Fabella

As fabella ( lat. Diminutive of lat. Faba "Bean"), even Os sesamoideum musculi gastrocnemii or Vesalisches sesamoid (by Andreas Vesalius ) is called a sesamoid (into a tendon intercalated ossicles ) in the original tendon of the musculus gastrocnemius . It is located on the back of the knee joint , just above the condyle of the femur .

When looking at lateral x-rays of the knee joint , the question of a traumatically detached bone fragment often arises. However, in contrast to a fragment, the fabella has a cortex on all sides without interruption of continuity and is to be regarded as a standard variant .

In this context, the Stieda-Pellegrini-Koehler shadow , an ossification in the tendon attachment of the adductor magnus , gracilis or in the inner lateral knee ligament, which can be acquired (calcification) or caused by trauma, should also be included in the differential diagnosis . However, this only occurs medially (on the inside).

From a physiological point of view, the fabella is a kind of pulley (med. Hypomochlion ), which enables more effective muscle forces through more favorable angles of the tendons.

The fabella occurs in 10 to 20% of all people at the origin of the lateral head of the gastrocnemius muscle, somewhat more frequently in women than in men. 2 or 3 such bones ( Fabella bi- or tripartita ) are less common . In predators (e.g. dogs , cats ) fables always occur on both sides, i.e. in the tendons of both heads of the gastrocnemius muscle.

The fabella has appeared more and more over the past 150 years. A meta- study based on 58 studies found a 3.5-fold increase in incidence in 2019. In 1918, 11% of the world's population still owned a table, a hundred years later it was 39%.

"Fabella Syndrome"

If a patient's pain comes from the area in which the fabella is located, the jargon term “ Fabella syndrome ” is used in some cases (as a working diagnosis) . If, in special cases, the fabella is actually the starting point and cause of the complaints ( fabella dolorosa ), surgical removal could possibly be carried out if there is a groundbreaking indication .

Individual evidence

1. ↑ Fabella prevalence rate increases over 150 years, and rates of other sesamoid bones remain constant: a systematic review . ResearchGate.net , April 2019; accessed on July 22, 2019.
2. ↑ Tiny Knee Bone, Once Lost in Humans, Is Making a Comeback . the-scientist.com, April 19, 2019; accessed on July 22, 2019.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !