Anatomy of the Airway: An Overview

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Embryologic development of the supralaryngeal vocal tract

The head and neck are formed by pharyngeal (branchial) arches. These arches appear in the fourth and fifth weeks of development and contribute to the characteristic external appearance of the embryo. In humans, there are 5 pairs of arches. These arches correspond in numbers I, II, III, IV, and VI. The pharyngeal arches consist of bars of mesenchymal tissue separated by pharyngeal pouches or clefts. Each arch has its own outer covering of ectoderm, an inner covering of endoderm, and a core of

Growth and development

According to Enlow, “morphogenesis works constantly toward a state of composite, architectonic balance among all the separate growing parts. This means that the various parts developmentally merge into a functional whole, with each part complimenting the others as they all grow and function together. During development, balance is continuously transient and can never actually be achieved because growth itself constantly creates ongoing, normal, regional imbalances.”8

Enlow and Hans8 state, “The

Differences between infant and adult larynx

The infant larynx is more inferior. The cricoid cartilage is approximate to C3 and C4 but not C6. The epiglottis is longer, stiffer, and further away from the anterior pharyngeal wall. The narrowest portion is the cricoid cartilage, not the vocal cords. The tongue is relatively larger compared with that of the adult. Other differences include a more rostral larynx, angled vocal cords, differently shaped epiglottis, and funnel-shaped larynx, the narrowest part of which is the cricoid cartilage,

Klinorynchy

Klinorynchy is described as the posterior migration of the facial skeleton under the brain case.1 According to Barsh's9 studies, the maxilla and other facial bones, along with the mandible, moved posteriorly and rotated downwardly. This posterior migration caused the pharynx to become compressed. To preserve the pharynx for respiration and deglutition, the mandible and maxilla, along with the ethmoid and palate, became shortened.9 Evidence of this change is seen within the teeth also. The

Structural overview of the pharynx

The pharynx is a fibromuscular, funnel-shaped tube, which is approximately 15 cm long. It serves as a common passageway for air and food. It extends from the base of the skull superiorly to the esophagus inferiorly.13 The pharynx is divided into 3 parts: (1) the nasopharynx, posterior to the nasal cavity and superior to the soft palate, (2) the oropharynx, posterior to the oral cavity, between the palate and the hyoid bone, and (3) the laryngopharynx, posterior to the larynx, from the hyoid

Anatomy of the larynx

The larynx connects the pharynx with the trachea. It functions as a valve that separates the trachea from the narrow digestive tract and maintains a patent airway. It also provides an instrument for vocalization. The larynx is made up of cartilages, ligaments, and membranes that connect the cartilages and muscles to cause movement of various parts. It is lined with a mucous membrane of columnar ciliated cells and contains many mucous glands.

There are 3 unpaired cartilages (thyroid, cricoid, and

Muscles of the larynx

The muscles of the larynx can be divided into 2 broad groups: extrinsic muscles and intrinsic muscles. The extrinsic muscles of the larynx can be subdivided into 2 groups: suprahyoid and infrahyoid muscles. The suprahyoid group of muscles is composed of (1) the anterior belly of the digastric muscle, which draws the hyoid forward; (2) the posterior belly of the digastric muscle, which stabilizes and draws the hyoid back; (3) the genioglossus muscle, which elevates and advances the hyoid bone

Discussion

The oral apparatus is the “gateway to the gut.”13 The oropharyngeal system is in unbroken continuity with the pharynx and funnels food directly into the esophagus. The structure of the food channel is complicated by the peculiar crossing of the airway at the larynx. The oral apparatus not only prepares food but also initiates swallowing. It is designed to function in close coordination with the pharynx. The oropharyngeal system is meticulously integrated with the production of speech. One of

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References (16)

  • T.M. Davidson

    The great leap forward: the anatomic basis for the acquisition of speech and obstructive sleep apnea

    Sleep Med

    (2003)
  • T.W. Sadler

    Langman's medical embryology

    (2000)
  • G.C. Schoenwolf

    Larson's embryology

    (2009)
  • T. Humphrey

    The development of mouth opening and related reflexes involving the oral area of human features

    Ala J Med Sci

    (1968)
  • T. Humphrey

    The relation between human fetal mouth opening reflexes and closure of the palate

    Ala J Med Sci

    (1969)
  • Auvenshine RC. The relationship between structure and function in the development of the squamomandibular joint in...
  • A.A. Pitsillides

    Early effects of embryonic movements

    J Anat

    (2006)
  • D.H. Enlow et al.

    Essentials of facial growth

    (2008)
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