In this post we have discussed almost all the important questions topics of abdomen, So you can also read this as a ‘Quick Revision Series’.
Meaning/ Definition :
The Abdominal cavity is a large cavity which is surrounded by Diaphragm superiorly, Inferiorly it continues with the pelvic cavity, Abdominal wall is placed anteriorly, Posterior abdominal wall is situated posteriorly, and laterally lower ribs and parts of muscles of the anterior abdominal wall.
The Pelvic cavity is funnel shaped structure, It is surrounded by pelvic inlet superiorly, Pelvic diaphragm inferiorly, Sacrum and coccyx posteriorly, Pubic bones anteriorly and Hip bones laterally.
What are the important topics :
1. Bones of Abdomen :
The bones of the Pelvis and Abdomen are as follows :
- Lower ribs and costal cartilage
- Lumbar vertebrae
- Hip bone
2. Rectus Sheath :
This is an aponeurotic sheath enclosing the rectus abdominis muscle on either side of the linea alba.
- Increasing the strength of the rectus abdominis muscle during contraction by preventing it from bowing as it contracts.
- It also maintains the strength of the abdominal wall.
3. Femoral Sheath and Femoral Canal :
Femoral sheath : The upper 3.75cm of femoral vessels are encased in a funnel-shaped fascial sheath.
Femoral Canal : This is a narrow facial tube that narrows rapidly from the top to the bottom and is closed inferiorly by fusion of the wall.
- Anterior : Inguinal ligament
- Posterior : Pecten pubis
- Medial : Sharp edge of the lacunar ligament
- Lateral : Femoral vein
4. Inguinal Canal :
This is a 4cm long oblique intermuscular passage that runs above the inguinal ligament’s medial half.
- Anterior wall (From superficial to Deep) : Skin, Superficial fascia, External oblique aponeurosis, Internal oblique fibres,
- Posterior wall (Superficial to Deep) :reflected part of the inguinal ligament, conjoint tendon, Fascia transversals.
- Roof : Formed by the lower arched fibres of internal oblique and transversus abdominis muscles.
- Floor : Formed by , Upper surface of the inguinal ligament, Abdominal surface of the lacunar ligament at the medial end.
5. Peritoneum :
This is a wider and thin serous membrane that lines the inside of the abdomen and pelvis.
A. Layers : Parietal layer(Parietal peritoneum) and Visceral layer(Visceral peritoneum).
B.Folds : These are formed by the visceral layer of the peritoneum.
C. Classification of the Peritoneal Fold : Mesentery/Mesocolon, Omenta(Greater momentum, Lesser momentum and Gastrosplenic momentum) and Ligaments(Gastrosplenic ligament, Lienosplenic ligament, Coronary ligament)
6. Foramen Epiploicum (Foramen Winslow) :
The lesser sac of peritoneum interacts with the greater sac of peritoneum through this vertical long narrow opening.
- Anterior : Right free border of the lease momentum which contains the bile duct, portal vein and vertical part of hepatic artery.
- Posterior : Right suprarenal gland and Inferior vena cava
- Superior : Caudate process of the caudate lobe of the liver
- Inferior : First part of Duodenum and horizontal part of the hepatic artery.
7. Rectouterine Pouch(Pouch of Douglas) :
This is a pouch like structure which is situated between the rectum and uterus.
- Anteriorly : Uterus and the upper one third of the vagina.
- Posteriorly : Rectum
- Inferiorly : Rectovaginal fold
8. Stomach :
It is situated between the oesophagus and the duodenum, and it is the most distensible part of the elementary canal.
External features : Two ends(Cardiac and Pyloric), Two curvatures (Greater and Lesser), Two surfaces(Anterior and Posterior).
Parts : Cardiac part, Fundus, Body and Pyloric part.
Arterial Supply : left gastric artery, Right gastric artery, Left gastroepiploic artery, Right gastroepiploic artery and Short gastric artery.
9. Spleen :
This organ is a Lymphoid organ and it is the largest lymphoid organ in our body.
- Removing exhausted RBCs and microbial agents from the blood to filter the Blood.
- Manufacturing : RBCs in fetal life and Lymphocytes after birth.
- Immunity : Provides immunity to the body by producing IgM by plasma cells.
- RBC Management : Stores RBC and release them in the blood when needed.
- Gastrosplenic Ligament : Connects the hilum of the Spleen to the upper one-third of the greater curvature of the stomach.
- Lienorenal Ligement : Hilum of the spleen to the anterior surface of the left kidney.
- Phrenicocolic Ligament : Left colic flexure to the diaphragm opposite to the 10th rib.
- Sphenocolic Ligement : Connecting the Splenic capsule to the transverse colon.
10A. Liver :
This is the largest organ of the body which placed at the right upper part of the Abdominal cavity.
Surfaces : Two well-defined surfaces – Diaphragmatic and Visceral and one well-defined inferior border.
Lobes of the Liver :
Anatomical Lobes : Total 4 in number – Right Lobe, Left lobe, Quadrate lobe, Caudate lobe.
Surgical Lobes : 2, 3, 4A ,4B ,5 ,6 ,7 ,8
Blood Supply :
Arterial blood Supply : The hepatic artery
Venous blood supply : Portal vein
Venous drainage : Left hepatic vein, Middle hepatic vein, Right hepatic vein.
False Ligaments :
- Falciform ligament
- Coronary ligament
- Right triangular ligament
- Left triangular ligament
- Lesser momentum
False Ligaments :
- Ligamentum teres hepatis
- Ligamentum venosum
10B . Extrahepatic Biliary Apparatus :
It has five components :
- Right and left hepatic ducts
- Common hepatic duct
- Cystic duct
- Bile duct
10C. Gall Bladder :
This is an elongated pear-shaped sac of 30-50 ml capacity.
—> It stores and concentrates the bile and discharges it into the duodenum by the muscular contraction.
10D. Cystohepatic Triangle of Calot:
Triangle looking structure is formed by the common hepatic duct on left side, Cystic duct on right side and inferior surface of liver stays at above.
11. Duodenum :
It has mainly 4 parts :
- First part : Beginning at the pylorus, it travels upward, backward, and laterally to the right side of the vertebral column, eventually reaching the gallbladder’s neck. The duodenum then curves downward and continues with the second segment.
- Second part : It starts at the Superior Duodenal Flexure, descends in front of the medial part of the right kidney until it reaches the lower border of the L3 vertebra, and then curves to the left to begin with the third part.
- Third part : It runs horizontally to the left, through the lower part of the L3 vertebra’s body, crosses in front of the IVC, and then curves upward to join the ascending part of the duodenum.
- Fourth part : From the end of the third section to the upper border of the L2 vertebra, where it bends forward to become continuous with the jejunum, it runs upward, or immediately to the left of the abdominal aorta.
12. Pancreas :
Has four parts :
- Splenic artery which is a branch of coeliac trunk
- Superior Pancreaticoduodenal artery
- Inferior Pancreaticoduodenal artery
13. Portal Vein :
This is an important venous channel which collects blood from – Abdominal and pelvic parts of the alimentary tract, Gallbladder, Pancreas and Spleen.
Portocaval Anastomoses :
The important sites wofmportocaval anastomeses are :
- Lower end of esophagus
- Anal canal
14. Intestine :
Small Intestine :
This extends from he pylorus to the ileocaecal junction and it is about 6 m long and divided into 3 parts : Duodenum, Jejunum and Ileum
Large Intestine :
1.5 m long and has four parts :
- Caecum and appendix
- Anal canal
15. Kidney :
Bean shaped organs two in number. Lies on the posterior abdominal wall, behind the peritoneum and opposite 12th thoracic and upper three lumbar vertebra.
Anterior Relations :
- Right suprarenal gland
- Right lobe of the liver
- Second part of the duodenum
- Hepatic flexure
Renal fascia, Macroscopic structure,Arterial supply, Venous drainage, Nerve supply.
16. Ureter :
- Parts and relations
- Arterial Supply
- Nerve Supply
- Suprarenal gland relations
17. Pelvis :
- Difference between the Male and Female Pelvis
- Levator Ani muscle
- Pelvic diaphragm
18. Lumbosacral Trunk :
Thick cord formed by the descending part of the ventral ramous of L4 nerve and entire ventral ramous of L5 nerve.
19. Urogenital Triangle :
This is an triangular area between the ischiopubic rami, infant of a horizontal line which is joining the anterior ends of the two perineal tuberosities.
20. Urinary Bladder :
- External features and Relations
- Interior of the Bladder
- Nerve Supply
21. Urethra :
- Parts of the Male urethra
22. Prostate :
- Shape and Size
- External features and relations
- Lobes of the Prostate
- Capsule of the Prostate
23. Fallopian Tube :
- Arterial Supply
- Venous Drainage
24. Uterus :
- Relations of the Uterus
- Lymphatic drainage
- Supports of the Uterus
25. Anal Sphincters :
Internal sphincter and External Sphincter.
—-Surgical Spaces related to the Anal Canal