A 4-hour-old girl with a cleft lip is breastfeeding without difficulty. The infant was born vaginally after an uncomplicated pregnancy and delivery. Routine antenatal sonography at 20 weeks gestation showed no abnormalities. Physical examination shows an intact palate and a unilateral cleft lip on the left side. No other abnormalities are seen. This child's cleft lip resulted from failure of which of the following intrauterine processes?

Question

A 4-hour-old girl with a cleft lip is breastfeeding without difficulty.  The infant was born vaginally after an uncomplicated pregnancy and delivery.  Routine antenatal sonography at 20 weeks gestation showed no abnormalities.  Physical examination shows an intact palate and a unilateral cleft lip on the left side.  No other abnormalities are seen.  This child's cleft lip resulted from failure of which of the following intrauterine processes?

Quizplus · Accepted Answer

11ec160b_373a_e2f5_9249_03a00cbe2714_MD0001_00 The lip and palate form during the fifth-sixth week of embryonic development through a series of fusions: (Choice A) Failure of the medial nasal prominence to fuse and form the intermaxillary segment is associated with severe midline defects, such as holoprosencephaly. (Choice C) During the seventh-eighth week of embryonic development, the maxillary prominences give rise to palatine shelves. The thin sheets of tissue that comprise the palatine shelves grow medially and fuse into the secondary palate. Fusion of the secondary palate with the posterior aspect of the primary palate forms the complete palate. Failure of any of these processes can lead to cleft palate. The presence of a cleft lip increases the risk of cleft palate, but either can occur in isolation. (Choice D) The orbits normally arise from the sides of the face and rotate medially. However, excessive tissue from the frontal nasal prominence could result in orbital hypertelorism (wide-set eyes) in addition to a broad forehead and wide nasal bridge. (Choice E) Micrognathia is characterized by hypoplasia of the mandibular prominence. In Pierre-Robin sequence, the severe micrognathia results in posterior displacement of the tongue (glossoptosis) and prevents fusion of the secondary palate (cleft palate). Educational objective: Cleft lip results when the maxillary prominence fails to fuse with the intermaxillary segment during the fifth-sixth week of embryonic development. Cleft palate occurs when the palatine shelves fail to fuse with one another or with the primary palate. Cleft lip and palate can occur together or in isolation. __________ References: Cleft lip and palate: understanding genetic and environmental influences. (http://www.ncbi.nlm.nih.gov/pubmed/21331089) Cleft lip and palate: an evidence-based review. (http://www.ncbi.nlm.nih.gov/pubmed/26208773)

A 4-Hour-Old Girl with a Cleft Lip Is Breastfeeding Without