'' around the

axillary artery In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb. Its origin is at the lateral margin of the first rib, before which it i ...

''(arteria axillaris)''. The lateral cord ''(fasciculus lateralis)'' is formed by the upper and middle trunk, all three trunks join to form the posterior cord ''(fasciculus posterior)'', the lower trunk continues to the medial trunk ''(fasciculus medialis)''. The nerves (containing motor and

sensory Sensory may refer to: Biology * Sensory ecology, how organisms obtain information about their environment * Sensory neuron, nerve cell responsible for transmitting information about external stimuli * Sensory perception, the process of acquiri ...

fibers) to the

shoulder The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder m ...

and to the upper limb emerge from the brachial plexus.

Lumbar plexus

Since the Lumbar plexus and Sacral plexus are interconnected, they are sometimes referred to as the Lumbosacral plexus. The intercostal nerves that give rami to the chest and to the upper parts of the abdominal wall efferent motor innervation and to the pleura and

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesot ...

afferent Afferent may refer to: Anatomical structures Meaning "conveying towards a center": * Afferent arterioles, blood vessels that supply the nephrons * Afferent lymphatic vessels, lymph vessels that carry lymph to a lymph node * Afferent nerve fiber ...

innervation are the only ones that do not originate from a plexus. The ventral rami of L1-L5 spinal nerves with a contribution of T12 form Lumbar plexus. This plexus lies within the

psoas major muscle The psoas major ( or ; from grc, ψόᾱ, psóā, muscles of the loins) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the il ...

. Nervi of the plexus serve the skin and the muscles of the lower abdominal wall, the

thigh In human anatomy, the thigh is the area between the hip ( pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of ...

and

external genitals A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, ...

. The largest nerve of the plexus is the femoral nerve. It supplies anterior muscles of the thigh and a part of skin distal to the inguinal ligament.

Sacral plexus

Ventral rami of L4-S3 with parts of L4 and S4 spinal nerves form the Sacral plexus. It is located on the posterior wall of

pelvic cavity The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reprod ...

(pelvis minor). Nervi of the plexus innervate the perineal region,

buttocks The buttocks (singular: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are compose ...

and the lower limb. The largest nerve of the human body, the sciatic nerve, is the main branch that gives rami to the motor innervation of the muscles of the

, the leg, and the foot. Common peroneal nerve and its branches innervate some parts of the skin of the foot, the peroneal muscles of the leg, and the dorsal muscles of the foot.

Coccygeal plexus

Coccygeal plexus originates from the ventral rami of spinal nerves S4, S5, and Co. It is interconnected with the lower part of Sacral plexus. The only nerve of the plexus is the coccygeal nerve, that serves sensory innervation of the skin in the coccygeal region.

Autonomic plexuses

Autonomic plexuses can contain both sympathetic and parasympathetic neurons. The cardiac plexus is located near the aortic arch and the carina of the trachea. The pulmonary plexus supplies innervation to the bronchial tree. The celiac, or solar plexus, is located around the celiac trunk and contains the celiac ganglia. The solar plexus is the largest autonomic plexus and provides innervation to multiple abdominal and pelvic organs. The superior mesenteric plexus includes the superior mesenteric ganglia and is located around the superior mesenteric artery. The inferior mesenteric plexus includes the inferior mesenteric ganglia and is located around the inferior mesenteric artery. Together, these plexuses innervate the intestines. Some other plexuses include the

superior Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake ...

and inferior hypogastric plexus, renal plexus, hepatic plexus, splenic plexus, gastric plexus, pancreatic plexus, and testicular plexus / ovarian plexus.

Sources

* Henry Gray: Anatomy of the human body (Bartleby.com; Great Books Online) * Richard S. Snell: Clinical neuroanatomy (Lippincott Williams & Wilkins, Ed.6th 2006) Philadelphia, Baltimore, New York, London. * Eldra P. Solomon - Richard R. Schmidt - Peter J. Adragna : Human anatomy & physiology ed. 2nd 1990 (Sunders College Publishing, Philadelphia) * Jochen Staubesand (Ed.); R. Putz, R. Pabst,

Johannes Sobotta Robert Heinrich Johannes Sobotta (31 January 1869, in Berlin – 20 April 1945, in Bonn) was a German anatomist. He studied medicine in Berlin, where he subsequently worked as a second assistant at the institute of anatomy. From 1895 he serve ...

: Sobotta Atlas of Human Anatomy I-II. (Urban & Schwarzenberg, München 1982) * Saladin, Kenneth S. ''Anatomy & Physiology: The Unity of Form and Function''. New York, NY: McGraw-Hill, 2007. Print.

References

Instant Anatomy, 2010, webpage

External links

* *{{MerckHome, 06, 095, d - Plexus disorders Peripheral nervous system