Anatomy EX2 - Nerves Flashcards
Phrenic n.
- Originates from C3-C5 spinal segments
- Explains paralysis of diaphragmatic respiration from cervical cord injuries
- Paralyzed hemidiaphragm cannot contract (descend) , remains high in thorax, recognizable on radiographic chest films
What are the nerves of the Anterior Abdominal Wall?
- Ventral rami of T7-L1 spinal nn.
- They run between IO and TA mm.
Which ventral rami supply region above umbilicus?
- T7, T8 & T9
Which ventral ramus supplies umbilicus region?
- T10
Which ventral rami supply region below umbilicus?
- T11, T12 & L1
What does injury to T11, T12, & L1 result in?
- weakens mm in inguinal region
- Predisposes to developing direct inguinal hernias
Innervation to viscera is via ….
autonomic n. plexuses
Sympathetic fibers that inverted viscera originate from ….
T5-L2(3) – thoracolumbar
Parasympathetic fibers that inverted viscera originate from ….
CN X & S2-4 – craniosacral
Parasympathetic synapses in abdomen occur …
- within effector organs
Preganglionic nerves from CN X to abdomen travel on ….
- upper arterial branches, celiac trunk, SMA, renal aa, and all their branches
Preganglionic nerves from S2-S4 to abdomen travel on ….
- lower arterial branches, IMA and branches
Preganglionic sympathetics going to abdomen synapse in …
- collateral ganglia
Postganglionic sympathetics in abdomen leave ganglia …
- reach effector organs
Post-synaptic sympathetics in abdomen travel on …
- all main arterial branches, celiac trunk, SMA, renal aa, IMA and all their branches
The Celiac Ganglion plexus travels with …
- Celiac brs.
The Superior Mesenteric Ganglion plexus travels with …
- SMA brs.
The Aorticorenal Ganglion plexus travels with …
- renal brs.
The Inferior mesenteric ganglion plexus travels with …
- IMA brs.
The Celiac Ganglion, the Superior Mesenteric Ganglion, the Aorticorenal Ganglion & all receive …
- thoracic splanchnic nn & CN X brs
The Inferior mesenteric ganglion receives …
- lumbar splanchnic nn & S2-S4 brs
What are the nerves of the posterior abdominal wall?
- Ventral rami T12-L4
- Lumbar plexus of nn., located beneath fascia of posterior abd. mm.
Subcostal n. (T12)
- ~1cm inferior to 12th rib
- Supplies sensory to ant./lat. abd. wall
- Supplies motor to abdominal mm.: EO, IO, TA, pyramidalis, RA, QL
Iliohypogastric & Ilioinguinal Nn. (L1)
- Can arise from common trunk
descend ant. to QL - Iliohypogastric n. supplies skin of suprapubic region
- Ilioinguinal n. runs thru inguinal call to supply it
- Both also supply abd. mm.
Lateral Femoral Cutaneous N. (L2-L3)
- Descends ant. to iliacus m.
- Passes deep to inguinal ring
- Inferior to ASIS
- Supplies ant./lat. skin of thigh
Femoral N. (L2-L4)
- Runs between iliacus & psoas major mm.
- Passes deep to inguinal ligament
- Inferior to ASIS
- Supplies sensory & motor to anterior thigh
Genitofemoral N. (L1-L2)
- Pierces psoas major m.
- descends along ant. surface
- Splits to femoral br. & genital br.
- Supplies skin inf. & med. to inguinal ligament
- Supplies cremaster m. (of spermatic cord)
Obturator N. (L2-L4)
- Runs medial to psoas major mm.
- Passes thru obturator foramen
- Supplies sensory & motor to medial thigh
Lumbosacral Trunk (L4-L5)
- Large n. trunk crosses over ala of sacrum
- Descends into pelvis to help form sacral plexus
- Provides general contributions to both plexuses
Sacral Plexus (L4-S4)
-Somatic innervation
Forms 3 nn.:
-Sciatic & Gluteal nn
-Pudendal n.
L4-L5
- forms LS trunk & crosses over sacral ala
S1
- emerges above piriformis m.
S2 & S3
- emerges thru piriformis m.
S2-S4
- contributes to pudendal n.
L4-S3
- form sciatic & gluteal nn.
What are the Autonomic Sympathetic Plexuses of the Pelvis & Peritoneum?
- T10 – L2(3) – prevertebral plexus
- Symp. S2-S4 = Sacral splanchnic nn.
What are the Autonomic Parasympathetic Plexuses of the Pelvis & Peritoneum?
- S2 – S4
- P-symp = Pelvic splanchnic nn.
Superior Hypogastric Plexus
- Contains mostly sympathetic fibers
- Covers bifurcation of aorta & upper sacrum
- Condenses to form 2 hypogastric nn.
In thorax, sympathetic chains are lateral to vertebrae they move ____ as they descend .
medially
Pelvic Sympathetic fibers converge & terminate anterior to coccyx as …
Ganglion impar
Hypogastric Nerve
- Contains mostly sympathetic fibers
- Diverge & curve outward bilateral to rectum
- Expands to form inferior hypogastric plexus.
Sacral splanchnic nn. are made up of …
- tiny symp. fibers off symp chain
Pelvic splanchnic nn. are made up of …
- tiny p-symp. fibers off S2-S4
Both Sacral & Pelvic Splanchnic Nn. enter inferior hypogastric plexusand fibers travel on ____ to ______.
- arterial brs., pelvic organs
Splanchnic nn. are easily inured during rectal surgery or radical hysterectomy, this results in …
- impaired bladder control or sexual function
Inferior Hypogastric Plexus
- Contains both sympathetic & parasympathetic fibers
- Found covering pelvic viscera bilaterally
- Serves as main autonomic plexus of pelvis
