Surgical Anatomy

A 38 years old woman presented in emergency room with the complaints of pain right epigastrium, vomiting and malaise of about 3 hours duration. She gave past history of occasional pain abdomen, whenever she had heavy meals. An ultrasonography was performed, which diagnosed her as chronic cholecystitis with cholelethiasis. Since her liver enzymes were normal and there was no history of previous jaundice, an elective surgery was planned on the next  day.  Patient was cleared for the surgery in pre anesthetic check-up and she underwent laproscopic surgery.During surgery, the operative surgeon was unable to identify the cystic duct in the patient, although the dissection was fairly easy, and there were minimal adhesions. Rest of the structures like common hepatic duct, right hepatic duct and cystic artery were visualized properly and they were normal. Reason for inability of identification of cystic duct is