The Anterior Scalene Beneath the Skin of a Male Viewed Laterally

Description

Lateral exposure of the male neck highlights the anterior scalene as a deep strap muscle descending from the anterior tubercles of the cervical transverse processes (classically C3 to C6) to its insertion on the scalene tubercle of the first rib. Superficial landmarks include the mandibular ramus and temporomandibular joint superiorly, the hyoid bone at the anterior neck, and the clavicle and superior ribs inferiorly. Posterior to the anterior scalene lies the middle scalene, while the subclavian artery and the trunks of the brachial plexus pass laterally between them within the interscalene interval. The phrenic nerve typically courses on the anterior surface of the anterior scalene, running inferiorly toward the thoracic inlet. A tight space. This lateral relationship matters when you teach or plan interventions around the thoracic outlet, because a hypertrophied anterior scalene or a cervical rib can narrow the interscalene triangle and provoke neurogenic thoracic outlet syndrome with paresthesia in the ulnar distribution. Anesthetists rely on these planes for an interscalene brachial plexus block, where spread toward the phrenic nerve on the anterior scalene can produce ipsilateral hemidiaphragmatic paresis. Surgeons also use the muscle as a landmark during supraclavicular approaches to the subclavian artery, where the vein remains anterior and inferior to the artery at the root of the neck. Use this illustration in gross anatomy and head and neck modules to orient learners to deep cervical musculature beneath the sternocleidomastoid and platysma, and in regional anesthesia or vascular surgery texts that discuss the scalene triangle, thoracic outlet compression, and line placement near the clavicle. It also fits exam-prep materials that contrast the courses of the subclavian artery and vein around the anterior scalene. Anatomical accuracy verified by SciePro's Medical Advisory Board.