Miles Samantha, McCauley Charles, Carossino Mariano, Del Piero Fabio, Liu Chin-Chi, Gaschen Lorrie
Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America.
Department of Pathobiological Sciences and Louisiana Animal Disease Diagnostic Laboratory, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America.
PLoS One. 2025 Jul 21;20(7):e0327880. doi: 10.1371/journal.pone.0327880. eCollection 2025.
Manica flexoria tears are increasingly recognized as a cause of lameness in horses resulting in a need for improved pre-operative diagnosis. Partial tears are difficult to pre-operatively diagnose and thus research for diagnostics of manica flexoria tears has been seen in increasing frequency over the past decade, though a deficit of information exists for the features of this structure on MRI, which is best suited for evaluation of soft tissues. The goal is to perform an observational study on the morphometry of the normal manica flexoria prospectively and describe it retrospectively on MRI. Inclusion criteria includes: MRI of the metacarpophalangeal/metatarsophalangeal regions in non-lame limbs without MRI tendon abnormalities identified, and the entire manica flexoria included on transverse proton density-weighted images. The manica flexoria on MRI was measured at the proximal and distal margins, halfway between (middle), and halfway between the middle and proximal margin (proximal fourth), with measurements including dorsal, lateral/medial and dorsolateral/dorsomedial thickness. Eighteen MRI studies fit the inclusion criteria: 6 forelimbs, 12 hindlimbs. The manica flexoria on gross dissection was thicker proximally in forelimbs, and thinner proximally in hindlimbs where it blends with overlying fascia. On proton density-weighted images, the manica flexoria was hyperintense to the superficial digital flexor tendon (12/18), isointense (3/18), or hyperintense proximally and isointense distally (3/18). The proximal fourth dorsal measurements were the thickest in both forelimbs and hindlimbs on MRI images compared to other measurement sites within the same limb. The forelimb medial aspect was thicker than the lateral aspect in the proximal fourth and middle (average 17.1% thicker, p = 0.0372, 22.7% p = 0.0183, respectively), and in the hindlimb the lateral aspect was thicker in these regions (average 50.4% thicker p = 0.0099 and 23.7% p = 0.0394, respectively). This study provides an anatomical and morphometric reference for future studies evaluating abnormalities of the manica flexoria on MRI.
掌侧腱鞘撕裂越来越被认为是马匹跛行的一个原因，因此需要改进术前诊断。部分撕裂很难在术前诊断出来，因此在过去十年中，对掌侧腱鞘撕裂诊断方法的研究越来越频繁，不过对于最适合评估软组织的MRI上该结构的特征，目前仍缺乏相关信息。目的是对正常掌侧腱鞘的形态进行前瞻性观察研究，并通过MRI进行回顾性描述。纳入标准包括：非跛行肢体掌指关节/跖趾关节区域的MRI，且未发现MRI肌腱异常，横断质子密度加权图像包含整个掌侧腱鞘。在MRI上，测量掌侧腱鞘近端和远端边缘、两者中间（中部）以及中部与近端边缘中间（近端四分之一处）的厚度，测量包括背侧、外侧/内侧以及背外侧/背内侧厚度。18项MRI研究符合纳入标准：6个前肢，12个后肢。大体解剖时，前肢掌侧腱鞘近端较厚，后肢近端较薄，且与上方筋膜融合。在质子密度加权图像上，掌侧腱鞘相对于指浅屈肌腱呈高信号（12/18）、等信号（3/18），或近端高信号、远端等信号（3/18）。与同一肢体的其他测量部位相比，MRI图像上前肢和后肢近端四分之一处的背侧测量值最厚。在前肢近端四分之一处和中部，内侧比外侧厚（平均厚17.1%，p = 0.0372；平均厚22.7%，p = 0.0183），在后肢这些区域外侧比内侧厚（平均厚50.4%，p = 0.0099；平均厚23.7%，p = 0.0394）。本研究为未来评估MRI上掌侧腱鞘异常的研究提供了解剖学和形态学参考。
