350 MUSCLES OF THE BACK. 



N. B. Where it is inseparablj' united to its fellow in the 

 nape of the neck, it is attached to the Ligamentum ISuchce, or 

 Colli. — This ligament is the representative of an important 

 elastic ligament in quadrupeds which by its peculiar properties 

 relieves the action of the muscles, in supporting the heavy 

 pendant head. The two trapezii taken together, have some 

 resemblance to the monk's cowl hanging over the neck, hence 

 the name of cucullares given to them. When the trapezius 

 is dissected on both sides, the two muscles represent a trapezium 

 or diamond shaped quadrangle on the back of the shoulders. 

 The anterior border of each muscle, forms in the neck the pos- 

 terior boundary of the posterior triangle of the neck, so impor- 

 tant to be understood in the operation upon the subclavian artery 

 above the clavicle. — 



2. Latissimus Dorsi, 



Arises, by a broad thin tendon, from the posterior part of the 

 spine of the os ilium, from all the spinous processes of the os 

 sacrum and vertebrae of the loins, and from the seven inferior 

 ones of the vertebrae of the back ; also tendinous and fleshy, 

 from the extremities of the three or four inferior ribs, a little 

 beyond their cartilages, by as many distinct slips. The inferior 

 fibres ascend obliquely, and the superior run transversely, over 

 the inferior angle of the scapula, towards the axilla where they 

 are collected, twisted, and folded. — Sometimes a few addi- 

 tional fibres of the muscle, arise from the inferior angle of the 

 scapula. — 



Inserted, by a strong thin tendon, into the inner edge of the 

 groove for lodging the tendon of the long head of the biceps. 



Use. To pull the arm backwards and downwards, and to roll 

 the OS humeri. 



N. B. The insertion of this muscle should not be prosecuted 

 till the muscles of the os humeri, to which it belongs, are 

 dissected. 



The second layer consists of three pair, two on the back, and 

 one on the neck. 

 On the back : 



