Anatomy EX2 - Nerves

Question 1

Phrenic n.

Answer 1

• 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

Question 2

What are the nerves of the Anterior Abdominal Wall?

Answer 2

• Ventral rami of T7-L1 spinal nn.

- They run between IO and TA mm.

Question 3

Which ventral rami supply region above umbilicus?

Answer 3

• T7, T8 & T9

Question 4

Which ventral ramus supplies umbilicus region?

Answer 4

• T10

Question 5

Which ventral rami supply region below umbilicus?

Answer 5

• T11, T12 & L1

Question 6

What does injury to T11, T12, & L1 result in?

Answer 6

• weakens mm in inguinal region

- Predisposes to developing direct inguinal hernias

Question 7

Innervation to viscera is via ….

Answer 7

autonomic n. plexuses

Question 8

Sympathetic fibers that inverted viscera originate from ….

Answer 8

T5-L2(3) – thoracolumbar

Question 9

Parasympathetic fibers that inverted viscera originate from ….

Answer 9

CN X & S2-4 
– craniosacral

Question 10

Parasympathetic synapses in abdomen occur …

Answer 10

• within effector organs

Question 11

Preganglionic nerves from CN X to abdomen travel on ….

Answer 11

• upper arterial branches, celiac trunk, SMA, renal aa, and all their branches

Question 12

Preganglionic nerves from S2-S4 to abdomen travel on ….

Answer 12

• lower arterial branches, IMA and branches

Question 13

Preganglionic sympathetics going to abdomen synapse in …

Answer 13

• collateral ganglia

Question 14

Postganglionic sympathetics in abdomen leave ganglia …

Answer 14

• reach effector organs

Question 15

Post-synaptic sympathetics in abdomen travel on …

Answer 15

• all main arterial branches, celiac trunk, SMA, renal aa, IMA and all their branches

Question 16

The Celiac Ganglion plexus travels with …

Answer 16

• Celiac brs.

Question 17

The Superior Mesenteric Ganglion plexus travels with …

Answer 17

• SMA brs.

Question 18

The Aorticorenal Ganglion plexus travels with …

Answer 18

• renal brs.

Question 19

The Inferior mesenteric ganglion plexus travels with …

Answer 19

• IMA brs.

Question 20

The Celiac Ganglion, the Superior Mesenteric Ganglion, the Aorticorenal Ganglion & all receive …

Answer 20

• thoracic splanchnic nn & CN X brs

Question 21

The Inferior mesenteric ganglion receives …

Answer 21

• lumbar splanchnic nn & S2-S4 brs

Question 22

What are the nerves of the posterior abdominal wall?

Answer 22

• Ventral rami T12-L4

- Lumbar plexus of nn., located beneath fascia of posterior abd. mm.

Question 23

Subcostal n. (T12)

Answer 23

• ~1cm inferior to 12th rib
• Supplies sensory to ant./lat. abd. wall
• Supplies motor to abdominal mm.: EO, IO, TA, pyramidalis, RA, QL

Question 24

Iliohypogastric & Ilioinguinal Nn. (L1)

Answer 24

• 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.

Question 25

Lateral Femoral Cutaneous N. (L2-L3)

Answer 25

- Descends ant. to iliacus m. - Passes deep to inguinal ring - Inferior to ASIS - Supplies ant./lat. skin of thigh

Question 26

Femoral N. (L2-L4)

Answer 26

- Runs between iliacus & psoas major mm. - Passes deep to inguinal ligament - Inferior to ASIS - Supplies sensory & motor to anterior thigh

Question 27

Genitofemoral N. (L1-L2)

Answer 27

- 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)

Question 28

Obturator N. (L2-L4)

Answer 28

- Runs medial to psoas major mm. - Passes thru obturator foramen - Supplies sensory & motor to medial thigh

Question 29

Lumbosacral Trunk (L4-L5)

Answer 29

- Large n. trunk crosses over ala of sacrum - Descends into pelvis to help form sacral plexus - Provides general contributions to both plexuses

Question 30

Sacral Plexus (L4-S4)

Answer 30

-Somatic innervation Forms 3 nn.: -Sciatic & Gluteal nn -Pudendal n.

Question 31

L4-L5

Answer 31

- forms LS trunk & crosses over sacral ala

Question 32

S1

Answer 32

- emerges above piriformis m.

Question 33

S2 & S3

Answer 33

- emerges thru piriformis m.

Question 34

S2-S4

Answer 34

- contributes to pudendal n.

Question 35

L4-S3

Answer 35

- form sciatic & gluteal nn.

Question 36

What are the Autonomic Sympathetic Plexuses of the Pelvis & Peritoneum?

Answer 36

- T10 – L2(3) – prevertebral plexus | - Symp. S2-S4 = Sacral splanchnic nn.

Question 37

What are the Autonomic Parasympathetic Plexuses of the Pelvis & Peritoneum?

Answer 37

- S2 – S4 | - P-symp = Pelvic splanchnic nn.

Question 38

Superior Hypogastric Plexus

Answer 38

- Contains mostly sympathetic fibers - Covers bifurcation of aorta & upper sacrum - Condenses to form 2 hypogastric nn.

Question 39

In thorax, sympathetic chains are lateral to vertebrae they move ____ as they descend .

Answer 39

medially

Question 40

Pelvic Sympathetic fibers converge & terminate anterior to coccyx as ...

Answer 40

Ganglion impar

Question 41

Hypogastric Nerve

Answer 41

- Contains mostly sympathetic fibers - Diverge & curve outward bilateral to rectum - Expands to form inferior hypogastric plexus.

Question 42

Sacral splanchnic nn. are made up of ...

Answer 42

- tiny symp. fibers off symp chain

Question 43

Pelvic splanchnic nn. are made up of ...

Answer 43

- tiny p-symp. fibers off S2-S4

Question 44

Both Sacral & Pelvic Splanchnic Nn. enter inferior hypogastric plexusand fibers travel on ____ to ______.

Answer 44

- arterial brs., pelvic organs

Question 45

Splanchnic nn. are easily inured during rectal surgery or radical hysterectomy, this results in ...

Answer 45

- impaired bladder control or sexual function

Question 46

Inferior Hypogastric Plexus

Answer 46

- Contains both sympathetic & parasympathetic fibers - Found covering pelvic viscera bilaterally - Serves as main autonomic plexus of pelvis