Abdominal and GI anatomy Flashcards
What are the missing labels?
What are the boundaries of abdominal cavity?
Pelvic diaphragm/ floor at bottom
Diaphragm at top
Pelvic cavity and abdominal cavity are seperated by the pelvic brim although are still one cavity
What are the different layers of the abdominal wall?
- Skin
- Superficial fascia (split into two)
- Muscle layers
- Fascia related to muscles
- Extraperitoneal fascia
-Parietal peritoneum
What are the two layers of superficial fascia in the anterior abdomin wall?
Fatty layer- Camper’s fascia
Membranous layer- Scarpa’s fascia
Where in the abdomen is the deep fascia?
There is no deep fascia in the abdomen
Where do blood vessels lie in the abdomen wall?
Muscles are divided into 3 layers, blood vessels and vasculature lie between the middle and innermost layers
What is the most superficial layer of anterior abdominal muscle?
External oblique
What is the linea alba?
A thin line of connective tissue that runs down the fron of the abdomen
It begins at the lower end of your sternum (breastbone) and ends at the public bone.
Formed by aponeurosis of external oblique?
What is aponeurosis?
Sheet-like fibrous membrane
An aponeurosis is a thin sheath of connective tissue that helps connect your muscles to your bones.
What way do the fibres of external oblique pass?
Downwards and medial
Where does external oblique muscles run from and to?
Lower 8 ribs to iliac crest and aponeurosis
What are the outermost, middle and innermost abdominal muscles?
Outer= external oblique
Middle= Internal oblique
Inner= Transverse abdominus
What way do the fibres of internal oblique run?
Upwards and medial
Where does internal oblique run from?
Origin= iliac crest, inguinal ligament
Inserts at inferior border of lower 3 ribs
What are these muscles?
Yellow= internal oblique
Red= external oblique
What forms the roof of the inguinal canal?
The roof of the canal is formed by the internal oblique and transversus abdominis as they merge to form the conjoint tendon running from the pubic crest to the pectineal line of the pelvis.
Where does transverse abdominis run?
Origin- inguinal ligament, iliac crest, costal cartilages of ribs
Insertion- linea alba
What muscle is this?
Pyramidalis
What is rectus abdominus made of?
Made of a series of muscles that are joined by tendinous intersections
What is the arcuate line?
The posterior layer of the rectus sheath does not go all the way down, stops at the arcuate line
Between the umbilicus and the pubic symphysis
How is the rectus sheath formed below and above the arcuate line?
What are the dermatomes of the abdominal wall?
What is the nerve supply to the anterior abdominal wall?
Pass around body from posterior to anterior in an medial direction
T7-T12 and L1 spinal nerves
What are the missing labels?
What is the principle blood supply of the anterior abdominal wall?
Superior epigastric artery from internal thoracic artery
Inferior epigastric artery from external iliac artery
What are the functions of the anterior abdominal wall?
Movement of trunk- lateral muscles laterally flex trunk and rotate spine
Houses and protects major body organs
Assists with bodily functions- childbirth, defecation, breathing
What is the inguinal canal?
Canal found in medial part of the inguinal region which conveys the spermatic cord or round ligament of the uterus
Starts at the deep inguinal ring and finishes at the superficial inguinal ring
How is the inguinal canal formed?
It is formed by testes pushing through the abdominal wall
What is the Gubernaculum?
Is the rudder that guides the testes
What is the processus vaginalis?
An extension of the abdominal space
The processus vaginalis is a blind‐ended evagination of the abdominal wall that develops during fetal life and typically undergoes obliteration in early life
How does the inguinal canal develop?
Where are the remenents of the gubernaculumin males and females?
Female= round ligament
Male= below testes
What is the floor and the roof of the inguinal canal?
Floor= formed by medial half of inguinal ligament
Roof= formed by the lower curved fibres of internal oblique and transverse abdominus
What are the deep and the superficial rings of the inguinal canal?
The deep ring is formed by the transversalis fascia and lies lateral to the epigastric vessels. The superficial or external ring is the terminal end of the inguinal canal. It is located just superior to the pubic tubercle.
What forms the anterior wall of the inguinal canal?
The aponeurosis of external oblique and some of the internal oblique muscles
What forms the posterior wall of the inguinal ligament?
Transversalis fascia
What is the inguinal shutter?
The arching fibres of the internal oblique and transversus abdominus contract when the muscles of the abdomen contract. This acts as a shutter on the posterior wall to protect it from herniation. This is termed the Shutter Mechanism.
What are the layers of spermatic cord made of?
Thinned out layers of the abdominal wall
External oblique= external spermatic fascia
Transversus and internal oblique= cremasteric fascia
Transversalis fascia= internal spermatic fascia
What is in the inguinal canal?
Male: spermatic cord and ilioinguinal nerve
Female: round ligament of the uterus and ilioinguinal nerve
What structures are present in the spermatic duct?
3 arteries; testicular, cremasteric, ductus deferens artery
3 nerves; genital branch of genitofemoral nerve, sympathetic fibers, ilioinguinal nerve
Pampiniform pleux of veins and lymphatics
What is a hernia?
Protrusion of organ from one place to another
In the inguinal hernias, can be direct or indirect
What are direct and indirect inguinal hernias?
What is a femoral hernia?
Organ or fatty tissue pushes through the abdominal wall to the femoral canal
What muscle can be seen below?
Rectus abdominis
What muscle can be seen below?
External oblique
What muscle can be seen below?
Internal oblique
What muscle can be seen below?
Transversus abdominis
What are the 5 muscles of the anterior abdominal wall and what direction do their fibres run?
External oblique- downward, medial
Internal oblique- upward, forward
Transversus abdominins- transverse (horizontal)
Rectus abdominis- verticle
Pyramidalis
What are the origins and insertations of external oblique?
Origin= lower 8 ribs
I- linea alba via rectus sheath, iliac crest and lower border forms inguinal ligament
What are the origins and insertations of internal oblique?
Origin= iliac crest, lateral two thirds of inguinal crest
Insertion= costal margin, linea alba, pubic crest and pectineal line via conjoint tendon
What are the origins and insertations of transversus abdominus?
Origin= costal margin, iliac crest, lateral 1/3 of inguinal ligament
Insertion= linea alba, pubic crest and pectineal line via conjoint tendon
What is the origin and insertion of rectus abdominis?
Origin= pubic crest
Insertation= costal cartilages 5,6,7
What are the nerve supplies of the anterior abdominal wall muscles?
Lower 6 thoracic spinal nerves (T7-T12), iliohypogastric and ilioinguinal (L1) for the fibres of the conjoint tendon (inguinal shutter mechanism)
What are the actions of the muscles of the anterior abdominal wall?
Move trunk (flexsion and lateral rotation), compresses abdomen for expiration, support of viscera and control of inguinal shutter mechanism
The neurovascular plane lies between which two muscle layers in the abdominal and thorax anterior wall?
The neurovascular bundle lies between the middle and inner layers of the body wall (internal
oblique and transversus abdominis in abdomen; ; internal and innermost intercostal in thorax)
What is the rectus sheath formed by?
Formed by the aponeuroses of the anterolateral abdominal wall muscles- external oblique, internal oblique and transverse abdominis as they insert into the linea alba
What is the linea alba?
the midline fibrous structure running from xiphisternum to pubic symphysis.
What is the most common means of accessing the abdominal cavity during surgery and why?
The linea alba- it is a bloodless plane
What are the 3 areas the rectus sheath can be split into?
Above the costal margin, between the costal margin and arcuate line and below arcuate line
What is the arrangement of the aponeuroses of the anterolateral abdominal wall
muscle at the following levels?
a) above the costal margin
b) between the costal margin and the arcuate line
c) below the arcuate lin
a) Anterior sheath only= from external oblique aponeurosis
b) Anterior and posterior sheath (internal oblique splits)
c) anterior sheath only= from all 3 aponeuroses
What does the rectus sheath contain?
Rectus abdominis, pyramidalis, superior and inferior epigastric vessels and lower and intercostal nerves
In a midline incision, what layers would be transversed before en
Skin -> Superficial fasica (fatty Camper, membranous scarpa) -> linea alba -> transversalis fascia -> extraperitoneal fat -> parietal peritoneum
What does the inguinal canal contain in the male and female?
Male- spermatic cord, ilioinguinal nerve and obliterated remains of the processus vaginalis
Female- round ligament of the uterus in the female
What structures form the anterior and posterior walls, roof and floor of the inguinal canal?
Anterior wall= Superficial ring (medially; weak), EO aponeurosis and IO muscle (laterally; strong)
Posterior wall= Conjoint tendon (medially, strong); transversalis fascia and deep ring (laterally; weak)
Roof= Lowermost fibres of IO and TA muscles (insert via conjoint tendon; form ‘inguinal shutter’)
Floor= Inguinal and lacunar ligaments
From where are the coverings of the spermatic cord derived?
External spermatic fascia – from EO aponeurosis
Cremasteric fascia – from IO and TA muscles
Internal spermatic fascia – from transversalis fascia
What are the 3 layers of the spermatic fascia?
What are the contents of the spermatic cord?
3 arteries: testicular, cremasteric, artery of vas
3 nerves: ilioinguinal, genital branch of genitofemoral, sympathetic fibres
3 others: corresponding veins (incl. pampiniform plexus), lymphatics, vas deferens
AND the obliterated remains of processus vaginalis
What are the 3 types of groin hernia?
Inguinal hernia- direct and indirect
Femoral hernia
What is the following bony landmark?
Anterior superior iliac spine
What is the following bony landmark?
Pubic tubercle
What structures are located at the mid point of the inguinal ligament and where is it?
The deep ring of the inguinal canal
Midway vetween ASIS and pubic tubercle
What structures are located at the mid inguinal point and where is it?
Femoral artery
Midway between ASIS and pubic synthesis
Where does the inguinal ligament run from?
Extends from the anterior superior iliac spine to the pubic tubercle
How can you tell the difference between a direct and indirect inguinal hernia?
They are distinguished based on a relationship to the inferior epigastric vessels
Indirect= lateral to femoral vessels (as is canal), direct= medial to vessels
How can you tell the diffence between a direct inguinal hernia and a femoral?
They are both medial to the femoral vessels, they are distinguished based on their relationship to the pubic tubercle
- Inguinal emerges above and medial to tubercle
- Femoral emerges below and lateral to tubercle
What are the boundaries of the inguinal triangle of Hesselbach and why is it useful to define?
Boundaries: inguinal ligament, inf. epigastric vessels, edge of rectus sheath (linea semilunaris)
Significance: a direct inguinal hernia pushes forward through the triangle (medial to the IEA)
What are the following labels showing the inguinal area?
What is the peritoneum?
Your peritoneum is a membrane, a sheet of smooth tissue that lines your abdominopelvic cavity and surrounds your abdominal organs.
Two layers- visceral and parietal
The outer layer is the parietal peritoneum, which attaches to the abdominal and pelvic walls. The inner visceral layer wraps around the internal organs located inside the intraperitoneal space
Which of the following organs are intraperitoneal and retroperitoneal?
Where does the greater sac extend to vertically?
From the diaphragm to the pelvic cavity
What are the boundaries of the greater sac?
What are the boundaries of the lesser sac?
Anterior wall= liver, lesser omentum, stomach, greater omentum (anterior 2 layers)
Posterior wall= Peritoneal that covers structures that form the stomach bed, transverse mesocolon, transverse colon and greater omentum
What structures form the stomach bed?
What is the only opening to the lesser sac?
The epiploic foramen
What are the boundaries of the epiploic foramen?
Superiorly= liver
Inferiorly= 1st inch of the duodenum
Posteriorly and anteriorly:
Where is the lesser and greater omentum located?
Lesser= a fold of peritoneum extends from the liver to the lesser curvature of the stomach and 1st inch of duodenum.
Greater= is a peritoneal fold extends from the greater curvature of the stomach to the transverse colon folded up on itself.
What is the falciform ligament?
It is a sickle shaped fold of peritoneum connecting the anterior abdominal wall to the liver.
Where is the Gastrosplenic ligament located?
It is a peritoneal fold connecting the spleen to the stomach.
Part of lesser omentum
Where is the splenorenal ligament located?
It is a peritoneal fold connecting the left side kidney to the spleen.
Where is the mesentery located?
It is a fan-shaped peritoneal fold (formed of two layers) enclosing the free part of the small intestine.
Where is the sigmoid mesocolon located?
It is a peritoneal fold enclosing the sigmoid colon.
Where is the transverse mesocolon located?
It is a peritoneal fold enclosing the transverse colon
What is the arrow pointing to?
Mesoappendix: It is a triangular peritoneal fold enclosing the vermiform appendix
What is the arrow pointing to?
Transverse mesocolon
What are the arrows pointing to?
Top= mesentery
Bottom= sigmoid mesocolon
What are the different types of folds of peritoneum?
What is contained within the peritneal cavity?
It is a potential spce between parietal and visceral peritoneum
Contains peritoneal fluid which enables viscera to move against each other (for digestion and breathing)
What are the different parts of the mesentery?
Small intestine= just mesentery
Transverse mesocolon- to transverse colon and sigmoid mesocolon to sigmoid colon
What are the following labels?
What are the following labels?
What are the following labels?
What are the following labels?
Where is the opening to the lesser sac located?
Posterior to the free edge of the lesser omentum
Where is the gastrocolic ligament located?
Somach -> transverse colon
Apron-like part of greater omentum
What are the different ligaments labeled?
What can the peritoneal spaces be split into?
Supracolic compartment- stomach, liver, spleen
Infracolic- small intestine, ascending, descending colon
The division is the transverse mesocolon and transverse colon
What is the root of the mesentery?
The ‘root’ of the mesentery is the point where the mesentery attaches to the posterior abdominal wall
What are the paracolic gutters?
Depressions in the gaps between haustra
Passage between supracolic & infracolic compartments
Spread of infection can occur
Where is the subphrenic recess?
A potential space between diaphragm and diaphragmatic surface of liver
Superior and anterior to liver
Falciform ligament seperates right and left spaces
Where is the hepatorenal recess?
Between liver and right kidney/suprarenal gland
Where is the hepatorenal recess?
Between liver and right kidney/suprarenal gland
When does the lesser omentum become the greater omentum?
Liver to stomach= lesser, then splits and encloses stomach and comes back together to form greater omentum
This then reflects back to enclose the transverse colon and becomes transverse mesocolon
The transverse mesocolon ascends and reaches the pancreas where it splits into an upper layer and a lower layer
The lower layer descends and a reflection to cover the jejunum and ileum- mesentery
Where does the oesophagus begin?
At the cricoid cartilage- C6
What are the 3 parts of the oesophagus?
Cervical (behind trachea)
Thoracic (runs in posterior mediastinum)
Adominal (after diaphragm)
Where are the natural constrictions in the oesophagus?
- Boundary between the pharynx and oesophagus
- When oesophagus is crossed by arch of aorta
- When oesophagus is compressed by left main bronchus
- Diapgragm
Where does the oesophagus become the abdominal oesophagus?
When it passes through the right crus of the diaphragm at T10
What attaches to the lesser and greater curve of the stomach?
Lesser=lesser omentum
Greater= greater omentum and gastrosplenic ligament
What are the following parts of the stomach?
What are the gastric rugae?
Longitudional folds directed towards the pylorus in the stomach
Allow the stomach to expand- dissapear during expansion
What are the different parts of the small intestine?
Pyloric orifice -> duodenum -> jejenum -> ileum -> ileocecal junction