I20 - THE MUSCl.ES. 



its lateral end it touches the occipitoscapularis (Fig. 73, a), 

 serratus anterior (/), levator scapula; (//), supraspinatus (Fig. 

 75, a), and infraspinatus (Fig. 75, c), and the teres major (Fig. 



75. ^0- 



Action. — Draws the scapula toward the vertebral column. 



M. cleidomastoideus (clavicular portion of the human sterno- 

 cleidomastoid) (Fig. 65, h). — A narrow flat muscle between 

 the mastoid process and the clavicle. 



Origin from the apex and caudal margin of the mastoid 

 process of the temporal bone, by tendon and muscle fibres. 

 The muscle passes caudad, becoming broader and thinner. 



Insertion into the lateral four-fifths of the clavicle within 

 the insertion of the clavotrapezius, and into the raphe which 

 continues laterad of the clavicle. 



Relations. — Outer or lateral surface at the caudal end with 

 the clavotrapezius (Fig. 65, j)\ further craniad with the 

 depressor conchas (Fig. 64, //), the platysma, and the sterno- 

 mastoid (Fig. 65, g). Inner or medial surface with the supra- 

 spinatus (Fig. 75, a) caudad, with the mass of fat in the axilla 

 at its middle, with the levator clavicular ventralis (Fig. 65, /] 

 and obliquus capitis superior (Fig. 71, c) craniad. 



Action. — Pulls the clavicle craniad when the head is fixed. 

 Turns the head and depresses the snout when the clavicle is 

 fixed. 



M. levator scapulae ventralis, or levator clavicular (Fig. 

 68,/; Fig. 65, /; Fig. 72, c, c', c") (not usually found in man). 



Origin (Fig. 72, c' , c") in two parts. (1) By fleshy fibres 

 from the ventral surface of the atlantal transverse process near 

 its caudal border {c'). (2) By a small tendon from the ventral 

 surface of the basioccipital opposite the middle of the length of 

 the bulla tympani {c") in common with the longus capitis {a). 

 The two heads unite to form a flat band which passes caudo- 

 ventrad and is inserted (Fig. 76, /) by a flat short tendon, 

 about eight millimeters broad, into the outer surface of the 

 metacromion along its ventral border, and into the infraspinatus 

 fossa for one or two millimeters distad of that border. 



Relations. — Near the insertion the dorsal border overlaps 

 the border of theacromiotrapezius (Fig. 68, h), and the ventral 



