THE SENSES. 281 



Nerves : N. cochlecs, the anterior stronger branch of n. acusticus enters 

 through the inferior anterior fossa of meat, auditor, interims at the basis of the 

 modiolus in its canals, and thence between the layers of the lamina spiralis, 

 where the most delicate fasciculi (in loops) spread out as far as the external 

 border. N. vestibuli, the posterior branch of the acusticus, divides at the 

 basis of meatus auditorius internus into three fasciculi, the strongest of which 

 goes to the sacculus oblongus and the Ampulla of the vertical superior and 

 horizontal semicircular canal; the central to the sacculus rotundus, and the 

 inferior smallest to the ampulla of the vertical inferior semicircular canal. 



516. HI. The Organ of Smell, Organon olfactus. 



The nose, nasus, consists of an external portion projecting upon 

 the face and an internal covered with mucous membrane. 



517. A. The external Nose, Nasus externus, 



consists, above, of an osseous (ossa nasi and process, nasales) 

 below, of a cartilaginous skeleton, which are immediately covered 

 with periosteum and perichondrium, nearer the surface with 

 muscles (see Myology), and cutis, on the internal surface with 

 mucous membrane. Portions : The root of the nose, close under 

 the forehead, the back or dorsum of the nose, the point or tip 

 of the nose, the lateral parietes, alee s. pinna nasi, openings 

 of the nose, nares, the partition, septum narium. 



518. 1. The Nasal cartilages, five, Cartilagines nasi. 



a. Cartilago lateralis, the lateral cartilages, are situated (one on either 

 side) at the most superior part of the cartilaginous nose ; triangular, 

 attached above and behind by fibrous uniting tissue with ossa nasi. 

 The internal borders of the two meet upon the dorsum nasi, where 

 they are also firmly attached to the cartilage of the septum. The infe- 

 rior border is convex, and meets anteriorly with &, behind with the 

 fibrous membrane of the alee nasi. 



b. Cartilago narium (s. spinalis), one on either side, is a more irregular 

 semi-elliptical cartilage, the external thinner arch is situated in the 

 groove above the ales nasi and point, whilst the internal reaches below 

 the septum mobile as far as the spina nasalis. A fibrous plate between 

 the pinnal cartilages and the inferior border of the lateral nasal carti- 

 lages forms the skeleton of the alee nasi, in which (generally) small flat 

 cartilaginous nuclei (cart, sesamoidece) exist. 



c. Cartilago septi narium, the septal cartilage, thick, flat, and triangular, 

 meets with its superior posterior border, the lamina perpendicularis of 

 the Ethmoid bone ; its inferior border is placed between the two plates 

 of the Vomer; its anterior border unites upon the back of the nose with 

 the cartt. laterales, and below with the cartt. narium. Behind a pro- 



