Morphologic and morphometric study of the musculus obliquus dorsalis of the dog

Abstract

In the present investigation, the dorsal oblique muscle of the right ocular globe was removed from six adult dogs weighing 40-50 kg and analyzed by light microscopy. Muscle samples were taken from the central portion of the muscle belly, subsequently ultrafrozen, cut and stained with m-ATPase at pH 4.6. Fibers were classified as type I or type II according to their reaction to the m-ATPase and detailed morphologic and morphometric studies were made. The muscles showed two clearly distinct layers, a central layer and a peripheral layer, mainly composed of type II fibers. The fibers in the central layer were larger in size than those in the peripheral layer. The peculiar stratigraphy of the dorsal oblique muscle should be taken into account when performing analyses of this muscle and investigating the significance of the fiber types it contains.