THE INTERCARPAL LIGAMENTS OF THE EQUINE MIDCARPAL JOINT .1. THE ANATOMY OF THE PALMAR AND DORSOMEDIAL INTERCARPAL LIGAMENTS OF THE MIDCARPAL JOINT

Objective-To describe in detail the structure of the medial palmar int ercarpal ligament (MPICL), the lateral palmar intercarpal ligament (LP ICL), and a dorsomedial intercarpal ligament (DMICL) of the equine mid carpal joint. Study Design-Dissections of equine midcarpal joints. Ani mals and Sample Population-Ten carpal joints from eight thoroughbred h orses. Methods-Detailed dissections of the midcarpal joint were perfor med, with particular attention paid to the MPICL, the LPICL, and the D MICL. The attachments and dimensions of these structures were recorded , as well as their behavior during joint movement. Results-The DMICL a rose from the dorsomedial surface of the radial carpal bone (CR) and c oursed palmarodistally to insert on the dorsomedial aspect of the seco nd carpal bone (C2). The LPICL attached proximally predominantly on th e distal part of the palmaromedial surface of the ulnar carpal bone (C U). From here the ligament coursed distomedially and slightly palmarly to the proximal palmarolateral surface of the third carpal bone (C3). The structure of the MPICL was complex. It attached proximally to the distolateral surface of the CR and distally to the proximal palmarome dial surface of C3, and the proximal palmarolateral aspect of the C2. It could be divided into four fiber bundles in all carpi. The predomin ant direction of fibers was dorsoproximal to palmarodistal, whereas th e palmaromedial bundle coursed palmaroproximal to dorsodistal. Conclus ions-The orientation of their fibers indicate that the MPICL and DMICL primarily resist dorsomedial displacement of CR, whereas the LPICL re sists dorsolateral displacement of the CU and intermediate carpal bone . Clinical Relevance-An understanding of the structure of the intercar pal ligaments of the midcarpal joint is important in interpreting thei r function and the reasons for damage to their structure. (C) Copyrigh t 1997 by The American College of Veterinary Surgeons.