Abstract
The authors observed the human digastric muscle to study precise morphology of the intermediate tendon which unites the anterior and posterior bellies; in particular, the shapes, supporting tissue such as the f ascial sling attached to the hyoid bone, synovial sheath-like lining structures, angles and distances from the hyoid bone were examined. Morphology of the fascial structures at the anterior belly side and the supporting structures of the intermediate tendon can be classified into four types, respectively. Morphometric evaluations of the intermediate tendon and its surroundings have been conducted. Synovial sheath-like lining structures increased with aging at the intermediate tendon. Discussions were conducted including morphometric evaluations concerning the shapes of the digastric muscle in relation to the hyoid bone. Textbook descriptions, including changes of aging, must be revised.
