164: THE ANATOMY OF THE HORSE. 



It supplies that muscle, and is continued down the neck, as already 

 seen (page 144). 



AuBicuLAR Beanohes of the 1st Cervical Nebve. These, which are 

 derived from the superior primaiy branch of that nerve, appear in the 

 poll between the obliquus capitis superior and the rectus capitis posti- 

 cus muscles. Crossing the cervico-auriculares muscles, they are distri- 

 buted at the inner side of the base of the ear. 



Auricular Branches of the 2nd Cervical Nerve. These are derived 

 from the stellate group which the inferior primary branch of that nerve 

 forms on the mastoido-humeralis, behind the wing of the atlas. They 

 reach the ear by crossing over the parotid gland, and are distributed 

 mainly to the skin of the concha on its posterior aspect (when the 

 opening is directed outwards), but some branches reach its inner side. 



Auricular Branch of the Lachrymal Nerve. This nerve, which 

 emerges from the orbital sheath, crosses the direction of the anterior 

 auricular branch of the 7th on the zygomatic arch, and is distributed 

 to the skin in front of the ear. 



Cartilages of the Ear. 



The Conchal Cartilage. This and the other cartilages are com- 

 posed of yellow (elastic) fibro-cartilage. Although its name expresses 

 some likeness to a shell, it bears more resemblance to a trumpet. The 

 opening of the trumpet is somewhat elliptical, and can be directed 

 forwards, outwards, or backwards. The margins of the opening meet 

 above and below in acute angles. Beneath the lower angle, or commis- 

 sure, the cartilage forms a complete tube, which is slightly inflated in 

 form. At its termination it becomes narrow, and slightly embraces the 

 annular cartilage, over the outer side of which it sends a peaked pro- 

 cess, whose fibrous extremity is attached to the wall of the guttural 

 pouch. 



The Annular Cartilage. This has the form of a ring surrounding 

 the edge of the auditory process ; and it is itself embraced by the con- 

 chal cartilage, the three structures being related to one another like the 

 tubes of a telescope. This connection between the cartilages is main- 

 tained by connecting elastic tissue, and by the lining membrane of the 

 ear in passing from the one structure to the other. 



The ScuTiFORM Cartilage is superposed to the temporal muscle in 

 front of the base of the concha, to which it is connected only by the 

 muscles already described. It is thin, flexible, and irregularly triangular 

 in shape. 



THE PAROTIDEAL REGION. 



The Parotid Gland (Plates 27, 29, and 30). This is the largest of the 

 salivary glands. It derives its name from its proximity to the ear, below 

 the root of which it is placed. From tha,t point it stretches downwards, 



