Anterior Abdominal Wall and Inguinal Region Flashcards
What are the 3 muscle layers of the abdominal wall?
- external oblique
- internal oblique
- transversus abdominis
What direction does the external oblique travel in and attach to?
- Fibres run in an anterior-infection direction
- attaches to iliac crest, to ASIS and pubic tubercle so inbetween ASIS and pubic tubercle external oblique is not attached to anything = inguinal ligament
- finish at mid-clavicular line where it becomes an aponeurosis
What direction does the internal oblique travel in?
middle layer, fibres run in anterior-superior direction
- finish at mid-clavicular line where it becomes an aponeurosis
In what direction does the transversus abdominis travel in?
Deep layer, fibres run in a transverse direction
- finish at mid-clavicular line where it becomes an aponeurosis
What are some features of the rectus abdominis?
- runs from xiphoid process superiorly to pubic symphysis inferiorly
- has tendinous intersections along muscle length
- enclosed by aponeurotic sheath derived from aponeuroses of external oblique, internal oblique and transversus abdominis
- linea alba down the middle
- strengthens middle part of abdominal wall where it becomes aponeurotric
What blood supply is there to the rectus sheath?
inferior epigastric from external iliac from inguinal ligament coming up
superior epigastric from internal thoracic
What nerves supply the abdominal wall muscles?
T7 - xiphoid
T10 - umbilicus
T12 - subcostal
L1 - iliohypogastric and ilioinguinal branches
(all are motor to these muscles and sensory to the skin of that area)
Genitofemoral nerve which arises from L1/L2 and has a genital branch and a femoral branch (sensory to thigh only)
What are the roots of the subcostal, iliohypogastric and ilioinguinal nerves?
Subcostal nerve root is T12
Iliohypogastric and ilioinguinal nerve root is L1
How is the inguinal ligament formed?
the inferior border of external oblique’s aponeurosis rolls under itself
What does the spermatic cord contain?
- structures running to and from the testes suspending the testes within the scrotum
- testicular artery, ductus deferens, pampiniform venous plexus, genital branch of genitofemoral nerve, ilioinguinal nerve
What surrounds the spermatic cord?
Layers of the abdominal wall - external spermatic fascia, cremaster muscle, internal spermatic fascia
In which layers does the genitofemoral nerve lie?
Between the internal spermatic fascia and the cremaster muscle
Where does the ilioinguinal nerve lie?
Outside the external spermatic fascia
Where is the superficial inguinal ring?
point at which the spermatic cord emerges from the abdominal wall
Where is the deep inguinal ring?
point at which the contents of the spermatic cord enter the abdominal wall
How do the testes develop?
- on the posterior abdominal wall and descend through the inguinal canal to reach the scrotum around the 9th month of development
What is an inguinal hernia?
Protrusion of peritoneum and viscera such as small intestine through an opening or weakness
Count for 75% of abdominal hernias
By themselves are usually harmless but nearly all have potential risk of becoming strangulated (having blood supply cut off)
What is direct inguinal canal?
acquired commonly in males over 40 years old hernia passes directly through abdominal wall (Hasselbach's triangle) rarely enters scrotum medial to inferior epigastric vessels
What is indirect inguinal canal?
- congenital (patent process vaginalis)
- more common (2/3 of cases)
- transverses canal within the processus vaginalis (patent processus vaginalis as doesn’t fibrose and deteriorate)
- commonly enters scrotum
- lateral to inferior epigastric vessels
What are the borders of Hasselbach’s triangle?
inferior epigastric vessels
lateral border of rectus abdominis
inguinal ligament
What other hernias are there?
- incisional: following surgery to abdomen scar creates weakness in abdominal wall
- umbilical: usually in babies, rectus abdominis is not fully joined in the midline
- femoral: herniation into femoral canal, most common in females
Where is the femoral canal?
beneath the inguinal ligament so below and lateral to pubic tubercle
What is the significance of the arcuate line?
Above the arcuate line: internal oblique splits so one layer goes behind the rectus abdominis (with transversus abdominis and transversalis fascia) and one goes in front (with external oblique)
Under the arcuate line: all aponeuroses pass anterior to the rectus abdominis and posteriorly is only transversalis fascia
Where do the femoral artery, vein and nerve pass?
Through a gap between the pelvis and inguinal ligament
