Anatomy

Anatomy

The skin is thinner and more mobile in the upper two thirds of the nose, and it is thicker and more adherent in the lower third portion of the face. The thinner and older the skin is, the more wrinkling is to be formed on the nasal dorsum. The nose contains three main muscles: the procerus, the nasalis and the depressor septi nasi. The procerus draws the medial part of the eyebrow down. It originates at the nasal root and blends with the frontalis fibres. The depressor septi nasi drops the tip of the nose when contracted. Finally, the m. nasalis is the most important one for causing the bunny lines and will be the main focus of treatment. Although the m. levator labii superioris alaeque nasi is not an intrinsic nasal muscle, it can contribute to the bunny lines due to its medial fibres. The nasalis originates in the transition from the nasal bone with the maxilla and inserts into the aponeurosis of the nasal dorsum. It looks like an upside-down horseshoe, with the upper or curved part formed by transverse fibres on the nasal dorsum. Its action is to narrow the nostrils (also denominated as compressor naris). The transverse fibres of the nasalis lead, when contracted, to the lateral nasal lines and to additional lines in the internal infra-ocular region. The two lower parts of the nasalis run vertically down the sides of the nose (also known as the dilator nasi) and their action is to open the nostrils.