29.12.2021 Views

Diagnostic ultrasound ( PDFDrive )

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

140 PART II Abdominal and Pelvic Sonography

FL

L

L

LO

St

St

Sp

DM

P

Sp

P

RK

Ao

LK RK LK

Ao

A

B

L

St

RK

Ao

P

LK

Sp

C

FIG. 5.1 Embryologic Development of the Spleen. Schematic axial drawings of the upper abdomen. (A) Embryo: 4 to 5 weeks. The mesentery

anterior to the stomach (St) is the ventral mesentery. The ventral mesentery is divided into two portions by the liver (L) into the falciform ligament

(FL) anteriorly and the gastrohepatic ligament or lesser omentum (LO) posteriorly. Posterior to the stomach is the dorsal mesentery (DM),

which contains the developing spleen (Sp) and pancreas (P). The dorsal mesentery is divided into two portions by the spleen: the splenogastric

ligament anteriorly and the splenorenal ligament posteriorly. The pancreas (P) has not yet become retroperitoneal and remains within the dorsal

mesentery. (B) Embryo: 8 weeks. The stomach rotates counterclockwise, displacing the liver to the right and the spleen to the left. The portion

of the dorsal mesentery containing the pancreas, splenic vessels, and spleen begins to fuse to the anterior retroperitoneal surface, giving rise to

the splenogastric ligament and the “bare area” of the spleen. If fusion is incomplete, the spleen will be attached to the retroperitoneum only by

a long mesentery, giving rise to a mobile or “wandering” spleen. (C) Newborn. Fusion of the dorsal mesentery is now complete. The pancreas

is now completely retroperitoneal, and a portion of the spleen has fused with the retroperitoneum. Note the close relation of the pancreatic tail to

the splenic hilum. Ao, Aorta; LK, left kidney; RK, right kidney.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!