92 THE BACK. 



Muscles of the Neck. Before speaking of the muscles 

 of the back a few of those of the neck had best be taken 

 up. They are numerous but mostly of minor importance. 

 Largest and most important is the sterno-cleido-mastoid 

 muscle, which has its origin on the upper part of the 

 sternum and the inner third of the clavicle and is in- 

 serted into the mastoid process of the temporal bone. 

 It passes obliquely across the side of the neck and 



FIG. 34. Muscles of the right side of the head and neck: 1, Frontalis; 2, supe- 

 rior auricular; 3, posterior auricular; 4, orbicularis palpebrarum; 5, pyramidalis 

 nasi; 6, compressor naris; 7, leyator labii superiqris alseque nasi; 8, levator labii 

 superioris; 9, zygomaticus major; 10, orbicularis oris; 11, depressor labii in- 

 ferioris; 12, depressor angulioris; 13, anterior belly of digastric ;14, mylohyoid; 

 15, hyoglossus; 16, stylohyoid; 17, posterior belly of digastric; 18, the masseter; 

 19, sternohyoid; 20, anterior belly of omohyoid; 21, thyrohyoid; 22, 23, lower 

 and middle constrictors of pharynx; 24, sternomastoid; 25, 26, splenius; 27, leva- 

 tor scapulae; 28, anterior scalenus; 29, posterior belly of omohyoid; 30, middle 

 and posterior scalenus; 31, trapezius. (Borland's Dictionary.) 



serves to flex the head to the side and to draw the face 

 in the opposite direction. When both muscles contract 

 the head is flexed on the neck and the neck on the 

 chest. In wry neck or torticollis this muscle is constantly 

 contracted. The platysma myoides arises from the fascia 

 over the pectoral, deltoid, and trapezius muscles and is 

 inserted into the lower jaw, the angle of the mouth, and 

 the loose tissue in the lower part of the face. It 



