Orbicularis Oculi, Lateral View

Description

Wrapped concentrically around the orbital rim, the orbicularis oculi is emphasized laterally in red, with fibers spanning from the medial canthus across the palpebral fissure to the lateral canthus and overlying the lateral orbital margin. From this side view, the palpebral part is readable within the eyelids, while the thicker orbital part fans over the zygomatic bone and toward the temporal region, lying superficial to the bony orbit. Medially, the lacrimal portion sits adjacent to the lacrimal sac area, positioned posterior to the medial palpebral ligament and blending with the surrounding periorbital soft tissues. Functionally, this muscle is the dominant sphincter of the eyelids, and the lateral perspective makes it easier to teach how forceful closure recruits the orbital part while gentle blinking relies more on the palpebral fibers. That distinction matters in facial nerve palsy, where weakness of orbicularis oculi produces lagophthalmos and poor blink, predisposing to exposure keratopathy; clinicians often assess closure by asking for tight eye squeeze and looking for asymmetry at the lateral canthus. Surgical planning benefits as well, since incisions for lateral canthotomy/cantholysis or lower blepharoplasty intersect the orbicularis plane, and mismanagement can contribute to ectropion or altered lid position. Alongside the highlighted orbicularis, adjacent muscles of facial expression and mastication are shown for orientation, including the temporalis superiorly, the masseter over the mandibular ramus, and the sternocleidomastoid descending posterolaterally in the neck. A good teaching plate. Use it in gross anatomy and head and neck modules, oculoplastics and ENT lectures, facial nerve examination guides, and patient education materials explaining blink mechanics and eye protection strategies in VII nerve dysfunction. Anatomical accuracy verified by SciePro's Medical Advisory Board.