Paper - The Development of the Nose and of the Pharynx and its Derivatives in Man
Embryology - 20 May 2024    Expand to Translate
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Sadler, MT. The Development of the Nose and of the Pharynx and its Derivatives in Man. (1902)
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The Development of the Nose and of the Pharynx and its Derivatives in Man
By
Mervin T. Sudler, Ph.D., M. D.
From the Anatomical Laboratory of the Johns Hopkins University.
WITH 13 Text figures.
The presence of visceral folds homologous with the branchial arches of the fishes and lower vertebrates, the progressively changing circulatory system, the origin of the vertebrate mouth and its relation to the head and brain have combined to make the study of this region one of the most interesting and important divisions of mammalian embryology. In fact a knowledge of the development of this region not only aids us in understanding the adult anatomy but has been of the greatest service in giving us facts upon which to base definite ideas in regard to the evolution of these structures. There is scarcely a series of phenomena anywhere in the whole science of embryology that better illustrates the idea that “ontogeny repeats phylogeny” than the development of this region in the mammalia.
Most of the work done on this region has dealt with the visceral folds, the circulation and the origin of the thyroid and thymus glands, and the exact form of the pharyngeal cavities have had comparatively little attention, especially in man. The work of His[1] is especially valuable. Hammer[2] has also studied this region in man. He reconstructed the cavities and his work on the fate of the first branchial pocket and the origin of the Eustachian tube is complete and exhaustive. Piersol[3] has modeled the pharyngeal clefts in a complete series of rabbit embryos.
It seemed desirable to have a knowledge of the exact form of the cavity of the human mouth and nose in the early stages of development, and hence at the suggestion of Dr. Mall I have made a series of models of the cavities of the mouth and nose of the valuable series of human embryos contained in his collection. The wax plate method of Born[4] was used throughout the work. The embryos used represent the first seven weeks of foetal development. The magnifications were varied to suit the thickness and size of the sections of the different embryos used. In all the figures the cavities are represented as solid models and hence it is necessary to bear in mind that one is looking at a negative picture and not a positive one. The reverse is true, however, for the thyroid, thymus and salivary glands as these are solid objects and are so represented by the solid models. In nearly all of the models the mucous membrane was included. In the model of embryo XII and in one of the two made of embryo CLXIII only the cavity was modeled. For the model of embryo XII I am indebted to Dr. Mall. In making the illustrations to this paper an effort has been made to preserve enough of the embryo to make the relations of the model clear. At the same time details have‘~been omitted in order to avoid making the whole appear too complicated and obscure the most important structures. For pictures of the entire embryos the reader is referred to the beautiful illustrations of Bardeen and Lewis,[5] where embryos CLXIII, CIX, and XXII are figured. These authors also refer to the articles previously written describing the embryos used for this paper. The following table will show the comparative size and age of the embryos used for these models:
++++++++++++++++++++++++++++++++++++++++++++++++++
Number Size of Proba- Number Size of P1-oba_ ‘ of Length in mm. Ovum in ble of Length in mm. Ovum in ble Embryo. mm. age. Embryo. mm. age. " Weeks ' ‘— Wee_ks XII..... 2.1 1Sx‘l8x18 2 CVI....NB.15.5 VB. 17 5;II . . . . . . NB.7 VB.6 25x 25 4 CLXIV . NE. 12 VB. 14 40 x 30 x30 51} CLXIII.. NB.9 VB.9 35 X85 x 20 31} XLIII .. NE. 14 VB. 16 6
CIX....NB.'10.5VB. 11 30x30 5 XXII.-- NB. 18VB. 20 85x30x30 7 CLXXV. NE. 13 VB. 13 5;
Embryo XII
This embryo is 2.1 mm. long and about 13 days old ; and hence it represents a late two weeks’ or early three weeks’ embryo. The entire embryo has been modeled by Dr. Mall and I have used his model and the figure of it. In this embryo the pharynx is still in a very simple condition. The stomodaeum has not yet broken through to form the mouth, the endodermal cavity shows Seesel’s pocket and diverticula corresponding to the 1st and 2nd visceral pouches. The general structures and relations can be seen in fig. 1. To describe the modelin detail from points of View not shown in the figure: Seen from above it presents a flattened slightly curved plate; the oral end resembling an ordinary cloverleaf in outline. The middle leaf represents Seesel’s pocket, while the two lateral prominences correspond to the first pair of visceral pouches. Directly behind these are two smaller lateral swellings which fit into the 2nd pair of visceral pouches. These are not exactly symmetrical as the right is caudal to the left one. Behind these distinct prominences two pairs of waves can be discovered in the outline of the edge of this flattened surface. These are the first traces of the developing 3rd and 4th visceral pouches. In the figure they have been almost completely lost. This surface is curved convexly between the prominences of the 2nd pair of visceral pouches and gradually flattens oralwards and caudalwards. Viewed from the side (fig. 1) the same structures as noted from above, as well as some others on the caudal side of the plate, are visible. Directly under the prominence representing Seesel’s pocket there is another of similar shape, but smaller, for the mouth. Just in front (ventral) of this the stomodaeum appears as a decided pouch or pit.
Fig. 1. Lateral View of the model of embryo XII (after Mall). Br.’ and Br./’, flrst and second visceral pouches; M, month just behind the stomodaeum; L, rudiment of the liver; T, median thyroid rudiment.
On the under side of the model, on each side a ridge runs toward the middle line from the first pair of visceral pouches. At their point of junction in the middle line the median thyroid rudiment shows as a rounded eminence. This rudiment looked at directly from below is broader laterally than it is dorsoventrally.
The lack of bilateral symmetry of the pharynx and of the oesophagus is very marked. The position of the 2nd pair of visceral pouches has already been mentioned; in addition the left side of the (esophagus is thicker and heavier. At its caudal end it curves ventrally and ends in an eminence representing the rudiment of the liver. On the right side the oesophagus comes to a rounded edge. A cross-section would be wedge-shaped with the base of the wedge toward the left and the apex toward the right.
Embryo II
This embryo has a vertex-breach length of 6 mm. and a neck-breach length of 7 mm. It is about 24 days old or, in round numbers, it is an embryo of the 4th week. The model of this region shows that marked changes occur in the period intervening between this and the preceding stage. The various regions are easily recognized. Seen from above this model is nearly an isosceles triangle, The base represents the mouth and hypophysis and the rounded apex the dorsal wall of the oesophagus. The sides of the triangle show three rounded swellings (see fig. 3) corresponding to the 1st, 2nd and 3rd visceral pouches. The last named is the least prominent from this View since it is on a lower level and partly hidden by the projection of the 2nd. At this stage the 4th is well developed but much lower (caudal) and hidden from view by the 3rd.
Seen from the side, as in fig. 2, the model bends almost at right angles. At the bend there is a rounded prominence extending dorsally. Opposite to this prominence the 3rd and 4th visceral pouches project at right angles to the line of the oesophagus and trachea. The 2nd projects downward and is curved oralward. The 1st visceral pouch shows on ‘its cephalic angle a greater degree of prominence than the other part of it. This is the first indication of the outgrowth of this part of the pouch to form the Eustachian tube. In this view there is much to suggest the model of the rabbit embryo shown by Piersol° in fig. 8 of his paper.
Fig. 2. Lateral view of the model of the pharynx of the model of embryo II. The embryo is represented as transparent. Magnified 25 diameters. Hyp., hypophysis; 0e., oesophagus; Tr., trachea, V. PJ, V. P.’/, V. P!” and V. P.", first, second, third and fourth visceral pouches.
From below the general shape is the same as when seen from above, but the picture is very much complicated by the projection of the visceral pouches, median, thyroid, rudiment, etc.
From the base of the prominence representing the 1st pouch a ridge runs backward on each side and terminates in the middle line. From the dorsal edge of this angle the median thyroid rudiment arises. It is still connected with the endoderm by a solid stalk (fig. 3). Directly in front of this angle there is a rounded depression corresponding to the tuberculum impar. The walls of this depression unite in the middle line and form a ridge running oralwards in the middle line. On either side of this the depressions correspond to the mandibular processes.
Directly back of the ridges connecting the first visceral pouches there are two deep rounded grooves; of which the two prominences of the 2nd visceral pouches form the dorsal boundaries. The model gradually narrows toward the oesophagus, and the two successive flat ridges, following one another and almost at right angles to the rest, represent the 3rd and 4th visceral pouches. The latter pair is not bilaterally symmetrical as pharynx of embryo 11- Iiyp-.hyporhysis;0e-. the one on the right side is (esophagus; T. 1., depression of the tuberculum
impar; Thyr.m.,median thyroid rudiment;Tr., aboral to the one on the left trachea; V- P-’. V-P-”» V-P-’” Mid V-1’-"G side. This is not so decided
flrst, second, third and fourth visceral pouches. . . .
in this embryo as in embryo XII just described. The left is also decidedly larger than the right one, and both show a tendency to become double at their extremities. This does not seem true in the next stage, represented by embryo CLXIII, although it is distinctly true for later stages. The disappearance and reappearance of this condition is not understood and in the absence of sufficient material it is suggested that there may be an individual variation in embryo CLXIII.
In relation to the fate of the 2nd visceral pouch, His first stated that it formed the fossa of Rosenmiiller and the tonsil. This is the description that is also given in text-books. Kastschenko[6] believes the fossa of Rosenmiiller arises from a furrow between the inner border of the 2nd and 3rd arches. His,‘ in a recent article, agrees that it does not come from the 2nd visceral pouch.
In the middle line between the prominences of the 4th visceral pouches there is a thin flat projection, the beginning of the larynx.
In this embryo the mouth is a transverse slit with only the hypophysis to break the lines. In none of my models does it appear as a five—sided object usually described since His first mentioned it as such in human embryos of the 3rd week. Hammar[7] also disagrees with His and finds it always as a transverse slit.
Fig. 4. Lateral View of the model of the pharynx of embryo CLXIII. Magnified 15 diameters. Hyp., hypophysis; N., outline of the side of the nasal depression; 0e., (esophagus; Thyr. m., median thyroid rudiment; Tr., trachea; V. P.’, V.P.”, V. P./” and V. P.", flrst, second, third and fourth visceral pouches; A. B., line of section seen, fig. 6.
Embryo CLXIII
This embryo has a vertex-breach of 9 mm. and a neck-breach 9 mm. in length. It is about 30 days old or an embryo of the early 5th week of development. Two models were made of the pharyngeal cavity of this embryo. The first represents the cavity simply, while the second one includes also the mucous membranes lining it. The description will apply to the model of the cavity alone and the second model will be
mentioned only where it is markedly different. The same structures are easily recognized here that were prominent in the embryo just described. However, the shape, size and relative proportions have changed markedly. Seen from the side (fig. 4) another sharp bend has appeared at the oral end in addition to that at the aboral end already noted in embryo II. The part below this ventral (oral) end corresponds more nearly to the adult buccal cavity, especially the roof of it, than any structures that we have yet encountered. Just below this angle the hypophysis joins the mouth. From this angle the model runs dorsally in almost a straight line. This line is broken by the 1st visceral pouch and the flattened process of the 2nd. Then there is another sharp turn caudalward with a slight dorsal prominence at the angle already mentioned in the description of embryo II. The line then bends slightly ventrally and shows the prominences of the 3rd and 4th visceral pouches.
Fig. 5. Ventral view of the model of the pharynx of embryo CLXIII. D. Th. g1., ductus thyreoglossus; Hyp., hypophysis; 0e., (esophagus; Tr., trachea; V. P.’ V. P.’’, V. P./” and V. PJV, flrst, second, third and fourth visceral folds.
Seen from above the model is roughly square. The hypophysis being at the ventral angle, the curved dorsal wall of the pharynx at the dorsal end and the two prominences of the 1st pair of visceral pouches at the angles of the square towards the sides of the embryo. Just behind these there is a deep rounded fossa and then a decided process projecting outward and backward, representing the 2nd pair of visceral pouches. The 1st pair of visceral pouches are shown as prominent ridges running outward and backward. In the model of the cavity only, they project much farther free than in the one in which the model includes the mucous membrane. A para-sagittal section of this region of the embryo would show a relatively large opening, then a narrow one running dorsally and connecting with the cavity of the 2nd visceral pouch. This cavity (shown as a ridge on the model), representing the oral part of the 1st visceral pouch was called by Moldenhaur the sulcus tubo-tympanicus. Hammar uses the same term to mean the oral lengthening and development of the 1st visceral pouches as first used by Moldenhaur. Compare this structure in figs. 2, 3, 4 and 5. Seen directly from behind (dorsally) all four pairs of visceral pouches are visible. The 1st pair running slightly upwards (cephalic). The 2nd pair show as two ridges flattened dorsoventrally and projecting downward. The 3rd pair stand out at right angles to the oesophagus and the cells have already begun to proliferate around it as a comparison of the two models will show. In the one in which the endoderm is included this pair of pouches is very much larger and exhibits processes which are not suggested by the model, showing only the cavity. The
Fig. 6. View of reconstruction of embryo CLXIII from a ventral-caudal 4th pair are peculiarly shaped structures prodectmg at mght angles to superior maxillary process; N., nasal
view. B. v., blood vessel; CIL, notochord L. rudiment of larynx; Max.
the oesophagus and then bending tossa; N. x., vagusnerve; Ph., pharynx;
sharply dorsally on themselves. Their ends are enlarged and their outline ls visceral folds. Section on a line indinearly triangular. They are relatively much larger in the model that includes the mucous membrane than in the one of the cavity only. In this model, however, they do not show a tendency to divide into two prominences as in embryo II or in others to be described later. Just beneath the 4th visceral pouch the whole pharynx constricts notably and marks off sharply the beginning of the oesophagus. See fig. 4. A section of the pharynx taken at any point between the dorsal angle and the prominence of the 4th visceral pouch is crescentic in outline with a part projecting ventrally as shown in fig. 5. Seen from the inside (caudal surface) the model shows the two ridges running from the prominences of the 1st visceral pocket toward the middle line. They are not so pronounced in the model of embryo II and are less prominent in the model of this embryo (CLXIII) that includes the mucous membrane than in the one where only the cavity is modeled. At the point of junction of these ridges in the middle line a small cylindrical projection marks the remnant of the thyreoglossal duct. The median thyroid rudiment has separated completely and sunken to the level of the 3rd visceral cleft. In front of these ridges the tuberculum impar has made a large depression. The median ridge seen in the model of embryo II has disappeared. Behind these ridges are two depressions showing the position of the two dorsal tongue rudiments. Behind (dorsalward) is still another depression situated in the median line the significance of which is not clear. Two ridges run caudalward and unite in the middle line to form a flattened body. This is the rudiment of the larynx.
Embryo CIX
This embryo has a neck-breach length of 10.5 mm. and a vertex-breach of 11 mm. It is about 33 days old and so would be an embryo of the latter part of the fifth week. In spite of the apparently short time between this stage and the one just -described very decided changes have occurred. The model includes the mucous membrane and is relatively large. In this model the angles are not so sharp and the various structures show a tendency to become rounded. Seen from the side as in fig. 7 the same prominent bends are recognized but they are not so pronounced as in the model of embryo CLXIII. The ventral bend is larger and is joined to the nasal cavity as the illustration shows. The hypophysis is relatively higher and nearer the angle of the bend. The nasal cavities join the oral cavity at its edge and the posterior nares are in a position similar to the permanent condition in the frog. The prominence of the 1st visceral pocket is more complicated and the ridge running in from it toward the median line noted in the other two models is somewhat broken and irregular. The 2nd visceral pouch shows as a small knob projecting caudalward. The 3rd visceral pouch has disappeared as such and the 4th is prolonged into a hollow tube with two knobs on its caudal end. These will be described later as the lateral rudiments of the thyroid. At the point where they are attached the pharynx abruptly constricts into the oesophagus. The oesophagus is shown as a rounded body and the cavity does not exhibit the typical Maltese cross shape as described by Minot.[8]
The trachea can be seen between the oesophagus and the 4th visceral pouch. At this level a section of it resembles a rounded bean With the hilum facing dorsally. Seen from above (cephalic) the model re-
FIG. 7. Lateral view of the model of the pharynx of embryo CIX. Magnified 15 diameters. The embryo is represented as transparent. Hyp., hypophysis; L., rudiment of larynx; N., nasal cavity; Oe., oesophagus; Thym., thymus; Thyr. m., median thyroid rudiment; Tr., trachea; V. P/, V. P.” and V. P.", first, second and fourth visceral pouches.
402 Nose, Pharynx and its Derivatives in Man
sembles the one just preceding in general outline except that the anglesare decidedly rounded. The 1st visceral pouch appears as a prominentridge (salcus tubo—tympanicus) running outwardly and dorsally andending in a rounded free prominence. The rounded fossa just backof it in embryo CLXIII has become here a flattened surface. Seenfrom the inside (caudal surface) there is a large central rounded cavityoccupied by the tongue. A prominent U—shaped ridge separates itfrom a similar shaped groove, marking the position of the mandible.At the dorsal end of the tongue cavity a small conical projection marksthe position of the thyreoglossal duct. Directly dorsal from that thelarynx arises and the cavity shows as a T-shaped body. The top ofthe T facing ventrally. Caudalward the shape of the cavity changesgradually until the trachea is reached, when it has assumed the shapealready described. Seen from the front (ventrally) the nasal cavitiesproject outward from a large elevated fold in the middle line. Theyproject away from the middle line at an angle of about 20°.
Embryo CLXXV
This embryo has a length of neek—breach 13 mm., vertex—breach 13 mm. It is an embryo of the early part of the 6th week. Thismodel also includes the mucous membrane and with a few interestingexceptions very much resembles the one just described. Looked at from the side the 1st visceral pouch has become somewhat complicated and altered. The most noticeable change being a prominent fold run- ning from the 1st visceral pouch ventrally. The most striking difference noted from the side view is the lack of symmetry of the two sides. On the right side the hollow stalk connecting the lateral thyroid rudiment to the pharynx still persists. On the left side it has separated completely and the enlarged double end is fused with the now enlarged horseshoe-shaped median thyroid rudiment. On the right side the enlarged end of the lateral rudiment is in contact with the median rudiment but has not fused with it. Seen from above, this model differs from that of CIX chiefly in the increased rounding of the angles. The 1st visceral pouch, however, has changed and the fold running ventrally is much more prominent. This stage resembles the one figured by Piersol in Fig. 13 of his article already referred to. The hypophysis has just separated, although a slight thickening of epithelial elements mark its position on the model.
Seen from below (the inside) the model presents an even rounded hollow with the horseshoe-shaped groove surrounding it. This horse-
- ↑ His: Anatomle Menschlicher Embryonen. Leipzig, 1880. Also Beobachtungen ‘zur Geschlchte der Na.sen- und Gaumenblldung beim menschlicheu Embryo. Abhandl. der math.-phys. Classe der Ktinlgl. Gesell. der Wiss., Bd. xxvll, No. ill, 1901.
- ↑ J. Aug. Hammer: Studien uber die Entwlckelung des Vorderdarms und einlgerangrenzenden Organe.
- ↑ G. A. Piersol: Ueber die Entwickelung der embryonalen Schlundspalten und ihre Derivate bei Siiugethlex-en. Zeltschr. f. wiss. Zoo1., Bd. 47, 1888.
- ↑ Morph. Jahrb., ii; Arch. 1?. mikr. Anat., xxii, p. 584. Also C. R. Bardeen, Johns Hopkins Hospital Bulletin, Vol. xii, Apri1—May—June, 1901.
- ↑ Charles Russell Bardeen and Warren Harmon Lewis: Development of the Limbs, Body-wall and Back in Man. This Journal, Vol. 1, No. 1, 1902.
- ↑ Kastschenko: Das Schicksal der embryonalen Schlundspalten bei Saiigethieren. Arch. f. mikros. Ana.t., Bd 30.
- ↑ Ang. Hemmer: Notiz fiber die Entwicklung der Zunge und Mundspeicheldriisen beim Menschen. Anat. Anz., Bd. XIX, 1901.
- ↑ Charles Sedgwick Minot: Human Embryology. New York, 1892.
Cite this page: Hill, M.A. (2024, May 20) Embryology Paper - The Development of the Nose and of the Pharynx and its Derivatives in Man. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Paper_-_The_Development_of_the_Nose_and_of_the_Pharynx_and_its_Derivatives_in_Man
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