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 tensor fascia latae (tensorfascia femoris) is a short, thick, teardrop-shaped muscle that is located on the outer front corner of the ilium (pelvis). It connects the ilium to the tissues of the thigh. The muscle's form begins at the front point of the hip, where it originates from the anterior superior spine and adjacent lateral surface of the ilium, and ends where the muscle inserts in the iliotibial band. The tensor fascia latae is innervated by the superior gluteal nerve and supplied by the gluteal artery and somewhat by the femoral cricumflex artery. In the standing position, the belly of this muscle becomes stretched into an elongated oval shape, but as the thigh is flexed, it changes into its characteristic teardrop shape. This muscle flexes, abducts, and medially rotates the thigh. Research Tensor Fascia Latae
The tensor tarsi muscle is located on the inner side of the orbit of the oculi orbit. It is a small thin muscle about three lines in breadth and six in length. This muscle draws the eyelid inward and compresses the lachrymal sac, producing tears. Research Tensor Tarsi
The tensor veli palatini muscle (tensor palati; palatosalpingeus; sphenosalpingostaphylinus) is a small muscle of the soft palate. It originates from the sphenoid bone and the eustachian tube and inserts in the border of the hard palate. The tensor velati palatini is innervated by branches of the trigeminal nerve through the otic ganglion. This muscle tenses the soft palate, which opens the eustachian tube helping to equalize the air perssure within the middle ear. Research Tensor Veli Palatini
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Orbicularis Oculi
