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any of four pairs of muscles extending from the cervical vertebrae to the second rib; involved in moving the neck and in breathing

any of four pairs of muscles extending from the cervical vertebrae to the second rib; involved in moving the neck and in breathing

See under musculus.

Geometers employ this word to designate a triangle whose three sides are unequal. Anatomists have given the name to two muscles. 1. SCALENUS ANTICUS, Portion of the Costo-trachelian (Ch.), (F.) Scaline anterieur, is situate at the internal and inferior parts of the neck. It is long and triangular; and is inserted, below, at the upper surface of the first rib; and, above, at the anterior tubercle of the transverse processes of the 3d, 4th, 5th, and 6th cervical vertebrae. This muscle bends the neck, and draws it to its side. It can also raise the first rib. 2. SCALENUS POSTICUS, (F.) Scalene posterieur, Portion of the Costo-trachelian (Ch.), is situate behind the last. It is, also, long and triangular; but more bulky than the S. anticus. It is attached, below, to the outer surface of the first two ribs; and terminates, above, at the summit of the transverse processes of the last six vertebrae of the neck. This muscle bends the neck laterally, and can elevate the first two ribs. Some anatomists, as Albinus and Sommering, have described five scaleni muscles on each side, and have called them Scalenus prior, S. min'imus, S. latera'lis, S. me'dius, S. posti'cus. Riolan and Chaussier only describe one scalenus muscle on each side. Cowper and Douglas, and the generality of the English anatomists, admit three, S. anti'cus, me'dius, and posti'cus; or, primus, secun'dus, and ter’tius; Winslow, Boyer, and many of the French anatomists,-two, as above described.

An oblique muscle with unequal sides. See table of muscles, under muscle. [Gr.]