Variations in the anatomy of the extensor tendons of the manus in the domestic cat (Felis catus) with a revision of their common pattern: a cadaveric study

Given discrepancies identified in current veterinary anatomy textbooks, we aimed to re-examine the anatomic patterns of the extensor tendons of the manus considering their prevalence and measurements. This study was conducted based on the dissection of the right and left distal forelimbs of 22 domestic short-haired cats (12 females and 10 males), fixed in 10% formalin solution. In the most frequent specimens (23 of 44 distal limbs -52.3%-), the m. extensor digitorum lateralis consisted of three bellies which sent three tendons to digits III-V and a tendon branch to digit II, which united with the extensor digiti I et II tendon to that digit, or inserted onto the medial aspect of the metacarpophalangeal joint capsule of digit III in 9.1% of distal limbs. In other cases, the tendon branch to digit II was absent or arose directly from the most medial belly of this muscle in 25% and 13.6% of distal limbs, respectively. The m. extensor digiti I et II was found to have two unequal bellies, leading to two medial and lateral tendons. The tendons exhibited 5 different configurations. In the most common specimens (68.2%), the medial tendon was bifurcated into two branches to digit I and the medial aspect of digit II as well as the lateral tendon ran to the lateral aspect of digit II to join the corresponding tendon of the extensor digitorum communis. According to this study, the current concepts of veterinary anatomical texts about the common pattern of the extensor tendons of the manus of domestic cats need to be revised, which could greatly contribute to the teaching of veterinary anatomy.