Lecture 14: Abdominal Wall + Inguinal Region Flashcards
List the layers of the abdomen from superficial to deep
Skin
Superficial Fascia
Muscles covered by deep fascia
Transversalis fascia
Parietal Peritoneum
Abdominal cavity
What are the 4 Quadrants of he abdomen (going clockwise)
- LUQ
- LLQ
- RLQ
- RUQ
List the nine regions of the abdomen
image
What is the dividing line for the superficial lymphatic drainage of abdominal wall
Umbilicus
Describe lymph flow above the umbilicus
Axillary lymph nodes - specifically pectoral
Describe lymph flow below the umbilicus
Superficial inguinal lymph nodes
What is the dividing line for the superficial venous drainage of abdominal wall
Umbilicus
What drains the abdominal region above the umbilicus
Axillary V
What drains the abdominal region below the umbilicus
External Iliac + femoral veins
List the abdominal wall muscles superficial to deep
External oblique
Internal oblique
Transversus abdominis & Rectus abdominus
What are tendinous intersections
They subdivide the rectus abdominis into multiple segments
What forms the rectus sheath
Interlaced aponeuroses of abdominal muscles (ant/post rectus sheath)
What does the rectus sheath enclose
Rectus abdominis muscle
superior/inferior epigastric vessels
anterior rami T7-12
What is the linea alba
Fibrous vertical band connecting L/R sheaths
T/F: The rectus sheath is the same composition throughout all levels
False; it changes
What is the arcuate line?
Arched line where posterior sheath abruptly ends (approx b/t umbilicus and pubic symph.)
What is the rectus sheath composition like BELOW the ribs / ABOVE arcuate line. Also, describe the anterior/posterior rectus sheath at this level.
The internal oblique aponeurosis splits to enclose rectus abdominis muscles.
Ant rectus sheath: from external oblique and part of the internal oblique
Post rectus sheath: from transverse and part of internal oblique
What is the rectus sheath like below the arcuate line?
All 3 aponeuroses travel in front of muscle (no posterior rectus sheath)
Nerve supply ro rectus sheath/abdominal area
Anterior rami T7-11 [intercostal N]
T12 [subcostal nerve]
L1 [lumbar]
The L1 spinal nerve splits into two named nerves. What are they?
Iliohypogastric (sup)
Ilioinguinal (inf)
Does the ilioinguinal nerve travel through the inguinal canal?
yes
Where do nerves travel in relation to internal oblique and transversus abdominis muscles
Between
What is the plane called where nerves travel between int. oblique and transversus abdominis
Transversus abdominis plane
What is a transversus abdominis plane (TAP) block
Anesthetic technique to numb nerves of the abdominal wall. Done for laparoscopic surgeries, some hernia repairs, and hysterectomies.
Superior Epigastric Artery: continuation of _______ artery
Internal thoracic
Inferior Epigastric Artery: branch of _________artery
External iliac
Posterior Intercostal, Subcostal and Lumbar Arteries off of the _______
aorta
Superficial Epigastric Artery : branch of _______ artery
Femoral
What is the inguinal canal
Tunnel through inferior abdominal wall
What does the inguinal canal connect
abdominal cavity w/ scrotum/labia
What is a potential weak spit in the abdominal wall
Inguinal canal
The deep inguinal ring
Tunnel entrance; lateral ‘ring’, entrance of “tunnel” from abdominal cavity
Superficial inguinal ring
Medial ring, opening into scrotum/labia
What are the borders of the inguinal canal
Anterior wall: external oblique aponeurosis
Posterior wall: transversalis fascia (lateral 2/3) and conjoint tendon (medial 1/3)
Floor: inguinal ligament (inferior attachment of external oblique)
What are the contents of the inguinal canal
Ilioinguinal nerve
Spermatic cord or round ligament of the uterus
Genitofemoral nerve (quite small)
What is the function of the genitofemoral nerve
Sensory to thigh, motor to muscle of spermatic cord
a protrusion of abdominal contents through the abdominal wall is known as a
Hernia
Do you think inguinal hernias are more common in males or in females? Why?
Inguinal hernias are more common in males (b/c spermatic cord keeps that tunnel ‘open’)
What are the 2 types of inguinal hernias
indirect
direct
Indirect (‘congenital’) Inguinal Hernia - describe it
takes an indirect path out of the abdomen (through the entire “tunnel”)
Hernial sac starts lateral to the inferior epigastric vessels
More common with testes
Direct (Acquired) Inguinal Hernia
Hernia goes ‘directly’ through superficial ring (NOT through the canal)
Hernial sac leaves abdominal cavity medial to the inferior epigastric vessels
More common in older males (over age 40) with weak abdominal muscles
Direct Inguinal Hernia
‘neck’ of the hernial sac tends to be wide, since it isn’t constricted by the inguinal canal
Why does an inguinal hernia protude when coughing
B/c intra-abdominal pressure is increased, decreased abdominal space in abdomen
What peritoneum lines the abdominal wall
Parietal peritoneum
What peritoneum covers the abdominal/pelvic viscera
Visceral peritoneum
What is the peritoneal cavity
Serous fluid secreted in this space
Define mesentery
a double layer of peritoneum that connects some intestines to the posterior abdominal wall
What is found between the layers of mesentery?
Blood vessels, nerves, lymphatics, fat between the layers of mesentery
What is omentum?
A double layer (fold) of peritoneum that connects the stomach to another organ
What is greater omentum?
stomach –> transverse colon
What is lesser omentum?
Stomach (and part of duodenum) to liver
Parietal Peritoneum innervation
T7-L1 (same innervation as abdominal wall)
Where is pain felt in parietal peritoneum?
Tends to be precisely localized and severe
What is rebound tenderness?
common clinical sign of inflamed parietal peritoneum
Visceral peritoneum
Innervation via ANS
Visceral peritoneum pain tends to be…
Dull and poorly localized (referred pain)
What is the foregut supplied by?
Celiac trunk
What is the midgut supplied by?
Superior mesenteric artery
What is the hindgut supplied by?
Inferior mesenteric artery
Lymphatic drainage of the GI tract - lymphatic drainage will eventually go
go to nodes that cluster around arteries of the same name
Celiac lymph nodes
Superior mesenteric lymph nodes
Inferior mesenteric lymph nodes
Innervation of the GI tract
almost soley from ANS
Parasympathetics from Vagus (CN X) and pelvic splanchnic nerves (S2-S4)
Sympathetics from thoracic splanchnic nerves (T5-T12) and lumbar splanchnic nerves (L1, L2)
