Summary of lesser sac : lecture note

Lesser sac

•      It is the part of peritoneal cavity  behind Liver, lesser omentum,  the stomach, & 1^st two layers of greater omentum .  

•      Parts of lesser sac

•      Vestibule

•      Three recesses : superior, inferior and left

•      One opening  : epiploic foramen

•      Body : It has

1.      Two walls: anterior and posterior

2.      Four borders: superior, inferior , right and left 

•      Vestibule of lesser sac

•      It is a constricted area immediately left of the epiploic foramen situated in between right and left gastropancreatic fold of peritoneum  

•      Recesses of lesser sac :

Superior recess is situated just behind the caudate lobe of the liver

Inferior recess :
is formed by the junction between two anterior layers of greater omentum with its posterior two layers.

Splenic recess:  is situated in between gastrosplenic and lienorenal ligament

•      Body of lesser sac

•      Borders of lesser sac

•      Right border : epiploic foramen , peritoneal reflexion from the surface of 1^st part of duodenum to head of pancreas,Right border of greater omentum 

•    

•  Left border : gastrophrenic ligament , gastrosplenic ligament and left border of greater omentum 
•  

•      

•      Inferior border : Is formed by the junction between two anterior layers of greater omentum with its posterior two layers. 

•   Superior border : Is formed by the peritoneum extending from the caudate lobe of liver to  the diaphragm 
• 
  

Boundaries of body of lesser sac :

Anterior wall :

•        from above downward,

•      By the caudate lobe of the liver,

•       the lesser omentum,

•      back of the stomach

•      The anterior two layers of the greater omentum

•       

Posterior wall :

From above downward

•      The upper end of the left kidney

•      The left suprarenal gland

•      The upper surface of the pancreas

•      The ascending layer of the transverse mesocolon

•      The transverse colon

•      By the posterior two layers of the greater omentum, 

Clinical anatomy :

•      A pancreatic pseudocyst is a circumscribed collection of fluid rich in pancreatic enzymes, blood, and necrotic tissue, typically located in the lesser sac of the abdomen. Pancreatic pseudocysts are usually complications of pancreatitis

•      Surgical access of lesser sac

1.      Through lesser omentum

2.      Through Gastrocolic ligament (part of greater omentum )

3.      Through transverse mesocolon

•       

Summary of dorsal mesogastrium and its derivatives

Dorsal mesogastrium

Mesogastrium:

the portion of the primordial mesentery that encloses the stomach and from which the lesser omentum , greater omentum and other ligaments are  develops.

THE DORSAL MESENTERY extends from the lower esophagus to rectum and throughout its length serves as a pathway to the gut for blood vessels, nerves, and lymphatics

In the area of the stomach, it is called the dorsal mesogastrium 

Derivatives of dorsal mesogastrim

1.      Greater omentum

2.      Gastrosplenic ligament

3.      Gastrophrenic ligament

4.      Lienorenal ligament

Summary of ventral mesogastrium and its derivatives

Ventral mesogastrium

The gastrointestinal tract is developed from an endodermal tube which is known as the primitive gut which is held on to the body wall by the dorsal and ventral mesentery.

The primitive midline mesentery extending between future stomach and proximal duodenum and the anterior abdominal wall superior to the umbilicus (umbilical vein). The liver develops within it; consequently, the lesser omentum, coronary and falciform ligaments are derivatives of it. The umbilical vein runs in its caudal free edge, becoming the postnatal round ligament of the liver.

Derivatives of Ventral mesogastrium

1.      Lesser omentum

2.      Falciform ligament

3.      Coronary ligament

4.      Right and left triangular ligament

Summary of Lateral longitudinal arch

Lateral longitudinal arch

It is composed of the calcaneus, the cuboid, and the fourth and fifth metatarsals

It  is lower than the medial  longitudinal arch.

It is formed by less bone and joint

It is less mobile

It commonly bears body weight

The peak of the lateral longitudinal arch is located at the level of articular facets on the superior outermost layer of the calcaneum (i.e., at the level of subtalar joint).


The posterior column of the lateral longitudinal arch is composed by the lateral tubercle of the calcaneum and the anterior column is composed by the heads of the lateral 2 metatarsals.


The primary joint of the lateral longitudinal arch is calcaneocuboid joint.