What defines the abdominal region?
It is the region located from the diaphragm to the pelvic inlet. It has an anterior body wall consisting of the ribs and xiphoid process superiorly. The skin, muscles and fascia are located laterally and anteriorly. The lumbar vertebrae are located poster
What pelvic structure is palpated in order to determine where to do a lumbar puncture?
The iliac crest
What are the two attachments of the inguinal ligament and from which structure does the ligament arise?
The ligament runs from the anterior superior iliac spine to the pubic tubercle. It is formed by the most posterior portion of the external oblique aponeurosis
What are the names of the two other ligaments that the inguinal ligament give rise to?
The lacunar (triangular ligament) and the pectineal ligament (runs along the pectinal line of the pubis. These ligaments arise once the inguinal ligament attaches to the pubic tubercle
The four quadrants of the abdomen are formed by:
A vertical midstenal plane and a horizontal transumbilical plane
What are the 9 regions of the stomach and how are they formed?
The 9 regions are formed by drawing vertical lines from the midclavicular regions to the midlines between the ASIS and the pubic tubercles on the right and left sides. Horizontal lines are drawn immediately below the costal margin and at the transtubercle
What region is responsible for referred pain of the foregut? Midgut? Hindgut?
Foregut: epigastric
Midgut: umbilical
Hindgut: pubic
What is the clinical significance of the Transpyloric plane?
Runs at vertebral level L1 and defines where the spinal cord ends. This is also where the celiac trunk and superior mesenteric arteries emerge anteriorly off of the abdominal aorta respectively
What is the clinical significance of the Subcostal plane?
This is the approximate location of the inferior mesenteric plane (L3)
What is the clinical significance of the supracristal plane?
This is where the abdominal aorta bifurcates (L4) into the right and left common iliac arteries
What is the clinical significance of the intertubercular plane?
Level of L5: approximate location of where the left and right common iliac veins join to form the inferior vena cava
Name the superficial layers (3) of the anterior abdominal wall.
1. Skin
2 Camper's fascia (fat-->thickness depends on person's fitness level); superficial arteries, veins and nerves reside in it
3. Scarpa's fascia (membranous)
Describe the continuation of Scarpa's fascia and it's clinical significance.
Scarpa's fascia continues inferiorly to form the superficial perineal fascia (Colle's fascia) and Dartos fascia (scrotum and penis). It attaches to the fascia lata of the thigh sealing the two compartments off so that if fluid/air etc accumulates in the a
Describe the nerve innervation of the anterior abdominal wall.
The anterior abdominal wall receives nerve innervation from the anterior rami of spinal nerves T7-L1. These nerves supply both motor and sensory innervation to the skin and muscles of the abdominal wall as well as pain sensation from the parietal peritone
Describe the blood supply to the anterior abdominal wall.
Superiorly: the internal thoracic artery (branch from the subclavian) gives rise to two terminal branches: the musculophrenic (right) and the superior epigastric (left)
Laterally: 10th-12th intercostal arteries
Inferiorly: inferior epigastric (medially lo
What is the clinical significance of the inferior epigastric artery? Where does it pierce the posterior rectus sheath? Does it anastomose?
The inferior epigastric artery is a landmark for defining the type of inguinal hernia a person may have. A direct hernia is when the hernia goes medial to the inferior epigastric artery showing up in hasselbeck's triangle (inguinal ligament (floor), rectu
Describe the lymphatic drainage of the abdominal wall.
Superior to the umbilicus: axillary lymph nodes
Inferior to umbilicus: superficial inguinal lymph nodes-->external iliac-->lumbar lymph nodes
The superficial inguinal lymph nodes receive lymph from:
the lower abdominal wall, the buttocks the penis, the scrotum, the labium majoris, the lower parts of the vagina and the anal canal.
What are the lateral group muscles of the abdominal wall?
Outer to inner: external oblique, internal oblique, transverses abdominus
What are the anterior groups of the muscles of the abdominal wall?
The rectus abdominus and the pyramidalis muscle
What forms the rectus sheaths? Which muscle group is encased in the sheath?
Above the arcuate line:
The anterior rectus sheath is formed from the aponeurosis of the external oblique and 1/2 of the internal oblique aponeurosis
The posterior rectus sheath is formed by the transversus abdominus and 1/2 of the internal oblique aponeu
Where does the posterior rectus sheath end?
At the arcuate line midway between the umbilicus and the pubic crest. It is at this point where the inferior epigastric artery enters the posterior rectus sheath.
What happens to the aponeurosis at the level inferior to the arcuate line?
The aponeurosis of the external, internal and transversus muscles all travel anterior to the rectus abdominus muscles which is why the posterior rectus sheath disappears
What is the linea alba?
The linea alba is where the aponeurosis of the lateral abdominal wall muscles interlace in the midline of the body. The two rectus abdominus muscles lie on either side of the linea alba. It extends from the xiphoid process to the pubic symphysis
Where do the nerves and blood vessels supplying the lateral abdominal muscles lie?
Between the internal and transversus muscles
Name the action and nerve innervations of the lateral abdominal wall muscles
External oblique: Intercostal nerves T7-T11 and subcostal nerve T12; it acts to compress the abdomen and active in forced expiration
Internal oblique: Intercostal nerves T7-T11 and subcostal nerve T12, Iliohypograstric and ilioinguinal nerves; acts to com
Name the nerve innervation of the rectus abdominis muscles and their actions.
Intercostal nerves T7-T11 and subcostal nerve T12. They act to compress the abdominal wall, flex the vertebral column and tense the abdominal wall
What are the eight layers of the abdominal wall?
Skin
Campers fascia
Scarpas fascia
External oblique
Internal oblique
Transversus abdominis
Fascia transversalis
Extraperitoneal fat
Peritoneum
If I were to make a slice through the skin all the way to the visceral peritoneum just lateral of the linea alba and the umbilicus which structures would I pass through?
Skin, campers fascia, scarpas fascia, the anterior rectus sheath, the rectus abdominus muscle, the posterior rectus sheath, the transversalis fascia, the extraperitoneal fat, the parietal peritoneum, and the peritoneal cavity
Why must the testes move from an internal to external location in males?
Sperm are unable to develop at normal 37 degree celcius body temperature so they must be contained within the scrotum outside the body where the temperature is slightly cooler (33 degrees)
What is testicular descent? How long does it take to occur?
Testicular descent is when the testes in the male travel from inside the body cavity to outside into the scrotal sack via the inguinal canal. It takes about 6months to occur.
Describe the inguinal canal (location, borders, how it is designed to help prevent herniation) and the differences seen in men and women.
The inguinal canal is located superior to the medial portion of the inguinal ligament. It has two openings: a deep ring (formed by the transversalis fascia) and a superficial ring (formed by the external oblique aponeurosis).
Boundaries:
Superior border:
What makes up the conjoint tendon?
The aponeurosis of the internal oblique and the transversus abdominis muscles
What is the gubernaculum testis? What is directly anterior to the gubernaculum testis and what is its function?
It is a connective tissue that connects the testes to the external oblique aponeurosis so that the testes can travel down the inguinal canal and out of the body cavity. Directly anterior to the gubernaculum testis is the processus vaginalis which travels
What are the layers surrounding the testes and where do they originate from?
Skin
Dartos fascia (continuous with scarpas)
External spermatic fascia (continuous with external oblique aponeurosis)
Cremasteric muscle and fascia: internal oblique muscle and aponeurosis
Internal spermatic fascia: continuous with transversalis fascia
Ob
What is the cremasteric reflex?
The cremesteric muscle and fascia in the spermatic cord are derived from the internal oblique muscle. The cremasteric reflex is when stimulation of the inner thigh results in elevation of the corresponding testes into the inguinal canal. This reflex is br
What is cryptochidism?
An undescended testis. You need to perform an orchidopexy to surgically descend the testis
What is a hydrocele? Hematocele? Varicocele?
Hydrocele: presence of fluid in the processus vaginalis. The fluid originates from the peritoneal fluid and is an indication that the processus vaginalis remains patent
Hematocele: presence of blood in the processus vaginalis
Varicocele: enlargement of te
What is a hernia? What are the two types that relate to the inguinal canal?
An abdominal protrusion of a structure into an area where it does not belong. The two types that relate to the inguinal canal are the inguinal and the femoral hernias.
Describe inguinal hernias
They occur 30x more often in men than in women due to the fact that the spermatic cord weakened the canal in men.
Indirect: when the herniation is lateral to the inf. epigastric artery and the protrusion goes through the inguinal canal to the scrotum/labi
Describe femoral hernias
Occur when abdominal viscera protrude through the femoral ring below the inguinal ligament. It is more common in females and usually involves regions of the small intesetine going through the femoral ring and into the femoral canal. If left long enough, t
Name other common regions of herniations along the abdominal wall.
Umbilical: usually before age 3 and after 40 yrs
Linea alba: epigastric region and more common in males
Linea semilunaris: edge of the rectus abdominus muscle and usually slow to develop
Incisional: where scar tissue is present (C-sections)
What is a retroperitoneal organ versus an intraperitoneal organ?
retro: organs that are fixed to the posterior abdominal wall and are only partially covered by peritoneum
intraperitoneal: organs that are completely covered by visceral peritoneum and are attached to the posterior abdominal wall via mesentery which allow
What are the layers of the peritoneum?
Parietal peritoneum lines the body wall while visceral peritoneum lines the organs of the GI tract. The space between them is called the peritoneal cavity
What are the divisions of the peritoneal cavity?
1. The greater sack
2. The omental bursa or lesser sack (behind the stomach and liver)
They are continuous at the omental/epiploic foramen
What are the five organs of the digestive tract that are considered retroperitoneal?
duodenum, ascending colon, descending colon, pancreas and the rectum
Kidneys are also retroperitoneal
What is the lesser omentum, what does it contain, and where is it located?
The lesser omentum is a double layer of peritoneum made up of the heptaduodenal and the heptagastric ligaments. It extends from the porta hepatis to the lesser curvature of the duodenum. It forms the anterior wall of the lesser sack and contains the right
What is the greater omentum? Where is it? What does it contain?
The greater omentum is a four layer region of peritoneum that is attached to the greater curvature of the stomach and covers the transverse colon. It contains the right and left gastroepiploic arteries and it adheres to regions of inflammation
Describe the mesentary of the small intestine.
It is a fan-shaped layer of peritoneum that suspends the jejunum and the ileum from the posterior abdominal wall. It contains the jejunal and ileal arterial branches from the superior mesenteric artery as well as nerves and lymphatics. The root of the mes
Describe the transverse and sigmoid mesocolons.
The transverse mesocolon connects the transverse colon to the posterior abdominal wall while the sigmoid mescolon connects the sigmoid colon to the pelvic wall. The transverse mesocolon fuses with the greater omentum to form the gastrocolic ligament. It c
What is the function of the mesoappendix?
It connects the appendix to the mesentery of ileum and contains the appendicular artery (from the ileocecal branch of the SMA , nerve and lymphatics)
What are the main ligaments associated with the liver?
Falciform ligament: connects liver to the abdominal wall. It's free lower border contains the ligamentum teres hepatic
Ligamentum teres (round ligament): remnant of the umbilical vein
Coronary ligament: peritoneal reflection from diaphragmatic area of the
Peritoneal dialysis:
Fluid can be infused into the peritoneal cavity where it is absorbed into the blood stream. This can dilute the toxic material in the blood and be secreted back into the peritoneal cavity where it can be drained via paracentesis.
Why can infants have peritoneal blood transfusions?
They are capable of absorbing whole RBC through their peritoneum
Where is the greatest absorptive power of the peritoneum believed to be? How is this clinically relevant?
Under the diaphragm; often the site of anesthesia injection due to it's rapid absorption. It is also why patients with peritonitis are asked to sit up in bed so the infected fluid does not go under the diaphragm where it will be absorbed into the blood st
If you have fluid in the peritoneal cavity, where is it most likely to collect in females versus males?
It will collect in the lowest points of the peritoneal cavity. In the female: rectal-uterine/ductless pouch which is easily drained via insertion of needle through posterior vaginal wall (used to look for ectopic pregnancies)
In male: rectal vesicle pouch
What is the clinical relevance of the fact that the female peritoneal cavity is open? Is it open in males?
The female peritoneal cavity is open to the fallopian tubes which allows sexually transmitted infections to progress from the female reproductive tract into the peritoneal cavity causing peritonitis.
It is not open in males.
What is air in the peritoneal cavity called? Where would you see it on a chest CT?
It is called a pnemoperitoneum and it would be present above the liver and below the diaphragm on the right side of the patient.