Moll glands are small sweat glands located at the eyelid margin, near the eyelashes. They are a normal part of eyelid anatomy and are present in both upper and lower lids. Clinicians refer to Moll glands when describing eyelid health and certain eyelid lumps. They are most commonly discussed in eye exams, eyelid disease, and minor eyelid procedures.

Zeis glands are tiny oil (sebaceous) glands located at the base of the eyelashes. They open into eyelash follicles and produce an oily secretion that helps lubricate the lash line. In clinical eye care, they are most often discussed during eyelid exams and when evaluating “styes” near the lashes. They are part of the broader system of eyelid margin structures that support ocular surface comfort.

meibomian glands are oil-producing glands located in the eyelids. They release an oily substance (meibum) onto the eye’s surface. This oil helps stabilize the tear film and reduce tear evaporation. The term is commonly used in dry eye care, eyelid disease evaluation, and pre-surgical eye assessments.

A canaliculus is a small channel in the eyelid that helps drain tears from the eye. In eye care, canaliculus most often refers to the lacrimal canaliculus, part of the tear drainage system. It connects the punctum (the tiny opening on the eyelid margin) to the lacrimal sac near the nose. Clinicians talk about the canaliculus when evaluating watery eyes, infections, or eyelid injuries.

A punctum is a tiny opening on the eyelid margin near the inner corner of the eye. It is part of the tear drainage system that moves tears from the eye surface into the nose. Clinicians use the term punctum in exams, imaging, and procedures that manage tearing and dry eye. It is commonly discussed in relation to punctal stenosis, tear drainage obstruction, and punctal plugs.

The nasolacrimal duct is part of the tear drainage system that carries tears from the eye into the nose. It connects the lacrimal sac near the inner corner of the eyelids to the nasal cavity. Clinicians discuss the nasolacrimal duct when evaluating watering eyes (epiphora) and recurrent infections. It is also a key structure in several common eye and ENT-adjacent procedures.

The lacrimal sac is a small collecting chamber in the inner corner of the eye’s drainage system. It gathers tears from the eyelids and helps move them into the nose. Clinicians discuss the lacrimal sac when evaluating watery eyes, infections near the nose bridge, or tear drainage blockage. It is also a key landmark in tear-duct testing and certain surgeries.

The lacrimal gland is the main tear-producing gland of the eye. It sits in the upper outer area of the eye socket, just above the eyelid. Its tears help keep the front of the eye smooth, comfortable, and clear. Clinicians commonly discuss the lacrimal gland when evaluating dry eye, swelling near the outer upper eyelid, or orbital (eye socket) disease.

The orbital apex is the narrow, deep “back corner” of the eye socket (orbit). It is the area where key nerves and blood vessels enter the orbit to reach the eye and eye muscles. Clinicians use the term orbital apex when describing anatomy, imaging findings, and certain vision-threatening conditions. It is also referenced in planning surgeries near the orbit, sinuses, or skull base.

The orbital septum is a thin sheet of fibrous tissue in the eyelids. It forms a boundary between the eyelid tissues and the deeper orbital (eye socket) contents. Clinicians use it as an anatomic landmark in eye exams, imaging interpretation, and eyelid surgery. It is discussed often when evaluating eyelid swelling or planning procedures around eyelid fat.

The orbit is the bony socket and surrounding space that contains the eye and its supporting structures. It includes muscles, nerves, blood vessels, fat, and connective tissue that help the eye move and function. In everyday language, “orbit” often means the eye socket. In eye care, orbit is a common term in exams, imaging reports, and surgical planning.

The conjunctival sac is the space between the eyelids and the front of the eye. It is lined by the conjunctiva, a thin, clear tissue that helps protect and lubricate the eye. Clinicians commonly use the conjunctival sac to place eye drops or ointment and to examine the ocular surface. It is also a practical location for rinsing the eye or collecting certain diagnostic samples.

Tenon capsule is a thin layer of connective tissue that forms a sheath around the eyeball. It sits between the white of the eye (sclera) and the conjunctiva (the clear surface lining). It helps the eye move smoothly and provides a “potential space” used in some eye injections and anesthesia. It is commonly referenced in eye surgery, orbital procedures, and “sub-Tenon” anesthesia or medication delivery.

orbicularis oculi is the circular muscle that surrounds the eyelids. It closes the eyelids for blinking and eye protection. Clinicians assess it during eye and facial nerve examinations. It is also a common target in treatments for eyelid spasm and some eyelid position problems.

The levator palpebrae is the main muscle that lifts the upper eyelid. It works with eyelid tissues that connect the muscle to the lid margin. In eye care, it is commonly discussed when evaluating droopy eyelids (ptosis) and planning eyelid surgery. It is also relevant in neurologic conditions that affect eyelid position.

The inferior oblique is one of the six extraocular muscles that move each eye. It helps rotate the eye outward (torsion) and contributes to looking up, especially when the eye turns inward. It is discussed most often in strabismus (eye misalignment) exams and eye muscle surgery planning. It is also a key structure in teaching eye movement anatomy and cranial nerve function.

The superior oblique is one of the six extraocular muscles that move each eye. It helps control eye rotation and coordination, especially during reading and looking down. Clinicians discuss the superior oblique in strabismus (eye misalignment), double vision, and certain nerve conditions. It is commonly evaluated in ophthalmology and optometry eye movement exams.

The inferior rectus is one of the six extraocular muscles that move the eye. It mainly helps the eye look downward and also contributes to subtle rotational and inward movements. Clinicians refer to the inferior rectus during eye movement exams and when evaluating double vision or eye misalignment. It is also an important structure in certain types of strabismus and orbital surgery planning.

The superior rectus is one of the six extraocular muscles that move the eye. It sits at the top of the eye socket and attaches to the eyeball. Its main job is to help lift the eye upward, with additional effects depending on gaze position. It is commonly discussed in eye movement exams, strabismus (eye misalignment) care, and orbital disease evaluation.

The lateral rectus is one of the six extraocular muscles that move each eye. Its main job is to pull the eye outward, away from the nose. Clinicians assess the lateral rectus during eye movement exams and when evaluating double vision or eye misalignment. It is also a common target in strabismus (eye alignment) treatment planning and surgery.