Abdominal Wall Flashcards
What are the boundaries of the abdomen?
The abdomen extends between the thoracic diaphragm and pelvic diaphragm
Which organs are protected by the rib cage?
- Spleen
- Liver
- Stomach
- Part of the kidneys
What is the abdomino-pelvic cavity?
The inferior part of the abdomen without a physical boundary, extending from the 7th-10th ribs to the inguinal ligament
What are the 4 abdominal quadrants?
- Right Upper Quadrant (RUQ)
- Left Upper Quadrant (LUQ)
- Right Lower Quadrant (RLQ)
- Left Lower Quadrant (LLQ)
What divides the abdomen into left and right halves?
The Median Plane, extending from the xiphoid process to the pubic symphysis
What divides the abdomen into upper and lower halves?
The Trans-Umbilical Plane
What structures are found in the Right Upper Quadrant (RUQ)?
- Right lobe of the liver
- Gallbladder
- 1st part of the duodenum
- Right colic flexure
What structures are found in the Left Upper Quadrant (LUQ)?
- Left lobe of the liver
- Stomach
- Spleen
- Body of pancreas
- Left colic flexure
What structures are found in the Right Lower Quadrant (RLQ)?
- Ascending colon
- Appendix
- Cecum
- Lower portion of right kidney
- Right ureter
- Right parts of ovaries and uterus (females)
- Spermatic chords (males)
What structures are found in the Left Lower Quadrant (LLQ)?
- Descending sigmoid colon
- Lower portion of left kidney
- Left ureter
- Left parts of ovaries and uterus (females)
- Spermatic chords (males)
What is the transverse mesocolon?
A double-layered peritoneal fold connecting the transverse colon to the posterior abdominal wall
What do the supra-mesocolic compartments contain?
- Stomach
- Liver
- Spleen
- Pancreas
- Duodenum
What do the infra-mesocolic compartments contain?
- Small intestine
- Ascending colon
- Descending colon
- Lower duodenum
Define the linea alba.
A midline fibrous structure running from the xiphoid process to the pubic symphysis
What is the semilunar line?
A vertical, curved tendinous line found on each side of the abdomen
What does the umbilicus mark?
The site where the umbilical cord was attached in fetal life
What is the arcuate line?
A curved line found posterior to rectus abdominis, located ⅓ of the distance from the pubic crest to the umbilicus
What occurs above the arcuate line regarding the rectus abdominis?
Rectus abdominis is enclosed both anteriorly and posteriorly by the rectus sheath
What occurs below the arcuate line regarding the rectus abdominis?
Rectus abdominis is covered only anteriorly by the rectus sheath
Why is the area below the arcuate line more prone to hernia formation?
The rectus abdominis lacks a strong posterior sheath
What are tendinous intersections?
Fibrous bands running transversely across the rectus abdominis muscle
What are the major muscles of the abdominal wall?
- Rectus abdominis
- Pyramidalis
- External oblique
- Internal oblique
- Transversus abdominis
What is the origin of the rectus abdominis muscle?
Pubic Symphysis and Pubic Crest
What is the function of the rectus abdominis muscle?
Flexes trunk, stabilizes and controls tilt of pelvis
What is the origin of the pyramidalis muscle?
Pubis
What is the insertion of the pyramidalis muscle?
Linea alba
What is the primary function of the external oblique muscle?
Compresses and supports abdominal viscera, flexes and rotates trunk
What is the origin of the internal oblique muscle?
Lower back fascia, anterior two-thirds of iliac crest, deep connective tissue near the inguinal ligament
What is the function of the transversus abdominis muscle?
Compresses and supports abdominal viscera to help affect intra-abdominal pressure
What is an aponeurosis?
A flat tendon made of connective tissue that connects muscles to bones or other muscles
What are umbilical folds?
Peritoneal reflections that cover ligaments or vessels
What is the median umbilical ligament?
Extends from the apex of the bladder to the umbilicus, a remnant of the urachus
What do the medial umbilical ligaments represent?
Remnants of the occluded umbilical arteries
What is the round ligament of the liver?
A fibrous remnant of the umbilical vein within the falciform ligament
What are the two layers of subcutaneous tissue below the umbilicus?
- Camper fascia (superficial fatty layer)
- Scarpa fascia (deep membranous layer)
What does the rectus sheath enclose?
Rectus abdominis and pyramidalis muscles
What supplies the anterior abdominal wall?
Inferior epigastric vessels
Where do the inferior epigastric arteries arise from?
The external iliac artery, just above the inguinal ligament
What is the role of the superior-inferior epigastric anastomosis?
Provides a backup blood supply in cases of arterial blockage
What nerves supply the anterolateral abdominal wall?
Thoracic (T7–T12) and lumbar (L1) spinal nerves
What is the inguinal canal?
Located above the inguinal ligament, transmits the spermatic cord (males) or round ligament (females)
What is the femoral canal?
A small opening within the femoral sheath, below the inguinal ligament
What is the internal (deep) inguinal ring?
The entrance to the inguinal canal, at the midpoint of the inguinal ligament
What is the external (superficial) inguinal ring?
The exit of the inguinal canal, an opening in the external oblique aponeurosis
What is the site of femoral hernias more common in?
Females
What is the internal (deep) inguinal ring?
The entrance to the inguinal canal, located at the midpoint of the inguinal ligament
What is the external (superficial) inguinal ring?
The exit of the inguinal canal, located superior and lateral to the pubic tubercle
What does the inguinal ligament connect?
The ilium’s anterior superior iliac spine to the pubic tubercle
What is the lacunar (Gimbernat) ligament?
A triangular extension of the inguinal ligament
What is the pectineal (Cooper) ligament?
A continuation of the lacunar ligament, providing posterior reinforcement to the inguinal canal and femoral canal
What is the conjoint tendon?
A tendinous structure formed by the lower fibers of the internal oblique and transversus abdominis muscles
What does the spermatic cord contain?
Essential vessels, nerves, and ducts involved in testicular function
What is the retropubic (Retzius) space?
A fat-filled space located between the pubic symphysis and the bladder
What is the round ligament of the uterus?
A fibrous remnant of the female gubernaculum connecting the uterus to the labia majora
What is the Triangle of Hasselbach?
A potential area of weakness in the abdominal wall for hernia protrusion
Define inguinal hernia (direct)
Medial to the inferior epigastric vessels through Hesselbach’s triangle, does not pass through the deep inguinal ring
Define inguinal hernia (indirect)
Protrudes lateral to the inferior epigastric vessels, entering the deep inguinal ring
What is a femoral hernia?
Passes through the femoral ring, below the inguinal ligament, into the femoral canal
What is an umbilical hernia?
Protrusion through the umbilical ring, often seen in newborns and pregnant women
What is an epigastric hernia?
A midline hernia through the linea alba above the umbilicus
What is a Spigelian hernia?
Rare hernia that protrudes through the Spigelian fascia
What is liposuction?
Removing unwanted subcutaneous fat using a suction tube and high vacuum pressure
What is the space of Bogros used for?
Inguinal hernia repair with prosthetic mesh placement
List the six common causes of abdominal protrusion
- Food
- Fluid
- Fat
- Feces
- Flatus
- Fetus
What is the significance of palpating the anterolateral abdominal wall?
It helps assess for masses, organ enlargement, tenderness, or peritoneal inflammation
What does the superficial abdominal reflex assess?
Neuromuscular function and can indicate underlying neurological or abdominal pathology
What spinal nerves mediate the superficial abdominal reflex?
T7–T12 spinal nerves
What can an absent or diminished response in the abdominal reflex suggest?
Spinal cord injury, peripheral nerve damage, or upper motor neuron lesions
What injuries are the nerves of the anterolateral abdominal wall susceptible to?
Injury during surgical incisions or from trauma
What type of incisions provide wide access in surgery?
Vertical incisions (median, paramedian)
What is a potential complication of surgical incisions?
Incisional hernias due to improper healing of the abdominal wall
What structures run inferior to the 12th rib?
Subcostal artery, vein, and nerve
These structures supply the lateral and anterior abdominal wall.
From where does the subcostal artery arise?
Thoracic aorta
The subcostal artery is a branch of the thoracic aorta.
Into which system does the subcostal vein drain?
Azygos (right) or hemiazygos (left) system
This drainage is important for venous return from the abdominal wall.
What is the superior venous drainage from the medial side?
Internal thoracic vein → Subclavian vein
This pathway is important for draining blood from the upper abdominal wall.
What is the superior venous drainage from the lateral side?
Lateral thoracic vein → Axillary vein
This pathway helps drain the lateral aspect of the abdominal wall.
What is the inferior drainage pathway for the abdominal wall?
Superficial and inferior epigastric veins → Femoral vein → External iliac vein
This pathway is crucial for venous return from the lower abdominal wall.
What do deep circumflex iliac vessels supply?
Lateral abdominal wall and iliac region
These vessels arise from the external iliac vessels.
What do superficial epigastric vessels supply?
Lower abdominal wall and skin
These vessels arise from the femoral artery and vein.
What is the thoraco-epigastric vessels’ role?
Potential venous anastomosis between lateral thoracic vein and superficial epigastric vein
This anastomosis allows collateral circulation if the inferior vena cava is obstructed.
What do superficial/deep inferior epigastric vessels supply?
Rectus abdominis and lower abdominal wall
Superficial inferior epigastric vessels supply lower abdominal skin and subcutaneous tissue.
What do superficial/deep circumflex iliac vessels supply?
Deep abdominal wall and superficial lower abdominal wall and skin
These vessels arise from the external iliac vessels and femoral vessels respectively.
What do external pudendal vessels supply?
Skin of the lower abdomen, external genitalia, and perineum
These vessels have both superficial and deep branches.
What is the function of the Iliohypogastric Nerve (L1)?
Provides motor innervation to the internal oblique and transversus abdominis muscles and sensory innervation to the skin over the lower abdomen and suprapubic region.
The iliohypogastric nerve does not pass through the inguinal ligament, but runs superior to it.
Where does the Iliohypogastric Nerve (L1) arrive?
At the external oblique aponeurosis near the inguinal ligament.
This nerve is located above the ilioinguinal nerve.
What is the location of the Ilioinguinal Nerve (L1) in relation to the Iliohypogastric Nerve?
Below the iliohypogastric nerve.
The ilioinguinal nerve passes through the inguinal canal.
What muscles does the Ilioinguinal Nerve provide motor innervation to?
Internal oblique and transversus abdominis muscles.
It also provides sensory information to specific areas of the body.
What areas does the Ilioinguinal Nerve provide sensory innervation to?
Upper inner thigh, base of the penis, anterior scrotum (in males), mons pubis, and labia majora (in females).
This nerve is crucial for sensory function in these regions.
What are the components of the Genitofemoral nerve?
Femoral branch and Genital branch.
Each branch has distinct sensory and motor functions.
What does the Femoral branch of the Genitofemoral nerve provide?
Sensory innervation to the upper anterior thigh.
This branch does not provide motor innervation.
What is the function of the Genital branch of the Genitofemoral nerve?
Provides motor innervation to the cremaster muscle (in males) and sensory innervation to the scrotum (males) or labia majora (females).
This branch enters the inguinal canal.
What is the Lateral femoral cutaneous nerve?
A purely sensory nerve that supplies the skin of the lateral thigh.
It does not provide motor innervation.
