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plexus(pleks'us) plural.plexus, plexuses [L., plexus, a braid]
An interwoven network of nerves, blood vessels, or lymphatics. See: rete
aortic plexus, thoracic
A nerve plexus that coats the thoracic aorta; it is composed of axons from the upper thoracic ganglia of the sympathetic trunk along with axons from the greater splanchnic nerve. This plexus connects with the celiac plexus, further caudally.
A network of anastomosing arteries.
Auerbach plexusSee: Auerbach plexus
A nerve plexus of sympathetic or parasympathetic axons, often containing autonomic neurons or ganglia. Such a plexus typically extends along major arteries and is named for its underlying artery. The large autonomic nerve plexuses are the cardiac, pulmonary, celiac, superior hypogastric, and inferior hypogastric.
A venous sinus filled with anastomosing vascular channels; it is located in the dura that covers the clivus of the skull, under the brainstem. Rostrally, the basilar plexus interconnects with the cavernous sinuses, laterally with the superior and inferior petrosal sinuses, and caudally with the occipital and marginal sinuses and the vertebral venous plexuses, which continue outside the foramen magnum.
A nerve plexus extending from the lower neck to the axilla; in it, axons from spinal nerves C4-T1 (or C5-T2) rearrange to form the nerves of the shoulder, upper trunk, and arm. These nerves include the dorsal scapular, suprascapular, long thoracic, lateral pectoral, medial pectoral, upper scapular, thoracodorsal, subscapular (upper, middle, and lower), musculocutaneous, axillary, lower subscapular, medial (brachial and antebrachial) cutaneous, radial, median, and ulnar. In the rearranging segments, the spinal nerves merge to form three trunk nerves (upper, middle, and lower), and the trunks divide and merge to form two divisions (anterior and posterior) and then three nerve cords (lateral, posterior, and medial); individual nerves emerge from all segments of the plexus.
An anastomosing network of blood capillaries or of lymphatic capillaries, i.e., lymphatics.
The autonomic nerve plexus at the base of the heart. It is composed of parasympathetic axons from the vagus nerves and sympathetic axons from the sympathetic trunks; it also contains cells of the cardiac ganglion. The cardiac plexus provides both afferent and efferent axons to the heart and the great vessels.Synonym: plexus cardiacus
plexus cardiacusCardiac plexus.
1. Any of the autonomic nerve plexuses that coat the carotid arteries; all carotid plexuses receive postganglionic sympathetic axons from the superior cervical ganglia. The external carotid plexus sends axons to the smooth muscles of the face and upper neck, along branches of the external carotid artery. The internal carotid plexus sends axons to the trigeminal and ciliary ganglia, and the oculomotor, trochlear, ophthalmic, abducens, and glossopharyngeal nerves. Some axons leave the internal carotid artery at the foramen lacerum, inside the skull, to form the deep petrosal nerve, which runs to the pterygoid ganglion. Other carotid plexus axons continue along the anterior and middle cerebral arteries to provide sympathetic innervation of arteries of the brain.
2. A venous plexus that exits the skull through the carotid canal and interconnects the cavernous sinus inside the skull with the internal jugular vein outside the skull.
A plexus of a "cavernous" part of the body, including a venous plexus in the mucosa covering the superior and middle conchae of the nasal cavity, an autonomic nerve plexus at the base of the penis giving rise to large and small cavernous nerves, an autonomic nerve plexus at the base of the clitoris, and an autonomic plexus of the cavernous sinus in the skull.
A dense nerve plexus along the celiac artery and the trunk of the superior mesenteric artery; this plexus interconnects the two large celiac ganglia. The plexus's parasympathetic axons come from the vagus, while the sympathetic axons come from the greater and lesser splanchnic nerves. The celiac plexus gives rise to a number of secondary autonomic plexuses including the phrenic, hepatic, left gastric, splenic, suprarenal, renal, testicular, ovarian, superior mesenteric, and inferior mesenteric plexuses. Synonym: solar plexus
A nerve plexus, beneath the internal jugular vein in the neck, in which axons from cervical spinal nerves C1-C4 rearrange to form nerves to the neck muscles, to the diaphragm, and to the skin of parts of the head, neck, and chest. These nerves include the lesser occipital, great auricular, transverse cutaneous, supraclavicular, and phrenic nerves. (In general, axons from C1-C3 innervate parts of the head and neck, while axons from C3-C4 innervate parts of the shoulder and chest.)
Small, tufted projections into the third, fourth, and lateral ventricles of the brain that are made of blood vessels of the pia mater covered by a thin coat of ependymal cells. These projections secrete cerebrospinal fluid.
A network of autonomic nerve fibers that lies close to the base of the heart.
A network of sensory nerve fibers that are distributed to the teeth. The inferior alveolar nerve is distributed to the mandibular teeth; the anterior, middle, and posterior superior alveolar nerves contribute fibers to innervate the maxillary teeth.
Any of the nerve plexuses found throughout the dermis of the skin; these plexuses contain autonomic axons and cutaneous sensory axons.
A complex autonomic nerve plexus inside the walls of the gastrointestinal tract, from esophagus to anus. The plexus contains intrinsic sensory and motor axons connected through local ganglionic interneurons. It is also joined by postganglionic sympathetic axons from external autonomic ganglia and preganglionic parasympathetic axons from the vagus nerve. Peristalsis, vasodilation, vasoconstriction, and secretion and absorption of substances from the intestinal lumen are controlled by this intrinsic neural network. The ganglion cells and axons of the enteric plexus that are found between the circular and longitudinal layers of muscles in the lamina externa are collectively called the myenteric division of the enteric plexus; the ganglion cells and axons found in the submucosa are called the submucosal division of the enteric plexus.See: enteric nervous system
An autonomic nerve plexus surrounding the lower half of the thoracic esophagus. The plexus is formed by the vagus nerves: the left vagus nerve spreads around the front surface of the esophagus, while the right vagus nerve spreads around the back surface. The plexus is joined by sympathetic axons from the thoracic sympathetic trunk.
Any of the secondary autonomic nerve plexuses, derived from the celiac plexus, that follow the gastric arteries to the stomach.
hemorrhoidal plexusRectal plexus.
The superior or the inferior hypogastric plexus.
inferior hypogastric plexusAbbreviation: IHP
A long, thin descending extension from the superior hypogastric plexus on the right and the left sides. The inferior hypogastric plexus, which feeds into the pelvic, middle rectal, vesical, prostatic, and uterovaginal plexuses, contains sympathetic axons from the superior hypogastric plexus and the lowest lumbar splanchnic nerves and parasympathetic axons from the pelvic splanchnic nerves. The inferior hypogastric plexus (or a portion of it) is sometimes called the hypogastric nerve or the pelvic plexus.
inferior mesenteric plexus
A secondary nerve plexus found along the inferior mesenteric artery and its branches. It is connected to the celiac plexus and it also receives axons from the lumbar splanchnic (sympathetic) nerves. The inferior mesenteric plexus contains one or more inferior mesenteric ganglia found near the trunk of the inferior mesenteric artery.
A nerve plexus lying within the psoas major muscle, along the posterior abdominal wall. In this plexus, axons from spinal nerves L1-L4 rearrange to form nerves to muscles of the thigh and to skin of the thigh and leg.These nerves include the iliohypogastric, ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral, obturator, and accessory obturator nerves.
The lumbar plexus and the sacral plexus.
An anastomosing network of lymphatics.
Meissner plexusSee: Meissner plexus
The superior or the inferior mesenteric plexus.
An autonomic nerve plexus without ganglia found in the lamina propria in the wall of the gastrointestinal tract and is part of the enteric nervous system.
The division of the enteric plexus found in the external muscular layer (muscularis externa) of the walls of the gastrointestinal tract.Synonym: Auerbach plexus
A meshwork of axons, fascicles of axons, or nerves outside the central nervous system. Axons, which join the meshwork from incoming nerves, resort and exit the meshwork singly or with new companions.
A secondary autonomic nerve plexus that follows the ovarian artery to the ovary and the Fallopian tube. This plexus is connected to the celiac plexus and gets additional sympathetic axons from the lowest thoracic spinal segments and parasympathetic axons from the inferior hypogastric plexus.
In males, a venous plexus that surrounds the testicular artery inside the distal segment of the spermatic cord. The pampiniform plexus drains the testicular veins (from the testis and epididymis). Before the spermatic cord enters the inguinal canal from the scrotum, the pampiniform plexus empties into 3-4 parallel veins. After exiting the inguinal canal, these veins merge to form two testicular veins. In females, there is a homologous venous plexus located in the broad ligament; it intervenes between the veins draining the ovary and the final ovarian veins, which empty blood back into the systemic circulation.
A nerve plexus that ramifies throughout the junction between the reticular and papillary layers of the dermis of the skin. The plexus contains autonomic axons and cutaneous sensory axons.
pelvic plexusSee: inferior hypogastric plexus
An autonomic nerve plexus coating an artery..
1. A nerve plexus along the posterior surface of the middle pharyngeal constrictor muscle. The plexus contains sympathetic, parasympathetic, and somatic (branchial) axons from the pharyngeal branch of the vagus nerve, the glossopharyngeal and external laryngeal nerves, and the sympathetic trunk. Axons from the pharyngeal plexus innervate the muscles and mucosa of the pharynx and soft palate.
2. A venous plexus that drains the pharynx and that empties into the internal jugular and facial veins; it interconnects with the pterygoid plexus.
One of three plexuses of autonomic nerve division that lie in body cavities. These are the cardiac, celiac, and hypogastric (pelvic) plexuses.
1. In males, an autonomic nerve plexus that is an extension of the inferior hypogastric plexus. It sends axons to the prostate gland, the erectile tissue of the penis, and the seminal vesicles.
2. In males, a venous plexus anterior to the bladder and prostate gland. Its tributaries include the deep dorsal vein of the penis. It connects with the vesical plexus and the internal pudendal vein, and it empties into the vesical veins and internal iliac vein.
A venous plexus lying between the temporalis, lateral pterygoid, and medial pterygoid muscles. Many of the deeper veins of the front of the head, e.g., , deep temporal, sphenopalatine, inferior ophthalmic, dental, connect with this plexus, which empties into the deep facial vein and which is thus in communication with the cavernous sinus inside the skull.
An autonomic nerve plexus extending from the cardiac plexus into the lungs along the right and left pulmonary arteries. Parasympathetic axons come from the vagus nerves, and sympathetic axons from the sympathetic trunk. Axons from the pulmonary plexus follow the bronchi and the bronchial vessels and provide the autonomic innervation inside the lungs.
1. Any of three autonomic nerve plexuses — superior, middle, and inferior — innervating the rectum. The rectal plexuses are extensions of the inferior hypogastric plexus and they follow the three corresponding rectal arteries.
2. Any of three venous plexuses — external, internal, and superior — in and around the rectum. The external rectal plexus empties via the internal rectal vein, into the internal pudendal vein; the internal and the superior rectal plexuses empty into the superior rectal vein. When veins in the internal rectal plexus develop varices, the varicose segments are called "hemorrhoids." Synonym: hemorrhoidal plexus
A dense autonomic nerve plexus along the renal artery; it contains small ganglia and its axons follow the branches of the renal artery into the kidney.
1. A nerve plexus lying along the posterior wall of the pelvis, deep to the internal iliac blood vessels and anterior to the piriformis muscle. In this plexus, axons from spinal nerves L4-S4 rearrange to form sensory and motor nerves to the thigh, leg, and foot. These nerves include the superior gluteal, inferior gluteal, posterior femoral cutaneous, sciatic, and pudendal nerves. The lower portion of the sacral plexus also gives rise to the preganglionic parasympathetic axons of the pelvic splanchnic nerves.
2. A venous plexus, on the pelvic surface of the sacrum, that interconnects the lateral sacral veins.
solar plexusCeliac plexus.
A nerve plexus found in the deep dermis and between the dermis and the subcutaneous tissue; it contains autonomic axons and cutaneous sensory axons.
submucous plexusSubmucosal plexus.
The division of the enteric plexus found in the submucosal layer of the walls of the gastrointestinal tract. The most superficial (closest to the lumen) layer of the submucosal plexus is also called the Meissner plexus.Synonym: submucous plexus See: Meissner plexus
superior mesenteric plexus
A continuation of the celiac nerve plexus. It runs along the superior mesenteric artery and it provides autonomic innervation to the same intestinal segments supplied by the artery.
An autonomic plexus composed of sympathetic axons. Large sympathetic plexuses surround the midline (prevertebral) sympathetic ganglia, which are found near major midline arteries such as the celiac trunk.
A nerve plexus along the medial wall of the tympanic cavity. The axons of this plexus come from the glossopharyngeal nerve and the caroticotympanic nerves, i.e., sympathetic axons from the internal carotid plexus.
1. The autonomic nerve plexus that supplies axons to the walls of the vagina.
2. A venous plexus surrounding the vagina; it empties, via the internal pudendal vein, into the internal iliac vein.
A network of interconnecting veins.
1. An autonomic nerve plexus that runs along each vertebral artery and carries sympathetic axons to arteries inside the skull.
2. Any of the anastomosing networks of valveless veins draining the vertebral column and spinal cord. Outside the spinal canal, anterior vertebral plexuses lie in front of the vertebral bodies, while posterior plexuses surround the vertebral spines and other vertebral processes. Inside the spinal canal, dense vertebral plexuses run between the bone and the dura; at the top of the cord, the internal vertebral plexuses communicate with intracranial sinuses.
1. An autonomic nerve plexus that is an extension of the inferior hypogastric plexus; it supplies nerves to the bladder muscles and, in males, to the seminal vesicles and the ductus deferens.
2. A venous plexus surrounding and draining blood from the upper part of the urethra and the neck of the bladder. It empties, via vesical veins, into the internal iliac vein. In males, it connects to the prostatic plexus; in females, it connects to the vaginal plexus.
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