Anterior Abdominal Wall Flashcards
What is the nine region system of topographical division?
- divided by two vertical and two horizontal planes
- divided into nine regions
What are the vertical planes in the nine region system called and where are they located?
- midclavicular planes
- extend inferiorly from the midpoints of the clavicles to the midpoints of lines joining the anterior superior iliac spine to the pubic symphysis
What are the horizontal planes in the nine region system called and where are they located?
- subcostal plane: joins the lowest point of the costal margin on each side; lies at the inferior margin of rib 10 (L3 level)
- transtubercular plane: joints the tubercles of the iliac crests (L5 level)
What are the nine regions?
- right hypochondrium
- epigastric
- left hypochondrium
- right flank (lateral)
- umbilical
- left flank (lateral)
- right groin (inguinal)
- pubic
- left groin (inguinal)
How are the organs related to these nine regions?
- the liver lies mostly in the right hypochondrium and epigastric region
- the spleen and fundus and body of the stomach are found in the left hypochondrium region
How is pain related to these nine regions?
pain is localized to the regions
- example: appendicitis is localized to the right groin area
What is the quadrant system of topographical division?
- a simpler system that involves dividing the abdomen into four quadrants
- median plane: vertical plane through midline
- transumbilical plane: horizontal plane through the umbilicus
What are the four quadrants?
- right upper quadrant
- left upper quadrant
- right lower quadrant
- left lower quadrant
Why is the four quadrant system less precise?
the umbilicus is a variable landmark which lies between L2 and L5
- depends on age, weight, body position, etc.
What are the layers of the abdominal wall?
- skin
- superficial layer of superficial fascia (Camper’s fascia) - fatty layer
- deep layer of superficial fascia (Scarpa’s fascia) - thin and membranous layer
- deep (investing) fascia - ensheaths the muscles, thin/investing layer
- external oblique muscle
- internal oblique muscle
- transversus abdominis muscle
- transversalis fascia - thin and slippery
- extraperitoneal fascia - fatty
- parietal peritoneum - thin membrane
- peritoneal cavity - potential space
- visceral peritoneum
- abdominal organs
What are the two major layers of the fascia of the anterior abdominal wall?
- superficial fascia
- deep (investing) fascia
What are the subdivisions of the superficial fascia?
- superficial layer (Camper’s fascia)
- deep layer (Scarpa’s fascia)
What is Camper’s fascia?
a thin fatty layer of fascia which is continuous with the superficial fascia of the perineum and thigh
What is Scarpa’s fascia?
a membranous layer of fascia which is firmly fastened to the fascia lata of the thigh, just below the inguinal ligament
What does the deep (investing) fascia cover?
each of the anterior abdominal wall muscles on its anterior and posterior surface
What is extravasation of urine?
- Between Scarpa’s fascia and the deep fascia of the abdomen, there is a potential space, where fluid can accumulate.
- Rupture of the spongy urethra allows accumulation of urine within this space.
- Urine can spread superiorly in the anterior abdominal wall within this space.
- It cannot spread inferiorly into the thigh due to the firm attachment of Scarpa’s fascia to the fascia lata.
- This problem is almost exclusive to males because the urethra is longer, more superficial, and more horizontally oriented than in females.
- Cause: trauma
What is the linea alba?
- a median tendinous raphe which extends from the xiphoid process to the pubic symphysis
- anterior abdominal wall muscles insert into this raphe via their aponeuroses
What are the anterolateral muscles of the anterior abdominal wall?
- external oblique
- internal oblique
transversus abdominus
What is the origin, insertion, nerve supply, and function of the external oblique muscle?
- O: lower 8 ribs
- I: iliac crest, anterior superior iliac spine, pubic tubercle, and linea alba by aponeurosis
- N: anterior primary rami of lower 6 thoracic nerves
- F: compresses the abdomen, supports abdominal viscera, lateral flexor of trunk
In which direction do the fibers of the external oblique muscle travel?
downward and forward
What is the origin, insertion, nerve supply, and function of the internal oblique muscle?
- O: lumbar fascia, iliac crest, lateral two-thirds of inguinal ligament
- I: lower 3 ribs, linea alba by aponeurosis
- N: anterior primary rami of lower 6 thoracic and first lumbar nerves
- F: compresses the abdomen, supports abdominal viscera, lateral flexor of trunk
In which direction do the fibers of the internal oblique muscle travel?
downward and backward
What is the origin, insertion, nerve supply, and function of the transversus abdominis muscle?
- O: lower 6 costal cartilages, lumbar fascia, iliac crest, lateral third of inguinal ligament
- I: into linea alba by aponeurosis
- N: anterior primary rami of lower 6 thoracic and first lumbar nerves
- F: compresses the abdomen, supports abdominal viscera, acts as an internal back brace
In which direction do the fibers of the transversus abdominis muscle travel?
horizontally
