The SMAS and fat compartments of the nose: an anatomical study

The soft tissue envelope of the nose consists of skin, the superficial musculoaponeurotic system (SMAS), and multiple layers of fat. Similar layers have been well described in the neck and face regions but there are few reports of its detailed anatomy in the nose.

Nine fresh Caucasian cadaver noses were dissected in the subcutaneous, sub-SMAS, and submuscular layers. Specimens were examined to determine the extent and continuity of the nasal SMAS into the face. Fat distribution in different layers was also analyzed.

A distinct layer of SMAS in continuation with the facial SMAS was identified in all cadavers. The subcutaneous fat was found to be concentrated in the glabella, lateral wall of the nose, tip and supratip areas. Distribution of sub-SMAS fat was similar to that of superficial fat. An additional layer of fat underneath the transverse nasalis muscle was identified. The presence of an interdomal fat pad was confirmed. In the upper lateral wall of the nose, an area of deficient muscle, where the SMAS and a small amount of fat were the only soft tissue coverage, was observed.

We have confirmed the existence of the SMAS in the nose as a unique layer. We have also provided a detailed description of fat distribution. The knowledge of soft tissue coverage and fat distribution in the nose allows for various surgical modifications and provides an essential basis for procedures.

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