Embryology & Classification
🧬 Embryology in one screen
- Upper lip & primary palate — at the 4th–6th week five facial swellings form around the stomodeum (one frontonasal prominence, paired maxillary and mandibular prominences). The two medial nasal processes fuse in the midline → central lip, columella, nasal tip and intermaxilla / primary palate; they fuse with the maxillary prominences laterally → the rest of the upper lip. Failure here → cleft lip ± primary palate.
- Secondary palate — at the 6th week the palatal shelves grow vertically down from the maxillary prominences, lateral to the tongue; at 7–8 weeks the tongue descends, the shelves rotate to horizontal and fuse with each other, with the primary palate and with the nasal septum — complete by ~10 weeks. Failure here → cleft of the secondary palate.
- The incisive foramen is the landmark dividing the primary (anterior) from the secondary (posterior) palate.
- Cleft lip ± palate is commoner in males (and, when unilateral, on the left); isolated cleft palate is commoner in females.
Types of cleft lip & cleft palate
Cleft Lip
- Unilateral, bilateral or median
- Complete — full width of lip + alveolus, extending up to the floor of the nose
- Incomplete — part of the lip, not reaching the nasal floor
- Microform (forme fruste) — a notch in the vermilion border only
Cleft Palate
- May involve primary, secondary, or both; unilateral, bilateral or median
- Complete — primary + secondary palate, including soft palate and uvula
- Incomplete — cleft of part of the palate
- Submucous — muscle cleft covered by intact mucosa (bifid uvula, zona pellucida, notched hard palate) — not obvious on inspection
Veau classification of the cleft palate
| Veau group | Description |
|---|---|
| Group I (A) | Defect of the soft palate only |
| Group II (B) | Hard + soft palate, extending no further than the incisive foramen |
| Group III (C) | Complete unilateral cleft — soft palate to alveolus, usually involving the lip |
| Group IV (D) | Complete bilateral cleft (resembles Group III but bilateral) — the pre-maxilla is suspended from the nasal septum |
Limitation: the Veau system does not include the isolated cleft lip.
LAHSHAL / LAHSAL descriptive code
A striped-Y notation that records exactly which structures are cleft. The mouth is divided and read as if looking at the patient — the first character is the patient's right, the last the patient's left:
| L | A | H | S | H | A | L |
|---|---|---|---|---|---|---|
| Lip (R) | Alveolus (R) | Hard palate (R) | Soft palate | Hard palate (L) | Alveolus (L) | Lip (L) |
A capital letter = complete cleft of that structure, a lower-case letter = incomplete cleft, and a dot (·) = no cleft. (The 6-structure LAHSAL variant merges the hard palate into a single character.)
Nagpur classification (Dr C. Balakrishnan)
| Group | Structures cleft |
|---|---|
| Group I | Cleft lip only |
| Group Ia | Cleft lip + cleft alveolus |
| Group II | Cleft palate only |
| Group III | Cleft lip + cleft alveolus + cleft palate |