MYOLOGY 85 



Insertion. — Passes obliquely upward in front of the spinal column 

 to the inner tubercle on the basal ridge of the basi-temporal bone, 

 by a subcompressed tendon. 



Shape. — ^A somewhat thick fasciculus. 



Relations. — Superiorly with the trachelo-mastoideus, interiorly 

 with the longus colli anterior, and extemaUy with the skin. 



Action. — Singly, puUs the head down and to one sidej acting with 

 its fellow, pulls the head downwad. 



Trachelo-mastoideus (Fig. 19, No. 16). (Synonym. — Longissi- 

 mus capitis et atlantis.) 



Location. — Laterally on the anterior portion of the neck. 



Origin. — Semitendinous from the diapophyses of the second, the 

 third, the fourth, and the fifth cervical vertebrae. 



Insertion. — By subcompressed tendon to the base of the cranium, 

 at the outer tubercle of the basal ridge of the basi-temporal. 



Shape. — Flattened from side to side; broad at the posterior por- 

 tion, becomes angular at the anterior portion. 



Action. — Singly, pulls the head down and to one side; acting with 

 its feUow, pulls the head downward. 



Interspinales (Fig. 17, A, No. 2). Location. — Superior to the. 

 vertebra. 



Origin and Insertion. — ^A series of muscles connecting the superior 

 neural spines of the cervical vertebrae. 



Shape. — Thin, flat. 



Relations. — ^Anteriorly the posterior border of the vertebrae in front 

 and posteriorly the anterior border of the succeeding vertebrae, 

 inferiorly by the vertebrae. 



Action. — To approximate the spinous portion of the vertebrae. 

 -— Interarticulares (Fig. 17, No. .4, 4). Location. — Supero-laterally 

 to the vertebrae. Between the postzyga pophysis. . 



Origin and Insertion. — From the posterior margin of the ring of 

 the atlas to the postzygapophysis of the axis. Then in the suc- 

 ceeding vertebrae from the postzygapophysis of the vertebra to 

 the same of the succeeding vertebra. 

 ' Shape. — Muscular bundle. 



Relations. — Inferiorly with the vertebrae. Supero-laterally with 

 the obhquo-transversales. 



Action. — Aids in approximating the vertebrae in a supero-lateral 

 direction. 



