Eyelid and Facial Anatomy

Abstract

The eyelids are made up of an anterior lamella of thin skin and orbicularis oculi, and a posterior lamella of tarsal plate and palpebral conjunctiva. The upper lid retractors are levator palpebrae superioris and tarsalis superior (Müller). The lower lid retractors are fascia capsulopalpebralis and tarsalis inferior. The lid margin has three distinguishing landmarks: the lash line, the grey line, corresponding to the pretarsal part of the orbicularis oculi, and the meibomian gland orifices. Vascular supply is rich and characterised by anastomoses between the internal and external carotid arteries. The nerve supply is by branches of the ophthalmic nerve for the upper lid and branches of the maxillary nerve for the lower lid. The zygomatic bones and the mental protuberance of the mandible are the bony structures that stand out in determining facial characteristics. The facial muscles are grouped around the facial orifices. In the cheek region a cranial extension of the platysma, the so-called superficial musculoaponeurotic system (SMAS), lies in the plane of the facial muscles. Facial nerve branches run underneath it. Sensory innervation of the face comes from the three divisions of the trigeminal nerve. The arterial supply to the face is by branches of the external and internal carotid arteries. The border between both vascular territories is at the level of the eye fissure. The external nose consists of bony and cartilaginous pyramids, and the lobule. Overlap between bone, triangular cartilage and lobular cartilage as well as a continuous periosteal-perichondrial envelope contribute to the integrity of the three parts. The tip is formed by the domes of the lobular cartilages and their medial crura form the columella.