European Journal of Anatomy

Official Journal of The Spanish Society of Anatomy
Cover Volume 22 - Number 2
Eur J Anat, 22 (2): 103-109 (2018)

Fabella and cyamella of the human knee joint: discovery by dissection and ultrasound examination

Claudio Corvalan, Cynthia Tang, Marcus Robinson

Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, NSW Australia

ABSTRACT Perhaps due to the lack of clinical relevance, several anatomical structures such as the fabella and cyamella of the knee have been overlooked or not included in anatomical textbooks, suggesting that they are not significant enough to be acknowledged. This occurs despite studies that have demonstrated recurrent presence of these particular structures. The purpose of the current study was to characterize the finding of two sesamoid bones from the human knee: the fabella and cyamella. The basis of this study used 111 knees of embalmed cadavers from 74 individuals from the donor bequest programme at The University of Sydney. Of these, 37 were paired knees and 37 were unilateral knees (39 female, 35 male). The mean age of the donors was 84 years (range 45-97 years). Comparative analysis using ultrasound imaging was performed followed by dissection to confirm findings. Overall, 63 fabellae were found, with 60.8% of the cadavers having at least one fabella (65.7% in male and 56.4% in female). Three cyamellae were found in three donors respectively. Considering all cadavers, the incidence of cyamellae was 2.7%, making this an incidental finding rather than an anatomical variant. Due to the low prevalence, imaging diagnostic techniques may be useful in identifying these anatomical structures and characterising their variations in detail.Furthermore, they could provide an insight to these ‘forgotten’ structures and their potential roles in failure correlated with surgical techniques, misdiagnoses or prevalence of chronic pathologies of the knee.

Keywords: Sesamoid bones – Cyamella – Fabella – Knee – Variations

European Journal of anatomy
ISSN 2340-311X (Online)