McGuigan M P, Wilson A M
Veterinary Basic Sciences, The Royal Veterinary College, North Mymms, Hatfield, Hertfordshire, UK.
Equine Vet J. 2001 Mar;33(2):166-71. doi: 10.2746/042516401778643363.
Horses with navicular disease have an increased load on the navicular bone in early stance. This has been suggested to be a response to pain in the heel region. Seven horses with clinical, radiographic and scintigraphic signs of navicular disease underwent forceplate and kinematic analysis before and after desensitisation of the heel region with a bilateral palmar digital nerve block. The compressive force exerted on the navicular bone during stance, and stride kinematics, were determined in each state. After regional analgesia of the palmar digital nerves (PDNB) the compressive force on the navicular bone was lower throughout stance. The mean +/- s.d. peak force at the beginning of stance was 7.05+/-1.10 N/kg before, and 6.46+/-1.15 N/kg after PDNB (P = 0.01) and at the end of stance the mean peak values were 5.00+/-2.05 N/kg before, and 4.39+/-1.65 N/kg after PDNB (P = 0.05). We explained this finding as indicating that the horse responds to heel pain (including pain in the navicular region) by contracting the deep digital flexor muscle to unload the heels. This increases the compressive load on the navicular bone, which may cause remodelling and, in some horses, damage to the overlying flexor cartilage, which is then painful and identified as navicular disease. This mechanism identifies navicular disease as a possible end point for a variety of heel related conditions.
患有舟状骨病的马匹在站立初期舟状骨承受的负荷会增加。这被认为是对蹄跟区域疼痛的一种反应。七匹具有舟状骨病临床、放射学和闪烁扫描征象的马匹，在通过双侧掌侧指神经阻滞对蹄跟区域进行脱敏前后，接受了测力板和运动学分析。测定了每种状态下站立期间施加在舟状骨上的压力以及步幅运动学参数。在掌侧指神经区域镇痛（PDNB）后，整个站立过程中舟状骨上的压力较低。站立开始时的平均±标准差峰值力在PDNB前为7.05±1.10 N/kg，PDNB后为6.46±1.15 N/kg（P = 0.01）；站立结束时的平均峰值在PDNB前为5.00±2.05 N/kg，PDNB后为4.39±1.65 N/kg（P = 0.05）。我们将这一发现解释为表明马匹通过收缩指深屈肌以减轻蹄跟负荷来应对蹄跟疼痛（包括舟状骨区域的疼痛）。这会增加舟状骨上的压缩负荷，这可能会导致重塑，并且在一些马匹中会对上覆的屈肌软骨造成损伤，进而引起疼痛并被认定为舟状骨病。这种机制将舟状骨病确定为各种与蹄跟相关病症的一个可能终点。
