Anterior Abdominal wall and Inguinal region Flashcards
what are the 3 layers of muscle that wrap around the lateral aspect of the abdomen
- External oblique
- Internal oblique
- Transverse abdominis
Describe external oblique
- its fibres run in a anterior-inferior direction.
- Most outer layer
- Attaches to the iliac crest
- Forms the inguinal ligament from the ASIS to the pubic tubercles
- Inferior border of external oblique is the inguinal ligament
- Muscle fibres end at the midclavicular line then becomes aponeurotic, insets at midpoint of the abdomen at the linea alba
describe internal oblique
- Internal oblique, is the most middle layer of the abdominal wall, its fibres run in a anterior-superior direction.
- The muscle fibres end at the midclavicular line
- Sheet of muscle becomes aponeurotic and insets on the linea alba
describe transverses abdominis
- Transversus abdominis deep layer of the abdominal wall
- Fibres run in a transverse direction
- Ends at midclavicular line
- Sheet becomes apenurotic inserts on linea alba
what are the attachments of the rectus abdomens
- Rectus abdominis is a large muscle running from the xiphoid process superiorly to the pubic symphysis inferiorly.
- it protects the trunk
describe the structure of the rectus abdominis
- The muscle has tendionous intersections along the length of the muscle.
- There are tendinous intersections as the muscle fibres are split up into smaller portions
- Llinea alba is in between these
what is the rectus abdominis enclosed by
- the aponeurotic sheath which is derived from the aponeuroses of external oblique, internal oblique and transversus abdominis, this forms the rectus sheath
describe the layers of the rectus sheath above the arcuate line
- External oblique is anterior to rectus abdominis
- Internal oblique half runs anterior half runs posterior
- Transverse abdominis runs posterior to the rectus abdominis
- transversals fascia is posterior to the rectus abdominis
describe the layers of the rectus sheath below the arcuate line
- All run anterior to the rectus sheath, (transverse abdominis, internal oblique and external oblique), transversalis fascia runs behind the rectus sheath
what is transversals fascia
- it is a sheath that is behind transverse abdominis
describe the blood supply to the anterior abdominal wall
- Internal thoracic artery continuous into the abdomen when it becomes the superior epigastric artery – supplies superior portion of the rectus abdominis
- Inferior epigastric artery supplies inferior portion of rectus abdominis, it is a branch of the external lilac artery, it runs along the deep surface of the abdominal wall
- Lowe intercostal arteries from T11-T12 wrap around and supply the abdominal wall
- Lumbar arteries supply it as well
describe the nerve supply of the anterior abdominal wall
• T7 = xiphoid • T10 = umbillicus T12 • subcostal nerve L1 • Iliohypogastric nerve • Ilioinguinal nerve
what is the final intercostal nerve
T11
what is T12 known as
Subcostal nerve as it runs below the ribs, runs beneath the 12th rib
what 2 nerves does L1 split into
- Iliohypogastric nerve
- Ilioinguinal nerve
where does the gentiofemroal nerve emerge from
L1 and L2
- it pierces through posas major and then splits into two branches - a genital branch and a femoral branch
what is the inguinal ligament
Inguinal ligament is a free inferior border of the external oblique muscle
what forms the inguinal ligament
apernosis is connecting to ASIS and pubic tubercle which forms the inguinal ligament, from the external oblique muscle
what passes underneath the inguinal ligament
NAV
- femoral nerve
- femoral artery
- femoral vein
what are the main structures that pass through the inguinal canal
– spermatic cord,
- rough ligament of the uterus
in males the inguinal canal is…
more developed then it is in females
what does the spermatic cord contain
The spermatic cord contains structures running to and from the testes, and suspends the testes within the scrotum
name the structures in the spermatic cord
- Testicular artery
- Ductus/Vas deferens
- Pampiniform venous plexus
- Genital branch of genitofemoral nerve
- Ilioinguinal nerve (runs with cord)
what are the layers that surround the spermatic cord
- External spermatic fascia
- Cremaster muscle
- Internal spermatic fascia
what layer is the genitofemoral nerve is between
- internal spermatic fascia
- cremaster muscle
what layer is the illoinguinal nerve in between
- it is on the outside of the external spermatic fascia
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
what is the superficial inguinal ring
- The superficial inguinal ring is the point at which the spermatic cord emerges from the abdominal wall
where do the testes develop
- The testes develop on the posterior wall and descend through the inguinal canal to reach the scrotum
name the months in which the testes develop and what happens to them
- Primordial testes 7th week on abdominal wall
- 7th month start to descend
- 9th month descend from the pelvis to the inguinal canal into the scrotum
describe how the testes develop
- As they descend they take there neurovascular supply with them and there lymphatic drainage, this is why the testicular artery is derived from the aorta at L2
- As the testes are in the pelvis it is underneath the peritoneum, the peritoneum is sticky and sticks to the testes so everywhere the peritoneum goes it drags the testes with it
- The first layer of the abdominal wall that the testes push through is the transverslis fascia, this just gives the layer of fascial to the outside of the testes and all of the structures that it is going with such as the neruovascular structure, it then takes the name internal spermatic fascia
- Next layer it comes to is transversus abdominis, the transversus abdominis arches over the point where it passes through the wall so it doesn’t give a covering to the testes or the contents of the spermatic cord
- The next layer is the internal oblique layer therefore it takes this muscular covering with it, this muscular layer surrounds the testes, testicular neurovascular and muscles is called the cremaster muscle, this is innervated by the genitofemerol nerve (L1 L2)
- The testes then reach the external oblique which covers it and forms the external spermatic fascia, the external oblique is apneruotic in this region so it gives a connective tissue covering
- As the testes descend through the abdominal wall and the peronteium is dragged with it you get an investigation of the perineum this is called the processus vaginalis
- When the testes make it down into the scortum process vagianlises seals offer superirorly then renames itself to tunica vaginalis
- This is alaso how the inguinal canal is also created, creates the deep inguinal ring and the superficial inguinal ring
describe the branches fo the genitofemral nerve
- genital branch is motor
- femoral branch is purely sensory
what is a hernia
- A hernia is a protrusion of peritoneum and viscera such as small intestine through a opening or weakness
why can hernias be a problem
- Hernias by themselves usually are harmless, but nearly all have a potential risk of having their blood supply cut off (becoming strangulated).
- If the blood supply is cut off at the hernia opening in the abdominal wall, it becomes a medical and surgical emergency
what percentage of hernias are inguinal hernias
Inguinal hernia’s account for 75% of abdominal hernia’s
describe a direct inguinal hernia
- Often acquired
- Commonly in males over 40 years old
- Hernia passes directly through abdominal wall (Hasselbach’s triangle) emerges through the superficial ring
- Goes straight through the abdominal wall, doesn’t bother going through the deep inguinal ring
- Rarely enters scrotum
- Medial to inferior epigastric vessels
where does a direct inguinal hernia pass
- Hernia passes directly through abdominal wall (Hasselbach’s triangle) emerges through the superficial ring
- Goes straight through the abdominal wall, doesn’t bother going through the deep inguinal ring
describe indirect inguinal hernias
- Often congenital (patent process vaginalis)
- More common (2/3)
- Transverses canal within the processus vaginalis
- Commonly enters scrotum
- Lateral to inferior epigastric vessels
- Passes through the deep inguinal ring alogn the inguinal canal and into the superficial ring
- Occurs due to patent process vaginalis
what is a cause of an indirect hernia
patent process vaginalis
where does an indirect inguinal hernia pass
• Passes through the deep inguinal ring alogn the inguinal canal and into the superficial ring
what is hasselbachs triangle
Direct hernia’s occur due to a weakness in the anterior abdominal wall, Hasselbach’s triangle.
what are the boundaries of hasselbachs triangle
- Inguinal ligament
- Inferior epigastric vessels
- Altera border of rectus abdominis
name the other types of hernias you can have
- Incisional
- Inguinal
- Umbilical
- Femoral
what causes an incisional hernia
Following surgery to the abdomen the scar creates a weakness in the abdominal wall
what is an inguinal hernia
Above and medial to pubic tubercle
what is an umbilical hernia caused by
Usually in babies, when the rectus abdominis is not fully joined in the midline
what is a femoral hernia caused by
Herniation into the femoral canal (beneath the inguinal ligament so below and lateral to pubic tubercle) most common in females
where is the testicular artery derived from and why is it there
- As the testes descend they take there neurovascular supply with them and there lymphatic drainage, this is why the testicular artery is derived from the aorta at L2
what becomes the
- internal spermatic fascia
- cremaster layer
- external spermatic fascia
- transversals fascia
- internal oblique layer
- external oblique layer
what does the tunica vaginalis do
– this allows free movement
