ORGANS OF EXPRESSION. 325 



occipital bone, and from the mastoid process of the tempo- 

 ral. The fibres ascend, and soon terminate in one broad 

 sheet of tendon, called the epicranial aponeurosis, which 

 spreads over the superior and lateral parts of the cranium, 

 as far forward as the coronal suture, where it again 

 becomes fleshy, forming the two anterior bellies which are 

 inserted into the skin of the eyebrow, and mingle their 

 fibres with those of the corrugator supercilii, and orbicu- 

 laris palpebrarum muscles. 



This muscle is regarded by some as a digastric muscle 

 by others, as quadriceps two frontal and two occipital 

 muscles, having, in either case, the central aponeurosis as 

 their common point of insertion. There extends down 

 from this muscle a fleshy slip along the nasal bones, which 

 is attached to the internal angular process of the frontal 

 bone. It is considered as a distinct muscle, and called the 

 pyramidalis nasi, orfronto nasalis. 



This muscle is loosely connected to the cranium, but 

 closely to the scalp. Function to elevate the eye-brows and 

 throw the forehead into transverse wrinkles ; to raise* the 

 upper lids and expose the ball of the eye as in staring ; and 

 to draw the scalp either backward or forward as the ante- 

 rior or posterior bellies become the fixed points of action. 



Corrugator Supercilii, (Fig. 55.) Dissection. Turn down 

 the integument of the eyebrow from the transverse incis- 

 ion of the frontal muscle, beneath which this muscle will 

 be seen. It arises from the internal angular process of the 

 os-frontis, and proceeds upward and outward between 

 the occipito frontalis, and orbicularis palpebrarum, to be 

 inserted into these and the middle of the eyebrow. 



This muscle is said to be peculiar to man alone, and 

 to be found in none of the inferior animals. It is con- 

 nected largely with expression, and the exhibition of men- 

 tal operations. 



Function. To draw the eye-brows towards each other 

 as in frowning, and to throw the forehead into vertical 

 wrinkles. 



Compressor nasi, (Fig. 55,) a small, thin, triangular 



