Cleft lip

Cleft lip

The abnormalities in cleft lip are the direct consequence of disruption of the muscles of the upper lip and nasolabial region. The muscle continuity is disrupted, leading to the cleft lip and also abnormal insertions of the muscle at the cleft edge. - The e ff ect of this can be seen on the nasal septum and the nose itself. - Unilateral cleft lip In the unilateral cleft lip, the muscle rings are disrupted on - one side, resulting in an asymmetric upper lip and/or nose. This involves the external nasal cartilages, nasal septum and anterior maxilla (premaxilla). This influences the mucocuta - neous tissues, causing a displacement of nasal skin onto the lip and a retraction of labial skin, as well as changes to the vermil - ion and lip mucosa. All these changes need to be considered in planning the surgical repair of the unilateral cleft lip. (a) Bilateral cleft lip In the bilateral cleft lip the disruption is greater but often symmetrical. Muscular continuity is disrupted bilaterally , producing a flaring of the nose (caused by a lack of nasolabial muscle continuity), a protrusive premaxilla and an area of skin in front of the premaxilla devoid of muscle, known as the prolabium. As in the unilateral cleft lip, the muscular, carti laginous and skeletal deformities influence the mucocutaneous tissues, which must be respected in planning the repair of the bilateral cleft lip.

A B C (b) Figure 50.4 (a) Schematic representation of disruption of the nasola bial and bilabial muscle chains in unilateral (right) cleft lip. A, nasola bial; B, bilabial; C, labiomental. (b) Unilateral cleft lip before muscular reconstruction (courtesy of William P Smith).