The Anatomy of the Articularis Genus Muscle and Its Relation to the Extensor Apparatus of the Knee

Abstract

Background:The anatomy of the articularis genus muscle has prompted speculation that it elevates the suprapatellar bursa during extension of the knee joint. However, its architectural parameters indicate that this muscle is not capable of generating enough force to fulfill this function. The purpose of the present study was to investigate the anatomy of the articularis genus, with special emphasis on its relationship with the adjacent vastus intermedius and vastus medialis muscles.Methods:The articularis genus muscle was investigated in 18 human cadaveric lower limbs with use of macrodissection techniques. All components of the quadriceps muscle group were traced from origin to insertion, and their affiliations were determined. Six limbs were cut transversely in the middle third of the thigh. The modes of origin and insertion of the articularis genus, its nerve supply, and its connections with the vastus intermedius and vastus medialis were studied.Results:The muscle bundles of the articularis genus were organized into 3 main layers: superficial, intermediate, and deep. The bundles of the superficial layer and, in 60% of the specimens, the bundles of the intermediate layer originated from both the vastus intermedius and the anterior and anterolateral surfaces of the femur. The bundles of the deep layer and, in 40% of the specimens, the bundles of the intermediate layer arose solely from the anterior surface of the femur. The distal insertion sites included different levels of the suprapatellar bursa and the joint capsule. A number of connections between the articularis genus and the vastus intermedius were found. While the vastus medialis inserted into the whole length of the vastus intermedius aponeurosis, it included muscle fibers of the articularis genus, building an intricate muscle system supplied by nerve branches of the same medial deep division of the femoral nerve.Conclusions:The articularis genus, vastus medialis, and vastus intermedius have a complex, interacting architecture, suggesting that the articularis genus most likely does not act as an independent muscle. With support of the vastus intermedius and vastus medialis, the articularis genus might be able to function as a retractor of the suprapatellar bursa. The finding of likely interplay between the articularis genus, vastus intermedius, and vastus medialis is supported by their concurrent innervation.Clinical Relevance:The association between the articularis genus, vastus medialis, and vastus intermedius may be more complex than previously believed, and this close anatomical connection could have functional implications for knee surgery. Dysfunction, scarring, or postoperative arthrofibrosis of the sophisticated interactive mechanism needs further investigation.

The morphology of the subacromial and related shoulder bursae. An anatomical and histological study

“…The deltoid muscle fibres which insert into the SAB subdeltoid fascia are further hypothesised to contribute to the control of bursal movement during shoulder abduction, by lifting the SAB roof to avoid entrapment underneath the acromion (Birnbaum & Lierse, 1992; Birnbaum et al, 1998). This mechanism could be likened to the relationship of the articularis genus muscle and suprapatellar bursa in the knee (Grob et al, 2017). However, functional studies are needed to establish the role of deltoid and the subdeltoid fascia on the SAB.…”

Ectopic Fibres of Articularis Genu

“…1 Karl Grob MD et al (2017) conducted a study on the Anatomy of articularis genu muscle on 18 specimens and reported 3 to 6 mucle bundles in all specimens. 2 Reportedly the articularis genu muscle is present in 80-100% individuals. Types of fibres present in the muscle was described by a study conducted by Kobayashi et al (2018).…”

Suprapatellar bursitis in a newborn

“…В нашем случае, исходя из данных анамнеза, клинической картины и результатов инструментальных исследований, мы не стали назначать антибактериальную терапию, сделав предположение, что бурсит является не гнойным, а асептическим. В качестве предпосылок для возникновения асептического бурсита у новорожденных, полагаем, следует рассматривать анатомические и топографические особенности супрапателлярной сумки [11,12], которые, в сочетании с чрезмерным внешним механическим воздействием на коленный сустав, например, при форсированном удержании рукой во время проведения какой-либо процедуры, могут быть сопоставимы с получением травмы у детей других возрастных групп при ударе, падении или от других внешних причин. Хотя описание подобных случаев для детей в периоде новорожденности в литературе мы не обнаружили.…”