An ultrasound examination shows dilated intrahepatic biliary channels with a small gall bladder. The most likely possibility is
Gall bladder stone
Pancreatic calculus
Common bile duct stone
Carcinoma of the head of the pancreas
In obstruction of the CBD due to a stone,distension of gallbladder seldom occurs.The organ is usually shrivelled.In obstruction from other causes ,distension of gallbladder is common by comparison. Reference:Bailey & Love's sho practise of surgery,25th edition,page no:1125
G.I.T