M. STERNO-MASTOIDEUS. 331 



margin of the vertelbral border, opposite the triangular space at the 

 vertebral end of the mesoscaptda ; (C) the next 2-2.3 cm. is at- 

 tached by a thin tendon, 2-3 mm. long, upon the ectal margin of the 

 vertebra,! border from opposite the middle of the space just men- 

 tioned, and thus slightly overlapping part B, to within 8-10 mm. of 

 the gleno- vertebral angle of the scapula ; (D) the caudal 5-6 mm. 

 is separated from the rest by an interval 1-5 mm. wide, and is in- 

 serted by fleshy or very short tendinous libers upon the ectal aspect 

 of the gleno-vertebral angle in apposition with the origin of the 

 teres. The scapular end of the muscle may be separated more or 

 less readily into four divisions corresponding with the parts of the 

 insertion just described, and the caudal division is sometimes quite 

 distinct, with a decided extension toward the teres. 



M. STBRNO-MASTOIDEUS. 



Remark. — This is strictly a muscle of the neck, but is here described on account of its 

 close relations with the muscles of the shoulder and with blood-vessels. 



§ 623. Synonymy. — The sternal part of the human sterno-deido-mastoid, G., A, 357; 

 Q., A, 1, 293 ; sterno-mastoidien, S.-D., A, II, 248 ; stemo-maxUlaire, Ch., A, 310 ; sterno- 

 maxiUa/ris, Ch. (PI.), A, 198; sterno-mastoid, Miv., B, 134. 



Figures. — Lateral aspect of cephalic half (66) ; lateral aspect (67) ; united sternal por- 

 tions (73) ; sternal portion (73). 



§ 623. General Description. — Tseniate, along the ventro-cephalic 

 border of the clavo-trapezius, from the prcBsternum to the mastoid 

 process of the temporal bone and the ventral part of the crista 

 lambdoidalis. 



Posture.— Latericumbent ; a block transversely under the neck ; 



the head ha;nging. 



Exposure. — Connect the angle of the mouth with the occipito- 

 presternal line (§ 610) by an incision corresponding with the direction 

 of the margin of the upper lip. Note that the skin of the cheek, 

 especially in old males, is very thick. Dissect up both edges of the 

 skin for about 1 cm. 



The zygoma (Fig. 30, 56, 67) may be felt as a firm bony arch 

 between the M. temporalis (Fig. 67) dorsad, and the M. masseter 



ventrad. 



Just caudad of the zygoma may be felt the cartilaginous meatus 

 auditorius (Fig. 67, Mt. au. ex.), partly embraced by the small, 

 pale and rather loose-textured parotid gland (Fig. 87, 107). Divide 

 the meatus close to the head, and reflect the flap, together with the 



