Korean J Otolaryngol-Head Neck Surg.  2005 Mar;48(3):338-346.

Early Development of the Nose in Human Embryo: A Stereomicroscopic and Histologic Analysis

• Kim CH
• Yoo JB
• Shin WC
• Kim MB
• Park HW
• Yoon JH

Abstract

BACKGROUND AND OBJECTIVES
We aimed to analyze the morphologic features of the nose in the human embryo from 4th to 8th developmental weeks according to the Carnegie stage. MATERIALS AND METHOD: A total of 27 cases of embryos, ranging from Carnegie stage of 13 to 23, were analyzed. The external morphology was observed with a stereomicroscope, photographed and analyzed. The histologic features were observed with a light microscope in the horizontally-transected specimens stained with hematoxylin-eosin staining. RESULTS: The nasal placode was observed at the stage 13, and it became flat or even concave at the stage 14. At the stage 15, the nasal pit was formed. At the stage 16, the nasal sac and nasal fin were observed. At the stage 17, the oronasal membrane was formed by thinning of the nasal fin. At the stage 18, the primitive choana was established by rupture of the oronasal membrane. At the stage 19, the lateral palatine process projected vertically below the level of the tongue. The cartilaginous nasal capsule was formed at the stage 20. At the stage 21, the olfactory area was localized to the upper portion of the lateral nasal wall and the nasal septum. At the stage 22, the lateral palatine process developed in a somewhat horizontal orientation. At the stage 23, the premaxilla and primitive choana were formed. CONCLUSION: The development of the nose is most active from the Carnegie stage of 13 to 19, which corresponds to the end of the 4th embryonic week to the end of the 7th week. Thus, this period is considered to be the most important period in human nasal embryonic development.

Keyword

Human embryo; Nose; Early development; Carnegie stage

MeSH Terms

Embryonic Development
Embryonic Structures*
Female
Humans*
Membranes
Nasal Septum
Nose*
Pregnancy
Rupture
Tongue