Human Anatomy and Physiology (with Age-Related Features of the Child's Body) - Sapin M.R., Sivoglazov V.I. 2002

The Doctrine of the Viscera (Splanchnology)
Digestive System
Gallbladder

The gallbladder serves as a reservoir for Bile, with a capacity of approximately 40 cm³. Its wide end forms the fundus, while the narrowed portion forms the neck, which transitions into the cystic duct through which bile enters and leaves the gallbladder. The body of the gallbladder is located between the fundus and the neck. The lower and lateral surfaces of the gallbladder are covered by the Peritoneum, whereas its upper part is adjacent to the Liver. The outer walls are composed of loose Fibrous Connective Tissue, featuring a muscular layer and a mucous membrane that forms folds and villi, facilitating the intensive absorption of Water from bile. The cystic duct merges with the common hepatic duct to form the common bile duct, which is about 7 cm long. Running downwards between the layers of the hepatoduodenal ligament, the common bile duct pierces the wall of the descending part of the duodenum and, together with the pancreatic duct, opens at the summit of the major duodenal papilla. At the site where the common bile duct empties into the duodenum, a smooth-Muscle sphincter regulates the flow of bile into the intestinal lumen.

Age-related Features of the liver and gallbladder

In newborns, the liver is large and occupies more than half of the Abdominal cavity volume. The mass of a newborn's liver is 135 g, which accounts for 4.0–4.5% of body weight (compared to 2–3% in adults). The left lobe of the liver is equal to or larger than the right lobe. The lower margin of the liver is convex, and the colon lies beneath its left lobe. In newborns, the inferior border of the liver projects 2.5–4.0 cm below the costal margin along the right midclavicular line, and 3.5–4.0 cm below the xiphoid process along the anterior median line. Occasionally, the lower edge of the liver reaches the iliac crest on the right. In children aged 3–7 years, the inferior border of the liver is located 1.5–2.0 cm below the costal margin (along the midclavicular line). After 7 years of age, the lower margin of the liver no longer extends below the costal margin: only The Stomach lies beneath the liver. From this point onward, the skeletotopy of a child's liver is nearly identical to that of an adult. In children, the liver is highly mobile, and its position easily shifts with changes in body posture.

In newborns, the gallbladder is elongated (3.4 cm), yet its fundus does not project below the inferior border of the liver. By 10–12 years of age, the length of the gallbladder increases approximately 2- to 4-fold.

The gallbladder is projected onto the anterior abdominal wall below the costal margin, 2 cm to the right of the anterior median line. Inferior to the gallbladder lie the duodenum, the loops of the mesenteric part of the Small Intestine, and the transverse colon.