264 MUSCLES OF THE HEAD AND NECK. 



III. MUSCLES AND FASCIA OF THE HEAD AIsTD ]VECK. 



EPICRANIAL REGION. 



Fascia. — The superficial fascia is little developed on the head and 

 neck generally, and is in great measure blended with structures described 

 under other names. A layer of considerable firmness, l>:)wever, inter- 

 venes between the aponeurosis of the occipito-frontalis muscle and the 

 skin, uniting them together : from the surface of the occipital part of 

 the muscle it becomes continuous with a superficial covering of the 

 posterior muscles of the neck, and on each side of the epicranial apo- 

 neurosis it descends over the temporal fascia, and contains between its 

 lamina the external muscles of the ear, with the superficial temporal 

 vessels and nerves. 



Muscles. — Under the title of occipito-frontalis muscle are compre- 

 hended the occipital and frontal muscles, nnited together by a thin 

 aponeurosis which extends over and covers the upper part of the 

 cranium. 



The occipitalis muscle, thin and subcutaneous, is attached infe- 

 riorly by short tendinous fibres to the external two-tliirds, sometimes 

 less, of the superior curved line of the occipital bone, and to the mastoid 

 portion of the temporal bone, immediately above the attachment of the 

 Bterno-mastoid muscle. Its fleshy fibres, from one to two inches in 

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

 continuous with the epicranial aponeurosis. The interval between the 

 muscles of opjwsite sides is occupied by the aponeurosis. 



The frontalis muscle, larger and of a paler colour than the occi- 

 pitalis, arises superiorly in a convex line from the epicranial aponeurosis, 

 while inferiorly its innermost fibres are continuous with the pyramidalis 

 nasi muscle; some take attachment to the internal angular process of 

 the frontal bone, and the others are blended with the corrugator 

 supercilii and with the orbicularis palpebrarum as far as the outer side 

 of the orbit. The fibres are nearly vertical, running slightly inwards; 

 the margins of the right and left muscles are united for a short dis- 

 tance above the root of the nose, but are separated by an angular 

 interval superiorly. 



The eijicranial or occipito-frontal aponeurosis extends over the 

 upper surface of the cranium uniformly from side to side, without 

 division. Posteriorly it is attached to tlie occipitales muscles, and to 

 the protuberance and superior curved lines of the occipital bone, and 

 anteriorly it terminates iu the frontalcs muscles, while laterally it pre- 

 sents no distinct margin, but below the temporal ridge 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, constituting 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 attaclied by a delicate connective tissue devoid of fat. 



Varieties. — Both, parts of tlie occipito-frontalis muscle are subject to variation in 

 their fulness or extent, and in their places of attachment. The occipitalis some- 

 times approaches the middle line, and is occasionally broken up into separate 



