MUSCLES OF THE SHOULDER AND ARM. 



83 



Rectus capitis posticus minor. — Origin, from the tubercle of the 

 atlas. Insertio7i^ into the occiput, at the inferior semicircular ridge, 

 and below it. 



Obliquus superior. — Origin, from the transverse process of the 

 atlas. Insertion, into the outer end of the inferior semicircular 

 ridge of the occiput. 



Obliquus ififerior. — Origin, from the spinous process of the den- 

 tata. Insertion, into the transverse of the atlas. 



Inter spinales. — Between the spinous processes of all the vertebrae. 

 In the neck they are double : in the back, tendinous ; in the loins 

 single and well-marked. 



Inter-transversarii.^^ — Between all the transverse processes. In 

 the neck, double ; in the back, tendinous ; in the loins fleshy and 

 single. Use ; to approximate these processes. 



Levatores costaruni.^"^ — Origi7i, from the transverse processes of 

 the last cervical and eleven upper dorsal vertebrte. Insertion, into 

 the upper edge of the two ribs below. Use ; to elevate the ribs. 



MUSCLES OF THE SHOULDER AND ARM. 

 FASCIA. 



The brachial fascia covers the muscles of the upper extremity, 

 commencing at the spine of the scapula and clavicle. Upon the 

 deltoid it is thin. At the elbow it sends several processes to the 

 bone, which serve for the origin of muscles, and in front it receives 

 a portion of tendon from the biceps muscle, which renders it tense. 



At the wrist it fornis the anterior and posterior annular ligaments, 

 which bind down the tendons of the hand, and in the hand it forms 

 the palmar aponeurosis. 



Deltoid.^ — Origin, from the spine of the scapula, the acromion 

 process, and the external third of the clavicle. Insertion, into a 

 triangular roughness near the middle of the humerus. Use; it 

 raises the humerus. (Fig. 62.) 



Supra-spinatiis.^'^ — Origin, from the whole of the fossa supra- 

 spinata. Insertion, into the inner facet of the greater tuberosity of 

 the humerus. Use ; it raises the arm and turns it outwards. 



Infraspinatus.^^ — Origin, from the whole of the fossa infra- 

 spinata. Insertion, into the middle facet of the greater tuberosity 

 of the humerus. Use ; it rotates the humerus outwards and back- 

 wards. 



Teres minor.^^ — Origin, from the lesser costa of the scapula. 

 Insertion, into the outer facet of the greater tuberosity of the humerus. 

 Use ; it rotates the humerus outwards, and draws it downwards and 

 backwards. 



Teres major.^^ — Origin, from the posterior surface of the angle 

 of the scapula, and a part of its lesser costa. Insertion, into the 

 posterior edge of the bicipital groove of the humerus in common 



