Gross, computed tomographic, and endoscopic anatomy of the equine carpal extensor tendon sheaths.
Authors: Baldwin Christopher M, Morgan Rhiannon E, Crawford Andrew L, Villarino Nicolas F, Rubio-Martínez Luis M
Journal: Veterinary surgery : VS
Summary
# Equine Carpal Extensor Tendon Sheath Anatomy: Improving Clinical Access Pathology affecting the extensor carpi radialis sheath (ECRS) and common digital extensor sheath (CDETS) presents a diagnostic and therapeutic challenge in equine practice, yet detailed anatomical guidance for endoscopic treatment has been limited. Baldwin and colleagues used 30 cadaver equine thoracic limbs to map the three-dimensional anatomy of these sheaths via computed tomography and gross dissection, then validated single-portal endoscopic techniques for visualising each structure. CT imaging proved consistent with gross anatomical findings, and endoscopic examination was feasible via a medial portal at the level of the extensor carpi obliquus-radialis intersection (for ECRS) and a lateral portal 5 cm proximal to the lateral styloid process of the ulna (for CDETS), with substantial to moderate interobserver agreement (κ = 0.73 and 0.53 respectively). These standardised single-portal approaches provide clinicians with reproducible techniques for thorough visualisation of the majority of both sheaths, enabling more confident diagnosis and treatment of tenosynovitis, foreign bodies, adhesions, and other intrathecal pathology without the need for multiple access points. For practitioners managing carpal lameness cases, these anatomically defined portals offer a practical foundation for implementing endoscopic treatment protocols with greater precision and potentially reduced morbidity compared to traditional open approaches.
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Practical Takeaways
- •These precise anatomical landmarks and portal locations enable practitioners to perform safe and effective single-portal endoscopic examination and treatment of carpal extensor tendon sheaths
- •CT imaging can reliably depict intrathecal anatomy of these sheaths before endoscopy, improving diagnostic confidence and surgical planning
- •Standard single-portal approach provides good visualization of most pathology in both sheaths, potentially simplifying clinical treatment protocols
Key Findings
- •ECRS and CDETS anatomy was consistent between gross dissection and CT examinations, validating CT as a diagnostic tool
- •Single-portal endoscopic technique achieved substantial interobserver agreement (κ=0.73) for ECRS visualization and moderate agreement (κ=0.53) for CDETS visualization
- •Optimal ECRS endoscopic portal is medial at the intersection of extensor carpi obliquus and extensor carpi radialis tendons; CDETS portal is lateral 5 cm proximal to lateral styloid process of ulna
- •Described single-portal endoscopic techniques allowed consistent visualization of the majority of both ECRS and CDETS with no iatrogenic damage reported