Posterior Superior Serratus

Description

Positioned deep to trapezius and rhomboid musculature, the serratus posterior superior is shown as a thin, quadrilateral sheet with serrated digitations coursing inferolaterally from the midline to the upper ribs. Its medial attachments arise from the lower cervical and upper thoracic spinous processes (typically C7 to T3) via the nuchal ligament and supraspinous ligament, then fan laterally to insert along the superior borders of ribs 2 to 5 near their angles. Posteriorly, the scapulae frame the upper thorax laterally while the cervical spine transitions into the thoracic vertebrae centrally. Small slips. Clear rib landmarks. Teaching the serratus posterior superior benefits from a posterior view because it forces correct layering: this muscle sits deep to trapezius and the rhomboids and superficial to the intrinsic back muscles and the posterior ribs, a relationship that explains why it is difficult to palpate and often missed in surface anatomy. Clinically, it matters in posterior thoracic approaches and rib exposure, where misidentifying the serratus posterior superior can lead to confusing its aponeurotic origin with the deeper erector spinae fascia, and in intercostal nerve blocks where the rib angle region marks the nearby course of the intercostal neurovascular bundle. Persistent focal pain along the upper rib angles is also a common referral pattern cited in myofascial pain discussions of this layer. Ideal for gross anatomy and musculoskeletal teaching modules on thoracic wall layers, respiration mechanics, and rib angle landmarks, as well as for surgical atlases covering posterior rib access, thoracotomy positioning, and regional anesthesia education. Medical publishers can pair it with plates of trapezius, rhomboid major/minor, and costotransverse joints to clarify what is removed, reflected, or spared in dissection. Anatomical accuracy verified by SciePro's Medical Advisory Board.