TBE EXTERNAL EAR. 847 



plate, placed at the lower part of the conchal plate, intermediate between 

 it and the auditory canal. The internal integumentary membrane, with some 

 yellow elastic fasciculi, unite this cartilage to the other two portions 

 between which it is situated. Its relations with these are such that it 

 receives within its lower border the bony circular prominence forming the 

 margin of the auditory hiatus, whQe it may itself be received into the in- 

 fundibuhform canal of the conchal cartUage-an arrangement resembHng 

 the tubes oi a telescope. ° 



3. ScuTiroitM CAETiLAGE.-This is a small cartilaginous plate, situated 

 in front of the base of the concha, at the surface of the temporal muscle ; it 

 IS irregularly triangiilar, is attached to the conchal cartilage by some 

 muscular fasciculi, and transmits to that cartilage the action of some other 

 muscles which are lixed on the cranial bones. 



(The arteries of the concha proceed from branches of the external carotid, 

 and the veins pass to a trunk of the same name; the nerves are divisions 

 of the facial and the first cervical pair.) 



2. Muscles of ike External Ear. 



There are found, on the surface of the concha, within and without, some 

 fleshy fibres, which are veritable intrinsic muscles. But the slight importance 

 of these induces us to pass them over, in order to study exclusively the 

 extrinsic muscles, which move the conchal apparatus. These are ten in 

 number : in the first layer are the zygomaiico-auricularis, temporo-atiricularis 

 externus, scuto-auricularis externus, three cervico-auriculares, and the parotido- 

 auricularis ; in the second layer, the temporo-auricularis internus, scuto- 

 auricularis internus, and the mastoido-auricularis. 



1. Ztgomatico-aubiculaeis (attolens anterior — Percivall ; temporo- 

 auricularis — Leyh. Figs. 110,5; 396). — This muscle is generally composed 

 of two fleshy bands joined by cellular tissue, and rising from the zygomatic 

 process of the temporal bone by means of an aponeurosis common to it 

 and the orbicularis palpebrse. The inferior of these two bands is inserted 

 to the outside of the base of the concha, its fibres mixing with those of the 

 parotido-auricularis ; the superior band terminates on the outer border of 

 the scutiform cartilage. 



Placed immediately beneath the skin, this muscle partly covers the 

 superior extremity of the parotid gland, and the zygomatic process. 

 It draws the ear forward. 



2. Tempoeo-attricularis Externus (attolens maximus — Percivall. Figs. 

 110, 1 ; 396). — A very thin, wide muscle, covered by the skin, lying on the 

 temporal muscle, united posteriorly to the superior cervico-auricularis, in 

 front and outwardly to the zygomatico-auricularis. It arises from the 

 whole of the parietal crest or ridge,^ mixing in its upper half or third with 

 the muscle of the opposite side ; it terminates, by one portion, on the inner 

 margin of the scutiform cartilage, and by another, on the inner side of 

 the conchal cartilage, by means of a thin fascia that covers part of the 

 former cartilage and the external scuto-auricularis. 



It acts as an adductor of the concha, drawing it inwards ; it also carries 

 it forwards, and concurs in making it pivot on itself, so as to bring the 

 opening of the ear forward. (In the Ox, the common muscles of the ear do 



' Owing to this crest bordering the temporal fossa, Girard has thought proper to give 

 to the two muscles of the ear attached thereto, the name of temporo-aurioulares ; but it 

 would be more appropriate to designate them the parieto-auriculares. 



