AURICULAR REGION. 241 



half in length, arises from the outer two-thirds of the superior curved line of the 

 occipital bone, and from the mastoid portion of the temporal. Its fibres of origin 

 are tendinous, but they soon become muscular, and ascend in a parallel direction 

 to terminate in the tendinous aponeurosis. The frontal portion is thin, of a quad- 

 rilateral form, and intimately adherent to the skin. It is broader, its fibres are 

 longer, and their structure paler than the occipital portion. Its internal fibres are 

 continuous with those of the Pyramidalis nasi. Its middle fibres become blended 

 with the Corrugator supercilii and Orbicularis ; and the outer fibres are also 

 blended with the latter muscle over the external angular process. From this 

 attachment, the fibres are directed upwards and join the aponeurosis below the 

 coronal suture. The inner margins of the two frontal portions of the muscle are 

 joined together for some distance above the root of the nose ; but between the 

 occipital portions there is a considerable, but variable, interval. 



The aponeurosis covers the upper part of the vertex of the skull, being continu- 

 ous across the middle line with the aponeurosis of the opposite muscle. Behind, 

 it is attached, in the interval between the occipital regions, to the occipital protu- 

 berance and superior curved lines above the attachment of the Trapezius ; in front<, 

 it forms a short angular prolongation between the frontal portions ; and on each 

 side, it has connected with it the Attollens aurem and Attrahens aurem muscles. 

 In this situation it loses its aponeurotic character, and is continued over the temporal 

 fascia to the zygoma by a layer of laminated areolar tissue. This aponeurosis is 

 closely connected to the integument by a dense fibre-cellular tissue, which contains 

 much granular fat, and in which ramify the numerous vessels and nerves of the 

 integument ; it is loosely connected with the pericranium by a quantity of loose 

 cellular tissue, which allows of a considerable degree of movement of the integu- 

 ment. 



Nerves. The frontal portion of the Occipito-frontalis is supplied by the supra- 

 orbital and facial nerves ; the occipital portion by the posterior auricular branch 

 of the facial, and, sometimes, by the small occipital. 



Actions. The frontal portion of the muscle raises the eyebrows and the skin 

 over the root of the nose ; at the same time throwing the integument of the fore- 

 head into transverse wrinkles, a predominant expression in the emotions of delight. 

 By bringing alternately into action the occipital and frontal portions, the entire 

 scalp may be moved from before backwards. 



2. AUKICULAK EEGION (fig. 148). 



Attollens Aurem. Attrahens Aurem. 



Betrahens Aurem. 



These three small muscles are placed immediately beneath the skin around the 

 external ear. In man, in whom the external ear is almost immovable, they are 

 rudimentary. They are the analogues of large and important muscles in some of 

 the mammalia. 



Dissection. This requires considerable care, and should be performed in the following man- 

 ner. To expose the Attollens aurem, draw the pinna or broad part of the ear downwards, 

 when a tense band will be felt beneath the skin, passing from the side of the head to the upper 

 part of the concha ; by dividing the skin over the tendon, in a direction from below upwards, 

 and then reflecting it on each side, the muscle is exposed. To bring into view the Attrahens 

 aurem, draw the helix backwards by means of a hook, when the muscle will be made tense, and 

 may be exposed in a similar manner to the preceding. To expose the Retrahens aurem, draw 

 the pinna forwards, when the muscle being made tense may be felt beneath the skin, at its 

 insertion into the back part of the concha, and may be exposed in the same manner as the other 

 muscles. 



The Attollens Aurem, the largest of the three, is thin, and fan-shaped; it 

 arises from the aponeurosis of the Occipito-frontalis, and its fibres converge to 

 be inserted by a thin, flattened tendon into the upper part of the cranial surface 

 of the pinna. 

 16 



