The "levator septi nasi muscle" and its clinical significance.

It is strange that all textbooks of anatomy describe the depressor septi nasi muscle singly, without an antagonist. Incidentally, in 1986, a small rod of soft tissue was found between the medial crura of the two alar cartilages during a rhinoplastic operation with the external approach technique of Anderson and Ries. From 1990 through 1995, anatomic dissections of the nasolabial region under 3.5x loupe magnification were performed on 14 Chinese formalin-preserved cadavers, one fresh Chinese cadaver, and one fresh American white female cadaver. The small soft-tissue rod was found in every one of the dissected cadavers, and it was seen to be a pair of muscles. Each one of these paired small muscles arose from the aponeurosis on the dorsum of the nose and inserted into the muscular substance of the upper lip at the base of the columella and to the anterior spine of the maxilla. Histologic examinations of these muscles stained with hematoxylin and eosin and Masson trichrome showed that they were striated muscles. According to its origin and insertion, this newly found muscle was called the "levator septi nasi." Its clinical significance in cleft lip deformity and its relations to the orbicularis oris muscle, the dermocartilaginous ligament of Pitanguy, and the nasal superficial musculoaponeurotic system of Letourneau and Daniel are all discussed.