THE PKEVERTEBRAL MUSCLES. 311 



The rectus capitis anticus minor, partly covered by the major, arises from 

 the front of the root of the transverse process of the atlas, and is inserted into 

 the basilar process, between the margin of the foramen magnum and the preceding 

 muscle, half an inch from its fellow. 



The rectus capitis lateralis is a short thick muscle arising from the upper 

 and fore part of the enlarged extremity of the transverse process of the atlas, and 

 inserted into the rough under surface of the jugular process of the occipital bone. 

 This and the foregoing muscle complete the series of inter trans versales muscles, 

 which are described along with the deep muscles of the back. 



The longus colli muscle rests on the front of the vertebral column from the 

 atlas to the third dorsal vertebra ; it consists of three sets of fibres, of which one is 

 vertical and two are oblique, a. The vertical part arises by a series of flattened 

 muscular and tendinous processes from the bodies of the lower two cervical and 

 upper two or three dorsal vertebras, and along its outer border it receives slips also 

 from the transverse processes of the lower three or four cervical vertebras ; it is in- 

 serted into the bodies of the second, third and fourth cervical vertebrae. 1). The lower 

 oUique part, the smallest of the three, takes origin in common with the vertical part 

 from the bodies of the upper dorsal vertebrae, and is inserted by narrow tendinous slips 

 into the anterior tubercles of the transverse processes of the fifth and sixth cervical 

 vertebrae, c. The upper oblique part arises by separate tendinous slips from the 

 anterior tubercles of the transverse processes of the third, fourth and fifth cervical 

 vertebrae, and is inserted into the lateral part of the tubercle on the anterior arch 

 of the atlas, becoming connected also with the upper end of the vertical part. 



Relations. By its anterior surface the longus colli muscle is in contact with the pharynx 

 and oesophagus, the great vessels of the neck contained in their sheath, the sympathetic and 

 recurrent laryngeal nerves, and the inferior thyroid artery. Behind, it rests upon the vertebrae. 



Varieties. The number of attachments, and the degree of separation of the several 

 parts are subject to variation. A slip of the lower oblique part is sometimes inserted into 

 the head of the first rib, or a fasciculus may be continued into the rectus capitis anticus major. 



The transversals cermets anticus is a muscle arising from the front of the transverse 

 processes of some of the cervical vertebrae from the fourth to the seventh, and inserted into 

 one or more of the first three. 



Nerves. The rectus anticus minor and rectus lateralis are supplied by branches from 

 the first cervical nerve ; the scaleni and long prevertebral muscles receive branches from the 

 adjacent cervical nerves. 



Actions. The scalene muscles, acting from their vertebral attachments, are elevators of 

 the upper ribs, and thus come into play in the movement of inspiration, contracting forcibly 

 in laboured breathing, while in tranquil respiration a moderate degree of action suffices to 

 fix the first rib and support the lung where it projects through the upper aperture of the 

 thorax. Taking their fixed point at the ribs they act as lateral flexors of the neck, and the 

 muscles of the two sides acting together (especially the anterior scaleni) can bend the neck 

 forwards. The recti antic I are flexors of the head 011 the spine, and the rectus lateralis can 

 only bend the head to the side. The longus colli is chiefly a flexor of the neck, but its upper 

 and lower oblique parts may produce a certain amount of rotation. 



IV. THE MUSCLES AND FASCIA OP THE TRUNK. 



The muscles passing between the trunk and the upper limb having been already 

 described, those which belong exclusively to the trunk itself will now be treated of 

 under the three heads of, 1. Dorsal muscles ; 2. Thoracic muscles, including the 

 diaphragm ; and 3. Abdominal and Perineal muscles. 



DOESAL MUSCLES AND FASCL2E. 



The muscles to be described under the above head, taken as a whole, occupy the 

 hollow between the line of vertebral spines and the prominences formed by the 

 mastoid process, the cervical transverse processes, the most projecting parts of the 



