The development of the face lips and palate with special reference to their congenital deformities Fig 195

Around the primitive mouth, or stomodaeum, develop the following:

1 the frontonasal process which projects down from the cranium. Two olfactory pits develop in it and rupture into the pharynx to form the nostrils. Definitively, this process forms the nose, the nasal septum, nostril, the philtrum of the upper lip (the small midline depression) and the premaxilla — the V-shaped anterior portion of the upper jaw which usually bears the four incisor teeth;

2 the maxillary processes on each side, which fuse with the frontonasal process and become the cheeks, upper lip (exclusive of the philtrum), upper jaw and palate (apart from the premaxilla);

3 the mandibular processes which meet in the midline to form the lower jaw.

Fig. 195 The ventral aspect of a fetal head showing the three processes, frontonasal, maxillary and mandibular, from which the face, nose and jaws are derived.


Olfactory pit


Olfactory pit

Frontonasal Maxilar Process

Abnormalities of this complex fusion process are numerous and constitute one of the commonest groups of congenital deformities. It is estimated that one child in 600 in England is born with some degree of either cleft lip or palate (Fig. 196).

Frequently, these anomalies are associated with other congenital conditions such as spina bifida, syndactyly (fusion of fingers or toes), etc. Indeed, it is good clinical practice to search a patient with any congenital defect for others.

The following anomalies are associated with defects of fusion of the face.

1 Macrostoma and microstoma are conditions where either too little or too great a closure of the stomodaeum occurs.

2 Cleft upper lip (or 'hare lip')—this is only very rarely like the upper lip of a hare, i.e. a median cleft, although this may occur as a failure of development of the philtrum from the frontonasal process. Much more commonly, the cleft is on one or both sides of the philtrum, occurring as failure of fusion of the maxillary and frontonasal processes. The cleft may be a small defect in the lip or may extend into the nostril, split the alveolus or even extend along the side of the nose as far as the orbit. There may be an associated cleft palate.

3 Cleft lower lip — occurs very rarely but may be associated with a cleft tongue and cleft mandible.

4 Cleft palate is a failure of fusion of the segments of the palate. The following stages may occur (Fig. 196):

(a) bifid uvula, of no clinical importance;

(b) partial cleft, which may involve the soft palate only or the posterior part of the hard palate also;

(c) complete cleft, which may be unilateral, running the full length of the maxilla and then alongside one face of the premaxilla, or bilateral in which the palate is cleft with an anterior V separating the premaxilla completely.

5 Inclusion dermoids may form along the lines of fusion of the face. The most common of these is the external angular dermoid at the lateral extremity

Development Cleft Lip And Palate
Fig. 196 Types of (a) cleft lip and (b) cleft palate.

of the upper eyebrow. Occasionally this dermoid extends through the skull to attach to the underlying dura.

The 6 Principles To Six Pack Abs

The 6 Principles To Six Pack Abs

This powerful tool will provide you with everything you need to know to be a success and finally achieve your dream of shedding the tummy fat and reveal your six pack abs. Making weight loss promises to yourself is easy but making them stick is something else which requires much more than just some words and thoughts. In the quest to make weight loss resolutions that eventually see some level of success there needs to be some careful planning and thought exercised beforehand.

Get My Free Ebook

Post a comment