MUSCLES, ETC., OF THE HEAD. 103 



/ The subscapulo hyoideus, from nnder the shoulder-blade, to the body of the o» 

 hyoides (the bone at the root of the tongue formed like a Greek u, v) ; to draw 

 back that bone. 



g The masseter (chewing) j a moat powrerful muscle, constituting the cheek of the 

 horse r~-from the upper jaw bone into the rough surface round the anglb of 

 the lower : in conjunction with the temporal muscle to close the moath and 

 chew the food. 



h The orbicularis (circular) surrounding the eye and closing the lida. 



i The zygomatieas^ from the zygomatic arch and masseter to the comer of the 

 mouth, to draw back the an^e of the mouth. 



k The buccinator (trumpeter), from the inside of the mouth and cheeks, to the 

 angle of the mouth, to draw it back. 



I The vasalis Itzbii snperiorifi (belonging to the nose and upper lip), from a depres- 

 sion at the junction of the superior maxillary and malar bones, to the angle 

 of the nosti-il : to raise the lip, and dilate tlie nostrils, 



m Dilator naris lateralis (side dilator of the nostril), reversed to show the vessels 

 and nerves which it covers, going from the covering of the nasal and frontal 

 bones, to the angle of the mouth, and side of the nostril : to retract the upper 

 lip and dilate the nostrils. 



n Dilator jjiagnus (great dilator), assisting in the same office. 



Depressor labii it^erioris (puller down of the under lip), to the sides of the un- 

 der lip : to pull it down. 



p Orbicularis oris (circular muscle of the mouth), surrounding the mouth : to 

 close the lips and dilate the nostrils. 



g The upper portion of the parotid gland (gland near the ear) reversed, to show 

 the blood-vessels and nerves beneath it. 



r The parotid duct piercing the cheek, to discharge the saliva into- the mouth. 



s The maxillary gland (gland of the lower jaw) with its duct. 



t The jugular (neck) vein, after the two branches have united. 



u At this letter, the submaxillary artery, a branch of the jugular, and the parotid 

 duct, pass under and within the angle of the lower jaw ; they come out again 

 at w, and climb up the cheek to be distributed over the face. 



V The vein and artery, passing under the zygomatic arch. 



c A branch of the iifth pair, the sensitive nerve of the face, emerging from under 

 the parYitid gland. 



/ The main branch of the porfio dura, (hard portion) of the seventh pair, the motor 

 (moving) nerve of the face coming out from beneath the parotid gland, to 

 spread over the face. 



z Branches of both nerves, vdth small blood-vessels. 



There are also four distinct cartilages attached to the nostrils, 

 which, by their elasticity, bring back the nostrUs to their former 

 dimensions, as soon as the muscles cease to act. The bones of 

 the nose {a a, Fig. 2, and Fig. 3), are also sharpened off to a 

 point, to give wider range for the action of the muscles ; while 

 the cartilages are so contrived, as not only to discharge the 

 office we have mentioned, but to protect this projection of bone 

 from injury. 



The membrane of the nose, as already stated, is an excellent 

 guide to the degree and character of many diseases. In health, 

 and iminfluenced by exercise, that portion of the membrane seen 

 in the nostrils is a pale uniform pink. An increased blush of 

 red betokens some excitement of the system — a streaked appear- 

 ance, inflammation commenced — intense redness, acute inflam- 

 mation — pale ground with patches of vivid red, half-subdued 

 but still existing fever — uniform color, but somewhat redder than 

 natural, a return to healthy circulation — paleness approaching 



