THE MUSCLES OF THE HE^D. lOI 



Relations. — Outer surface with the abductor longus {m), a 

 small strand of the platysma and the concha. Inner surface 

 with the temporal muscle (;;). 



Action. — Pulls the concha caudad. 



M. epicranius (or occipitofrontalis) (Fig. 63, // and h'). 

 Origin on the sagittal crest or suture, just craniad of the 

 origin of the levator longus auris, to the inner surface of which 

 this muscle is closely united. From the origin the fibres pass 

 craniad forming a band {/i) about 8 or 10 millimeters in width, 

 the two muscles lying close to one another and partly united 

 in the middle line. About two centimeters craniad of their 

 origin the fibres ot both muscles end in a tendinous sheet, the 

 galea aponeurotica, which covers the surface of the skull in the 

 region between the ears and eyes, and is formed by the inner 

 surface of the intermedins scutulorum {a) and other muscles of 

 this region. The galea aponeurotica passes craniad onto the 

 surface of the nose, where it gives origin again to a thin sheet 

 of muscle-fibres (//') which are inserted into the integument 

 near the cranial ends of the nasal bones. 



M. epicranius is thus formed of two muscular portions 

 [h and h'), connected by a long tendinous sheet. The caudal 

 portion is frequently distinguished as the occipital muscle 

 (M. occipitalis, //), the cranial portion, on the nose, as the 

 frontal muscle (M. frontalis, //'). 



Relations. — Outer surface of the occipitalis [h) with the 

 intermedins scutulorum {a), the levator auris longus [g), and 

 the integument; inner surface with the auricularis superior [h), 

 the abductor auris longus, and the bone. Outer surface of 

 the frontalis {li') with the integument; inner surface with the 

 bones of the skull. 



Action. — Moves the integument of the dorsal surface of the 

 head and of the nose. 



Ventrad of the external ear the following three differen- 

 tiated portions of the platysma may be distinguished. 



M. zygomaticus (major) (Fig. 64, d). — A slender band 

 connecting the angle of the mouth with the scutiform cartilage 

 of the ear. 



At the angle of the mouth the fibres arise from among those 



