| Abstract: | The Mm. scaleni of 20 bovine cadavers were dissected and their attachments and nerve supply are described and illustrated. The literature is reviewed and the principles of subdividing the muscles are discussed. The emerging roots of the brachial plexus rather than the axillary vessels are taken as the dividing line between the middle and ventral scalene muscles. This principle can also be applied to the other domesticated species. Fascicles formerly described as M. iliocostalis cervicis are grouped with the M. scalenus medius as its Pars superficialis on the ground of their nerve supply. The scalene muscles are innervated by the ventral branches of spinal nerves C4—T2. The subdivisions and innervation in the ox are as follows: 1. M. scalenus dorsalis, C5—T2. 2. M. scalenus medius: Pars superficialis, C4—C8; Pars profunda, C8. 3. M. scalenus ventralis, C4—T2. |
