364 MUSCLES. 



the front of it. It is superficial, being placed immediately below 

 the skin of the scalp, and has four bellies of muscular fibres, two 

 behind and two before, connected by a thin tendon, which covers 

 all the top of the head. The tendon adheres by a short cellular 

 tissue, having no adeps, to the pericranium below, and is at- 

 tached to the common integuments above. The common in- 

 teguments on the hairy scalp are formed by skin and by a 

 closely adhering, and, indeed, almost inseparable layer of 

 granulated adeps, 'intermixed with the capsules of the hairs. 



This muscle arises from the superior semicircular ridges of 

 the os occipitis by tendinous and fleshy fibres, which form two 

 distinct bellies (musculus occipitalis) about an inch and a half 

 long, one on each side of the bone. Its tendon, when carefully 

 traced, will be found terminating a little in front of the coronal 

 suture, in the two anterior fleshy bellies (musculus frontalis) 

 which cover the whole front part of the os frontis. The internal 

 edges of these latter are in conjunction below. 



It is inserted, on each side, fleshy, into the superior margin 

 of the orbicularis oculi and of the corrugator supercilii; and,. by 

 its nasal slip, into each internal angular process of the os frontis, 

 and into the root of the os nasi. 



It pulls the skin of the head backwards and forwards, and 

 throws that of the forehead into horizontal wrinkles. It also 

 elevates the supercilia.* 



Compressor JVaris. 



The compressor naris arises by a pointed beginning from the 

 root of the ala nasi, and spreads like a fan over the lateral parts 

 of the nose below; it is inserted into its fellow of the opposite 

 side on the dorsum of. the nose, and into the lower part of the 

 os nasi, where it is connected with the nasal slip of the occipito- 

 frontalis. 



This muscle consists of thin and pale fibres placed immediate- 

 ly under the skin. If it act from'both extremities, by its curved 

 fibres being made straight, it will compress the nostril; but if it 



* Varieties. Its fleshy portion is said to have covered, in some instances, the 

 whole skull-cap. 



