Splenius Capitis Muscle, Lateral View

Description

Positioned on the posterolateral neck, the splenius capitis is rendered as an oblique muscular sheet running superolaterally from the lower cervical and upper thoracic spinous processes toward the mastoid process and the lateral third of the superior nuchal line. Its posterior border sits deep to the trapezius and adjacent to the levator scapulae, while anteriorly it relates to the sternocleidomastoid as the neck turns toward a true lateral profile. Inferiorly, continuity of the posterior trunk musculature is suggested by the erector spinae columns, including iliocostalis, longissimus, and spinalis thoracis, stacked lateral to medial along the thoracic spine. Breast tissue and overlying pectoralis major are included in the same field, anchoring the orientation of the shoulder girdle and upper thorax. Clear landmarks. Clinically, this lateral relationship to the mastoid process and superior nuchal line matters when localizing posterior cervical pain generators and planning safe needle trajectories. Trigger points in splenius capitis can refer pain to the occiput and temporal region and are often confused with cervicogenic headache or occipital neuralgia, so seeing its fiber direction relative to sternocleidomastoid helps explain why rotation and extension can reproduce symptoms. For procedural anatomy, this view also supports teaching palpation and injection approach in the posterior triangle region while respecting the deeper suboccipital compartment and nearby neurovascular structures that become relevant with deeper dissection. Use it in head and neck anatomy labs to contrast superficial landmarks with deeper posterior cervical layers, and in physiotherapy or sports medicine materials covering posture-related neck pain and the erector spinae chain. The inclusion of female breast anatomy makes it suitable for publications that require sex-specific surface anatomy context in lateral profile, such as clinical examination handouts and patient education diagrams. Anatomical accuracy verified by SciePro's Medical Advisory Board.