Annular pancreas in Thais.

Objective: To study a congenital malformation of pancreas, the annular pancreas, and openings of pancreatic ducts. This abnormality can cause duodenal obstruction. Methods: The annular pancreas and duodenum of an 86-year-old Thai female cadaver was removed. The length and width of the annular pancreas were measured, as well as the internal diameter of the duodenum at the surrounded part and also the higher level. The openings of pancreatic duct were also carefully observed. Results: The second part of the duodenum was completely surrounded by the pancreatic tissue. The uncinate process extended over the anterior surface of the third part of the duodenum. The differences between the diameter of the duodenum at the surrounded part and at the higher level were 0.2 cm. there is no duodenal obstruction in this case. There were 2 openings of the pancreatic duct which opened to the second part of the duodenum. These ducts situated higher than the normal level, and were the primitive remains of the dorsal and ventral pancreatic buds. Conclusions: Not all the cases of the annular pancreas cause duodenal obstruction. In the cases that the pancreatic tissue loosely surrounds the duodenum, the diameters of the duodenum at the surrounding and at the slightly higher level are nearly the same. The pancreatic openings showed the primitive characters, i.e., there were 2 openings represented 2 origins of the pancreatic buds.

The infraorbital foramen In Thais study in relation to the mesioincisal point of the central incisor, the tip of the canine, the tip of the buccal cusp of the second premolar of the ipsilateral side.

Sixty-six Thai dry skulls, 34 males and 32 females, were used in measuring the distances from the infraorbital foramen to the mesioincisal point of the central incisor, to the tip of the canine and to the tip of the buccal cusp of the second premolar of the ipsilateral side. The average distances are 5.548 + 0.036, 4.695 + 0.040 and 4.320 + 0.038 cm. respectively. The angles between the occlusal plane and the lines joining the infraorbital foramen to the mesioincisal point of the central incisor, to the tip of the canine and to the tip of the buccal cusp of the second premolar of the ipsilateral side were calculated. The value of the angles are 59.372 + 0.546, 106.538 + 0.569 and 93.0.707 degrees respectively. On each central incisor, an imaginary rectangle was made by using the width of the occlusal edge as the base and the height of the anatomical crown as the height of the rectangle. The average angle between the occlusal edge and the diagonal line is 52.454 + 0.366 degrees. The study of the direction of the opening of the infraorbital foramen revealed that most of the infraorbital foramens of the Thai skulls directed downward and medially.