Progressive urethral dilation in male horses undergoing perineal urethrotomy for cystolith removal: 22 cases.

This retrospective case series describes the use of progressive urethral dilation in 22 client-owned male horses undergoing perineal urethrotomy (PU) for cystolith removal. Medical records of horses undergoing PU and urethral dilation for treatment of cystolithiasis were reviewed. Dilation of the pelvic urethra was performed following PU and using customized dilators with the same length (30cm) and with various outer diameters (25 to 45mm). Analyzed data included: signalment, cystolith size, renal ultrasound findings, method used for cystolith removal, diameter of urethral dilators, intra- and post-operative complications, and hospitalization time. Cystolith size ranged between 37mm and 90mm. Dilation of the pelvic urethra was as follows: 35mm (n=8), 25mm (n=6), 39mm (n=3), 33mm (n=2), 28mm (n=2) and 45mm (n=1). In 6 cases, the cystolith was removed without fragmentation. In the remaining 16 horses, lithotripsy was performed with forceps (n=9) or a pneumatic scaler (n=7). In 15 horses a retrieval device was used to aid in calculi removal. Hospitalization time ranged between 1 and 5 days. Intra-operative complications occurred in one horse. No post-operative complications were recorded. Follow-up information was available for 21 horses (range 1-8 years). Urethral dilation via PU may be a viable option for cystolith removal in male horses.

Ex-vivo articular cartilage removal from equine proximal interphalangeal joints using cannulated drill bits.

Objective: This report evaluates the use of 4.5- and 5.5-mm cannulated drill bits for articular cartilage removal from the proximal interphalangeal joints of equine cadaver limbs. Animals: Limbs from 8 equine cadavers, all with normal proximal interphalangeal joints. Procedure: Proximal interphalangeal joints of 32 limbs from 8 equine cadavers were drilled using either 4.5- or 5.5-mm cannulated drill bits. Pastern joints were then disarticulated, and intra-articular drilling was evaluated by visual inspection. Results: Post-drilling evaluation revealed complete intra-articular drilling occurred in all 32 joints. Conclusion: Canulated 4.5- and 5.5-mm drill bits resulted in consistent accurate intra-articular drilling in the proximal interphalangeal joint of horses. Clinical relevance: Cannulated drill bits provided an effective and consistent modality for articular cartilage removal with potential for improved accuracy of articular drilling and applications in minimally invasive proximal interphalangeal joint arthrodesis.

Objectif: Ce rapport évalue l'utilisation de forets canulés de 4,5 et 5,5 mm pour l'élimination du cartilage articulaire des articulations interphalangiennes proximales des membres de cadavres équins. Animaux: Membres provenant de huit cadavres équins, tous avec des articulations interphalangiennes proximales normales. Procédure: Les articulations interphalangiennes proximales de 32 membres de huit cadavres équins ont été percées à l'aide de forets canulées de 4,5 ou 5,5 mm. Les articulations du paturon ont ensuite été désarticulées et le forage intraarticulaire a été évalué par inspection visuelle. Résultats: L'évaluation post-forage a révélé qu'un forage intra-articulaire complet s'était produit dans les 32 articulations. Conclusion: Les forets canulés de 4,5 et 5,5 mm ont permis un forage intra-articulaire précis et constant dans l'articulation interphalangienne proximale des chevaux. Pertinence clinique: Les forets canulés ont fourni une modalité efficace et constante pour l'élimination du cartilage articulaire avec un potentiel d'amélioration de la précision du forage articulaire et des applications dans l'arthrodèse de l'articulation interphalangienne proximale de manière minimalement invasive.(Traduit par Dr Serge Messier).

Standing flank laparotomy for colic: 37 cases.

BACKGROUND: Standing flank laparotomy can be an alternative to ventral midline laparotomy in horses with colic. Standing flank laparotomy avoids general anaesthesia, provides excellent access to some regions of the abdominopelvic cavity and costs less than ventral midline laparotomy. OBJECTIVE: To report a series of cases of peritoneal and intestinal diseases other than SC diseases managed with standing flank laparotomy. STUDY DESIGN: Retrospective case series. METHODS: Records from equids with colic subjected to standing flank laparotomy at five hospitals (2003-2020) were reviewed. Descriptive data analysis was performed. RESULTS: Thirty horses (sixteen survived to discharge), six ponies (four survived) and one donkey (euthanised) were subjected to standing flank laparotomy via the left flank (n = 31), right flank (n = 2) or both flanks (n = 4). The primary disease affected the peritoneum (0/5 survived), SI (5/9 survived) and caecum and/or LC (15/23 survived). Enterotomy was performed in four animals (all survived). Partial typhlectomy was performed in one horse (euthanised). Resection-anastomosis of the SI or LC was performed in three animals (one survived). Three animals had intraoperative complications that negatively affected the outcome: Two ponies had intolerance to abdominopelvic exploration; one mare had spontaneous exteriorisation of a long segment of the SI leading to a large tear in the mesentery. In seven cases, severe/extensive lesions found during standing flank laparotomy warranted immediate euthanasia. The survival rate was 54%. All owners were satisfied with the decision to perform standing flank laparotomy. MAIN LIMITATIONS: The retrospective design, lack of a control group, small number of cases and lack of standardised protocols between hospitals. CONCLUSIONS: Although ventral midline laparotomy is the standard of care for horses with colic, standing flank laparotomy is a viable approach for some types of colic. Systemic administration of analgesics may not produce sufficient peritoneal analgesia, which can lead to intolerance to abdominopelvic exploration during standing flank laparotomy in horses with colic and may negatively affect the outcome.

Challenges in Intercultural Communication.

With the increasing diversity of our clients or potential clients it is important for us as veterinary professionals to recognize the opportunities this affords us to serve a larger demographic. However, along with this opportunity comes the challenges of serving clients for whom English may be a second language as well as clients who may have very different understanding of health care options for their animal. By seeking to become more culturally aware, we can have significant impact on the care of our patients. This article focuses on both awareness and skills to aid this process.

A Strategy for Effective Generational Communication in Veterinary Medicine.

In today's veterinary practices, 5 generations (traditionalists, baby boomers, Generation X, millennials, and Generation Z), each with a unique way of looking at the world, are trying to work together effectively. Common strategies for managing this multigenerational workplace include villainizing "other" generations or merely tolerating their presence. Conflict, disagreements, and misunderstanding often get in the way of practicing quality medicine. Thus, veterinary health professionals must develop strategies that allow for effective communication, not only within the practice but also with clients, vendors, and other stakeholders, a strategy that builds bridges among the generations through engagement, regardless of generation.

Treatment of temporohyoid osteoarthropathy in horses with a basihyoid-ceratohyoid disarticulation technique: 6 cases (2018-2019).

OBJECTIVE: To describe a technique for basihyoid-ceratohyoid disarticulation (BCD) in standing sedated horses affected by temporohyoid osteoarthropathy (THO) and report outcomes for horses that underwent the procedure. ANIMALS: 6 client-owned horses. PROCEDURES: Electronic medical records of a veterinary teaching hospital were searched to identify horses that underwent BCD for treatment of THO from 2018 to 2019. Signalment, clinical data, use of the horse, and complications were recorded. Follow-up data obtained by telephone interview with owners included the clinical outcome and time to improvement after surgery, any persistent clinical signs, horse's activity level before onset of clinical signs and after BCD, subsequent use of the horse, and whether they would pursue the same treatment again. RESULTS: All horses tolerated the procedure well, with no complications and improved neurologic function after BCD. Five of 6 horses had a reported activity level equal to or greater than that prior to having signs of THO. Three of 3 horses with acute ataxia prior to BCD reportedly had full resolution of this sign; 3 of 4 horses with facial nerve deficits prior to BCD had mild residual facial nerve deficits at follow-up. All owners indicated they would pursue BCD again. CONCLUSIONS AND CLINICAL RELEVANCE: The BCD procedure was performed safely in this sample of THO-affected horses that were sedated while standing, avoiding risks associated with general anesthesia and resulting in no adverse effects such as iatrogenic injury to neurovascular structures.

Effects of head position on internal and external carotid pressures in standing sedated horses.

The effects of head position on internal carotid artery (ICA) and external carotid artery (ECA) pressures in standing sedated horses were evaluated in this study. The common carotid artery (CCA) was catheterized in 6 horses using an ultrasound-guided technique to facilitate placement of a pressure transducer within the ICA and ECA at the level of the guttural pouch. Transducer position was confirmed by endoscopic visualization. Mean arterial pressure (MAP) was measured with horses in both a head-up and head-down position. The dorsal metatarsal artery was catheterized as a control. Maintaining a head-up position decreased MAP in both the ICA (median: 75.21 mmHg) and ECA (median: 79.43 mmHg), relative to the head-down position (ICA median: 104.65 mmHg; ECA median: 102.26 mmHg). Mean arterial pressure in the dorsal metatarsal artery was not affected by head position. The head-up position resulted in lower arterial pressures in both the ICA and ECA (P = 0.03) compared with the head-down position in standing sedated horses.

Cette étude a évalué les effets de la position de la tête sur la pression artérielle au niveau de l'artère carotide interne (ICA) et de l'artère carotide externe (ECA) chez des chevaux sous sedation debout. L'artère carotide commune (CCA) a été cathétérisée chez six chevaux en utilisant une technique échoguidée pour faciliter le placement d'un transducteur de pression dans l'ICA et l'ECA au niveau de la poche gutturale. La position du transducteur a été confirmée par endoscopie. La pression artérielle moyenne (MAP) a été mesurée chez les chevaux avec la tête en position haute et en position basse. L'artère métatarsienne dorsale a été cathétérisée et a servi comme témoin. Les MAP enregistrées au niveau de l'ICA (médiane: 75,21 mmHg) et de l'ECA (médiane: 79,43 mmHg) lorsque la tête est en position élevée sont plus faibles que celles enregistrées lorsque la tête est en position basse (médiane ICA: 104,65 mmHg; médiane ECA: 102,26 mmHg). La MAP de l'artère métatarsienne dorsale n'a pas été affectée par la position de la tête. En conclusion, chez les chevaux sédatés et debout, la position élevée de la tête produit des pressions artérielles plus faibles au niveau de ICA et ECA (P = 0,03) que celles obtenues lorsque la tête est en position basse.(Traduit par les auteurs).

The Use of Pneumatic Impact Lithotripsy in a Laparoscopic Retrieval Pouch for Removal of Large Cystoliths in Two Female Horses.

Two mares, aged 15 and 21 years, were examined because of urinary incontinence, intermittent hematuria, and urine scalding. On admission of both horses, physical parameters were within normal limits and urine scalding of the skin at the ventral perineum was noted. Transrectal palpation and cystoscopy revealed a large type I cystolith (>10 cm) with associated hyperemia and focal ulceration of the bladder mucosa. In horse 1, hemogram, serum biochemical analysis, and renal ultrasound were not performed because of owner finances. In horse 2, results from hematological and serum biochemical analysis were unremarkable and renal ultrasonography did not reveal any abnormalities. Pneumatic impact lithotripsy in a laparoscopic retrieval pouch was performed under cystoscopic guidance after caudal epidural anesthesia, with the horses standing and under sedation. A laparoscopic retrieval device was passed alongside a flexible endoscope into the urinary bladder and the cystolith was manipulated into the pouch. A customized single stainless-steel rod scaler attached to an air compressor was used for fragmentation of the cystolith contained within the retrieval pouch. Lithotripsy time was 42 minutes for horse 1 and 31 minutes for horse 2. Both horses were released from hospital the day of surgery. Both horses were continent and voided normal streams of urine for the duration of the follow-up periods of 27 and 19 months for horse 1 and horse 2, respectively. Pneumatic impact lithotripsy in a laparoscopic retrieval pouch provided a time-efficient and minimally invasive surgical treatment option for removal of large cystoliths in mares.

A Standing Percutaneous Technique for Proximal Interphalangeal Joint Arthrodesis in Twelve Horses (2014-2017).

OBJECTIVES: This report describes the use of a minimally invasive standing pastern arthrodesis technique for the treatment of osteoarthritis in horses and documents its clinical outcome in 12 horses. MATERIALS AND METHODS: Medical records and radiographs of horses diagnosed with proximal interphalangeal joint osteoarthritis that underwent standing pastern arthrodesis using transarticular screws were reviewed. Follow-up information for determination of outcome was obtained via phone interview with the owners. RESULTS: Twelve horses (15 limbs) were included in the study. Radiographical findings revealed severe osteoarthritis in 12/15 limbs and moderate osteoarthritis in 3/15 limbs. Follow-up information was available for 11/12 cases (13/15 limbs). Phone surveys with the owners revealed that 8/11 horses were performing at their previous activity level or higher. Two horses remained lame. One horse developed a surgical site infection and was euthanatized. The average time for horses to return to their previous level of activity was 6.5 months (range: 1-18 months). CLINICAL SIGNIFICANCE: Stabilization of the proximal interphalangeal joint in horses with moderate-to-severe osteoarthritis can be performed using this minimally invasive standing technique. This procedure can be performed safely and provides a similar outcome when compared with other described techniques.

Face, construct, and concurrent validity of a simulation model for laparoscopic ovariectomy in standing horses.

OBJECTIVE To develop and validate a simulation model for laparoscopic ovariectomy in standing horses. DESIGN Prospective cohort study. SAMPLE 15 third-year veterinary students and 4 equine surgeons with experience in laparoscopy. PROCEDURES A simulation model that mimicked laparoscopic ovariectomy in standing horses was developed. Face validity of the model was determined with a questionnaire completed by the equine surgeons. Construct validity was determined by comparing performance scores (based on time to completion and accuracy completing various operative tasks) for simulated laparoscopic ovariectomy performed in the model for the students with scores for the equine surgeons. Concurrent validity was assessed by comparing performance scores with scores obtained with the validated McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS). RESULTS Questionnaire responses indicated that the simulation model replicated the operative experience to a high degree (face validity). Performance scores for simulated laparoscopic ovariectomy performed in the model were significantly different between the students and the equine surgeons (construct validity). Performance scores for the simulation model were significantly correlated with scores for the MISTELS (concurrent validity). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the simulation model had face, construct, and concurrent validity, suggesting that it may be useful when training students to perform laparoscopic ovariectomy in standing horses.

Comparison of incisional bursting strength of 2-strand continuous crossing and simple continuous patterns for closure of the equine linea alba.

The objective of this study was to assess and compare the bursting pressure and mode of failure of a 2-strand continuous crossing suture pattern and a simple continuous suture pattern for closure of the equine linea alba. No difference in bursting strength or mode of failure was found between the 2 suture patterns.

Comparaison de la force d'éclatement des incisions des sutures simples continues et des sutures croisées continues à deux fils pour la fermeture de la linea alba des équidés. Cette étude avait pour objectif d'évaluer et de comparer la pression d'éclatement et le mode d'échec d'un type de suture croisée continue à deux fils et d'un type de suture simple continue pour la fermeture de la linea alba des équidés. Aucune différence de force d'éclatement ou de mode d'échec n'a été constatée entre les deux types de suture.(Traduit par Isabelle Vallières).

Morcellation for testes extraction in horses undergoing standing laparoscopic cryptorchidectomy.

The major objective of this study was to describe the use of morcellation for standing laparoscopic cryptorchidectomy in 30 client-owned horses. A second objective was to describe a laparoscopic-assisted standing scrotal technique for removal of a descended testis in unilateral cryptorchids. Morcellation for extraction of abdominal testes is effective, efficient, and well-tolerated. Morcellation enabled safe and straightforward extraction of testes from the abdomen through an approximately 13- to 20-mm incision using a 2-portal technique. No incisional or morcellator-related complications occurred. Our laparoscopic-assisted standing scrotal technique for removal of a descended testis in unilateral cryptorchids entails intra-abdominal sealing and transection of the spermatic cord under laparoscopic viewing and subsequent removal of the testis through a scrotal incision. This technique enabled the surgeon to confirm hemostasis after transection of the spermatic cord and allowed tension-free removal of the descended testis. No intra-operative or incisional complications were encountered.

Morcellement pour l'extraction des testicules chez les chevaux subissant une cryptorchidectomie laparascopique debout. L'objectif majeur de cette étude consistait à décrire l'utilisation du morcellement pour la cryptorchidectomie laparascopique debout chez 30 chevaux appartenant à des clients. Un second objectif était de décrire une technique scrotale debout assistée par laparascopie pour l'enlèvement d'un testicule descendu pour les cryptorchides unilatéraux. Le morcellement pour l'extraction des testicules abdominaux est efficace et bien tolérée. Le morcellement a permis une extraction sûre et simple des testicules par l'abdomen par une incision d'environ 13 à 20 mm à l'aide d'une technique à deux portails. Aucune complication cicatricielle ou liée au morcellateur ne s'est produite. Notre technique scrotale debout assistée par laparoscopie pour l'enlèvement des testicules descendus dans les cryptorchides unilatéraux implique un scellement intra-abdominal et le sectionnement transversal du cordon spermatique sous une vue laparascopique et l'enlèvement subséquent des testicules par une incision scrotale. Cette technique a permis au chirurgien de confirmer l'hémostase après le sectionnement transversal du cordon spermatique et a permis l'enlèvement sans tension des testicules descendus. Aucune complication intra-opératoire ou cicatricielle ne s'est produite.(Traduit par Isabelle Vallières).

Evaluation of a New Surgical Treatment for Equine Hind Limb Proximal Suspensory Desmitis.

OBJECTIVE: To evaluate the effects of a new microfracture and ligament splitting procedure on ligament healing and to examine the usefulness of magnetic resonance (MR) imaging for monitoring ligament healing over time using a collagenase model of hind limb proximal suspensory desmitis. STUDY DESIGN: Experimental in vivo study. ANIMALS: Healthy adult horses (n=6). METHODS: Horses were free of lameness with normal hind limb proximal suspensory ligaments (PSL). The origin of both hind limb PSL was injected with collagenase and underwent MR imaging 2 weeks later, followed by the microfracture and ligament splitting procedure on 1 limb, with the opposite limb serving as the sham-operated control. Serial lameness and MR examinations were performed. Horses were euthanatized 210 days after surgery, the PSL harvested, and histology, biochemistry, and gene expression performed on both PSL. RESULTS: Collagenase lesions viewed on MR images appeared similar to those seen clinically. Serial MR images demonstrated resolution of abnormal signal intensity and tissue formation in the microfracture sites within the third metatarsal bone. Treated limbs had histologic evidence of connective tissue appearing to originate from the small perforations and blending into the ligament but no statistical differences were identified. Gene expression for cartilage oligomeric matrix protein and decorin were significantly increased in treated compared to control limbs. CONCLUSION: The microfracture and ligament splitting procedure did incite a tissue response but further clinical investigation is necessary to determine if this tissue remodeling at the bone-ligament interface translates to improved clinical outcome. MR imaging may be useful to follow healing in horses with hind limb proximal suspensory desmitis.

Imaging diagnosis--muscular hypertrophy of the small intestine and pseudodiverticula in a horse.

A 14-year-old Thoroughbred gelding was presented for chronic colic and weight loss. Transcutaneous and transrectal abdominal ultrasonography revealed distended, thickened small intestine with primary thickening of the muscularis and a focally more thickened loop with an echoic structure crossing the wall from the mucosa to the serosa. Visualization of diffuse thickening of the muscularis (muscular hypertrophy of the small intestine) and a focal lesion (pseudodiverticulum) helped clinicians make informed decisions. This case illustrates the importance of transabdominal and transrectal ultrasonography in horses with chronic colic and the relevance of considering the abnormalities in layering pattern of the intestinal wall.

Use of a motorized morcellator for elective bilateral laparoscopic ovariectomy in standing equids: 30 cases (2007-2013).

OBJECTIVE: To describe the use of a motorized morcellator for elective bilateral laparoscopic ovariectomy in standing equids and to evaluate long-term outcome. DESIGN: Retrospective case series. ANIMALS: 30 equids (20 horses, 9 mules, and 1 pony). PROCEDURES: Medical records of equids undergoing elective bilateral laparoscopic ovariectomy from 2007 to 2013 were evaluated. Cases were selected on the basis of use of a motorized morcellator for ovary extraction. Data collected included age, breed, reason for surgery, surgery date, surgical approach, intraoperative complications, surgery and morcellation times, postoperative complications, and duration of hospitalization. Long-term follow-up was obtained by telephone interview with owners, and included effectiveness at resolving original reason for surgery, time to return to usual activity, incision site appearance, signs of estrus after surgery, and overall owner satisfaction. RESULTS: 30 equids underwent laparoscopic bilateral ovariectomy with the morcellator technique. Median surgery time was 102 minutes (range, 47 to 150 minutes). Median single ovary morcellation time was 3.5 minutes (range, 2 to 8 minutes). Intraoperative complications occurred in 2 of 30 cases and included iatrogenic organ damage (uterus; 1) and persistent hemorrhage (1). Nineteen of 20 mares for which long-term follow-up was available returned to their previous use at a median of 60 days after surgery (range, 21 to 180 days). CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study indicated that use of a mechanical morcellator with a 2-portal technique for bilateral laparoscopic ovariectomy in clinically normal equids eliminated the need for a larger laparotomy incision as well as a third portal. Few complications occurred, and clients were satisfied with the procedure. The morcellator technique may offer advantages over other techniques but should only be used by experienced laparoscopic surgeons following adequate training.

Telephone communication in emergency cases: a training program for veterinary students.

The purpose of this project was to evaluate the incorporation of a telephone communication exercise into the junior surgery laboratory at Washington State University. Subjectively, the communication component seemed to encourage greater student preparedness and participation or ownership of cases in the surgical laboratory. Simulated clients were asked to score students on specific tasks and give any specific feedback. Students evaluated themselves on identical material. Areas of communication most likely to result in disparity of scores between the client's evaluation and the student's self-assessment were related to the patient's aftercare. Student survey results were consistently positive in regard to the value of the telephone communications exercise. Communication training in the veterinary curriculum could benefit from identifying opportunities to further integrate client communication experiences into other courses or laboratory experiences.

Analgesic effects of butorphanol tartrate and phenylbutazone administered alone and in combination in young horses undergoing routine castration.

OBJECTIVE: To compare the analgesic efficacy of administration of butorphanol tartrate, phenylbutazone, or both drugs in combination in colts undergoing routine castration. DESIGN: Randomized controlled clinical trial. ANIMALS: 36 client-owned colts. PROCEDURES: Horses received treatment with butorphanol alone (0.05 mg/kg [0.023 mg/lb], IM, prior to surgery and then q 4 h for 24 hours), phenylbutazone alone (4.4 mg/kg [2.0 mg/lb], IV, prior to surgery and then 2.2 mg/kg [1.0 mg/lb], PO, q 12 h for 3 days), or butorphanol and phenylbutazone at the aforementioned dosages (12 horses/group). For single-drug-treated horses, appropriate placebos were administered to balance treatment protocols among groups. All horses were anesthetized, and lidocaine hydrochloride was injected into each testis. Physical and physiological variables, plasma cortisol concentration, body weight, and water consumption were assessed before and at intervals after surgery, and induction of and recovery from anesthesia were subjectively characterized. Observers assessed signs of pain by use of a visual analogue scale and a numerical rating scale. RESULTS: Significant changes in gastrointestinal sounds, fecal output, and plasma cortisol concentrations were evident in each treatment group over time, compared with preoperative values. At any time point, assessed variables and signs of pain did not differ significantly among groups, although the duration of recumbency after surgery was longest for the butorphanol-phenylbutazone-treated horses. CONCLUSIONS AND CLINICAL RELEVANCE: With intratesticular injections of lidocaine, administration of butorphanol to anesthetized young horses undergoing routine castration had the same apparent analgesic effect as phenylbutazone treatment. Combined butorphanolphenylbutazone treatment was not apparently superior to either drug used alone.

Comparison of endotracheal intubation techniques in llamas.

This study evaluated a retrograde orotracheal intubation technique and compared it to the traditional normograde intubation technique used in llamas. Oral anatomical features, which can impair visualization of the epiglottis and laryngeal structures, and the production of excessive salivary secretions make it difficult to establish an airway under emergency conditions. Normograde intubation involves placing a stylet through the mouth into the trachea and advancing the endotracheal tube over the stylet into the trachea. For retrograde intubation, a nested trochar with cannula is placed into the cervical trachea and a stylet is advanced through the cannula and out the mouth. The endotracheal tube is advanced over the stylet back into the trachea. Our evaluation of both techniques found no statistical difference in time to place the stylet or endotracheal tube; however, fewer attempts were needed to place the tube using the retrograde technique. We found the retrograde technique to be a viable option for intubating llamas.

Injury of the collateral ligaments of the distal interphalangeal joint diagnosed by magnetic resonance.

We describe the clinical, imaging, and necropsy findings of two horses with severe injury of the collateral ligaments of the distal interphalangeal (DIP) joint diagnosed using magnetic resonance (MR) imaging. In MR images it was possible to examine the collateral ligaments of the DIP joint from the origin at the middle phalanx to the insertion on the distal phalanx. Both horses in this report had abnormal high signal intensity within the collateral ligaments of the DIP joint, and one horse had abnormal high signal intensity within the bone of the distal phalanx on short tau inversion recovery (STIR) and T2-weighted imaging sequences. High signal intensity on STIR and T2-weighted images represents abnormal fluid accumulation indicative of inflammation, within ligament, tendon, or bone on these imaging sequences. Abnormalities were confirmed on necropsy in both horses. Injury of the collateral ligaments of the DIP joint should be considered as a source of pain in horses with lameness localized to the foot.