J/. CLAVO-MASTOIDEUS. 223 



tendon of the subjacent splenius (Fig. 67) there is sometimes a well- 

 detined depression. 



M. CLAVO-MASTOIDEUS. 



§ 635. Synonymy. — The claucular part of the human sterno-cleido-mastoid, G., A, 

 357 ; Q., A, I, 292 ; " deido-mastoidien," S.-D.. A, II, 333 ; part of the " mastoido-humeral," 

 Ch., A, 209, Fig. 90; part of the mastoido-humeralis, Ch. (FL), A, 196; part of the cephalo- 

 humeral, Miv., B, 147 ; cUido-madoid, Wood, 9, 101, Fig. 23, "6." 



Figures. — Lateral aspect (67) ; ventral border of clavicular part (72). 



General Description, — Narrow, tseniate, from the clamcle to the 

 mastoid process. 



Posture.— Latericum bent, the block transversely under the neck, 

 and the head hanging. 



Exposure. — By the reflection of the claxo-trapezius and the 

 sterno-mastoideus. 



Dissection. — The dorsal border is apparent at about its middle. 

 Raise it, and draw the muscle dorsad so as to indicate its ventral 

 border. In reflecting the cephalic part, note that, about 18 mm. 

 from the head, the muscle is perforated by a nerve, near which, 

 entad of the muscle, lies the separate lateral half of the thyroid 

 body. In reflecting the caudal part, note the constant increase in 

 width to the clavicle, that the V. jugularis lies mesad of it, and 

 usually a lympliatic gland entad of it, while its dorsal border is 

 attached by a firm fascia to the ventral border of the le^)ator cla- 

 mculce. 



§ 626. Origin. — In two nearly equal parts : (A) the ventral part 

 arises, with the corresponding part of the insertion of the clam-tra- 

 pezius, from the ventro-cephalic border of the sternal half or three 

 fifths of the clavicle ; (B) the remainder arises from the ental aspect 

 of the tTapezio-deltoid raphe, but is connected with the scapular 

 part of the clavicle by a strong fascia which might be regarded 

 as a common tendon of attachment for the corresponding parts of 

 the claxo-trapezius, cla/GO-mastoideus and clavo-deJtoideus. 



Insertion. — By fleshy fibers upon the ventral and caudal bor- 

 ders of the mastoid process., and upon its mesal side. 



Remark. — Respecting the choice of origin and insertion for this 

 muscle, see § 579. 



M. LEVATOR CLAVICUL^. 



§ 627. Synonymy. — " Transverw-scapidaire,'' S.-D., A, II. .331; "levator daticulm," 

 Wood, 9, 9o, Fig. 23, "e"; trdchelo-acromialis, Huxley, A, 418; levator scapularis, Miv., 

 B, 148 ; not found normally in man. 



Figures. — Scapular part (66, 67) ; insertion area (45). 



