Talk:Paper - Anomalies in the development of salivary glands (1927)
ANOMALIES IN THE DEVELOPMENT OF. SALIVARY GLANDS
By Dr U. V. NAYAK, M.B.B.S. Assistant Professor of Anatomy, Madras Medical College
AND Dr A. ANANTHANARAYANA AYYAR, B.A., M.B.B.S. Senior Demonstrator of Anatomy, Madras Medical College
Dorine the session 1925-6, out of 90 bodies put out for dissection, two showed defects in the development of the salivary glands. Such defects are exceedingly rare in the human subject, and we could not trace any such cases hitherto recorded in the journals of anatomy.
CasE 1. Absence of parotid glands on both sides of the face
This abnormality was seen in the body of a fairly well-built adult male subject. The absence of the Stensen’s duct drew our attention to the condition of the parotid glands. The skin over the region of the parotids was entire and showed no marks of any injury or operation. A careful dissection was made over the whole region to find out if there were any traces or rudiments. The entire parotid space was filled with fatty areolar tissue through which passed the facial nerve, external carotid artery and the post facial vein which usually course through the parotid substance. The facial nerve divided behind the posterior margin of the ramus of the mandible and the branches entered the face by winding over its rounded margin. The other salivary glands were dissected out and found normal both in size and shape.
CasE 2. Absence of submazillary gland on one side
This was observed in the body of a middle-aged female. The gland and its duct were entirely absent on one side and the external maxillary artery which usually passes through a groove in the posterior border of the gland was conspicuously seen winding over the lower border of the mandible. The gland on the opposite side showed a slight increase in. its size. All other salivary glands were found to be normal in size and shape.
These congenital defects of salivary glands in the cases noted must necessarily be due to an anomaly in embryological development. The salivary glands arise as buds from the ephithelial layer of the primitive mouth. The parotid, the earliest to appear (sixth week), forms in the lateral or the buccoalveolar recess. The parotid duct is at first a groove, but later becomes a canal by the enclosure of the groove. The submaxillary and the sublingual glands arise in the hollow between the tongue and the mandibular arch; first 262 U. V. Nayak and A. Ananthanarayana Ayyar
two furrows appear, the medial for the submaxillary, the lateral for the sublingual. The gland tissue is formed by extensive budding of part of the epithelium of the furrow and the duct from the rest of the epithelium which, surrounded by the invading mesoderm, forms a cord, and later becomes canaliculised. This is the way of usual development. But what factors in early foetal life prevent such development and lead to anomalies is hard to guess. These glands are accessory to the function of mastication and are hence developed only in Mammals. The facts that they are absent in the lower Vertebrates and that they may be removed without any harmful effects in the lower Mammals throw some light on the possibility of such defects being consistent with a healthy life.
In conclusion we wish to express our indebtedness to Dr S. Swaminathan, L.R.C.P., L.R.C.S., Professor of Anatomy, Madras Medical College, for his kind permission to publish the above notes.
REFERENCES TO LITERATURE
(1) Kerra. Human Embryology and Morphology. (2) Hatiisurton. Hand-book of Physiology. (3) Bucnanan. Manual of Anatomy. 4th edition.