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Mesenteric Plexuses
The mesenteric plexuses are autonomic nerve networks associated with the superior and inferior mesenteric arteries. They distribute sympathetic, parasympathetic, and visceral afferent fibers to large portions of the small and large intestines.
RegionAbdomen
SystemDigestive System
The mesenteric plexuses are networks of autonomic nerves associated with the major mesenteric arteries of the abdomen. They form important pathways through which autonomic fibers reach the small intestine and large intestine.
The two principal mesenteric plexuses are the superior mesenteric plexus, associated with the superior mesenteric artery, and the inferior mesenteric plexus, associated with the inferior mesenteric artery.
These plexuses contain sympathetic fibers, parasympathetic fibers, and visceral afferent fibers. Their branches generally follow arteries and their subdivisions toward the gastrointestinal organs they supply.
Autonomic Plexuses of the Abdomen
The abdominal autonomic nervous system contains interconnected plexuses surrounding the major branches of the abdominal aorta.
Important plexuses include the celiac, superior mesenteric, intermesenteric, inferior mesenteric, aortic, and superior hypogastric plexuses.
Periarterial Organization
Many autonomic nerves in the abdomen form networks around arteries.
This arrangement allows nerve fibers to use the arterial tree as an anatomical pathway to reach abdominal organs.
Superior Mesenteric Plexus
The superior mesenteric plexus is an autonomic nerve network surrounding the origin and branches of the superior mesenteric artery.
It distributes autonomic fibers primarily to structures derived from the embryological midgut.
Location of the Superior Mesenteric Plexus
The superior mesenteric plexus is concentrated around the origin of the superior mesenteric artery from the abdominal aorta.
Its fibers continue along the artery and its branches into the mesentery and intestinal wall.
Superior Mesenteric Ganglion
Small collections of sympathetic neuronal cell bodies associated with the superior mesenteric plexus are collectively related to the superior mesenteric ganglion.
These ganglionic structures participate in the distribution of postganglionic sympathetic fibers to midgut derivatives.
Relationship to the Celiac Plexus
The superior mesenteric plexus is continuous superiorly with the extensive autonomic networks surrounding the celiac trunk and abdominal aorta.
This continuity allows autonomic fibers to pass between neighboring abdominal plexuses.
Relationship to the Superior Mesenteric Artery
The superior mesenteric plexus closely surrounds the superior mesenteric artery.
Its branches accompany the major arterial branches arising from this vessel toward their target organs.
Branches Accompanying the Superior Mesenteric Artery
Autonomic fibers follow branches including:
- Inferior pancreaticoduodenal arteries
- Jejunal arteries
- Ileal arteries
- Ileocolic artery
- Right colic artery
- Middle colic artery
Distribution of the Superior Mesenteric Plexus
The superior mesenteric plexus contributes autonomic innervation to much of the gastrointestinal tract supplied by the superior mesenteric artery.
This territory extends approximately from the distal duodenum through the proximal portion of the transverse colon.
Duodenal Distribution
Fibers associated with the superior mesenteric plexus contribute to autonomic innervation of distal portions of the duodenum.
There is overlap with autonomic fibers associated with the celiac and pancreaticoduodenal plexuses.
Jejunal Distribution
Autonomic fibers reach the jejunum by following the jejunal branches of the superior mesenteric artery through the mesentery.
These fibers ultimately communicate with intrinsic enteric neural networks in the intestinal wall.
Ileal Distribution
The ileum receives autonomic fibers accompanying the ileal branches of the superior mesenteric artery.
These fibers influence intestinal smooth muscle, glands, blood vessels, and enteric neurons.
Cecal Distribution
Fibers accompanying the ileocolic artery reach the cecum and adjacent intestinal structures.
They form part of the autonomic supply of the ileocecal region.
Appendicular Distribution
Autonomic fibers reach the vermiform appendix along vessels associated with the appendicular artery and mesoappendix.
Visceral afferent fibers from the appendix also travel through autonomic pathways toward the central nervous system.
Ascending Colon
The ascending colon receives autonomic fibers distributed primarily along branches of the ileocolic and right colic arteries.
These fibers are associated with the superior mesenteric plexus.
Transverse Colon
The proximal portion of the transverse colon receives autonomic fibers associated with branches of the middle colic artery and superior mesenteric plexus.
More distal portions of the transverse colon have different parasympathetic and arterial relationships.
Sympathetic Supply to the Superior Mesenteric Plexus
Sympathetic fibers reaching the superior mesenteric plexus arise ultimately from thoracic spinal cord levels and travel through thoracic splanchnic nerves.
Preganglionic fibers synapse within prevertebral ganglia, after which postganglionic fibers follow mesenteric arteries toward the gastrointestinal tract.
Thoracic Splanchnic Nerves
The thoracic splanchnic nerves carry preganglionic sympathetic fibers from the sympathetic trunks toward prevertebral autonomic plexuses and ganglia in the abdomen.
Fibers reaching mesenteric pathways can then be redistributed along the arterial branches supplying the intestine.
Postganglionic Sympathetic Fibers
After synapsing in prevertebral ganglia, postganglionic sympathetic fibers enter periarterial plexuses.
They travel along the superior mesenteric artery and its branches to reach midgut structures.
Parasympathetic Supply to the Superior Mesenteric Plexus
Parasympathetic fibers supplying midgut structures arise primarily from the vagus nerves.
Vagal fibers pass through abdominal autonomic plexuses without synapsing in the sympathetic prevertebral ganglia.
Vagal Fibers
Preganglionic vagal fibers are distributed along periarterial pathways toward the gastrointestinal tract.
They ultimately synapse with neurons located within or close to the walls of the target organs.
Inferior Mesenteric Plexus
The inferior mesenteric plexus is an autonomic nerve network associated with the inferior mesenteric artery.
It contributes to the autonomic innervation of structures derived primarily from the embryological hindgut.
Location of the Inferior Mesenteric Plexus
The inferior mesenteric plexus is located around the origin of the inferior mesenteric artery from the abdominal aorta.
Its branches accompany the inferior mesenteric artery and its subdivisions toward the distal large intestine.
Inferior Mesenteric Ganglia
Small prevertebral sympathetic ganglia are associated with the inferior mesenteric plexus.
Postganglionic sympathetic fibers from these ganglia are distributed along branches of the inferior mesenteric artery.
Relationship to the Abdominal Aortic Plexus
The inferior mesenteric plexus is continuous with the autonomic network surrounding the abdominal aorta.
Connections with the intermesenteric and hypogastric plexuses integrate autonomic pathways between the abdomen and pelvis.
Relationship to the Inferior Mesenteric Artery
The inferior mesenteric plexus surrounds the inferior mesenteric artery near its origin and extends along its branches.
This periarterial arrangement distributes nerve fibers to hindgut structures.
Branches Accompanying the Inferior Mesenteric Artery
Autonomic fibers follow branches including:
- Left colic artery
- Sigmoid arteries
- Superior rectal artery
Distribution of the Inferior Mesenteric Plexus
The inferior mesenteric plexus contributes autonomic fibers to the distal transverse colon, descending colon, sigmoid colon, and upper rectum.
Its distribution overlaps with other autonomic plexuses, particularly toward the rectum and pelvis.
Distal Transverse Colon
The distal portion of the transverse colon lies within the hindgut autonomic territory.
Autonomic fibers reach this region through networks associated with the inferior mesenteric circulation and neighboring colonic plexuses.
Descending Colon
The descending colon receives fibers that travel primarily along the left colic arterial branches.
These fibers regulate vascular tone and interact with the intrinsic enteric nervous system.
Sigmoid Colon
Autonomic fibers reach the sigmoid colon along the sigmoid arteries within the sigmoid mesocolon.
Both sympathetic and parasympathetic pathways contribute to its extrinsic innervation.
Rectal Distribution
The superior rectum receives autonomic fibers associated with the superior rectal artery and neighboring autonomic plexuses.
Inferiorly, these pathways communicate extensively with pelvic autonomic networks.
Sympathetic Supply to the Inferior Mesenteric Plexus
Preganglionic sympathetic fibers destined for hindgut structures arise from lower thoracic and upper lumbar spinal cord levels.
They reach prevertebral plexuses through splanchnic pathways and synapse in associated ganglia.
Lumbar Splanchnic Nerves
The lumbar splanchnic nerves provide important sympathetic contributions to the abdominal aortic and inferior mesenteric plexuses.
They carry preganglionic sympathetic fibers from the lumbar sympathetic trunks toward prevertebral ganglia and plexuses.
Postganglionic Fibers to the Hindgut
Postganglionic sympathetic fibers travel from prevertebral ganglia along branches of the inferior mesenteric artery.
They ultimately reach the distal colon and related structures.
Parasympathetic Supply to the Inferior Mesenteric Territory
Parasympathetic innervation of the hindgut differs from that of the foregut and midgut.
Hindgut parasympathetic fibers arise from the pelvic splanchnic nerves rather than the vagus nerve.
Pelvic Splanchnic Nerves
The pelvic splanchnic nerves arise from spinal cord segments S2-S4.
They carry preganglionic parasympathetic fibers into pelvic autonomic plexuses and toward hindgut structures.
Ascending Parasympathetic Fibers
Some parasympathetic fibers from the pelvic splanchnic nerves ascend from pelvic plexuses toward the distal colon.
They can travel through plexuses associated with the inferior mesenteric circulation before reaching the intestinal wall.
Midgut and Hindgut Parasympathetic Boundary
The parasympathetic transition between vagal and pelvic splanchnic innervation occurs near the boundary between midgut and hindgut derivatives.
This transition is commonly associated with the region around the proximal two-thirds and distal one-third of the transverse colon.
Superior and Inferior Mesenteric Plexuses
| Feature | Superior Mesenteric Plexus | Inferior Mesenteric Plexus |
|---|---|---|
| Associated artery | Superior mesenteric artery | Inferior mesenteric artery |
| Main embryological territory | Midgut | Hindgut |
| Parasympathetic source | Vagus nerve | Pelvic splanchnic nerves |
| Major sympathetic pathways | Thoracic splanchnic pathways | Lumbar and related splanchnic pathways |
| Major intestinal distribution | Small intestine and proximal large intestine | Distal large intestine |
Intermesenteric Plexus
The intermesenteric plexus is part of the autonomic network on the abdominal aorta between the superior and inferior mesenteric arteries.
It provides continuity between the upper and lower abdominal autonomic plexuses.
Aortic Plexus
The abdominal aortic plexus consists of interconnected autonomic fibers extending along the abdominal aorta and its major branches.
The mesenteric plexuses can therefore be regarded as specialized periarterial extensions of a broader abdominal autonomic network.
Superior Hypogastric Plexus
Inferiorly, fibers of the abdominal aortic and intermesenteric plexuses contribute to the superior hypogastric plexus.
This creates anatomical continuity between abdominal and pelvic autonomic pathways.
Sympathetic Functions
Sympathetic fibers distributed through the mesenteric plexuses influence intestinal smooth muscle, sphincters, glands, blood vessels, and enteric neural circuits.
Their effects are coordinated with the intrinsic nervous system of the gastrointestinal tract.
Effect on Intestinal Motility
Increased sympathetic activity generally reduces gastrointestinal motility.
Much of this effect occurs through modulation of enteric neurons rather than direct innervation of every smooth muscle cell.
Effect on Gastrointestinal Secretion
Sympathetic activity can reduce gastrointestinal secretory activity through direct and indirect neural mechanisms.
Effect on Blood Vessels
Sympathetic fibers innervate smooth muscle in the walls of mesenteric blood vessels.
Activation can produce vasoconstriction and alter blood flow through the intestinal circulation.
Effect on Sphincters
Sympathetic pathways can influence gastrointestinal sphincter tone.
The overall effect depends on the specific region and interaction with enteric and parasympathetic pathways.
Parasympathetic Functions
Parasympathetic fibers reaching the intestine through vagal and pelvic splanchnic pathways generally support gastrointestinal motility and secretory activity.
They exert many of their effects through neurons of the enteric nervous system.
Relationship to the Enteric Nervous System
Extrinsic autonomic fibers carried through the mesenteric plexuses communicate with the enteric nervous system within the intestinal wall.
The enteric nervous system can coordinate many digestive functions independently but remains strongly modulated by sympathetic and parasympathetic input.
Myenteric Plexus
The myenteric plexus, or Auerbach plexus, lies between layers of the muscularis externa.
It is particularly important in regulation of gastrointestinal motility.
Submucosal Plexus
The submucosal plexus, or Meissner plexus, lies within the submucosa of much of the gastrointestinal tract.
It participates in regulation of secretion, absorption, mucosal activity, and local blood flow.
Extrinsic and Intrinsic Plexuses
The mesenteric plexuses are extrinsic autonomic plexuses located outside the intestinal wall.
The myenteric and submucosal plexuses are intrinsic enteric plexuses located within the gastrointestinal wall.
Mesenteric Plexus Versus Enteric Plexus
| Feature | Mesenteric Plexuses | Enteric Plexuses |
|---|---|---|
| Location | Around mesenteric arteries and within mesenteries | Within gastrointestinal wall |
| Examples | Superior and inferior mesenteric plexuses | Myenteric and submucosal plexuses |
| System | Extrinsic autonomic nervous system | Enteric nervous system |
| Main role | Conveys and distributes extrinsic autonomic input | Coordinates local gastrointestinal activity |
Visceral Afferent Fibers
The mesenteric plexuses also provide pathways for visceral afferent fibers carrying sensory information from the gastrointestinal tract.
These fibers convey information related to distension, chemical conditions, reflex activity, and potentially painful stimuli.
Visceral Reflex Afferents
Many visceral afferent fibers participate in physiological reflexes and travel with parasympathetic pathways.
They provide information involved in regulation of digestive activity without necessarily producing conscious sensation.
Visceral Pain Afferents
Pain fibers from many abdominal gastrointestinal structures tend to travel centrally alongside sympathetic pathways.
They pass through prevertebral plexuses and splanchnic nerves toward spinal sensory pathways.
Midgut Pain
Visceral pain originating from midgut structures is typically poorly localized because visceral afferent pathways provide less precise spatial information than somatic sensory pathways.
Pain may initially be perceived in a region distant from the affected organ.
Appendicular Pain
Early visceral pain associated with the appendix is classically perceived in the periumbilical region.
This reflects the spinal segments receiving visceral afferent information from the midgut rather than the precise anatomical location of the appendix.
Hindgut Pain
Visceral afferent pathways from hindgut structures travel through autonomic networks associated with the inferior mesenteric and pelvic regions.
The precise pathway depends partly on the organ and whether sensory information is traveling above or below the pelvic pain line.
Mesentery as a Neurovascular Pathway
The mesentery provides a route not only for arteries and veins but also for lymphatics and autonomic nerves.
Periarterial nerve fibers can therefore travel directly from central abdominal plexuses toward intestinal segments.
Jejunal and Ileal Mesentery
Autonomic fibers accompanying jejunal and ileal vessels pass through the mesentery toward the small intestinal wall.
They enter the bowel alongside vascular branches and communicate with enteric neural networks.
Mesocolon
Autonomic fibers supplying the colon travel through mesocolic tissues with corresponding arterial branches.
The transverse and sigmoid mesocolons provide particularly clear examples of these neurovascular pathways.
Clinical Importance
The mesenteric plexuses are important in understanding visceral pain, gastrointestinal autonomic regulation, abdominal surgery, vascular procedures, and disorders affecting autonomic or enteric function.
Mesenteric Ischemia and Autonomic Fibers
The mesenteric arteries and their surrounding neural plexuses are anatomically closely associated.
Vascular disease affecting the mesenteric circulation can produce severe visceral pain transmitted through afferent pathways traveling within these autonomic networks.
Abdominal Surgery
Operations involving the mesentery, colon, or mesenteric arteries may encounter periarterial autonomic nerves.
The extent of functional consequences from nerve disruption depends on the location and amount of denervation and the extensive overlap of autonomic pathways.
Colorectal Surgery
During colorectal surgery, autonomic pathways near the inferior mesenteric artery and pelvic plexuses are important anatomical considerations.
Preservation of appropriate autonomic pathways can be important for gastrointestinal and pelvic organ function.
Autonomic Denervation
Loss of extrinsic autonomic input does not completely eliminate intestinal activity because the enteric nervous system retains substantial autonomous function.
However, extrinsic denervation can alter coordination, reflex responses, vascular regulation, and gastrointestinal motility.
Superior Mesenteric Plexus Distribution
| Structure | Major Arterial Pathway |
|---|---|
| Distal duodenum | Inferior pancreaticoduodenal branches |
| Jejunum | Jejunal arteries |
| Ileum | Ileal arteries |
| Cecum and appendix | Ileocolic branches |
| Ascending colon | Ileocolic and right colic arteries |
| Proximal transverse colon | Middle colic artery |
Inferior Mesenteric Plexus Distribution
| Structure | Major Arterial Pathway |
|---|---|
| Distal transverse colon | Left colic territory and communicating colic branches |
| Descending colon | Left colic artery |
| Sigmoid colon | Sigmoid arteries |
| Upper rectum | Superior rectal artery |
Autonomic Components
| Component | Major Source | Role |
|---|---|---|
| Midgut sympathetic | Thoracic splanchnic pathways and prevertebral ganglia | Modulates motility, secretion and vascular tone |
| Midgut parasympathetic | Vagus nerve | Supports motility and secretion |
| Hindgut sympathetic | Lumbar and related splanchnic pathways | Modulates motility, secretion and vascular tone |
| Hindgut parasympathetic | Pelvic splanchnic nerves, S2-S4 | Supports distal intestinal motility and secretion |
| Visceral afferents | Gastrointestinal tract | Carry reflex and sensory information centrally |
Key Features of the Mesenteric Plexuses
| Feature | Key Point |
|---|---|
| Main plexuses | Superior and inferior mesenteric plexuses |
| Anatomical arrangement | Periarterial nerve networks |
| Superior plexus artery | Superior mesenteric artery |
| Inferior plexus artery | Inferior mesenteric artery |
| Superior plexus territory | Primarily midgut derivatives |
| Inferior plexus territory | Primarily hindgut derivatives |
| Midgut parasympathetic supply | Vagus nerve |
| Hindgut parasympathetic supply | Pelvic splanchnic nerves, S2-S4 |
| Relationship to enteric system | Extrinsic fibers communicate with intrinsic enteric plexuses |
Anatomical and Clinical Importance
The mesenteric plexuses provide major autonomic pathways between the central autonomic nervous system and the intestines. Their close association with the superior and inferior mesenteric arteries allows nerve fibers to follow predictable vascular routes through the mesentery toward the gastrointestinal tract.
The superior mesenteric plexus primarily serves the midgut territory and carries parasympathetic fibers derived from the vagus nerve together with sympathetic and visceral afferent fibers. The inferior mesenteric plexus primarily serves the hindgut territory, where parasympathetic innervation is supplied by the pelvic splanchnic nerves.
These extrinsic plexuses communicate extensively with the myenteric and submucosal plexuses of the enteric nervous system. Understanding their organization is important for interpreting gastrointestinal autonomic regulation, visceral pain pathways, mesenteric vascular anatomy, and the preservation of autonomic nerves during abdominal and colorectal surgery.
Published on September 28, 2026
Last updated on September 28, 2026
Last updated on September 28, 2026