194 



SCALENUS POSTICUS. 



Fig- 89. t 





omo-hyoid muscle, with the cervicalis superficialis and posterior sca- 

 pular artery, with the phrenic nerve, and with the subclavian vein, by 

 which it is separated from the subclavius muscle and clavicle. By 

 its posterior surface with the nerves which go to form the brachial 

 plexus, and below with the subclavian artery. By its inner side it is 

 separated from the longus colli by the vertebral artery. Its relations 

 with the subclavian artery and vein are very important, the vein being 

 before and the artery behind the muscle.* 



The SCALENUS POSTICUS arises from the posterior tubercles of all 

 the cervical vertebrae excepting the first. It is inserted by two fleshy 



fasciculi into the first and 

 second ribs. The anterior 

 (scalenus medius) of the 

 two fasciculi is large, and 

 occupies all the surface of 

 the first rib between the 

 groove for the subclavian 

 artery and the tuberosity. 

 The posterior (scalenus pos- 

 ticus) is small, and is at- 

 tached to the second rib. 

 Albinus and Soemrnering 

 make five scaleni. 



Relations. By its ante- 

 rior surface with the bra- 

 chial plexus and subclavian 

 artery ; posteriorly with the 

 levator anguli scapulae, cer- 

 vicalis ascendens, transver- 

 salis colli, and sacro-lum- 

 balis ; internally with the 

 first intercostal muscle, the 

 first rib, the inter-trans- 

 verse muscles, and cervical 

 vertebras ; and externally 

 with the sterno-mastoid, 

 omo - hyoid, supra - scapular 

 and posterior scapular ar- 

 teries. 



* In a subject dissected in the school of the Middlesex hospital during the 

 winter of 1841 by Mr. Joseph Rogers, the subclavian artery of the left side 

 was placed with the vein in front of the scalenus anticus muscle. 



t The prsevertebral group of muscles of the neck. 1. The rectus anticus 

 major muscle. 2. The scalenus anticus. 3. The lower part of the longus colli 

 of the right side ; it is concealed superiorly by the rectus anticus major. 4. 

 The rectus anticus minor. 5. The upper portion of the longus colli muscle. 6. 

 Its lower portion; the figure rests upon the seventh cervical vertebra. /. The 

 scalenus posticus. 8. The rectus lateralis of the left side. Q. One of the inter- 

 transversales muscles. 



