Abdomen, Pelvis & Perineum Flashcards
What are the three flat muscles of the anterior abdominal wall? (Deep to superficial)
- transversus abdominis
- internal oblique
- external oblique
What is the action of the flat muscles of the anterior abdominal wall? (Together and individual)
- when all three contract = raise pressure inside abdominal cavity
- individual contraction = lateral flexion of lumbar spine & rotation of the thoracic spine
Where is the superficial inguinal ring found?
In the external oblique aponeurosis, superior and medial to the pubic tubercle
Where is the deep inguinal ring found?
In the transversalis fascia, immediately above the inguinal ligament
What is the innervation of the muscles of the anterolateral abdominal wall?
Receives motor innervation from the T6-T12 spinal nerves as well as the ilioinguinal and iliohypogastric nerves which are branches of the lumbar plexus
What is the blood supply to the muscles of the anterolateral abdominal wall?
Superior epigastric arteries (continuation of the internal thoracic arteries) and inferior epigastric arteries (branch of the external iliac artery) –> these two arteries anastomose together
What forms the inguinal ligament?
Lower border of external oblique aponeurosis
What is the difference between direct and indirect inguinal hernias?
- INdirect inguinal hernias go through the INguinal canal (push through the deep inguinal ring, lateral to the inferior epigastric artery)
- DIRECT inguinal hernias go DIRECTLY through the abdominal wall (medial to the inferior epigastric artery)
What are the muscles of the posterior abdominal wall?
- psoas major
- psoas minor
- quadratus lumborum
- iliacus
- aponeuroses of the origin of the transversus abdominis muscles
What is the iliopsoas muscle?
Psoas major combined with the iliacus forms the iliopsoas muscle responsible for flexing the hip
What is the function of the quadratus lumborum?
Fixes the 12th rib during inspiration as well as minor flexion of the trunk
What is the innervation of the quadratus lumborum?
Innervated directly from T12 spinal nerves and lumbar spinal nerves
What is the innervation of the iliopsoas?
Lumbar plexus
What is the blood supply to the muscles of the posterior abdominal wall?
Comes directly from the posteriorly situated abdominal aorta and inferior vena cava
Where does the foregut end and midgut begin?
Major duodenal papilla (where pancreatic enzymes and bile are drained)
What is included in the foregut, midgut and hindgut?
- foregut: abdominal oesophagus –> major duodenal papilla
- midgut: major duodenal papilla –> last 1/3 transverse colon
- hindgut: last 1/3 transverse colon –> superior rectum (inferior rectum is a pelvic structure)
What main branches of the abdominal aorta supply the foregut, midgut and hindgut?
- foregut: coeliac trunk
- midgut: superior mesenteric artery
- hindgut: inferior mesenteric artery
What are the intraperitoneal organs?
- 1st and 4th parts of duodenum
- stomach
- jejunum
- ileum
- caecum
- appendix
- transverse colon
- sigmoid colon
- liver and gallbladder
- spleen
- tail of pancreas
What are the retroperitoneal organs?
- 2nd and 3rd parts of duodenum
- pancreas (except tail)
- ascending colon
- descending colon
- superior rectum
- kidneys and ureters
- adrenal glands
- aorta and IVC
- abdominal oesophagus
What is the parietal peritoneum?
Single layer of peritoneum lining the abdominal walls and retroperitoneal organs
What is the visceral peritoneum?
Single layer of peritoneum in contact with the intraperitoneal organs
What is the omentum?
- double layer of peritoneum attaching the stomach to other peritoneal organs
- greater omentum attaches stomach to transverse colon
- lesser omentum attaches stomach to duodenum and liver
What are the peritoneal ligaments?
Double layer of peritoneum suspending some abdominal organs to the abdominal walls e.g. falciform ligament connects liver to anterior abdominal wall
What are the mesenteries?
- double layer of peritoneum attaching most of the gut tube to the back of the abdomen
- acts as a root to suspend the parts of the GIT in place
- sandwiched between two layers of peritoneum are the blood and nerve supply to the GIT
- mesenteries have different names depending on which part of the GIT they are attached to
- retroperitoneal parts of GIT do not have mesentery (only covered on anterior surface by peritoneum
What part of the nervous system innervates the parietal peritoneum?
Somatic nervous system (pain well localised and severe)
What part of the nervous system innervates the visceral peritoneum?
Autonomic nervous system (pain is dull and poorly localised, often refers to skin overlying midline of the abdomen as gut develops as midline structure and receives bilateral innervation)
