THE MIDDLE EAR 875 
3. The verticalis auriculz! is a thin stratum of muscular and tendinous fibers 
which extends upward on the convex surface of the concha from the eminentia 
conche. 
Actions.—The base of the concha is rounded and rests in a pad of fat (Corpus 
adiposum auriculz), so that the movements of the external ear resemble those of 
a ball-and-socket joint. It is noticeable that movements about the longitudinal 
and transverse axes are accompanied by rotation. When the ear is vertical or 
drawn forward (“‘pricked up’’), the opening is usually directed forward; conversely, 
when the ears are “laid back,” the opening faces backward. These movements 
evidently result from the codrdinated actions of several muscles which are very 
complex and cannot be discussed in detail here. The scutularis acting as a whole 
fixes the scutiform cartilage, so that the muscles which arise on the latter act 
efficiently on the concha. The anterior auricular muscles in general erect the ear 
and turn the opening forward. The interscutularis concurs in this action, causing 
adduction and a symmetrical position of the ears; it also acts directly on the 
conchal cartilage, since the scutulo-auricularis superficialis superior is in reality a 
conchal insertion of the interscutularis. The scutulo-auricularis superficialis 
accessorius draws the concha forward and turns the opening outward. The parieto- 
auricularis adducts the concha and inclines it forward. The cervico-auricularis 
superficialis is chiefly an adductor of the conchal cartilage, and directs the opening 
outward. The cervico-auricularis profundus major turns the opening outward and, 
acting with the parotido-auricularis, inclines the ear toward the poll. The cervico- 
auricularis profundus minor tends to direct the opening downward and outward. 
The parotido-auricularis draws the ear downward and backward, and acts with the 
cervico-auricularis profundus major in “‘laying back the ears.”’ The scutulo- 
auricularis profundus major chiefly rotates the concha so that the opening is turned 
backward. The scutulo-auricularis profundus minor assists in rotating the ear 
so that the opening is directed forward. The tragicus shortens the external acoustic 
meatus. The actions of the intrinsic muscles are inappreciable. 
Vessels and Nerves.—The arteries of the external ear are derived from the 
anterior auricular branch of the superficial temporal, the posterior or great auricular 
branch of the internal maxillary, and the anterior branch of the occipital artery. 
The veins go chiefly to the jugular and superficial temporal veins. The nerves 
to the muscles come from the auricular and auriculo-palpebral branches of the 
facial nerve and from the first and second cervical nerves. The sensory nerves are 
supplied by the superficial temporal branch of the mandibular nerve and the 
auricular branch of the vagus. 
THE MIDDLE EAR 
The middle ear (Auris media) comprises the tympanic cavity and its contents, 
the auditive or Eustachian tubes, and two remarkable diverticula of the latter, 
which are termed the guttural pouches. 
The tympanic cavity (Cavum tympani) is a space in the tympanic and petrous 
parts of the temporal bone situated between the membrana tympani and the in- 
ternal ear. It is an air-cavity, which is lined by mucous membrane, and communi- 
cates with the pharynx and the guttural pouches by the auditive or Eustachian 
tubes. It contains a chain of auditory ossicles by which the vibrations of the 
membrana tympani are transmitted to the internal ear. 
The cavity consists of: (1) A main part or atrium, which lies immediately to 
the medial side of the membrana tympani; (2) the recessus epitympanicus, situated 
above the level of the membrane and containing the upper part of the malleus 
‘Ellenberger and Baum regard this as the homologue of the transversus and obliquus 
auricule of man. 
