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abstract
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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.
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