407 



it is connected to the bone by a thin fibrous lamina, firmly adherent to the skin, 

 and wanting the lustrous, shining appearance of aponeuroses. At its origin from 

 the spines of the vertebra? it is connected to the bones by means of a broad semi- 

 elliptical aponeurosis, which occupies the space between the sixth cervical and the 

 third thoracic vertebra?, and forms, with the aponeurosis of the opposite muscle, 

 a tendinous ellipse. The rest of the muscle arises by numerous short tendinous 

 fibres. If the Trapezius is dissected on both sides, the two muscles resemble 

 a trapezium or diamond-shaped quadrangle; two angles corresponding to the 

 shoulders; a third to the occipital protuberance; and the fourth to the spinous 

 process of the last thoracic vertebra. The clavicular insertion of this muscle 

 varies as to the extent of its attachment; it sometimes advances as far as the middle 

 of the clavicle, and may even become blended with the posterior edge of the 

 Sternomastoid or may overlap it. This should be borne in mind in the operation 

 for tying the third part of the subclavian artery. 



Relations. By its superficial surface, the Trapezius is in relation with the integument; by its 

 deep surface, in the neck, with the Complexus, Splenius, Levator anguli scapulae, and Rhom- 

 boideus minor; in the back, with the Rhomboideus major, Supraspinatus, Infraspinatus, and 

 vertebral aponeurosis (which separates it from the prolongations of the Erector spinae), and 

 the Latissimus dorsi. The spinal accessory nerve and the superficial cervical artery and branches 

 from the third and fourth cervical nerves pass beneath the anterior border of this muscle. The 

 anterior margin of its cervical j.ortion forms the posterior boundary of the posterior triangle 

 of the neck, the other boundaries being the Sternomastoid in front and the clavicle below. 



The Ligamentum nuchae (Fig. 312) is a fibrous membrane, which, in the neck, 

 represents the supraspinous and interspinous ligaments of the lower vertebra?. 

 It extends from the external occipital protuberance to the spinous process of the 

 seventh cervical vertebra. From its anterior border a fibrous lamina (fascia 

 nuchae) is given off, which is attached to the external occipital crest, the posterior 

 tubercle of the atlas, and the spinous process of each of the cervical vertebra?, so 

 as to form a septum between the muscles on each side of the neck. In man it is 

 merely the rudiment of an important elastic ligament, which, in some of the lower 

 animals, serves to sustain the weight of the head. 



The Latissimus dorsi (m. latissimus dorsi) is a broad, flat muscle, which 

 covers the lumbar and the lower half of the thoracic regions, and is gradually 

 contracted into a narrow 7 fasciculus at its insertion into the humerus. It arises 

 by tendinous fibres from the spinous processes of the six inferior thoracic vertebra- 

 and from the dorsal layer of the lumbar fascia ( see page 410), by which it is attached 

 to the spines of the lumbar and sacral vertebra? and to the supraspinous ligament. 

 It also arises from the external lip of the crest of the ilium, behind the insertion 

 of the External oblique muscle, and by fleshy^ jiigitations from the three or four 

 lower ribs, which are interposed between similar processes of the External oblique 

 (Fig. 319, page 426). From this extensive origin the fibres pass in different 

 directions, the upper ones horizontally, the middle obliquely upward, and the 

 lower vertically upward, so as to converge and form a thick fasciculus, which 

 crosses the inferior angle of the scapula, and which usually receives a few fibres 

 of origin from it. The muscle curves around the lower border of the Teres major, 

 and is twisted upon itself so that the superior fibres become at first posterior and 

 then inferior, and the vertical fibres at first anterior and then superior. It ter- 

 minates in a short quadrilateral tendon, about three inches in length, which, 

 passing in front of the tendon of the Teres major, is inserted into the_bottom of 

 thebicipital groove of the humerus, its insertion extendmgTTTgher"on the humerus 

 than tnat of the tendon of the Pectoralis major. The lower border of the tendon 

 of this muscle is united with that of the Teres major, the surfaces of the two being 

 separated near their insertions by a bursa; another bursa is sometimes interposed 



