Categories: ANATOMY OF LARYNX, TRACHEA, BRONCHI AND ESOPHAGUS, ENDOSCOPICALLY CONSIDERED
Sources: A Manual Of Peroral Endoscopy And Laryngeal Surgery
A few of the anatomical details must be kept especially in mind when
it is desired to introduce straight and rigid instruments down the
lumen of the gullet. First and most important is the fact that the
esophageal walls are exceedingly thin and delicate and require the
most careful manipulation. Because of this delicacy of the walls and
because the esophagus, being a constant passageway for bacteria from
the mouth to the stomach, is never sterile, surgical procedures are
associated with infective risks. For some other and not fully
understood reason, the esophagus is, surgically speaking, one of the
most intolerant of all human viscera. The anterior wall of the
esophagus is in a part of its course, in close relation to the
posterior wall of the trachea, and this portion is called the party
wall. It is this party wall that contains the lymph drainage system of
the posterior portion of the larynx, and it is largely by this route
that posteriorly located malignant laryngeal neoplasms early
metastasize to the mediastinum.
 [FIG 46.--Esophagoscopic and Gastroscopic Chart
BIRTH 1 yr. 3 yrs. 6 yrs. 10 yrs. 14 yrs.ADULTS
23 27 30 33 36 43 53 Cm. GREATER CURVATURE
18 20 22 25 27 34 40 Cm. CARDIA
19 21 23 24 25 31 36 Cm. HIATUS
13 15 16 18 20 24 27 Cm. LEFT BRONCHUS
12 14 15 16 17 21 23 Cm. AORTA
7 9 10 11 12 14 16 Cm. CRICOPHARYINGEUS
0 0 0 0 0 0 0 Cm. INCISORS
FIG. 46.--The author's esophagoscopic chart of approximate distances
of the esophageal narrowings from the upper incisor teeth, arranged
for convenient reference during esophagoscopy in the dorsally
The lengths of the esophagus at different ages are shown
diagrammatically in Fig. 46. The diameter of the esophageal lumen
varies greatly with the elasticity of the esophageal walls; its
diameter at the four points of anatomical constriction is shown in the
Constriction Diameter Vertebra
Cricopharyngeal Transverse 23 mm. (1 in.) Sixth cervical
Antero-posterior 17 mm. (3/4 in.)
Aortic Transverse 24 mm. (1 in.) Fourth thoracic
Antero-posterior 19 mm. (3/4 in.)
Left-bronchial Transverse 23 mm. (1 in.) Fifth thoracic
Antero-posterior 17 mm. (3/4 in.)
Diaphragmatic Transverse 23 mm. (1 in+) Tenth thoracic
Antero-posterior 23 mm. (in.--)
For practical endoscopic purposes it is only necessary to remember
that in a normal esophagus, straight and rigid tubes of 7 mm. diameter
should pass freely in infants, and in adults, tubes of 10 mm.
The 4 demonstrable constrictions from above downward are at
1. The crico-pharyngeal fold.
2. The crossing of the aorta.
3. The crossing of the left bronchus.
4. The hiatus esophageus.
There is a definite fifth narrowing of the esophageal lumen not easily
demonstrated esophagoscopically and not seen during dissection, but
readily shown functionally by the fact that almost all foreign bodies
lodge at this point. This narrowing occurs at the superior aperture of
the thorax and is probably produced by the crowding of the numerous
organs which enter or leave the thorax through this orifice.
The crico-pharyngeal constriction, as already mentioned, is produced
by the tonic contraction of a specialized band of the orbicular fibers
of the lowermost portion of the inferior pharyngeal constrictor
muscle, called the cricopharyngeal muscle. As shown by the author it
is this muscle and not the cricoid cartilage alone that causes the
difficulty in the insertion of an esophagoscope.
This muscle is attached laterally to the edges of the signet of the
cricoid which it pulls with an incomprehensible power against the
posterior wall of the hypopharynx, thus closing the mouth of the
esophagus. Its other attachment is in the median posterior raphe.
Between these circular fibers (the cricopharyngeal muscle) and the
oblique fibers of the inferior constrictor muscle there is a weakly
supported point through which the esophageal wall may herniate to form
the so-called pulsion diverticulum. It is at this weak point that
fatal esophagoscopic perforation by inexperienced operators is most
likely to occur.
The aortic narrowing of the esophagus may not be noticed at all if
the patient is placed in the proper sequential high-low position. It
is only when the tube-mouth is directed against the left anterior wall
that the actively pulsating aorta is felt.
The bronchial narrowing of the esophagus is due to backward
displacement caused by the passage of the left bronchus over the
anterior wall of the esophagus at about 27 cm. from the upper teeth in
the adult. The ridge is quite prominent in some patients, especially
those with dilatation from stenoses lower down.
The hiatal narrowing is both anatomic and spasmodic. The peculiar
arrangement of the tendinous and muscular structure of the diaphragm
acts on this hiatal opening in a sphincter-like fashion. There are
also special bundles of muscle fibers extending from the crura of the
diaphragm and surrounding the esophagus, which contribute to tonic
closure in the same way that a pinch-cock closes a rubber tube. The
author has called the hiatal closure the diaphragmatic pinchcock.