Murray Rachel C, Roberts Bridget L, Schramme Michael C, Dyson Sue J, Branch Marion
Animal Health Trust, Lanwades Park, Kentford, Newmarket, CB8 7UU, UK.
Vet Radiol Ultrasound. 2004 Mar-Apr;45(2):103-11. doi: 10.1111/j.1740-8261.2004.04017.x.
Injury of the distal aspect of the deep digital flexor tendon (DDFT) is a recognized cause of lameness, but diagnosis is difficult. This study aimed to improve understanding of DDFT morphology and pathology using retrospective evaluation of magnetic resonance (MR) images. We hypothesized that: (1) The distal aspect of the DDFT in normal horses would have a repeatable proximal/distal pattern and symmetry between limbs and between lobes; (2) DDFT dimensions would be related to bodyweight, navicular bone dimensions and hoof size; (3) this symmetry and pattern would be lost in DDFT injury; and (4) DDFT size would increase with injury. MR images of 64 live horse limbs, 26 with no identified DDFT lesion and 38 with identified DDFT abnormalities, and 19 normal cadaver limbs were analyzed. Using standardized transverse images, measurements of DDFT cross-sectional area, medial-lateral (ML) width and dorsal-palmar depth were obtained at six preselected sites. A uniform distal to proximal shape pattern was identified in all horses. The flattened crescent shape at the insertion changed to a deeper bilobed shape more proximally, with the mid-navicular area having the greatest cross-sectional area. Strong ML (P < 0.0006) and left/right symmetry (P < 0.02) were observed. In addition, there was a strong association between DDFT cross-sectional area and horse weight (P = 0.005) and between DDFT and navicular bone ML width (P = 0.004). Symmetry between sides or between lobes was lost at sites with a unilateral lesion and correlation between horse weight and DDFT cross-sectional area was lost in the presence of lesions. DDFTs with core lesions had a consistent increase in cross-sectional area overall, but other lesion types had no significant increase in size. The shape and symmetry seen in normal tendons could be related to the mechanical demands placed upon individual lobes. The limited increase in cross-sectional area with injury may be explained by the restrictive structures of the hoof, possibly explaining the ongoing pain seen in such lesions.
指深屈肌腱（DDFT）远端损伤是导致跛行的一个公认原因，但诊断困难。本研究旨在通过对磁共振（MR）图像的回顾性评估，提高对DDFT形态学和病理学的认识。我们假设：（1）正常马匹的DDFT远端具有可重复的近端/远端模式，且四肢之间以及叶之间具有对称性；（2）DDFT尺寸与体重、舟骨尺寸和蹄大小相关；（3）DDFT损伤时这种对称性和模式会丧失；（4）DDFT大小会随损伤而增加。对64个活马肢体的MR图像进行了分析，其中26个未发现DDFT病变，38个发现了DDFT异常，另外还分析了19个正常尸体肢体的MR图像。使用标准化的横向图像，在六个预先选定的部位测量了DDFT的横截面积、内外侧（ML）宽度和背掌深度。在所有马匹中都识别出了从远端到近端的统一形状模式。在止点处扁平的新月形在更靠近近端处变为更深的双叶形，舟骨中部区域的横截面积最大。观察到较强的ML对称性（P < 0.0006）和左右对称性（P < 0.02）。此外，DDFT横截面积与马体重之间（P = 0.005）以及DDFT与舟骨ML宽度之间（P = 0.004）存在很强的相关性。在有单侧病变的部位，两侧或叶之间的对称性丧失，并且在存在病变的情况下，马体重与DDFT横截面积之间的相关性丧失。有核心病变的DDFT总体横截面积持续增加，但其他病变类型的大小没有显著增加。正常肌腱中所见的形状和对称性可能与各个叶所承受的机械需求有关。损伤时横截面积的有限增加可能由蹄的限制性结构来解释，这可能解释了此类病变中持续存在的疼痛。
