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Head and Neck
Published in Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno, Understanding Human Anatomy and Pathology, 2018
Rui Diogo, Drew M. Noden, Christopher M. Smith, Julia Molnar, Julia C. Boughner, Claudia Barrocas, Joana Bruno
The exact sites and extent of fusion between maxillary and medial nasal prominence vary across mammals, and even within a species, as demonstrated by the different “nose prints” seen in domestic species such as cats, dogs, and horses. The fact that each individual human face looks unique, despite being formed via the same embryonic processes, is probably due to subtle differences in rate and direction of programmed tissue outgrowth (e.g., cell proliferation) that “tweak” the shape of a nose or a chin. These processes are directed in large part by quantitative variations in patterns of growth-promoting genes that we inherit from our parents (e.g., “mom’s nose, dad’s chin”).
Cleft Lip and Palate
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
David M. Wynne, Louisa Ferguson
An understanding of the embryology responsible for the development of the cranium and face is important as it allows us to understand why CL±P and CPO are different entities. The five main prominences responsible for development of the face are the frontonasal prominence, the paired right and left maxillary prominences and the right and left mandibular prominences. Incomplete or aberrant timing of fusion of the frontonasal and maxillary prominences results in cleft lip and/or palate (Figure 18.4). The frontonasal prominence is split into medial and lateral nasal prominences by development of a nasal pit on the ventrolateral aspect of the frontonasal prominence. Formation of the lip occurs between the fourth and sixth weeks of gestation when the bilateral maxillary prominences fuse with the medial nasal prominence to form the lip and alveolus. The secondary palate begins to form during the sixth week of development as the palatine shelves, which are outgrowths from the maxillary prominences, advance obliquely downward to lie horizontally over the tongue. The palatine shelves fuse with the previously formed primary palate and then from anterior to posterior the palatine shelves fuse in the midline, so that by week 12 the palate is intact. Failure of any of these processes can result in clefting (Figure 18.5).
Case 2.9
Published in Monica Fawzy, Plastic Surgery Vivas for the FRCS(Plast), 2023
What is the embryological origin of the cleft lip and palate?The cleft lip is a failure of fusion of the maxillary prominence (derived from the first branchial arch) and the medial nasal prominence (derived from the central frontonasal prominence), which normally occurs in the 7th embryological week of development.A cleft palate is due to failure of fusion of the lateral palatal shelves:These initially project downwards from the maxillary prominences into the oral cavity on either side of the tongue at the 7th week.They then elevate into a horizontal position in a matter of hours in the following week, followed by fusion with one another and the nasal septum from anterior to posterior.The exact mechanism for the initiation of palatal elevation is unknown, but theories include:the hydration of glycosaminoglycans,a change in the connective tissue involving the inhibitors of metalloproteinases (TIMPs), anda mechanical component due to tongue depression – as a result of head elevation in the 8th week and foetal swallowing.This would help explain how micrognathia and glossoptosis – as seen in the Pierre Robin sequence – force the tongue to sit high in the mouth and prevent adequate palatal elevation.
Multiple lacrimal drainage anomalies in proboscis lateralis
Published in Orbit, 2021
Nandini Bothra, Milind Naik, Mohammad Javed Ali
Embryologically, the development of PL is unclear. Sakamoto Y et al.6 proposed that at the end of 4th week of gestation, in Group 2 PL, during the proliferation of the medial nasal prominence, a concavity or fissure accidentally develops and divides the nasal prominence into two parts. The medial segment joins the unaffected part and forms the columella and the lateral segment merges with lateral nasal prominence to form the proboscis lateralis, instead of ala nasi. In Groups 3 and 4, this is associated with varying degrees of hypoplasia of the maxillary prominence. However, Group 1 shows a different developmental pattern since the PL is associated with a normal nasal structure but resembles that of a double nose.6 Prenatal diagnosis of proboscis lateralis has been documented previously.7 It is more important in cases that are associated with holopros-encephaly, as this condition is then associated with varying skeletal and developmental defects and can be fatal.
Cone beam computed tomography imaging of superior semicircular canal morphology: a retrospective comparison of cleft lip/palate patients and normal controls
Published in Acta Odontologica Scandinavica, 2018
Oğuzhan Altun, Suayip Burak Duman, Ibrahim Sevki Bayrakdar, Yasin Yasa, Sacide Duman, Sevcihan Günen Yılmaz
Cleft lip and palate (CL/P) is a common birth defect (∼9.1 cases per 10,000 births) and varies by ethnic group, geographical location and socioeconomic conditions [1]. A cleft palate is attributable to complete or incomplete assembly of the medial nasal prominence(s) on one or both sides [2]. A CL/P compromises hearing, speech and facial configuration. For several reasons, it is essential to explore the relationship between CL/P and other malformations. In addition, the association of CL/P with other congenital anomalies would increase our understanding of the embryogenic situation underlying the malformation [3]. Children with CL/P experience feeding difficulties, dental anomalies (e.g. tooth agenesis or supernumary teeth) and an increased risk of infection; they may also eventually develop speech and socio-psychological problems because they are stigmatized. A CL/P occurs more often in newborn males than females. Although facial regions near the cleft may experience delayed growth, surgical intervention allows individuals born with a CL/P to exhibit craniofacial, catch-up skeletal growth [4,5]. As a CL/P can affect maxillofacial bone structure, we explored whether semicircular canal dehiscence (SSCD) is more common in CL/P patients than normal controls.