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The ”’frontonasal process”’, or ”’frontonasal prominence”’ is one of the five swellings that develop to form the face. The frontonasal process is unpaired, and the others are the paired [[maxillary prominence]]s, and the paired [[mandibular prominence]]s. During the fourth week of [[embryonic development]], an area of thickened [[ectoderm]] develops, on each side of the frontonasal process called the [[nasal placode]]s or olfactory placodes, and appear immediately under the [[forebrain]].<ref name=Langman’s>{{Cite book|title=Langman’s Medical Embryology|last=Sadler|first=T|year=2006|isbn=9780781790697|pages=280–284}}</ref>
The ”’frontonasal process”’, or ”’frontonasal prominence”’ is one of the five swellings that develop to form the face. The frontonasal process is unpaired, and the others are the paired [[maxillary prominence]]s, and the paired [[mandibular prominence]]s. During the fourth week of [[embryonic development]], an area of thickened [[ectoderm]] develops, on each side of the frontonasal process called the [[nasal placode]]s or olfactory placodes, and appear immediately under the [[forebrain]].<ref name=Langman’s>{{Cite book|title=Langman’s Medical Embryology|last=Sadler|first=T|year=2006|isbn=9780781790697|pages=280–284}}</ref>
By invagination these areas are converted into two [[Nasal placode|nasal pits]], which indent the frontonasal prominence and divide it into medial and lateral nasal processes.<ref>{{Cite book|title=Human embryology|last=Larsen|first=W|year=2001|isbn=0443065837|pages=365–368}}</ref>
By invagination these areas are converted into two [[Nasal placode|nasal pits]], which indent the frontonasal prominence and divide it into medial and lateral nasal processes.<ref>{{Cite book|title=Human embryology|last=Larsen|first=W|year=2001|isbn=0443065837|pages=365–368}}</ref>
==Nasal processes==
==Nasal processes==
[[File:Gray45.png|thumb|upright=0.6|Medial and lateral nasal processes shown on embryo.]]
[[File:Gray45.png|thumb|upright=0.6|Medial and lateral nasal processes shown on embryo.]]
The ”’medial nasal process”’ (”’nasomedial”’) on the inner side of each nasal pit merge into the [[intermaxillary segment]] and form the [[upper lip]], crest, and tip of the [[Human nose|nose]].<ref name=Langman’s/> The medial nasal processes merge with the maxillary prominences. The ”’lateral nasal process”’ from each side merge to form the [[Human nose#External nose|alae]] of the [[human nose|nose]].<ref name=Langman’s/>
The ”’medial nasal process”’ (”’nasomedial”’) on the inner side of each nasal pit merge into the [[intermaxillary segment]] and form the [[upper lip]], crest, and tip of the [[Human nose|nose]].<ref name=Langman’s/> The medial nasal processes merge with the maxillary prominences. The ”’lateral nasal process”’ from each side merge to form the [[Human nose#External nose|alae]] of the [[human nose|nose]].<ref name=Langman’s/>
==Clinical significance==
==Clinical significance==
Failure to fuse can cause a [[cleft lip]].<ref name=Langman’s/>
Failure to fuse can cause a [[cleft lip]].<ref name=Langman’s/>
==Genetics==
==Genetics==
The frontonasal process, or frontonasal prominence is one of the five swellings that develop to form the face. The frontonasal process is unpaired, and the others are the paired maxillary prominences, and the paired mandibular prominences. During the fourth week of embryonic development, an area of thickened ectoderm develops, on each side of the frontonasal process called the nasal placodes or olfactory placodes, and appear immediately under the forebrain.[1]
By invagination these areas are converted into two nasal pits, which indent the frontonasal prominence and divide it into medial and lateral nasal processes.[2]
The medial nasal process (nasomedial) on the inner side of each nasal pit merge into the intermaxillary segment and form the upper lip, crest, and tip of the nose.[1] The medial nasal processes merge with the maxillary prominences. The lateral nasal process from each side merge to form the alae of the nose.[1]
Clinical significance
[edit]
Failure to fuse can cause a cleft lip.[1]
There is some evidence that development involves Sonic hedgehog and Fibroblast growth factor 8.[3]
This article incorporates text in the public domain from page 67 of the 20th edition of Gray’s Anatomy (1918)
