Scalenes Information
The scalene muscles (from Greek σκαληνός, or skalenos, meaning uneven[1]) are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior.
They are innervated by the spinal nerves C4-C6.
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Origin and insertion
They originate from the transverse processes from the cervical vertebrae of C2 to C7 and insert onto the first and second ribs. Thus they are called the lateral vertebral muscles.[2]
Function
The action of the anterior and middle scalene muscles is to elevate the first rib and laterally flex the neck to the same side;[3] the action of the posterior scalene is to elevate the second rib and tilt the neck to the same side.
They also act as accessory muscles of inspiration, along with the sternocleidomastoids.
Relations
The scalene muscles have an important relationship to other structures in the neck. The brachial plexus and subclavian artery pass between the anterior and middle scalenes. The subclavian vein and phrenic nerve pass anteriorly to the anterior scalene as it crosses over the first rib.
The passing of the brachial plexus and the subclavian artery through the space of the anterior and middle scalene muscles constitute the scalene hiatus (the term "scalene fissure" is also used). The region in which this lies is referred to as the scaleotracheal fossa. It is bound by the clavicle inferior anteriorly, the trachea medially, posteriorly by the trapezius, and anteriorly by the platysma muscle.
References
- ^ Mosby’s Medical, Nursing and Allied Health Dictionary, Fourth Edition, Mosby-Year Book Inc., 1994, p. 1395
- ^ Henry Gray (1913). "Anatomy: Descriptive and Applied". http://books.google.com/books?id=lYRKAAAAMAAJ&output=html_text.
- ^ Buford JA, Yoder SM, Heiss DG, Chidley JV (Oct 2002). "Actions of the scalene muscles for rotation of the cervical spine in macaque and human". J Orthop Sports Phys Ther 32 (10): 488–96. PMID 12403200.
See also
Additional images
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Musculi coli base
The origin of the scalenes is 1st and 2nd ribs The insertion is the transverse processes of c2-c7.
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