18 DISSECTION OF THE HEAD. 



the lobule of the ear, and then forwards below the lobule. After the piece 

 of skin included by those cuts has been reflected towards the ear, the 

 retrahent muscle must be sought beneath the suhrutaiH'ous tissue; it 

 consists of rounded bundles of fibres, and is stronger and deeper than the 

 others. 



The ATTRAIIENS AUREM (fig. 1, l6 ) is a small fan-shaped muscle, and, 

 arises from the fore part of the aponeurosis of the occipito-frontalis. Its 

 fibres are directed backwards, and are inserted into a projection on the 

 front of the rim of the ear. Beneath it are the superficial temporal vessels 

 and nerve. 



The ATTOLLENS AUREM (fig. 1, 15 ) has the same form as the preceding 

 though its fibres are longer and better marked. Arising also from the 

 tendon of the occipito-frontalis, the fibres converge to their insertion into 

 the inner or cranial surface of the pinna of the ear into an eminence 

 corresponding with a fossa (that of the anti-helix) on the opposite asprct. 



The RETRAHENS AUREM (musculi retrahentes, Alb., fig. 1, ") consists 

 of two or three roundish but separate bundles of fibres, which are stronger 

 than those of the other muscles. The bundles arise from the root of the 

 mastoid process, and pass almost transversely forwards to be inserted by 

 aponeurotic fibres into the lower part of the ear (concha) at its cranial 

 aspect. The posterior auricular artery and nerve are in contact with this 

 muscle. 



Action. The three preceding muscles will move the outer ear slightly in 

 the directions indicated by their names : the anterior drawing it upwards 

 and forwards, the middle one upwards, and the posterior backwards. 



The OCCIPITO-FRONTALIS MUSCLK (fig. 1. *) covers the arch of the skull, 

 and consists of an anterior and a posterior fleshy part, with an intervening 

 tendon. 



Dissection. On the same side of the head (the left) the occipito-frontalis 

 is to be dissected. To bring this muscle into view, a cut may be made 

 along the middle line of the skull, from the root of the nose to the occipital 

 protuberance ; and it may be connected in front with the transverse incision 

 on the side of the head. The flap of skin, thus marked out, is to be raised 

 with the subjacent fat from before back ; whilst doing this the dissector 

 will meet first with the anterior fleshy part of the muscle, next with a 

 white shining thin aponeurosis, and lastly with the posterior fleshy belly 

 towards the lateral aspect of the cranium. The aponeurosis of the muscle 

 is easily taken away with the granular fat superficial to it ; and if the 

 under surface of the flap of integuments presents a white instead of a yel- 

 low appearance, the student may suspect he is removing that aponeurosis. 



The anterior or frontal part (*) is a thin muscular layer over the os 

 frontis, which is said to take its origin below. Along the line of the eye- 

 brow the fibres are blended with the following muscles, orbicularis palpe- 

 brarnm, corrugator supercilii, and pyramidalis nasi ; and they are also 

 fixed to the subjacent bone, viz., to the os nasi internally, and to the outer 

 angular process of the frontal bone externally (Theile). From these at- 

 tachments the fibres are directed upwards to the aponeurosis, and end in it 

 rather below the level of the coronal suture. 



The posterior or occipital part ( 4 ) is stronger than the anterior ; it arises 

 from the outer half or two-thirds of the upper curved line of the occipital 

 bone, and from the mastoid portion of the temporal bone. The fibres are 

 about one inch and a half in length, and ascend to the aponeurosis. 



The tendon, or epicranial aponeurosis, extends over the upper part of 



