Orbit Anatomy

Within our skull, we have a bony structure that holds our orbital anatomy: the globe, extraocular muscles, nerves, blood vessels, lacrimal apparatus, and adipose tissue. The orbital bones protect the eye, support movement/function of the eye, and connect the eye to the optic nerve, blood vessels, arteries, and tear duct. The orbit is actually structured like a pyramid with four sides, namely the roof, lateral wall, floor, and medial wall. These bones are thick at the front and back, and thinner at the floor/walls.

Subcutaneous tissue

Subcutaneous tissue within the orbital region consists of a thin layer of loose connective tissue beneath the eyelid skin. It contains very little fat and is the thinnest layer of skin on the body. Its loose connective tissue allows for some eyelid movement and flexibility. The orbital septum is a connective tissue region that keeps the eyelid separate from the orbital fat pads, preventing fat from herniating into the eyelids. Because of the minimal fat content in this region, eyelid skin is more likely to show signs of aging, such as wrinkles, droopiness, and puffiness.

Lacrimal Anatomy

Lacrimal Gland

The lacrimal gland is within the orbit and releases tears which cleanses and protects the eye’s surface as it lubricates and moistens it. More information on the lacimal gland is provided in the lacrimal system link.

Accessory Glands of Krause and Wolfring

The glands of Krause and Wolfring are accessory lacrimal glands that help produce tears and are located in the conjunctiva and tarsal plates. Specifically, the glands of Krause are located in the stroma of the conjunctival fornix and the Glads of Wolfring are located along the nonmarginal border of the tarsal plates.

Canalicular System

Within the eye orbit, the canalicular system contains a system of small channels (lacrimal canaliculi) which drains tears from the eye to the nasal cavity through the lacrimal system. This drainage system begins with small openings on the eyelid margin called puncta, goes to the canaliculi, then empties into the lacrimal sac.

Bony System

The eye orbit contains seven bones, namely the frontal, sphenoid, maxillary, zygomatic, palatine, ethmoid, and lacrimal bones. These bones serve to protect the eye and provide an attachment to muscles and ligaments.

Lacrimal Pump Model

The lacrimal pump model shows how the orbicularis oculi muscle contracts occur during blinking, causing the pumping of tears from the eye surface into the nasolacrimal duct. The conduit is through a system of openings, namely the puncta, canaliculi, and the lacrimal sac.