314 



MUSCLES OF THE NECK. 



that region. They draw the corner of the mouth downwards, 

 and constitute the musculus risorius of Santorini. — 



•2. Sterno-cleido-mastoideus, (see Jig. 77.) 



Arises hy two disthict orighis : Fig. 80.* 



the anterior tendinous and a 

 little fleshy, from the top of the 

 sternum near its junction with 

 the clavicle ; the posterior, 

 fleshy, from the upper and an- 

 terior part of the clavicle ; both 

 unite a little above the ante- 

 rior articulation of the clavicle, 

 to form one muscle, which runs 

 obliquely upwards and out- 

 wards, to be 



Inserted, by a thick strong 

 tendon, into the mastoid pro- 

 cess, which it surrounds ; and, gradually turning thinner, is 

 inserted as far back as the lambdoid suture. 



Use. To turn the head to one side, and bend it forwards. 



Muscles situated between the Lower Jaiv and Os Hyoides. 



There are four layers before, and two muscles at the side. 

 The four layers are, 



1. Digastiicus, (see jig. 78,) 



Arises, by a fleshy belly, intermixed with tendinous fibres, 

 from the fossa at the root of the mastoid process of the temporal 

 bone, and soon becomes tendinous ; runs downwards and for- 

 wards : the tendon passes generally through the stylo-hyoideus 

 muscle; then it is fixed by a ligament to the os hyoides; and, 

 having received from that bone an addition of tendinous and 

 muscular fibres, runs obliquely forwards, turns fleshy again, 

 and is 



* b, Buccinator, d, Depressor labii inferioris. h, Corrugator Supercilii. 

 n, Compressor naris, s, Sterno-cleido-mastoid. t, Temporal, u, Trapezius, 

 u, Splenius capitis, u, Splenius colli, x, Digastricus. y, Mylo-hyoid. z, Stylo 

 hyoid. tc, Hyo-glossus. 



