Middle Scalene Muscle Under the Skin, Anterior View

Description

Seen from an anterior oblique angle beneath the superficial tissues of an adult male neck, the middle scalene (scalenus medius) forms a thick muscular column lateral to the cervical vertebrae and posterior to the sternocleidomastoid. Its fibers course inferolaterally toward the superior surface of the first rib, placing it posterior to the anterior scalene and anterior to the posterior scalene, with the interscalene interval opening between the anterior and middle scalene bellies. Over the upper torso, the clavicles and upper ribs sit inferior to the cervical musculature, while facial muscles such as orbicularis oculi and orbicularis oris anchor the anterior portrait context. Select neck fibers are color-accented to isolate the scalenus medius against the surrounding grayscale anatomy. This orientation matters because the middle scalene defines the posterior boundary of the interscalene triangle, the corridor that transmits the roots and trunks of the brachial plexus and the subclavian artery toward the axilla, while the subclavian vein remains anterior to the anterior scalene and is not part of that space. A tight or hypertrophied scalenus medius can contribute to neurogenic thoracic outlet syndrome, with paresthesias and weakness reflecting lower trunk involvement, and it also influences the needle path and spread during interscalene brachial plexus block for shoulder surgery. Small distance, high stakes. Use this artwork in gross anatomy or kinesiology teaching to clarify scalene layering, first-rib insertions, and the relationship of cervical muscle planes to neurovascular bundles. It also supports anesthesia manuals, pain clinic patient education on thoracic outlet symptoms, and surgical anatomy figures for supraclavicular exposure where identifying scalenes and the clavicle-first rib frame helps orient the operative field. Anatomical accuracy verified by SciePro's Medical Advisory Board.