BY W. J. S. McKAY. 325 



Insertion. The muscle runs forward and outwards, the 

 aponeurosis giving way (about the level of the 7th I'ib) to muscular 

 fibres which arc inserted on the anterior three-fourths of the 

 external margin of the vertebral border of the scapula. 



Relations. Its costal origin is closely related to the origin 

 of the dernio-dorsi-cervicalis. It lies superficial to the latissimus 

 dorsi, and as it approaches its insertion it hides the origins of the 

 slip to the latissimus from the scapula, of the subscapularis, and 

 of the clavicular deltoid. (Fig. 10). 



Orxithorhynchus. 



Origin. («) The anterior jmrt of the trapezius arises from 

 the posterior of the two well-marked depressions on the parietal 

 bone, whose direction is from without posterior and inwards to 

 the median line, and from a ligamentous raphe common to it and 

 the rhomboid, attached in the mid-line of the occipital crest ; the 

 posterior limit of the origin of the muscle corresponding to about 

 the distal extremity of the spine of the axi.s. 



Insertion. The muscle, quadrilateral in outline, runs out- 

 wards and posterior over the lateral aspect of the head and neck, 

 tlie tendon of origin giving place to a thick fleshy sheet of muscle 

 which is inserted, (a) on the anterior extremity of the vertebral 

 border ; (6) along the inner border of the spine and acromion ; 

 (c) on the outer one-fourth of the anterior surface of the clavicle. 



Relations. At its origin the brachio-cephalic band of the 

 panniculus arises from the parietal bone immediately anterior to 

 the trapezius, and overlies it, as does also the aponeurosis connected 

 with the termination of the dermo-dorsi cervicalis band of the 

 panniculus. The muscle lies superficial to the rhomboid and 

 hides it anteriorly but not posteriorly. 



Origin, (b) Posterior part of the trapezius arises from the 

 spines of the 5th to about the 13th dorsal vertebra, the exact 

 number not being defined since the tendon of origin blends with 

 the general dorso-lnmbar aponeurosis attached to the spine in this 

 region. Besides the spinal origin the muscle arises by fleshy 





