Abdominal Wall & Cavity Flashcards
Camper’s fascia
Fatty layer camping out on top serving as an insulator
Scarpa’s fascia
Membranous layer loosely attaching skin to body wall; continuous with other regional fasciae
External abdominal oblique muscle
The largest and most superficial of the three flat muscles
Fibers run inferomedially (hands in pockets) on anterior wall
Attached to ribs 5-12 -> iliac crest, pubic tubercle and linea alba
Forms the inguinal ligament at the most inferior aspect of the EAO aponeurosis as it rolls down to its inferior attachements
IAO
Internal abdominal oblique muscle
Thin muscular sheet just deep to EAO
Fibers run perpendicular to those of EAO and aponeurosis (superiorly and anteriorly)
Attachements:
Origin - to inferior borders of ribs 10-12 and th elinea alba at midline
Insertion - to thoracolumbar fascia posteriorly, and the lateral third of inguinal ligament and anterior 2/3 iliac crest anteriorly
Transversus Abdominis muscle
Innermost of three (deep to EAO and IAO muscles)
Fibers run transversally at superior exten; run parallel to those of the IAO muscle more inferiorly
Fibers originate from the lateral 1/3 of the inguinal ligament, iliac crest, thoracolumbar fascia, and internal surface of 7th-12th costal cartilages -> linea alba with aponeuorses of IAO and EAO
Aponeurosis
An aponeurosis is a thin sheath of connective tissue that helps connect your muscles to your bones. Aponeuroses are similar to tendons. They support your muscles and give your body strength and stability. Aponeuroses absorb energy when your muscles move. You have aponeuroses all over your body
What are the three flat muscles of the abdomen?
From superficial to deep:
EAO
IAO
Transversus abdominis
Vertical muscles of the anterior abdomen wall
Rectus abdominis muscle
Pyramidalis muscle
Rectus abdominus
Paired muscle that are divided into segments (“6 pack”) - tendinous intersections anchor the muscle to the rectus
Paired muscles are separated in the midline by linea alba
Muscle fibers run vertically and are enclosed in the rectus sheath (sheath is formed by the convergin aponeuroses of the three flat muscles)
Attached to pubic symphysis and pubic crest - xiphoid process and costal cartilages of ribs 5-7
What nerves innervate the anterior abdominal wall?
Thoracoabdominal nerve (T7-T11)
Distal, abdominal parts of the ventral rami of intercostal nn. T7-T11
Subcostal (T12), iliohypogastric (L1), and ilioinguinal (L1-L2) nerves supply the rest of the skin and muscles inferior to umbilicos
L1 dermatome
The groin region
Arteries of the anterior abdominal wall
Internal thoracic artery-> superior epigastric and musculophrenic arteries
Aorta -> 10th and 11th posterior intercostal arteries and subcostal artery
External iliac artery -> inferior epigastric and deep cirumflex iliac arteries
Femoral artery -> superificial circumflex iliac and superficial epigastric arteries
What do intercostal T7-11 and the subcostal arteries supply?
The lateral aspect of the anterior abdominal wall in a segmental fashing (three flat muscles and overlying skin)
What do the superior and inferior epigastric arteries supply?
The rectus abdominis muscles (muscles only blood supply)
What do the superficial epigastric arteries supply?
The skin in the midline overlying the rectus muscles
Veins of the anterior abdominal wall
Deeper veins bare the same name and course as the arteries
Superficial veins are located in the superficial fascia (Camper’s)
-Thoracoepigastric veins - direct anastomotic channel between lateral thoracic veins and paraumbilical veins, superficial epigastric and circumflex iliac veins connecting the axillary and femoral veins
What does the rectus sheath enclose?
Vertical muscles (rectus abdominins and pyramdialis)
Superior and inferior epigastric vessels
Sheath is pierced by distal portions of thoracoabdominal nerves to supply the rectus abdominis muscle (supplying bessels are vertical, while the nerves path is horizontal inside the rectus sheath)
Where do the superior and inferior epigastric vessels anastomose?
Near the umbilicus
Where does the superficial epigastric vessels lie?
In the skin above the rectus sheath, not inside the sheath
Where do all areas of the abdominal wall fuse?
At the umbilicus
What makes the linea alba difficult to heal?
It is almost avascular because it does not transmit small vessels and nerves to the skin
What is always the most anterior layer of the rectus sheath?
EAO aponeurosis
What is always the most posterior layer of the rectus sheat?
The trasversalis fascia
Above arcuate line
IAO aponeurosis splits to contribute to both the anterior & posterior layers of the sheath
- Internal oblique aponeurosis splits into 2 layers— anterior & posterior laminae of the internal oblique
– one passing anterior & the other passing posterior to the rectus abdominis m.
- The anterior lamina of the IAO joins the aponeurosis of the EAO to form the anterior layer of the
rectus sheath (2 contributors to this layer) - The posterior lamina of the IAO aponeurosis joins the aponeurosis of the transversus abdominis and the transversalis fascia to form the posterior layer of the rectus sheath (3 contributors to this layer)
Below arcuate line
contributions from the 3 flat mm. all contribute to the anterior layer of the rectus sheath
* The aponeuroses of all 3 flat muscles pass anterior to rectus abdominis m. to form the anterior rectus sheath, and thin transversalis fascia is the only component of the posterior rectus sheath The internal lining of the abdominal wall is parietal peritoneum – this lining drapes over structures to form 5 peritoneal folds that run inferiorly from the umbilicus (infra umbilical folds) & one that runs superiorly (supraumbilical)
Falciform ligament
The only supraumbilical peritoneal fold
Reflects off the liver to run and join the parietal peritoneum on the internal surface of anterior abdominal wall just above the umbilicus
Round ligament of the liver is found in the falciform ligaments inferior, free edge and contains 2 structures - ligamentum teres hepatis (remnant of the umbilical vein) and paraumbilical veins
Median umbilical fold
1 - unpaired
Run inferiorly from the umbilicus to the urinary bladder
Formed as peritoneum covers the median umbilical ligament
Medial umbilical folds
2 - paired
Found lateral to the median umbilical fold
Formed as peritoneum covers the medial umbilical ligaments
Lateral umbilical folds
2- paired
Infraumbilical folds found lateral to the medial umbilical folds
Formed as peritoneum covers the inferior epigastric artery and accompanying veins
Contains a patent functional artery (bleeds if cut)
All medial fibers of inguinal ligament insert on pubic tubercle except _______ ?
Lacunar (Gimbernat’s) ligament - deep fibers attaching to superior pubic ramus to roll under spermatic coord
Pectineal (Cooper’s) ligament - most lateral fibers of lacunar ligament running along the pectin pubis
Contents traversing the inguinal canal and rings
- Spermatic cord or round ligament of uterus
- Iloinguinal nerve - sensory to skin on anterior scrotum/ mons pubis and labia majora via anterior scrotal/labial branches
- Genitofemoral nerve - sensory to skin of upper anterior thigh
Stomach
Intraperitoneal organ
Lesser curvature faces liver, greater curvature is convex border
Folds when stomach contracts - rugae (direct food toward pyloric part)
Small intestines
Doudenum
Jejunum
Ileum
Duodenum
oC-shaped around pancreatic head, and about 12” long
oSubdivide the duodenum into four parts:
■ 1st - continuous with pylorus; also called duodenal bulb
- Intraperitoneal at LV1 and connects to the liver via the hepatoduodenal ligament (only portion
that is intraperitoneal)
- Common site for duodenal ulcers
■ 2nd / descending
- Secondarily retroperitoneal at LV2
- Pancreatic and biliary ducts open into the lumen
■ 3rd / horizontal – secondarily retroperitoneal at LV3
■ 4th / ascending - ascends to LV2,
- Secondarily retroperitoneal
- Continuous with the jejunum where it becomes intraperitoneal
Jejunum
oIntraperitoneal, suspended by the mesentery proper and the root of the mesentery
oContinuous with the ileum
Ileum
oDistal 3/5 of the small intestine that terminates at ileocecal junction
oIntraperitoneal, suspended by the mesentery proper and the root of the mesentery
oSite of Meckel’s diverticulum
oSmaller diameter than the jejunum and increased fat deposition in the mesentery proper
Large intestines
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
Spleen
Intraperitoneal organ in the left upper quadrant of the abdominal cavity
- Found lateral & posterior to the stomach, tucked under the left dome of the diaphragm just superior to the left colic flexure
- Protected by ribs 9-11 (putting the spleen at risk when these ribs are broken)
- Splenic injury can often occur with abdominal trauma
oInjury is usually caused by blunt trauma, but can be penetrating injuries that tear the capsule
o Rupture occurs when there is a break in the capsule disrupting the underlying parenchyma.
oHighly vascular organ so rupture can cause profuse bleeding into the peritoneal cavity & lead to hemodynamic instability
oPain is often referred to the left shoulder (Kehr’s sign) due to its intimate relationship with the
diaphragm
A 25-year-old male presents with a sharp pain in his lower abdomen after lifting a heavy object.
Physical examination reveals a bulge in the groin area. The bulge is reducible and lies medial to the inferior
epigastric artery. Which layer is most likely involved in the formation of this hernia?
The external oblique aponeurosis
A 30-year-old female presents with abdominal pain localized around the umbilicus. She recalls
that the pain started after she was struck in the abdomen. Which dermatome is likely involved based on the
location of her pain?
T10 dermatome
During a surgical procedure, the surgeon needs to access the rectus abdominis muscle.
Which of the following structures will the surgeon encounter immediately anterior to this muscle?
External oblique aponeurosis
List the tissue layers of the external abdominal wall (superficial to deep)
- Skin
- Superifical fascia
Camper’s
Scarpa’s - Muscles of anterior wall: EAO, IAO, transversis abdominis, rectus abdominis, pyramidalis
- Transversalis fascia
- Extraperitoneal fat
- Parietal peritoneum
A 40-year-old male is diagnosed with an inguinal hernia that is lateral to the inferior epigastric vessels. Which type of hernia does he have?
Indirect inguinal hernia
A patient with a history of abdominal surgery presents with a bulge at the surgical site. On examination, the bulge is located just lateral to the rectus abdominis muscle. Which structure is likely involved?
Linea semilunaris
A medical student is asked to identify the layer of the anterior abdominal wall that is continuous with the superficial fascia of the thigh. Which layer should the student identify?
Scarpa’s fascia
A patient presents with pain in the lower abdomen and groin. Imaging reveals a structure
passing through the superficial inguinal ring but not the deep inguinal ring. Which muscle’s aponeurosis
forms this superficial ring?
The external oblique abdominal muscle’s fascia forms the inguinal ring
A 28-year-old woman presents with pain and a palpable mass just below her umbilicus. Upon surgical exploration, it is found that the mass is composed of extraperitoneal fat. Between which layers of the anterior abdominal wall is this fat located?
Extraperitoneal fat is found between the transversalis fascia and parietal peritoneum
During a physical examination, a physician palpates a firm structure extending from the pubic tubercle to the anterior superior iliac spine. This structure forms the inferior border of which muscle?
External oblique abdominal muscle
A previously healthy 20-year-old man comes to the physician because of a 6-month history of a painless mass in his left groin that has been gradually increasing in size. Physical examination shows a 3x3-cm oval, nontender left inguinal mass and a fluctuant, painless left scrotal swelling that increases in size with coughing. Which of the following is the most likely cause of this patient’s symptoms?
Failure of process vaginalis to close
A - runs over linea alba
H - nerves and arteries that run here
A 37-year-old woman comes to the physician because of right-sided lower abdominal pain for the past 8 weeks. During this period, the patient has had increased pain during activities such as walking and standing. There is a nonpulsatile, palpable groin protrusion above the inguinal ligament on the right side. The protrusion is palpable lateral to the location of the right inferior epigastric artery. Bulging is felt during the Valsalva maneuver. Which of the following apply to this type of abdominal hernia?
Indirect hernia
EAO origin and insertion
Origin - external surface of ribs 5-12
Insertion - linea alba, pubic tubercle, and anterior half of iliac crest
EAO origin and insertion
Origin - external surface of ribs 5-12
Insertion - linea alba, pubic tubercle, and anterior half of iliac crest
IAO origin and insertion
Origin - thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to inguinal ligament
Insertion - Inferiro borders of 10th-12th rubs, línea alba, and pubis via conjoint tendon
IAO origin and insertion
Origin - thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to inguinal ligament
Insertion - Inferiro borders of 10th-12th rubs, línea alba, and pubis via conjoint tendon
Transversus andominis origin and insertion
Origin - Internal surfaces of 7th-12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to inguinal ligament
Insertion - linea alba with aponeurosis of internal oblique, pubic crest, and pubis via conjoint tendon
Rectus abdominis origin and insertion
Origin - Pubic symphysis and pubic crest
Insertion - xiphoid process and and 5-7th costal cartilages
Rectus abdominis origin and insertion
Origin - Pubic symphysis and pubic crest
Insertion - xiphoid process and and 5-7th costal cartilages
EAO innervation
Thoracoabdominal and subcostal nerves (T7-12 anterior rami)
IAO innervation
Thoracoabdominal nerves (T7-11 anterior rami), subcostal and first lumbar nerve
Rectos andominis innervation
Thoracoabdominal and subcostal nerves (T7-12 anterior rami)
Action of EAO/IAO
Compress and support abdominal visceral, flex and rotate trunk
Median umbilical fold
Holds median umbilical ligament (embryological remains of urachus)
What covers the posterior surface of the inferior epigastric arteries?
The two lateral umbilical folds
What layer of fascia contains the obliterated umbilical arteries?
The two medial folds of the internal anterior abdominal wall
Lobes of the liver
Remnant of the umbilical vein
Round ligament of the liver
Falciform ligament
Separates the right and left lobes, and attaches the liver to the front of the body wall
(contains round ligament)
What holds the liver to the diaphragm?
The coronary ligament
Blood supply to the lesser curvature of the stomach
The left and right gastric arteries (gastric is a less word than gastromental - less words)
Blood supply to the greater curvature of the stomach
The left and right gastromental arteries
When disrupted, which stomach valve causes stomach burn?
The cardiac sphincter
Parasympathetic innervation of stomach
From celiac plexus, relaxes pyloric sphincter to allow chyme to flow into duodenum
Sympathetic innervation of stomach
Constricts the pyloric sphincter to prevent chyme from flowing into duodenum
What is the blood supply to the pyloric sphincter?
The gastroduodenal artery
What prevents the parietal and visceral peritoneum from adhering to each other?
The greater omentum
Function of greater omentum
Able to adhere to inflammed organs
Parasympathetic innervation of gallbladder
Vagus nerve = contracts the gallbladder to release bile
Sympathetic innervation of the gallbladder
Celiac plexus - inhibition of contraction to increase bile storage, also carries visceral sensory information
Blood supply to the gallbladder
The cystic artery
Blood supply and innervation of spleen
Blood - splenic artery
Parasympathetic and sympathetic innervation - celiac and splenic plexus
Immunosurveilance
What connects the spleen and stomach?
The gastrosplenic ligament, contains short gastric aa./vv and left gastroepipoic a and v
Duodenum function, innervation, and blood supply
Fx - mix chyme with digestive enzymes from pancrease and liver
Parsympathetic - celiac plexus increases motility
Sympathetic - celiac functions decreases motility
Blood - gastroduodenal
Parts of the duodenum
Innervation and blood supply to jejunum and ileum
Parasymp - superior mesenteric plexus from vagus n
Symp - superior mesenteric plexus from greater and less splanchnic nn
Blood - intestinal branches from superior mesenteric a.
Funtion of jejunum
Absorb sugars, amino acids, and fatty acids
Function of ileum
Absorbs nutrients: vitamins, minerals, carbohydrates, fats, and proteins
Also absorbs water
Cecum
Fx = bacterial breakdown of cellulose and remaining contents
Parasympathetic - superior mesenter plexus from vagus
Symp - Superior mesenteric plexus from greater and less splanchnic nerve
Blood - Ileocecal a.
Same innervation as ascending and transverse colons
Ascending colon
Fx - water absorbtion
Parasympathetic - superior mesenter plexus from vagus
Symp - Superior mesenteric plexus from greater and less splanchnic nerve
Blood - right colic a.
Same as transverse colon
Transverse colon
Fx - water absorbtion
Parasympathetic - superior mesenter plexus from vagus
Symp - Superior mesenteric plexus from greater and less splanchnic nerve
Blood - middle colic a.
Same as ascending colon
Descending colon
Fx - water absorbtion
Parasymp - inferior mesenteric plexus from pelvic splanchnic nn
symp - inferior mesenteric plexus from lumbar splanchnic nn
Blood - left colic a. of the inferior mesenteric a.
Sigmoid colon
Fx - water absorbtion
Parasymp - inferior mesenteric plexus from pelvic splanchnic nn
symp - inferior mesenteric plexus from lumbar splanchnic nn
Blood - sigmoidal a
Rectum
Fx - water absorbtion and stool concentration
Parasymp - inferior mesenteric plexus from pelvic splanchnic nn
symp - inferior mesenteric plexus from lumbar splanchnic nn
Blood - Superior, middle, and inferior rectal aa.
What attaches the intestines to posterior abdominal wall?
The root of the mesentery (located between the duodenojejenual flexure and vertebral column)
Intraperitoneal vs. retroperitoneal organs
Intraperitoneal - organs covered by visceral peritoneum
Retroperitoneum - organs covered on anterior surface by parietal peritoneum
Retroperitoneal organs
List the organs of the abdominal cavity
S - Suprarenal gland
A - Aorta/IVC
D - Duodenum
P - Pancrease
U - Ureters
C - Colon (ascending and descending)
K - Kidneys
E - Esophagus
R -Rectum
