422 PRACTICAL ANATOMY. 



The lachrymal gland is situated in a depression at 

 upper, outer angle of the orbit. It is about the shape and 

 size of the kernel of a small almond, and resembles the 

 salivary glands in structure. It has about ten short ducts 

 which open upon the upper, outer part of the conjunctiva. 

 The lachrymal canals begin in the papilla lacrymalis at 

 the puncta and lead into the canaliculi, which pass 

 inward and terminate in the lachrymal sac. The lach- 

 rymal sac is situated anteriorly to the lachrymal ridge on 

 the lachrymal bone. It is the upper dilated portion of 

 the nasal duct. Anteriorly it is covered by the tensor 

 tarsi muscle and an aponeurosis from the tendo oculi. 

 The nasal duct is a fibro-membranous canal about one 

 inch long, which opens into the inferior nasal meatus. 



THE EAR. 



The ear is the organ of hearing, and is divided into 

 three parts, the external, middle, and internal ; the 

 external ear presents the pinna, which is formed of yel- 

 low fibro-cartilage, folded so as to convey the vibrations 

 of sound to the external auditory meatus. The following 

 names have been applied to the different prominent 

 folds : The helix is the prominent rim ; in front of this 

 is the antihelix, and between them is the fossa of the 

 helix ; the antihelix divides above, and incloses a slight 

 depression, the fossa of the antihelix; within the 

 antihelix is a deep cavity, the concha; the antihelix 

 is notched below, and limited by an anterior nodule 

 the tragus and a posterior nodule, the antitragus. The 

 inferior portion of the pinna is soft and thick and devoid 

 of cartilage, and forms the lobule ; it is held to the 

 side of the head by an anterior and posterior liga- 

 ment. The muscles of the pinna are extrinsic and 

 intrinsic. The extrinsic have been described ; they are 



