Question

When maxillary and nasomedial processes fail to unite during embryonic development the condition is called
(A) Cleft lip
(B) Cleft palate
(C) Astomium
(D) Tongue tied

• A. Cleft lip
• B. Cleft palate
• C. Astomium
• D. Tongue tied

Hint:

Keep these congenital facial defects distinct:
- Cleft Lip \(\rightarrow\) Maxillary process fails to fuse with nasomedial process (external defect).
- Cleft Palate \(\rightarrow\) Maxillary process shelves fail to fuse with each other along the midline (internal defect).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The face develops from the fusion of several embryonic processes: the frontonasal process, the paired maxillary processes, and the paired mandibular processes.
Errors during this fusion process can lead to congenital facial malformations.

Step 2: Detailed Explanation:
Let us analyze the developmental origins of these facial structures:
- Facial Fusion: The medial nasal (nasomedial) processes fuse in the midline to form the nasal septum and the philtrum of the upper lip.
The lateral maxillary processes grow inward to form the lateral portions of the upper lip and the maxilla.
- Cleft Lip (Cheiloschisis): If the maxillary process fails to fuse with the nasomedial process on one or both sides, a gap remains in the upper lip.
This congenital defect is called a cleft lip, or "harelip."
- Evaluating other options:
- Cleft Palate (Palatoschisis): This defect occurs when the lateral palatine shelves (derived from the maxillary processes) fail to fuse along the midline of the hard palate.
- Astomium: This refers to the congenital absence of a mouth opening.
- Tongue-tied (Ankyloglossia): This condition is caused by an abnormally short or thick lingual frenulum that restricts tongue movement.
Therefore, the failure of the maxillary and nasomedial processes to unite specifically causes a cleft lip.

Step 3: Final Answer:
The resulting congenital condition is cleft lip. This corresponds to option (A).