anterior abdominal wall and inguinal region Flashcards
what are the 3 layers of muscles that make up the lateral abdominal wall?
external oblique
internal oblique
transversus abdominis
what is the most superficial layer of the abdominal wall?
external oblique
where do the muscle fibres of the abdominal wall muscles end?
end at the MCL to become the linea alba
where does the rectus abdominis run?
from the xiphoid process to the pubic symphysis
what splits up the rectus abdominis?
tendinous intersections
what is the rectus sheath?
Rectus abdominis muscle is enclosed by an aponeurotic sheath, which is derived from the aponeuroses of external oblique, internal oblique and transversus abdominis.
describe the rectus sheath above the arcuate line
innermost - transversalis fascia
transversalis abdominis
internal oblique - aponeurosis splits in half so half runs behind the rectus abdomonis and half runs in front
external oblique
all insert onto the linea alba
describe the rectus sheath below the arcuate line
All aponeurotic layers of the muscles run anterior to RA
Only the fascia that runs behind
where do the posterior intercostals branch off from?
descending aorta
where do the anterior intercostals branch off from?
internal thoracic artery either side of the sternum
what does the internal thoracic artery become?
superior epigastric artery
what does the superior epigastric artery supply?
superior portion of the rectus abdominis
what does the inferior epigastric artery branch off from?
external iliac artery
what is the final intercostal nerve?
T11
what level is the subcostal nerve?
T12
what is the subcostal nerve motor and sensory to?
Motor and sensory to abdominal wall not to the thoracic wall.
what are the 2 branches of L1?
Iliohypogastric nerve
Ilioinguinal nerve
what is L1 motor and sensory to?
Motor to abdominal wall and sensory to the lowest part of the abdomen and mainly the inguinal wall.
what makes the inguinal ligament?
The inferior border of external oblique’s aponeurosis rolls under itself to create the inguinal ligament
what passes through the inguinal canal?
allows passage for spermatic cord in males and round ligament of the uterus for women
what structures run in the spermatic cord?
Testicular artery Ductus/Vas deferens Pampiniform venous plexus Genital branch of genitofemoral nerve Ilioinguinal nerve (runs with cord)
what layers surround the spermatic cord (in order of innermost to outermost)?
Internal spermatic fascia
Cremaster muscle
External spermatic fascia
what is the superficial inguinal ring?
The superficial inguinal ring is the point at which the spermatic cord emerges from the abdominal wall.
what is the deep inguinal ring?
The deep inguinal ring is the point at which the contents of the spermatic cord enter the abdominal wall.
at what age have the testes descended to the scrotum?
9 months
where do the testes develop?
posterior abdominal wall
what is the internal spermatic fascia derived from?
tunica vaginalis
what is the cremaster muscle derived from?
internal oblique muscle
what nerve innervates the cremaster muscle?
genitofemoral nerve
what is the cremasteric reflex?
if you stroke the internal aspect of the male thigh, scrotum should go up a bit
are the branches of the genitofemoral nerve and what do they innervate?
femoral branch which goes to skin of the internal aspect of the thigh (purely sensory) and the genital branch which is purely motor (linked to the cremaster muscle)
what is the external spermatic fascia derived from?
the external oblique muscle
what is the processus vaginalis?
an in-folding of the peritoneum
what is a hernia?
is a protrusion of peritoneum and viscera such as small intestine through a opening or weakness
what is the risk with hernias?
have the risk to have their blood supply cut off
if the blood supply is cut off at the abdominal wall, it becomes a medical and surgical emergency
which hernias are acquired and which are congenital?
direct - acquired
indirect - congenital
who commonly gets direct hernias?
males over 40 years
are direct or indirect hernias more common?
indirect
where do direct hernias occur?
passes directly through abdominal wall (Hasselbach’s triangle)
rarely enters scrotum
medial to inferior epigastric vessels
where do indirect hernias occur?
transverses canal with processus vaginalis
commonly enters scrotum
lateral to inferior epigastric vessels
what are the borders of Hasselbach’s triangle?
inferior epigastric vessels
inguinal ligaments
lateral border of rectus abdominis
when and why do incisional hernias occur?
occur following a surgery to the abdomen bc the scar creates a weakness in the abdominal wall
where do inguinal hernias occur?
above and medial to the pubic tubercle
who do umbilical hernias commonly occur in?
babies, when the rectus abdominis is not fully joined in the midline
who is femoral hernias most common in?
females
where do femoral hernias occur?
Herniation into the femoral canal (beneath the inguinal ligament so below and lateral to pubic tubercle)
