Scalene muscles

The Scalene Muscles are a group of three pairs of muscles in the lateral neck, namely the anterior scalene, middle scalene, and posterior scalene. They are innervated by the fourth, fifth, and sixth cervical spinal nerves (C4-C6).

Anatomy

The scalene muscles originate from the transverse processes of the cervical vertebrae of C2 to C7 and insert onto the first and second ribs. Thus they form part of the floor of the posterior triangle of the neck.

Anterior Scalene

The anterior scalene (from Greek skalenos, meaning uneven) is named for its unequal size compared to the other two scalenes. It originates from the transverse processes of the lower six cervical vertebrae and is inserted into the scalene tubercle on the inner border of the first rib.

Middle Scalene

The middle scalene is larger than the anterior but smaller than the posterior. It arises from the transverse processes of the lower six cervical vertebrae and is inserted into the upper surface of the first rib.

Posterior Scalene

The posterior scalene is the largest and deepest of the three muscles. It originates from the transverse processes of the lower six cervical vertebrae and is inserted into the outer surface of the second rib.

Function

The scalene muscles elevate the first and second ribs, aiding in respiration. They also function to bend the neck to the same side and rotate it to the opposite side.

Clinical Significance

Scalene muscles can be involved in several clinical conditions, including scalene syndrome and thoracic outlet syndrome.

See Also

• Neck Muscles
• Respiratory Muscles
• Thoracic Outlet Syndrome
• Scalene Syndrome

Scalene_muscles

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  Scalenus
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  Scalenus anterior
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  Scalenus medius muscle
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  Scalenus posterior
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  Musculi coli base
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  Gray 384