Anatomy of the depressor septi nasi muscle: The basis for correction of deformities of the nose/lip junction

The purpose of this study was to analyse the macroscopic aspect of the depressor septi nasi muscle in cadavers according to its relations with the nasolabial region, and to describe a surgical technique developed out of the knowledge gained from its study to take care of nasal tip drooping and gummy smile. Twenty fresh adult cadavers were studied. All of them were men. A transverse incision was done at the gingivo-labial sulcus, through the frenulum, to expose the orbicularis oris and the depressor nasi muscles. These muscles were isolated and their anatomical aspect, localisation, origin, and insertion were registered. Sixteen of the cadavers presented the muscle. From these, 14 were bilateral and two were unilateral. Four cadavers did not present the muscle. Muscular fibres were vertically disposed and presented oblique direction towards the midline, in a quadrangular shape. From the 16 cadavers of the subgroup in whom the muscle was present, 14 originated in the orbicularis oris and its insertion was in the maxilla. Two of the cadavers presented the origin and insertion at the maxilla. According to these findings, a surgical approach of the muscles was proposed to treat the gummy smile deformity during rhinoplasty and two clinical cases are presented. The depressor nasi muscles presented an anatomical variation. In most cases it is intimately related with the orbicularis oris and the maxilla, being a relatively thick structure. We suggest its treatment simultaneously during rhinoplasty for a better result of the nasal tip and it benefits the "tense nose" aspect and the smiling deformity.