The degrees of deformity of the soft parts in the unilateral variety are shown in Figs. 149 to 151, respectively, representing the first, second, and third degrees of the cleft deformity, according to the involvement of the lip tissue. In first degree are included small notches in the prolabium only or extending upward somewhat above its margin, but not involving the entire lip. In the second degree both the vermilion border and the lip are divided, while in the third degree the cleft extends into the nose with an absence of part of the lip structure itself. Since the deformity in the division under discussion is so commonly met with it will be considered fully under its operative correction. =3. Facial Cleft.=—The third class of deformity includes either unilateral or bilateral fissure of the face. In the _unilateral_ variety the cleft usually begins at the outer section of the upper lip, involving, as a rule, only the soft parts, extending upward and irregularly around the alæ of the nose to the inner canthus of the eye, or going even beyond the orbit and over the forehead as far as the hair line. An illustration of such a case is shown in Fig. 152. The _bilateral_ form of this facial defect is rarely met with. A case reported by von Guersant is shown in Fig. 153. [Illustration: FIG. 152.—UNILATERAL FACIAL CLEFT. (Hasselmann.)] [Illustration: FIG. 153.—BILATERAL FACIAL CLEFT. (von Guersant.)] =4. Buccal Cleft.=—In the fourth variety the deformity involves the cheeks, the fissures extending from the angles of the mouth outward, causing an enlargement of this natural opening, and hence this defect is better known as _macrostoma_. It may affect one or both cheeks. The latter is elucidated in Fig. 154. [Illustration: FIG. 154.—BUCCAL FISSURE WITH MACROSTOMA.] On the other hand there may exist a congenital contraction of the mouth termed _microstoma_. This defect is rarely seen, and is due to a too free union of the maxillary and mandibular processes. When observed it is usually associated with improper development of the inferior maxillary bones. =5. Mandibular Cleft.=—In the fifth class the cleft is to be found in the median line of the lower lip. This fissure, though extremely rare, may involve only the soft tissue or extend to the inferior maxillary (Thorndike) and even to the tongue (Wölfler). From what has been said of the five varieties just mentioned it can be plainly seen that the defects of the second class are the most common. Since the correction of such involves methods of an extensive technique that can be followed more or less in the restoration of any of the above, this particular subdivision will be considered fully, but only to the extent of defects of the soft parts, leaving the osteoplastic and periosteoplastic operations to be studied elsewhere. The defects that have to do with facial and buccal clefts will be more specifically mentioned later on under Melo- and Stomatoplasty.