Objective The aim of this study was to characterize the radiographic alignment of thoracic and pelvic limbs and evaluate for intervertebral disc disease in cats with feline disproportionate dwarfism (FDD).

Study Design Observational cross-sectional study. Radiographic joint orientation angles were measured in 10 thoracic and pelvic limbs from 5 FDD cats and compared with those angles measured in 24 thoracic limbs and 100 pelvic limbs from skeletally normal cats. Magnetic resonance imaging of the spine was performed in 2 FDD cats for the evaluation of pathology of the intervertebral discs or vertebrae.

Results All limbs from FDD cats possessed deformities. FDD humeri demonstrated procurvatum proximally, and recurvatum distally in the sagittal plane, but showed no difference in the frontal plane. FDD radii possessed excessive recurvatum proximally, and procurvatum distally in the sagittal plane, and varus proximally and valgus distally in the frontal plane. Whereas no torsion was discernible in the humeri, all radii had external torsion. In the frontal plane, FDD femurs exhibited varus both proximally and distally whereas the tibia possessed proximal valgus and distal varus. No torsion in the pelvic limbs was observed. No spinal pathology was detected in the FDD cats included in the original study.

Conclusion Feline disproportionate dwarfism results in significant appendicular deformity in all limbs. The incidence of intervertebral disc degeneration in FDD cats is inconclusive.

目的 本研究的目的是表征不相称侏儒症 (FDD) 猫的胸部和骨盆四肢的放射线排列，并评估椎间盘疾病。

研究设计 观察性横断面研究。在 5 只 FDD 猫的 10 个胸椎和骨盆肢体中测量了射线照相关节方向角度，并与在骨骼正常猫的 24 个胸椎肢体和 100 个骨盆肢体中测量的角度进行了比较。对 2 只 FDD 猫进行了脊柱磁共振成像，以评估椎间盘或椎骨的病理学。

结果 FDD 猫的所有肢体都有畸形。FDD 肱骨在矢状面显示近端前屈和远端反屈，但在额状面上没有差异。FDD 桡骨在矢状面上近端过度后屈，在矢状面远端过度屈曲，在额状面近端内翻和远端外翻。虽然在肱骨中没有明显的扭转，但所有半径都有外部扭转。在额状面上，FDD 股骨在近端和远端均表现出内翻，而胫骨具有近端外翻和远端内翻。未观察到骨盆四肢扭转。在原始研究中包括的 FDD 猫中未检测到脊柱病理。

结论 猫不成比例的侏儒症导致四肢明显的阑尾畸形。FDD 猫椎间盘退变的发生率尚无定论。