MORPHOLOGY OF DIAPHRAGM IN THE CRAB-EATING MONKEY (MACACA-FASCICULARIS)

The diaphragm was studied in 30 adult crab-eating monkeys (Macaca fascicularis). The muscular bundle of the lumber part was derived from the tendinous origin, which attached to the anterior surface of the lumbar vertebra and intervertebral disc. The upper margin of the origin was at the one third of the second lumbar vertebra in both sides. The lower margin of the right and left tendons extend to lower one third and upper one third of the third lumbar vertebra, respectively. In 22 cases (73.3%) out of 30 specimens, some muscular bundles arose from the right crus with the collagenous sheath. They ran across the ventral aspect of the aortic hiatus and bounded the esophageal hiatus at the left side. The muscular fibers, which bound the esophageal hiatus at the right and left, are innervated by ipsilateral phrenic nerve. In four cases, the "Hilfsmuskel" after Treitz was observed. It arose from the connective tissue around the coeliac artery.