The angular artery begins at the end of the facial artery. It ascends toward the eye, supplying the lachrymal duct and orbicularis palpebrarum muscles. The angular artery also has branches in the cheek. Research Angular Artery
The eyelids are two folds of skin that shield the eyeball. The upper lid is larger and more movable. It regulates the opening and closing of the eye with the help of the orbicularis palpebrarum muscle. Lower-lid movement is slight. The eyelids sweep dirt from the surface of the eye, protect it from injury, and help distribute the tear fluid. When the eye is closed, the lids unite at the lid-slit in a downward curve. The corners of the eye are called the inner canthus, which is near the opening of the lachrymal duct, and the outer canthus, which ends in the crease where the upper lid overlaps the lower lid. The eyelid is lined with a mucousmembrane called the conjunctiva. This lining also covers the front of the eyeball. This covering, when washed with tears, gives the eye its glossy appearance. Research Eyelid
The levator palpebrae muscle (orbitopalpebralis) is a thin flat muscle with a triangular shape that is situated in the eyelid. It originates from the orbital portion of the lesser wing of the sphenoid bone and inserts in several places along the skin of the eyelid and the orbital walls. It is innervated by the oculomotor nerve. This muscle raises the eyelid, the direct opposite of the orbicularis palpebrarum muscle. These muscles are used together to blink and to close the eye during sleep. Research Levator Palpebrae Muscle
The levator palpebrae superioris is a thin flat muscle with a triangular shape that is situated in the eyelid. This muscle raises the eyelid, the direct opposite of the orbicularis palpebrarum muscle. These two muscles are used to blink and during sleep. The
levator palpebrae superioris originates from the lesser wing of the sphenoid bone and inserts into the walls of the orbit. It is innervated by the third cranial nerve (oculomotor) and is supplied by branches of the ophthalmic artery. Research Levator Palpebrae Superioris
The orbicularis oculi (sphincter oculi; orbicularis palpebrarum) muscle is a broad, thin, ring shaped layer of muscle that covers the eyelid and the surrounding orbit. Because of its shape it is classified as a sphincter muscle. The muscle is composed of three parts: the palpebral portion, the orbital portion, and the lachrimal portion. The palpebral portion covers the eyelid. It originates from the palpebral ligament, passes over each eyelid and inserts in the palpebral raphe. The orbital portion of the muscle surrounds the orbit, extending from the bottom of the forehead down to the front of the cheek. It originates from the frontal process of the maxilla (upper jaw), encircles the orbit, and inserts near its point of origin. The upper fibres of the orbital portion blend with the occipito- frontalis and corrugator supercilli. The lachrimal portion (tensor tarsi; Horner's muscle; Duverney's muscle) originates from the lachrimal crest inside of the bridge of the nose and passes across the lachrimal sac to insert with the palpebral portion of the muscle. This muscle is innervated by the facial nerve and supplied by the angular artery and branches of the temporal artery. The three portions work together to narrow the eye, thus causing the eye to close or blink. Research Orbicularis Oculi
The orbicularis palpebrarum refers to the palpebral portion of the orbicularis oculi (sphincter oculi) muscle. The orbicularis oculi is a broad, thin, ring shaped layer of muscle that covers the eyelid and the surrounding orbit. Because of its shape it is classified as a sphincter muscle. The muscle is composed of three parts: the palpebral portion, the orbital portion, and the lachrimal portion. The palpebral portion covers the eyelid. It originates from the palpebral ligament, passes over each eyelid and inserts in the palpebral raphe. The orbital portion of the muscle surrounds the orbit, extending from the bottom of the forehead down to the front of the cheek. It originates from the frontal process of the maxilla, encircles the orbit, and inserts near its point of origin. The upper fibres of the orbital portion blend with the occipito-frontalis and corrugator supercilli. The lachrimal portion (tensor tarsi; Horner's muscle; Duverney's muscle) originates from the lachrimal crest inside of the bridge of the nose and passes across the lachrimal sac to insert with the palpebral portion of the muscle. This muscle is innervated by the facial nerve and supplied by the angular artery and branches of the temporal artery. The three portions work together to narrow the eye, thus causing the eye to close or blink. Research Orbicularis Palpebrarum
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Angular Artery
