Encyclopedia entry
Piriformis
Abstract
The most frequent variation is the division of the muscle into two parts. This is usually associated with a high division of the sciatic nerve, with the peroneal portion of the sciatic emerging between the two parts. The muscle is rarely divided by the tibial division of the sciatic, or by the entire sciatic nerve. The cleavage generally affects only the muscle belly, but may involve the entire muscle. Subdivision into several fascicles has also been reported. The muscle has been reported absent as well.
The most frequent variation is the division of the muscle into two parts. This is usually associated with a high division of the sciatic nerve, with the peroneal portion of the sciatic emerging between the two parts. The muscle is rarely divided by the tibial division of the sciatic, or by the entire sciatic nerve. The cleavage generally affects only the muscle belly, but may involve the entire muscle. Subdivision into several fascicles has also been reported. The muscle has been reported absent as well. Fusion frequently takes place between piriformis and gluteus medius, gluteus minimus, superior gemellus, or in rare cases even the internal obturator muscle. Its digitations of origin may be reduced to two or increased to four. It may insert into the capsule of the hip joint.
Syn.: m. pyramidalis, iliacus externus (Riolan), Birnmuskel.
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.
- Beaton, L.E. and B.J. Anson. (1938) The relation between the sciatic nerve and of its subdivisions to the piriformis muscle. Anat. Rec. 70:1-5.
- Celli, E. (1914) Sur la morphologie du M. Piriformis. Arch. Ital. Biol. 41:132-133.
- Fredericq, H. (1908) Un cas de division complete du nerf grand sciatique accompagnee d'une duplicite complete du muscle pyramidal. L'Assoc. Anatomistes, Comptes Rendus 10:168-170.
- Henle, J. (1871) Handbuch der Muskellehre des Menschen, in Handbuch der systematischen Anatomie des Menschen. Verlag von Friedrich Vieweg und Sohn, Braunschweig.
- Kawano, M. (1930) On the M. piriformis. Kaibogaku Zasshi 2:1017-1021. In Japanese.
- Macalister, A. (1875) Observations on muscular anomalies in the human anatomy. Third series with a catalogue of the principal muscular variations hitherto published. Trans. Roy. Irish Acad. Sci. 25:1-130.
- Moore, A.T. (1922) An anomalous connection of the piriformis and biceps femoris muscles.Anat. Rec. 23:307-309.
Anatomical classification
- Systems:
- Muscular system
Content provenance
Adaptation
Adaptation of «Piriformis — Illustrated Encyclopedia of Human Anatomic Variation: Opus I: Muscular System» by Ronald A. Bergman, Adel K. Afifi, Ryosuke Miyauchi. Source: https://www.anatomyatlases.org/AnatomicVariants/MuscularSystem/Text/P/24Piriformis.shtml Original work distributed under the CC BY-NC-SA 4.0 licence (https://creativecommons.org/licenses/by-nc-sa/4.0/deed.it). Adaptation by Redazione AIVA. Changes from the original: Testo originale inglese riprodotto integralmente e riorganizzato nel formato scheda del portale (sintesi, testo, riferimenti), senza modificarne le affermazioni. La traduzione italiana non è ancora stata eseguita, e la pagina lo dichiara. Le figure non sono state copiate: sono collegate alla pagina d’origine. This publication is not approved or endorsed by the authors of the original work.
Licence
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