Abdominal Neurology Flashcards
Nerves of the Anterior Abdominal Wall:
- Thoracoabdominal N
- Subcostal N
- Iliohypogastric N
- Ilioinguinal N
Anterior Abdominal Wall Nerves travel between the __ ___ and ___ ___ muscles
- Internal Oblique
- Transversus Abdominis
Thoracoabdominal Nerve
- Continuations of the intercostal nerves from T7 to T11
- Provide motor and sensory innervation to the majority of the anterior abdomen
Subcostal Nerve
- Continuation of the T12 nerve
- Runs along the inferior border of the 12th rib
- Provides sensory innervation to the area superior to the iliac crest
Iliohypogastric Nerve
- One of the branches from L1; the first branch off the lumbar plexus
- Passes under the psoas major, across the quadratus lumborum
- Provides innervation to the internal oblique and transversus abdominis muscle
- Provides sensory innervation to the posterolateral gluteal skin and suprapubic skin (hypogastric region)
Ilioinguinal Nerve
- Second branch from L1; the second branch off the lumbar plexus
- Enters the inguinal canal
- Provides innervation to the medial thigh and associated genital area (male’s root of the penis and anterior scrotum, female’s mons pubis and labia majora)
What nerve innervates the female’s mons pubis and labia majora?
Ilioinguinal Nerve
Nerves of the Lumbar Plexus:
- Iliohypogastric
- Ilioinguinal
- Genitofemoral
- Lateral Cutaneous Nerve of the Thigh
- Femoral
- Obturator
Nerves that Pass Through the Inguinal Canal:
- Ilioinguinal N
- Genital Branch of the Genitofemoral N
Structures that Pass Through the Inguinal Canal: Males
- Spermatic Cord
- Ilioinguinal N
- Genital Branch of the Genitofemoral N
Structures that Pass Through the Inguinal Canal: Females
- Round Ligament of the Uterus
- Ilioinguinal N
- Genital Branch of the Genitofemoral N
Genital Branch of the Genitofemoral Nerve
- Provides innervation to the anterior labia majora, anterior scrotum, and adjacent thigh
- Provides motor innervation to the Cremaster Muscle
Genitofemoral Nerve pierces the:
Psoas Major Muscle
Femoral Branch of the Genitofemoral Nerve
- Travels under the inguinal ligament to enter the thigh
- Provides innervation to subcutaneous areas of anterior thigh
Nerve Roots of Genitorfemoral Nerve:
L1 and L2
Nerve Roots of Lateral Cutaneous Nerve of the Thigh:
L2 and L3
Nerve Roots of Femoral Nerve:
L2, L3 and L4
Nerve Roots of Obturator Nerve:
L2, L3, and L4
Nerves that Innervate the Posterior Abdominal Wall:
- Subcostal N
- Lumbar Plexus (Iliohypogastric, Ilioinguinal, Lateral Cutaneous N of the Thigh, Femoral, Obturator)
Lumbar Plexus is created by contributions from ___ and ___-___
- T12
- L1-L4
Lateral Cutaneous Nerve of the Thigh
- Associated with the lateral aspect of the inguinal ligament
- Provides sensory innervation to the anterior and lateral thigh
Femoral Nerve
- Travels outside the abdominopelvic cavity (under the inguinal ligament)
- Provides innervation to the muscles and skin of the anterior thigh and medial leg
Obturator Nerve
- Travels with the psoas major on its medial aspect, emerging near the common iliac artery
- Enters medial thigh through the Obturator Canal
- Provides motor and sensory innervation to the muscles of the medial thigh
Lumbosacral Trunk
- Created through the anterior rami of the 4th and 5th lumbar nerves
- Runs inferiorly on either side of the spinal column to interact with S1
- Helps create the sciatic, superior gluteal, and inferior gluteal nerves, and the nerves to the internal obturator, superior and inferior gemellus, and quadratus femoris muscles
Nerves that Provide Sympathetic Innervation:
- Greater Splanchnic N
- Lesser Splanchnic N
- Least Splanchnic N
- Lumbar Splanchnic N
- Sacral Splanchnic N
Thoracic Splanchnic Nerve
- Consists of 3 pairs of nerves above the diaphragm running inferiorly towards the abdomen to synapse within the ganglia located near the aorta
- Consists of preganglionic sympathetic nerve fibers from the sympathetic chain ganglion T5-T12
Greater Splanchnic Nerve
- Contains input from T5-T9
- Travels from thoracic sympathetic trunk inferiorly into the abdomen (passing thru the thoracic diaphragm) where it synapses on the Celiac Trunk Ganglion
Postsynaptic Fibers of the Greater Splanchnic Nerve Provide Sympathetics to these Structures:
- Esophagus
- Stomach
- Spleen
- Pancreas
- Liver
- Biliary System
- Duodenum
- Greater Omentum
What nerve helps create the enteric nervous system of the foregut structures?
Greater Splanchnic Nerve
Lesser Splanchnic Nerve
- Contains input from T10-T11
- Synapses at the Superior Mesenteric Ganglia (near where the superior mesenteric artery comes off the aorta)
Postsynaptic Fibers of the Lesser Splanchnic Nerve Provide Sympathetics to these Structures:
- Jejunum
- Ileum
- Cecum
- Ascending Colon
- Transverse Colon
What nerve provides sympathetics to the midgut organs?
Lesser Splanchnic Nerve
Least Splanchnic Nerve
- Contains input from T11 and/or T12
- Synapses at the Aortic Renal Ganglion
- Provides innervation to the kidneys
Lumbar Splanchnic Nerve
- Contains input from L1-L5
- Join with the celiac, inferior mesenteric, and superior hypogastric plexuses
- Postsynaptic fibers travel to the hindgut and pelvic organs
What nerve provides sympathetics to the hindgut organs?
Lumbar Splanchnic Nerve
Sacral Splanchnic Nerve
- Contains input from S1-S5
- Synapses at the Inferior Hypogastric Plexus
- Provide sympathetic innervation to the pelvis and perineum
- Travels with branches of the internal iliac artery
Ganglion Impar
- End of the sympathetic chain near the sacrococcygeal junction
- Left and Right sympathetic chains join here
- No white rami communicantes come into this ganglion, only gray rami travel out
- Sympathetic neurons travel to lower pelvic organs including the distal rectum and anus
Nerves that Provide Parasympathetic Innervation:
- Vagus N
- Pelvic Splanchnic N
Vagus Nerve
- Parasympathetic
- Originates in the brain stem
- Enters abdomen as the anterior or posterior vagal trunk (LARP = left anterior, right posterior) from the esophageal plexus
- Carries presynaptic parasympathetic and visceral afferent fibers (mainly for reflexes) to the abdominal aortic plexuses
What nerve provides parasympathetic innervation to the foregut and midgut?
Vagus Nerve
Pelvic Splanchnic Nerve
- Parasympathetic
- Contains input from the anterior rami of S2-S4
- Nerves travel to the inferior hypogastric plexus
- Provide parasympathetic innervation to the descending colon, sigmoid colon, rectum and anal canal, and structures of the pelvis and perineum
What nerve provides parasympathetic innervation to the hindgut?
Pelvic Splanchnic Nerve
Extrinsic Plexuses
Collections of sympathetic postganglionic axons and parasympathetic preganglionic axons (and some visceral sensory)
Celiac (Solar) Plexus
- Located underneath the thoracic diaphragm
- Associated with the Celiac Trunk
- Greater and Lesser Splanchnic nerves provide sympathetic contributions
- Posterior Vagal Trunk provides parasympathetic contributions
- Branches from this plexus travel to the foregut organs to help with controlling digestive processes
Celiac Ganglion
Where the sympathetic preganglionic and postganglionic axons synapse
Superior Mesenteric Plexus
- Located around the Superior Mesenteric Artery
- Connected to the Celiac Plexus
- Receives contributions from the Lesser & Least Splanchnic Nerves, and the first lumbar ganglion of the sympathetic trunk
- Provides innervation to the midgut structures
Inferior Mesenteric Plexus
- Located around the Inferior Mesenteric Artery
- Innervation from this plexus travels with the vessels from the Inferior Mesenteric Artery to innervated the hindgut
- Receives contributions from the intermesenteric plexus (networks between superior and inferior) and the lumbar sympathetic trunk
- ONLY SYMPATHETIC
Superior Hypogastric Plexus
- Located below the Inferior Mesenteric Plexus and is connected to it
- Provides sympathetic innervation to the pelvic viscera
Hypogastric Nerve
- Branches off of the Superior Hypogastric Plexus
- Connects the Superior Hypogastric Plexus with the Inferior Hypogastric Plexus
Inferior Hypogastric Plexus
- Located in the pelvis on either side of the rectum, cervix and urinary bladder
- Contains both sympathetic and parasympathetic innervation
- Sympathetic contribution comes from the Hypogastric Nerves (Superior Hypogastric Plexus)
- Parasympathetic contribution comes from the Pelvic Splanchnic Nerves
- Provides innervation to the Pelvic Viscera
Enteric Nervous System
- Wholly contained within the submucosal and myenteric plexuses in the wall of the GI tract
- Communicates extensively with the Parasympathetic and Sympathetic Nervous Systems
- Made up of intrinsic plexuses within the GI tract walls
- Contains visceral afferent neurons that relay sensory information back to the CNS
- Interactions between enteric neurons allow for reflex-like responses to help in the regulation of local GI responses
- CNS provides the ENS with more broad-scale environmental control
- Divided into the Myenteric Plexus and the Submucosal Plexus
Myenteric Plexus (Auerbach Plexus)
- Intrinsic plexus located between the layers of muscles within the abdominal viscera (btwn the circular muscle and longitudinal muscle)
- Helps in regulating the movement of the smooth muscle here
Submucosal Plexus (Meissner Plexus)
- Part of the enteric nervous system located within the submucosa of the abdominal viscera (btwn the submucosa and circular muscle)
- Functions to control both endocrine and exocrine secretions, vasomotion, micro-motility, and immune response
Midclavicular Plane
Two sagittal planes running down from the center of the right nad left clavicles
Transpyloric Plane (Addison’s Plane)
- Runs across the body at the level of L1
- Found by finding the midpoint between the jugular notch and pubic symphysis
- This line transects the pylorus of the stomach, gallbladder, pancreas, superior mesenteric artery, hepatic portal vein, transverse mesocolon, and hilum of the kidneys
Subcostal Plane
Line passes inferior to the 10th costal cartilage (L2); runs paralle to the transverse colon
Transtubercular (Intertubercular) Plane
- Line passes through the iliac tubercles
- Approximately at the level of the ileocecal junction
Interspinous Plane
- Line that connects the two ASIS’s together
- Runs around the level of the appendix and sigmoid colon
Right Hypochondriac Region
- Liver
- Gallbladder
- Right kidney
- Small Intestine
Right Hypochondriac Region
Right Upper Quadrant
- Liver
- Gallbladder
- Right kidney
- Small Intestine
Epigastric Region
Middle Upper Quadrant
- Stomach
- Liver
- Pancreas
- Duodenum
- Spleen
- Adrenal Glands
Left Hypochondriac Region
Left Upper Quadrant
- Spleen
- Colon
- Left Kidney
- Pancreas
Right Lumbar Region
Right Middle Quadrant
- Gallbladder
- Liver
- Right Colon
Umbilical Region
Middle
- Umbilicus
- Parts of Small Intestine
- Duodenum
Left Lumbar Region
Left Middle Quadrant
- Descending Colon
- Left Kidney
Right Iliac Region
Right Lower Quadrant
- Appendix
- Cecum
Hypogastric Region
Middle Lower Quadrant
- Urinary Bladder
- Sigmoid Colon
- Female Reproductice Organs
Left Iliac Region
Left Lower Quadrant
- Descending Colon
- Sigmoid Colon