

SALIVARY GLANDS. 1133 



(c) Acino-tubular, branched duct, with elongated narrow acini on terminal branches 

 e.g., pancreas, duodenal glands. 



General Structure of Glands. Whilst the small glands, such as those of the 

 mouth and pharynx, are placed in the mucosa or submucosa close to the point at 

 which their ducts open on the surface, the large glands forming distinct masses, often 

 lie at a considerable distance from the points at which their ducts open, and are generally 

 surrounded by special capsules. 



Each of these large glands of the acinous type, such as the parotid or submaxillary, 

 presents the following general arrangement. The gland is made up, as can be seen with 

 the unaided eye, of a number of masses, often as large as peas, which are surrounded and 

 held together by connective tissue. These are known as lobes, and to each a branch of 

 the duct passes. The lobes are in turn made up of a number of smaller masses lobules 

 each having a special branch of the lobar duct. These again are composed of smaller 

 lobules, and so on to a varying degree. Finally, the smallest are made up of a terminal 

 branch of the duct, with a cluster of acini or alveoli developed upon it. 



The acini or alveoli, the special secreting portions of the gland, are composed of a 

 basement membrane, often fenestrated or basket-like, formed of flattened cells, on the 

 outer side of which the blood- and lymph-vessels lie. The inner surface of this membrane 

 is lined by the secreting epithelial cells, usually polygonal in shape, which almost com- 

 pletely fill the alveolus. A small lumen, however, is left, into which the secretion of the 

 cells is shed ; thence it passes into the duct of the lobule, and thus to the main duct. 



The blood- and lymph-vessels, on entering the gland, break up and run, branching as 

 they go, in the connective tissue which conveys them to all parts of the gland. 



GLANDULE SALIVALES. 



Salivary Glands. This term is generally understood to include only the three 

 ^e masses of glandular tissue found on each side of the face and upper part 

 of the neck namely, the parotid, submaxillary, and sublingual glands. But, as 

 previously pointed out, numerous other small glands of a similar nature are found 

 in the lips, cheeks, palate, tongue, etc. These have already been sufficiently 

 described, and require no further mention. 



Glandula Parotis. The parotid gland is the largest of the salivary glands, 

 and lies on the side of the face, below and in front of the ear, and is prolonged 

 inwards deeply from the surface. 



It forms a lobulated mass, of a yellowish or light reddish-brown colour, with a 



large triangular superficial surface. From this mass a process of the gland 



passes medially posterior to the upper part of the ramus of the mandible below the 



i base of the skull almost to the side wall of the pharynx. It is known as the 



1 processus retromandibularis. 



The superficial surface extends upwards nearly to the zygoma, and downwards 

 as far as to the angle of the mandible. It is prolonged anteriorly on the 

 superficial surface of the masseter muscle in the form of a process, often triangular 

 in shape, called the facial process, while at the back it comes into contact with 

 the external acoustic meatus, the front of the sterno-mastoid muscle, and the 

 mastoid process. 



Processus Retromandibularis. This portion of the gland occupies a deep 

 fossa, called the parotid fossa, of considerable size, which has two nearly vertical 

 sides, an anterior and posterior. These sides converge towards one another and 

 meet deeply, and so form the apex of the fossa. This fact is well brought out 

 by a horizontal section through the head about the middle of the gland (Fig. 896). 



From this it will be seen that the posterior wall of the fossa is formed, medial 

 to the sterno-mastoid muscle, by the posterior belly of the digastric and the stylo- 

 hyoid muscles, with the occipital artery, and more deeply still, by the root of the 

 styloid process and the carotid sheath and its contents, and especially by the 

 internal jugular vein, separating the gland from the vertebral column. 



The anterior wall of the fossa is formed by the ramus of the mandible and 

 the masseter and internal pterygoid muscles. 



Fascia Parotideomasseterica. The parotid recess is covered over on the one hand, 



