Levator Palpebrae Superioris

Absence of the levator palpebrae superioris has been noted.

When the muscle is present, a slip (tensor trochleae [Budge]) may arise from its belly or proximal part and may pass to the sclera, trochlea of the superior oblique, or neighboring tissues.

Another slip (transversus orbitis [Bochdalek]) may be found between the medial and lateral walls off the orbita and connects with the levator in the midline.The reported frequency of these muscles (15 of 20 cases, 75%) is probably much too high as the rarity of these muscles has also been reported (Isomura, about 3%, 5 in 85 individuals).

Fleshy bundles may pass from the front and upper part of the planum of the ethmoid bone across the orbit to the levator.

A fasciculus that sometimes passes from the lateral border of the muscle to the lacrimal gland has an effective action as a retractor glandulae lacrimialis. Its presence replaces the normal fascial connection between the levator and lacrimal gland.

Macalister reports the following for this muscle; Levator palpebrae superioris:

1. may be joined to the superior rectus at its origin (Albinus, Kelly, Macalister). It may arise from the posterior margin of the frontal part of the roof of the orbit, in front of, and above the optic foramen, separate from other muscles
2. The muscle may be doubled (Albinus), the second muscle (comes obliqui superioris) being slender. This accessory oblique has been described by Bochdalek, Jr. (1868) as gracillimus orbitis and also by Sandifort (1783). Even Vesalius reported that the levator may be doubled. According to Macalister, Boldrini (1669) saw a similar slip but called it a fifth rectus muscle as did Kulmus (1724). Macalister described a case of absence of levator palpebra superioris existing without ptosis. He has also seen it attached:
3. to the upper margin of the tarsal cartilage
4. Into the tarsal cartilage, and into the conjunctiva of the superior palpebral sinus
5. Into the latter alone
6. Into the ciliary fibers of the orbicularis palpebrarum
7. Or a triple insertion into all three.

See also the extraocular muscles for illustrations.

Syn.: m. orbicularis internus s. palepbralis (Henle).

Riferimenti dell’opera originale

Elenco riportato come compare nella fonte, senza normalizzazione dei formati bibliografici.

• Anson, B.J., Ed. (1966) Morris' Human Anatomy,12th ed., The Blakiston Division, McGraw-Hill Book Company, New York.
• Henle, J. (1871) Handbuch der Muskellehre des Menschen, in Handbuch der systematischen Anatomie des Menschen. Verlag von Friedrich Vieweg und Sohn, Braunschweig.
• Isomura, G. (1977) Nerve supply for an anomalous ocular muscle in man. Anat. Anz. 142:255-265.
• Laterjet, A. 91948) Testut's Trait é D'Anatomie Humaine, 9th ed., G. Doin & Cie., Paris
• LeDouble, A.F. (1897) Traité des Variations du Systéme Musculaire de l'Homme et Leur Signification au Point de l'Anthropologie Zoologique, Libraire C. Reinwald, Scheicher Freres, Paris.
• Macalister, A. (1875) Additional observations on muscular anomalies in human anatomy (third series), with a catalogue of the principal muscular variations hitherto published. Trans. Roy. Irish Acad. Sci. 25:1-134.
• Posey, W.C. (1924) Concerning some gross structural anomalies of the muscles of the eye and its adnexia. Archives of Ophthalmology. 53:344-354.