Topographic study of the sphenomandibular muscle

Abstract

The temporal muscle is housed in the fossa of the bone bearing its name – the temporal bone. Its origin, body, and insertion have been well studied, and it has been described as a muscle consisting of three bundles and responsible for various functions. The advancement of technology has allowed the observation of yet another muscle next to this bundle of fibers and above the temporal muscle, namely the sphenomandibular muscle. The present study was designed to study the topography of the sphenomandibular muscle. Ten anatomical sets (five cadavers) were dissected with the intention of displaying the topography of the temporal and sphenomandibular muscles using the techniques of cutting and folding and conventional cross cuts. The folding of the structures and mapping of the muscles was carried out on four cadavers, analyzing their origins and describing their bodies and insertions. On another cadaver, cross-sectional (horizontal), 2 mm-thick slices were made in a sequential manner. We observed the topography of the muscle and its relationship with adjacent structures. The sphenomandibular muscle was found to be independent of the temporal muscle, for its origin is in the zygomatic-frontal complex, lateral to the orbit and overlaying the fiber of the anterior bundle of the temporal muscle. Its body is separated from the body of the temporal muscle by a thin fascia and is inserted on an oblique line external to the mandible presenting, therefore, its origin, body, and insertion independent of the origin, body, and insertion of the temporal muscle.