280 THE MUSCLES AND FASCIA OF THE HEAD AND NECK. 



line of the occipital bone, and to the mastoid portion of the temporal bone above the 

 attachment of the sterno-mastoid muscle. Its fleshy fibres, from one to two inches 

 in length, are directed upwards, and terminate in distinct tendinous fibres, con- 

 tinuous with the epicranial aponeurosis. The interval between the muscles of 

 opposite sides is occupied by the aponeurosis. 



The frontalis muscle, larger and of a paler colour than the occipitalis, arises 

 superiorly in a convex line from the epicranial aponeurosis between the coronal 

 suture and the frontal eminence. Inferiorly the fibres terminate in the subcutaneous 

 tissue at the root of the nose and along the whole length of the eyebrow, the inner 

 fibres appearing to be continued into the pyramidalis nasi muscle, while the larger 

 number interlace with those of the corrugator supercilii and orbicularis palpe- 

 brarum. The fibres are nearly vertical, running slightly inwards as they descend : 

 the margins of the right and left muscles are united for some distance above the root 

 of the nose, but are separated by an angular interval superiorly. 



The epicranial or occipito-frontal aponeurosis extends over the upper 

 surface of the cranium uniformly from side to side, without division. Posteriorly it 

 is attached to the occipitales muscles, and to the protuberance and highest curved 

 lines of the occipital bone, and anteriorly it terminates in the frontales muscles,, 

 while laterally it presents no distinct margin, but below the temporal lines becomes 

 thinner and less aponeurotic, and gives attachment to the superior and anterior 

 auricular muscles. Its fibres are chiefly longitudinal, and are most distinctly 

 tendinous where they give attachment to the occipitales muscles. Its outer surface 

 is firmly bound to the skin by an abundant network of connective tissue, constitut- 

 ing the so-called superficial fascia, by the meshes of which the subcutaneous fat is 

 divided into granules ; while its deep surface glides upon the subjacent pericranium,, 

 to which it is loosely attached by a delicate areolar tissue devoid of fat. Beneath 

 the lateral prolongation of the epicranial aponeurosis a thin fascia! layer springs 

 from the superior temporal line of the parietal bone, and is continued downwards on 

 the deep surface of the auricular muscles to the pinna of the ear. 



Varieties. Both, parts of the occipito-frontalis are subject to variation in their develop- 

 ment, and in their places of attachment. The occipitalis occasionally approaches the middle 

 line, and is frequently broken up into separate parts : its outermost fibres are sometimes 

 inserted into the back of the pinna, becoming continuous with the posterior auricular muscle. 

 The frontalis may send slips from its inner part to the frontal, nasal, or superior maxillary 

 bones, or into the levator labii superioris alseque nasi, or from its outer part to the external 

 angular process of the frontal bone, all of which have been described as normal by different 

 anatomists. 



Actions. By the contraction of the frontales muscles the eyebrows are elevated, the scalp 

 drawn forwards, and the skin of the forehead thrown into transverse wrinkles ; by the 

 contraction of the occipitales muscles the scalp is drawn backwards ; and by the alternate 

 action of bhe frontales and occipitales muscles the scalp is moved forwards and backwards. 

 In the majority of persons, however, there is only a partial control over the action of these 

 muscles, limited to the elevation of the eyebrows and horizontal wrinkling of the forehead. 



AURICULAR MUSCLES. 



Besides minute bundles of muscular fibres which pass from one part of the pinna 

 to another, and which will be most conveniently described with that structure, 

 there are attached to the external ear three larger, but still very slightly developed, 

 muscles, which serve to move it as a whole. 



The auricularis superior or attollens auriculam, the largest of the three, 

 arises in the temporal region of the head from the epicranial aponeurosis. Its fibres 

 are extremely delicate, and converge from a wide surface to be inserted by a com- 

 pressed tendon into the anterior part of the helix and into the eminence on the 

 inner surface of the pinna corresponding to the fossa of the antihelix. 



