ANATOMICAL FEATURES OF THE INCISIVUS LABII SUPERIORIS MUSCLE AND ITS RELATIONSHIPS WITH THE UPPER MUCOLABIAL FOLD, LABIAL GLANDS AND MODIOLAR AREA

详细

全文:

Aim. The current study examined the incisivus labii superioris muscle (ILS) and its morphologic and spatial relationships with the surrounding structures, especially focusing on the upper mucolabial fold, labial glands, and modiolar area. Material and Methods. ILSs were investigated in 52 specimens from embalmed Korean adult cadavers. Results and Discussion. ILSs were observed in all specimens (100%). The ILS had an oblique and linear origin. The ILS originated from the incisive fossa of the maxilla to the point just medial to the origin of the levator anguli oris muscle (LAO). The medial arising fibers of the ILS curved upward and laterally. The ILS was located between the orbicularis oris muscle (OOr) and the LAO with fan shape. As the ILS coursed arching laterally, it became the superolateral margin of the OOr, enlarging the dimension of the superior peripheral part of the OOr. The arising fibers of the ILS arched and covered the prominent labial glands at the superior margin of the OOr. After the ILS coursed laterally along the anterior part of the upper mucolabial fold, the ILS was divided into the superficial or deep inserting fibers in most specimens. The superficial inserting fibers of the ILS blended with the medial fibers of the LAO to converge toward the modiolus. The deep inserting fibers of the ILS blended with several muscles in the modiolar area. Conclusions. These specific results will be helpful for analyzing the movements of the mouth and performing various facial surgeries.