M. CLAVO-MASTOIDEUS. 223 



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

 defined depression. 



M. CLAVO-MASTOIDEUS. 



625. Synonymy. The clavicular 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 ; deido-mastoid, Wood, 9, 101, Fig. 23, "6." 



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



General Description. Narrow, tseniate, from the clavicle to the 

 mas fold process. 



Posture. Latericumbent, the block transversely under the neck, 

 and the head hanging. 



Exposure. By the reflection of the clavo-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. jugular is lies mesad of it, and 

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

 attached by a firm fascia to the ventral border of the levator da- 

 mculcB. 



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

 arises, with the corresponding part of the insertion of the clavo-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 trapezia-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 claw-trapezius, clavo-mastoideus and clavo-deltoideus. 



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 CLAVICULJ3. 



627. Synonymy. " Tramverxo-scapulaire" S.-D., A, II, 331; "levator clamculce," 

 Wood, 9, 95, Fig. 23, "e"; trachdo-acromiali*, Huxley, A, 418; levator scapularis, Miv., 

 B, 148 ; not found normally in man. 



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



