Anterior Scalene (Scalenus Anticus)

General information

The anterior scalene, or scalenus anterior, is part of a group called the scalene muscles. This group consists of scalenus anterior, scalenus posterior, and scalenus medius. These muscles are located on the sides of the neck.

Literal meaning

The term anterior comes from the Latin, comparative of ante, meaning before and scalene comes from the Greek “skalenos”, meaning uneven.

Interesting information

Approximately 30% of people have an additional scalene muscle called scalenus minimus. This extra muscle often appears asymmetrically (only occurring on one side).

The scalene muscles, including anterior scalene, are the primary contributors to thoracic outlet syndrome (TOS). The most recognizable symptom of TOS is pain originating in the shoulder and extending into the arm and occasionally the hand. This pain is caused by compression of blood vessels and nerves in the area between the neck and the axilla (armpit). Sufferers of TOS also often report tingling, numbness, and/or weakness in the affected limb.

Origin

Transverse processes of C3 – C6

Insertion

Superior surface of the first rib

Function 

Raises the first rib during inhalation, rotates the head to the opposite side, laterally flexes the neck to the same side

Nerve supply

Posterior rami of C3-C8

Blood supply

Ascending cervical artery (branch of interior thyroid artery)

Relevant research

This study investigated scalenus anterior from an anatomical perspective in order to determine the feasibility of palpating and measuring the muscle using electromyography (EMG). The obscured location of scalenus anterior during cadaver dissection suggests that palpitation and EMG measurement of the muscle are not as straightforward as the literature often depicts.

Kennedy E, Mercer S. “The posterior triangle of the neck: Where is scalenus anterior?”. NZ Journal of Physiotherapy, 2006, Volume 34 (3): 142-146

Anterior scalene exercise

Hook your fingers above your collar bone, and gently rotate your neck to the same side, then extend your neck backwards. You should feel the stretch at the front of your neck under your fingers. Hold the stretch for 30 seconds, and perform three times. This stretches the anterior scalene muscle.