Anatomy - Anterior Abdominal Wall & Inguinal Region Flashcards
Name the 7 layers of the abdominal wall
- Skin
- Superficial fascia (hypodermis)
- Deep fascia
- Musculature
- Transversalis fascia
- Extraperitoneal fat
- Peritoneum
Two layers of superficial fascia (hypodermis) in the lower abdominal region.
a) Camper’s fascia (fatty)
b) Scarpa’s fascia (membranous)
Deep fascia is a connective tissue layer that surrounds…
all muscles of the abdomen
Visceral peritoneum lines the…
Parietal peritoneum lines the…
Visceral peritoneum lines the GI tract.
Parietal peritoneum lines the body wall.
4 muscle layers of the abdomen.
External oblique
Internal oblique
Transversus abdominis
Rectus abdominis
External oblique muscles run in the same direction as…
the external intercostals of the thoracic cavity (hands in pockets)
What is the aponeurosis
A sheath of connective tissue (wide flat tendon) that helps connect the abdominal muscles to the skeleton. Located medially.
What is the inguinal ligament
Thick cord of connective tissue that runs from the ASIS to the pubic tubercle (differentiates abdominal cavity from thigh)
The inguinal ligament is primarily derived from…
the connective tissue of the external oblique muscle.
The internal oblique muscle runs in the same direction as…
internal intercostal muscles of the thoracic cavity (hands to chest).
Transversus abdominis muscle fibers run…
straight medial-lateral
What is particular about the aponeurosis of the transversus abdominis muscle?
There is an interruption in the connective tissue (forms a pocket).
More on this when we discuss the rectus sheath.
What is characteristic about the rectus abdominis muscle?
It has an intersected appearance due to horizontal tendinous intersections of connective tissue.
Rectus abdominis takes origin on..
the costal cartilages (rib 5-7)
Rectus abdominis courses down the abdomen and binds to…
the pubic symphysis
Small accessory muscle at the lower edge of the rectus abdominis
Pyramidalis muscle
What is the linea alba?
Midline connective tissue structure that separates the two rectus abdominis muscles from each other.
What is the linea semilunaris?
Connective tissue structure that runs along the external edge of the rectus abdominis muscle.
All aponeuroses of the abdominal wall muscles contribute to…
the rectus sheath, which encases the rectus abdominis muscle.
Where is the arcuate line?
Midway between the umbilicus and pubic symphysis (pocket in the rectus sheath).
What is the arcuate line?
A point at which the connective tissue changes position
Describe the difference between the tissue layers above and below the arcuate line.
Above the arcuate line: Rectus sheath encases the rectus abdominis muscle
Below the arcuate line: Rectus sheath is only anterior to the muscle (no rectus sheath posterior to the rectus abdominis)
What is the only layer between the rectus abdominis muscle and peritoneum beneath the arcuate line?
Transversalis fascia
What is the medical advantage of the arcuate line?
Can be used for surgical access
Blood supply: Arteries supplying the medial abdominal wall (2)
Superior epigastric artery
Inferior epigastric artery
Origins of the superior and inferior epigastric arteries
Superior epigastric artery: continuation of the internal thoracic artery
Inferior epigastric artery: continuation of the external iliac artery
Blood supply: The femoral artery (near the pelvis) gives rise to…
the superficial epigastric artery
The superior epigastric, inferior epigastric and superficial epigastric arteries course through different layers of the abdominal wall. Describe them.
Superior epigastric: Runs deep to the rectus abdominis (between the muscle and posterior rectus sheath/transversalis fascia)
Inferior epigastric: Runs deep to the rectus abdominis within the rectus sheath
Superficial epigastric: Courses in the superficial facia
Name the 3 peritoneal folds
Median umbilical fold
Medial umbilical fold
Lateral umbilical fold
The median umbilical fold lies above the…
median umbilical ligament
The medial umbilical fold lies above the…
medial umbilical ligament
Lateral umbilical fold lies above the…
inferior epigastric vessels
The median umbilical ligament and medial umbilical ligament are remnants of…
median: urachus
medial: umbilical artery
Thoraco-epigastric vein.
What layer does it run through? Where does it drain?
Superficial vein, runs in the hypodermis on midaxillary line.
Drains in the axillary vein.
Superficial epigastric vein drains to..
drains to the femoral vein.
2 veins running below the deep fascia and where do they drain
Superior epigastric vein (drains to internal thoracic vein)
Inferior epigastric vein (drains to external iliac vein)
What are the 2 main groups of lymph nodes in the abdominal region?
Axillary lymph nodes
Superficial inguinal lymph nodes
What is the generalized name of the nerves innervating the abdominal wall?
Thoraco-abdominal nerves
Thoraco-abdominal nerves are all branches of…
intercostal nerves
What are the 2 types of thoraco-abdominal nerves & their functions
Motor: Innervate muscle of the abdominal wall
Sensory: Transduce sensory stimuli
What spinal levels are the sensory nerves of the abdominal wall derived from?
They are branches of the 5 lowest intercostals (T7-T11) and subcostal (T12) nerves.
2 nerves derived from the lumbar plexus that innervate the abdominal wall
Iliohypogastric nerve
Ilioinguinal nerve
Innervate muscles and provide cutaneous sensation :)
Which nerve courses through the majority of the inguinal canal?
Ilioinguinal nerve (emerges through superficial inguinal ring)
Which nerve pierces through the aponeurosis of the external oblique?
Iliohypogastric nerve (emerges 3-5 cm above the superficial inguinal ring)
Define the inguinal canal
A canal communicating between the abdominal cavity and the scrotum/labia majora
What is the spermatic cord?
Bundle of structures that run to the scrotum through the inguinal canal in males.
What is the entry and exit point of the inguinal canal?
Entry: deep inguinal ring
Exit: superficial inguinal ring
Name the 3 layers (coverings) of the spermatic cord
External spermatic fascia
Cremasteric muscle
Internal spermatic fascia
Name the layers of the spermatic cord and what layers they are derived from.
External spermatic fascia: External oblique aponeurosis
Cremasteric muscle: Internal oblique muscle
Internal spermatic fascia: Transversalis fascia
What structures course through the centre of the spermatic cord?
Ductus deferens (sperm duct)
Arteries and veins
Which muscle layer does NOT contribute to the spermatic cord?
Transversus abdominis muscle (it arches over the spermatic cord)
What is the cremasteric reflex? What 2 nerves generated? What is the stimulus?
Reflex of the cremasteric muscle generated by the iliolinguinal nerve and genitofemoral nerve (femoral branch).
When stimulated by light touch, the nerves will trigger the cremasteric reflex (elevation of the testis).
The cremasteric reflex is used to test for…
Tests for testicular torsion (positive if reflex is absent).
Name 3 reinforcement structures of the inguinal canal.
Conjoint tendon
Lacunar ligament
Pectineal ligament
How does the conjoint tendon form? Where does it insert?
Fusion of aponeuroses of the internal oblique and transversus abdominis.
Inserts into pubic crest.
What is the lacunar ligament?
As the inguinal ligament reaches the pubic tubercle, it reflects laterally and attaches to the pectineal line as the lacunar ligament.
What is the pectineal ligament (of Cooper) ?
An extension of the lacunar ligament (runs on the pectineal line of the pubic bone).
How can the conjoint tendon prevent hernias?
It covers the deep inguinal ring (entrance of inguinal canal). It prevents bowel loops from penetrating through this weakness.
What is the equivalent of the spermatic cord in females?
round ligament of the uterus
The round ligament of the uterus is a remnant of…
the gubernaculum
What are the layers of the round ligament of uterus
Same as spermatic cord, but much thinner
Do females have an inguinal canal?
Yes, but it is a much smaller structure
