Body of the Gallbladder

The body of the gallbladder is the central and longest part of the gallbladder, lying between the fundus and the neck. It forms the primary reservoir for bile storage and expands significantly when the gallbladder is full. Unlike the fundus, which is a blind end, or the neck, which leads into the biliary duct system, the body serves as the main bile-storing chamber. Its smooth muscle layer contracts in response to hormonal stimuli, particularly cholecystokinin (CCK), expelling bile into the cystic duct and onward into the common bile duct. The body is also important in disease development, especially in gallstone formation, and plays a prominent role in diagnostic imaging and surgery.

Structure

The body of the gallbladder is cylindrical or slightly tapered in shape. It makes up the majority of the gallbladder’s volume and connects the fundus anteriorly and the neck posteriorly. Its walls are capable of stretching to accommodate bile but also contract rhythmically in response to digestive signals.

Gross Features

• Length: Approximately 4–7 cm in adults
• Diameter: Varies with degree of distension; typically 2–3 cm when filled
• Shape: Tubular and curved to conform to the liver’s contour

Wall Layers

Like the rest of the gallbladder, the body has a multi-layered wall, structured for absorption, storage, and expulsion of bile:

Layer	Description
Mucosa	Highly folded into mucosal ridges; made of simple columnar epithelium with microvilli
Lamina propria	Supports the mucosa; contains capillaries, lymphatics, and immune cells
Muscularis externa	Irregularly arranged smooth muscle responsible for contractions
Perimuscular connective tissue	Fibrous support layer containing larger blood vessels and nerves
Serosa	Visceral peritoneum covering the body on its free surfaces

These layers support bile storage and absorption while enabling contractile function when stimulated hormonally or neurally.

Location

The body of the gallbladder lies in contact with the visceral surface of the liver, embedded in a shallow depression called the gallbladder fossa. It is oriented obliquely, with the fundus anterior and the neck directed posteromedially.

Topographic Position

• Region: Upper right quadrant of the abdomen
• Surface contact: In direct contact with liver segments IV and V
• Inferiorly: May abut the transverse colon or duodenum

In most individuals, the peritoneum covers only part of the gallbladder body, and the remaining surface is attached directly to the liver (non-peritonealized). This anatomical variation has implications for inflammation spread and surgical mobilization.

Function

The body of the gallbladder performs most of the organ’s passive and active roles in bile management. It is the main area where bile is stored, concentrated, and prepared for release.

Bile Storage and Concentration

• Filling: When the sphincter of Oddi is closed, bile produced by the liver flows retrogradely into the gallbladder body via the cystic duct
• Concentration: The mucosa absorbs water and electrolytes, increasing bile concentration up to 10-fold
• Capacity: Normal gallbladder can hold 30–50 mL of bile

Contractile Response

Upon stimulation by CCK (released by duodenum when fat enters), the smooth muscle of the gallbladder body contracts, increasing pressure and pushing bile toward the neck and cystic duct. The contraction is coordinated with relaxation of the sphincter of Oddi to allow bile delivery into the duodenum.

Clinical Relevance

The body of the gallbladder is a common site of disease presentation, imaging focus, and surgical concern due to its central role in bile stasis and gallstone accumulation.

1. Cholelithiasis (Gallstones)

• Stone formation: The body is the main site where bile stasis and sludge occur, predisposing to stone formation
• Gravity effect: Sedimentation of cholesterol crystals happens primarily in the body during prolonged fasting or reduced motility

2. Acute and Chronic Cholecystitis

Inflammation of the gallbladder typically begins in the body and may extend to adjacent structures:

• Acute cholecystitis: Wall thickening, edema, and mucosal disruption are first seen in the body
• Chronic cholecystitis: Fibrosis and muscular hypertrophy may be localized in the body and fundus

3. Gallbladder Cancer

• Early tumors often originate in the body and may spread into adjacent liver parenchyma
• The body’s location near liver segment IV makes it susceptible to direct invasion and early vascular spread

4. Imaging Landmarks

On ultrasound, CT, and MRI:

• Wall thickness > 3 mm: Suggests inflammation or malignancy
• Double wall sign: Indicates edema between mucosal and serosal layers (seen in acute cholecystitis)
• Intraluminal echogenic foci: Suggest gallstones or polyps

5. Surgical Relevance

• Laparoscopic cholecystectomy: The body is grasped and retracted laterally and superiorly to expose Calot’s triangle
• Fundus-first dissection: Used when Calot’s triangle is obscured; begins at the body and proceeds toward the neck

The body is also commonly biopsied when a suspected mass or mural thickening is present, especially in patients with chronic cholecystitis or gallbladder wall calcification.