Superficial skeletal muscle activation is associated with an electric activity. Bidimensional High-Density Surface Electromyography (HD-sEMG) is a non-invasive technique that uses a grid of equally spaced electrodes applied on the skin surface to detect and portray superficial skeletal muscle activation. The goal of the study was to evaluate the feasibility of HD-sEMG to detect electrical activation of skeletal muscle and its application during rehabilitation exercises in horses. To fulfil this aim, activation of the superficial descending pectoral and external abdominal oblique core muscles were measured using HD-sEMG technology during dynamic mobilization exercises to induce lateral bending and flexion/extension tasks of the trunk. Masseter muscle was instrumented during mastication as a control condition. A 64 surface EMG channel wireless system was used with a single 64 electrode grid or a pair of 32 electrode grids. HD-sEMG provided unique information on the muscular activation onset, duration, and offset, along each motor task, and permitting inferences about the motor control strategy actuated by the central nervous system. Signals were further processed to obtain firing frequencies of few motor-neurons. Estimation of electromyographic amplitude and spectral parameters allowed detecting the onset of muscular fatigue during the motor tasks performed. HD-sEMG allows the assessment of muscular activation in horses performing specific motor tasks, supporting its future application in clinical and research settings.

Background/Objectives: The equine proximal interphalangeal joint (PIPJ), while often considered a low-motion joint, contributes to flexion/extension of the digit and accommodates multi-planar movements: the adduction/abduction and the internal/external rotation of the middle phalanx in comparison to the proximal phalanx. Its collateral ligaments are primary stabilizers, restricting movements of the equine digit outside the sagittal plane, and their injury often leads to joint instability and degenerative joint disease. End-stage degenerative joint disease in the PIPJ could be managed with surgical arthrodesis of the joint. After surgical arthrodesis of the PIPJ, joint fusion cause loss of PIPJ extension in late stance of the stride during locomotion, which is accommodated by increased extension of the distal interphalangeal joint (DIPJ). To validate joint-preserving repair techniques after a collateral ligament injury in replacement of arthrodesis, a reliable method for assessing PIPJ extrasagittal biomechanics is required. The objective of this study was to develop and validate a three-point bending test setup to quantitatively characterize the mechanical behaviour of the equine PIPJ during abduction/adduction, simulating loading conditions that challenge the collateral ligaments of the joint. Methods: Seven equine PIPJ specimens (five forelimb and two hindlimb) were tested. A customised 3D-printed system was used to stabilise the joints in an MTS testing system. A three-point bending test was performed to evaluate the joint's mechanical response to the mediolateral plane bending. A marker-based video analysis system with a custom MATLAB script was used to calculate the joint abduction/adduction bending angle. Results: The setup provided reproducible load-displacement and time-angle data. The use of a fixed loading rod and custom 3D-printed system minimized slippage and rotation. The forelimb PIPJs exhibited significantly greater maximum medio-lateral bending angles compared to hindlimb joints. No significant differences were observed between fresh and frozen-thawed specimens. Conclusions: The developed three-point bending test setup provides a reliable and reproducible method for the in vitro evaluation of the biomechanical of the equine PIPJ. This study establishes a baseline for healthy joints and is suitable for the future comparative assessment of novel surgical techniques for collateral ligament repair.

Internal bleeding and mucosal bleeding in hollow organs are uncommon conditions in equine medicine and endoscopy. Most of the times, they respond to treatment of the underlying primary condition. However, there are cases in which a rapid and effective control of blood loss is required and the animal is not suited for surgery or general anaesthesia. We report two cases referred to our Veterinary Teaching Hospital with signs of urinary disease and bladder haemorrhage identified by cystoscopy which were successfully managed with topical application of a haemostatic carboxymethyl-starch powder. The product was applied directly on the bleeding mucosa after bladder emptying either under endoscopic guidance or blindly, through a urinary catheter. The application of the haemostatic powder appears to be easy to perform, safe, and helpful in controlling mucosal bleeding in hollow organs in the short time, with no adverse reactions noticed. This approach should be considered in cases where mucosal bleeding can be identified by endoscopy and a prompt control of blood loss is required, also in the field.