Magnetic resonance imaging of the normal dromedary camel tarsus.

BACKGROUND: Magnetic resonance imaging (MRI) is the most versatile and informative imaging modality for the diagnosis of locomotor injuries in many animal species; however, veterinary literature describing the MRI of the dromedary camel tarsus is lacking. Our purpose was to describe and compare the MRI images of twelve cadaveric tarsi, examined in a 1.5 Tesla MRI scanner, with their corresponding anatomical gross sections. Turbo spin-echo (TSE) T1-weighted (T1), T2-weighted (T2), proton density-weighted (PD), and short tau inversion recovery (STIR) sequences were obtained in 3 planes. Tarsi were sectioned in sagittal, dorsal, and transverse planes. MRI images from different sequences and planes were described and compared with the anatomical sections. RESULTS: The soft and osseous tissues of the dromedary camel tarsus could be clearly defined on MRI images and corresponded extensively with the gross anatomic sections. The obtained MRI images enabled comprehensive assessment of the anatomic relationships among the osseous and soft tissues of the camel tarsus. Several structure were evaluated that cannot be imaged using radiography or ultrasonography, including the transverse inter-tarsal ligaments, the talocalcaneal ligament, the short dorsal ligament, branches of the short medial and lateral collateral ligaments and the tarsometatarsal ligaments. Specific anatomical features regarding the dromedary camel tarsus were identified, including the fused second and third tarsal bone, an additional bundle of the short medial collateral ligament connecting the talus and metatarsus and the medial and lateral limbs of the long plantar ligament. CONCLUSIONS: MRI images provided a thorough evaluation of the normal dromedary camel tarsus. Information provided in the current study is expected to serve as a basis for interpretation in clinical situations.

Biomechanical evaluation of 6 transarticular tibiotarsal immobilization methods in canine cadaveric limbs.

OBJECTIVE: To determine the effects of 6 types of transarticular immobilization techniques on tibiotarsal joint angles during stimulated weight bearing. STUDY DESIGN: Canine ex vivo biomechanical study. SAMPLE POPULATION: Canine cadaveric pelvic limbs (n = 15). METHODS: A validation study was conducted to determine tibiotarsal flexion before and after transection of the superficial digital flexor tendon in 5 canine cadaveric limbs without tibiotarsal joint immobilization. Six transarticular tibiotarsal immobilization techniques were tested sequentially in 10 canine cadaveric pelvic limbs. The tibiotarsal joint angles were measured from lateral projection radiographs before and during axial loading of 200 N. Mixed linear models were applied to determine the effects of the immobilization techniques on change in tibiotarsal joint angle under loading. RESULTS: There was no change of tibiotarsal joint angle between extended digits and flexed digits under both unloaded and loaded conditions. Change in tibiotarsal joint angles did not differ among any of the immobilization techniques tested here (mean change 1.36°, range 0-5). The main contributor to variance in angle explained by the final model was associated with the random effect for limb. CONCLUSION: Changes in tibiotarsal joint angles during single static loading in canine cadaveric limbs for the 6 immobilization techniques were minimal. CLINICAL SIGNIFICANCE: The 6 techniques appear equally effective at limiting tibiotarsal joint flexion during single axial loading of 200 N. Cyclic mechanical testing of these techniques is recommended to support our findings and validate their clinical application.

Repair of a Tibiotarsal Fracture in a Pomeranian Goose ( Anser anser) With a Locking Plate.

A 2-year-old Pomeranian goose ( Anser anser) weighing 8.1 kg was examined because of non-weight-bearing lameness of the right limb. A closed, transverse, diaphyseal fracture of the distal third of the right tibiotarsus with a craniolateral displacement of the distal fragment was diagnosed radiographically. Surgery under general anesthesia was performed to repair the fracture with a 14-hole, 2.7-mm locking plate fixed with 6 screws in a bicortical manner. Two days later, the bird was fully weight-bearing on the leg. Radiographs performed 4 and 8 weeks after surgery showed good healing of the affected bone with an appropriate callus formation bridging the fracture line. Sixteen weeks after surgery, the patient was readmitted because of lameness exhibited while staying outside exposed to subzero (°C) temperatures. On the basis of this finding, heat conduction was postulated as the possible cause of lameness because it disappeared after implant removal. To the best our knowledge, this case represents the first report of a surgical repair of a tibiotarsal fracture with a locking plate in waterfowl.

MAGNETIC RESONANCE IMAGING, GROSS POSTMORTEM, AND HISTOLOGICAL FINDINGS FOR SOFT TISSUES OF THE PLANTAR ASPECT OF THE TARSUS AND PROXIMAL METATARSAL REGION IN NON-LAME HORSES.

Injuries of the plantar soft tissues of the tarsus and proximal metatarsus can be a source of lameness in horses, however published information is lacking on high field MRI characteristics of these tissues. Objectives of the current anatomic study were to (1) describe high-field MRI features of the plantar tarsal and proximal metatarsal soft tissues; and (2) compare MRI findings with gross and histological appearances of selected structures for a sample of cadaver limbs from non-lame horses. Single hindlimbs for 42 horses, and right and left hindlimbs for eight horses were scanned using high-field MRI. The MRI findings were described for the 50 single limbs; and the MRI, gross postmortem and histological findings were compared for the eight pairs of hindlimbs. The superficial digital flexor tendon had uniform low signal intensity, surrounded by the flexor retinaculum of intermediate to high signal intensity on all sequences. The lateral digital flexor tendon had slightly higher signal intensity, enclosed on the plantaromedial aspects by the low signal intensity metatarsocalcaneal ligament. The accessory ligament of the deep digital flexor tendon varied in size and signal intensity. The proximal and distal plantar ligaments, accessory ligament of the suspensory ligament, and calcaneoquartal ligament had low signal intensity. The long plantar ligament comprised a number of related parts, separated by lines of high signal intensity corresponding with fibrous septae seen in gross anatomical specimens. The plantar aspect of the ligament had uniform low signal intensity in all sequences, but the dorsal half was more heterogeneous with multifocal spots or lines of higher signal intensity.

Surgical Management of Osteochondrosis in Foals.

Osteochondrosis is common in young, athletic horses. Some lesions respond to conservative therapy. Surgical management is the mainstay of treatment. Arthroscopic debridement is useful in the femoropatellar joint, tarsocrural joint, fetlock joint, and shoulder joint. Debridement is associated with good outcomes, except in the shoulder joint. Osteochondrosis lesions in the elbow may be difficult to access arthroscopically, thereby transosseous debridement. Surgical management of subchondral cystic lesions of the medial femoral condyle consists of debridement, debridement with grafting, transcondylar screws, and intralesional corticosteroid injection. Surgical management is indicated with lameness and persistent effusion, and in many horses intended for athletic use.

Capsaicin-sensitive sensory nerves exert complex regulatory functions in the serum-transfer mouse model of autoimmune arthritis.

OBJECTIVE: The K/BxN serum-transfer arthritis is a widely-used translational mouse model of rheumatoid arthritis, in which the immunological components have thoroughly been investigated. In contrast, little is known about the role of sensory neural factors and the complexity of neuro-immune interactions. Therefore, we analyzed the involvement of capsaicin-sensitive peptidergic sensory nerves in autoantibody-induced arthritis with integrative methodology. METHODS: Arthritogenic K/BxN or control serum was injected to non-pretreated mice or resiniferatoxin (RTX)-pretreated animals where capsaicin-sensitive nerves were inactivated. Edema, touch sensitivity, noxious heat threshold, joint function, body weight and clinical arthritis severity scores were determined repeatedly throughout two weeks. Micro-CT and in vivo optical imaging to determine matrix-metalloproteinase (MMP) and neutrophil-derived myeloperoxidase (MPO) activities, semiquantitative histopathological scoring and radioimmunoassay to measure somatostatin in the joint homogenates were also performed. RESULTS: In RTX-pretreated mice, the autoantibody-induced joint swelling, arthritis severity score, MMP and MPO activities, as well as histopathological alterations were significantly greater compared to non-pretreated animals. Self-control quantification of the bone mass revealed decreased values in intact female mice, but significantly greater arthritis-induced pathological bone formation after RTX-pretreatment. In contrast, mechanical hyperalgesia from day 10 was smaller after inactivating capsaicin-sensitive afferents. Although thermal hyperalgesia did not develop, noxious heat threshold was significantly higher following RTX pretreatment. Somatostatin-like immunoreactivity elevated in the tibiotarsal joints in non-pretreated, which was significantly less in RTX-pretreated mice. CONCLUSIONS: Although capsaicin-sensitive sensory nerves mediate mechanical hyperalgesia in the later phase of autoantibody-induced chronic arthritis, they play important anti-inflammatory roles at least partially through somatostatin release.

Ultrasonography of the normal donkey tarsus (equus asinus).

Tarsal joint illness is a frequent source of hind limb lameness due to the complex anatomy of the region and the presence of numerous bony and soft tissue structures. Proper lameness diagnosis aims to discover the structure provoking lameness. Ultrasonography documents valuable information of soft tissues and characterizes soft tissue injuries that have heretofore been difficult to obtain either noninvasively or via radiography. The objectives of the current study were to develop and describe a standardized ultrasonographic protocol for investigation of the tarsal region in donkeys. The donkey tarsal anatomy was investigated in 5 cadavers and the tarsi of 11 healthy lameness free adult donkeys were echographically investigated. The dorsal, plantar, lateral and medial aspects of the tarsal region were substantially evaluated at four anatomical landmarks in both the longitudinal and horizontal planes using a multi-frequency 5-12 MHz linear transducer. Sonoanatomy of the extensor and flexor tarsal tendons, collateral and plantar ligaments, and synovial pouches was delineated and described. Systematic echography of the tarsal region allowed accurate localization and thorough exploration of various soft tissues of clinical interest in the donkey tarsus. Sonograms provided in this study should serve as a reference database for tarsal ultrasonography in clinical circumstances.

Radiographic changes in Thoroughbred yearlings in South Africa.

This study involves the evaluation of pre-purchase radiographic studies of South African Thoroughbred yearlings. Radiographic changes were recorded and compared with similar international studies. The study differs from other studies in that a lower prevalence of pedal osteitis (1.26%), dorsal osteochondral fragmentation of the metatarsophalangeal joint (1.60%), distal metacarpal sagittal ridge changes (15.7%), ulnar carpal bone lucencies (8.33%), carpal osteophytes (1.19%), distal intertarsal and tarsometatarsal joint radiographic changes (9.92%), tarsal osteochondrosis lesions (4.40%) and stifle osteochondrosis lesions (0.4%) was found. The prevalence of dorsal osteochondral fragments in the metacarpophalangeal joint was similar to other studies (1.60%). A higher prevalence of vascular channels as well as irregular borders and lucencies was evident in the proximal sesamoid bones. There was a higher prevalence of palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments (2% and 7.10% respectively). Palmar metacarpal disease, metacarpal supracondylar lysis, proximal sesamoid bone fractures and carpal osteochondral fragmentation were absent in the current study. Additional findings recorded in the current study were proximal interphalangeal joint hyperextension (left front 15.13%, right front 18.91%), the solar angle (right front 2.38 degrees, left front 2.79 degrees), the prevalence of carpal bone 1 (30.95%) and carpal bone 5 (1.59%). Management, nutrition and genetics in the various groups of Thoroughbred yearlings should be further investigated in order to explain the reasons for the differences recorded in the current study.

Prevalence of various presale radiographic findings and association of findings with sales price in Thoroughbred yearlings sold in Kentucky.

OBJECTIVE: To estimate prevalences of various presale radiographic findings and of presale arthroscopy in horses offered for sale at the 2006 Keeneland September yearling sale and to compare sales prices between yearlings with and without various presale radiographic findings or a history of arthroscopy. ANIMALS: 397 Thoroughbred yearlings. DESIGN: Cross-sectional study. PROCEDURES: Presale radiographs and health records were examined to estimate prevalences of various radiographic findings and presale arthroscopy. Sales price records were used to compare sales prices between yearlings with and without various presale radiographic findings or a history of arthroscopy. RESULTS: In the forelimbs, the most common radiographic findings were vascular channels in the proximal sesamoid bones (23%), enthesophytes or osteophytes in the radiocarpal joint (22%), and osteochondritis lesions involving the sagittal ridge of the third metacarpal bone (20%). In the hind limbs, the most common radiographic findings were enthesophytes or osteophytes involving the proximal sesamoid bones (39%), abnormalities of the distodorsal aspect of the third metatarsal bone (36%), enthesophytes or osteophytes involving the distal intertarsal joint (27%), and osteochondritis lesions involving the stifle joint (8%). Thirteen percent of horses had a history of presale arthroscopy. Median sales price was significantly lower in horses with fragments of the proximal phalanx than in horses without. Median sales price was significantly higher in horses with a history of presale arthroscopy than in horses without. CONCLUSIONS AND CLINICAL RELEVANCE: Results revealed significant associations between a diagnosis of fragments of the proximal phalanx, presale arthroscopy, and sales price in Thoroughbred yearlings.

Radiographic Recognition of Tarsal Malformation in 8- to 9-Week-Old Bernese Mountain Dogs.

INTRODUCTION: Tarsal malformation is a skeletal malformation of unknown aetiology associated with a variety of morphologic changes to the tarsal and metatarsal bones of the dog. OBJECTIVE: The aim of this study was to determine if early diagnosis and prevalence of tarsal malformation could be obtained at approximately 8 to 9 weeks of age in multiple litters of Bernese Mountain dogs. METHODS: A prospective study of 51 Bernese Mountain dog puppies were evaluated from 12 litters in northern Italy. Dorsoplantar radiographic views of the tarsus were obtained at 60 ± 5 days of age. Tarsal malformation was defined as an abnormal extension of the central tarsal bone on its medial side, or the presence of ectopic bone located medially to the central tarsal bone, talus and second metatarsal bones (proximomedial, distomedial and metatarsal ossification sites respectively). RESULTS: All puppies were found to be clinically normal. Thirty-nine of the 51 puppies showed ossification sites medial to the tarsus as defined. A metatarsal ossification was present in all dogs with either a proximo- or distomedial ossification site. No central tarsal bone extensions were observed. The remainder of the tarsometatarsal joints were normal. CLINICAL SIGNIFICANCE: Tarsal malformation can be identified in the 8- to 9-week-old Bernese Mountain dog. The clinical significance of tarsal malformation remains to be determined, either as an incidental finding or a precursor to the development of other clinically relevant and related issues in the tarsus.

Treatment of a large osseous defect in a feline tarsus using a stem cell-seeded custom implant.

The aim of this study is to describe the treatment of an infected segmental bone defect in a cat using a novel, custom-designed titanium implant seeded with adipose-derived stem cells (AdMSCs) to facilitate osseous ingrowth and preserve limb function. Large bone defects occur secondary to trauma, infection, or neoplasia and often result in amputation. We established a novel autologous AdMSC-impregnated trabecular metal spacer made using 3D printing, to bridge the distal tibia and metatarsal bones in the left pelvic limb of a cat that had previously undergone right pelvic limb amputation. Six months postoperatively, there was radiographic evidence of bone growth and implant integration. A titanium spacer seeded with AdMSCs successfully encouraged bone ingrowth in a large defect site and successfully preserved limb function. However, further studies are needed to justify the use of differentiated stem cell impregnated mesh as a framework to bridge large bone defects.

Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 1: the soft tissues.

The equine tarsus is the most commonly affected hindlimb region associated with lameness. Diagnostic imaging is routinely applied but because of its complexity, being composed of 10 multifaceted bones and different joints, multiple ligaments, tendons and bursae, imaging this region can be a challenge. This is the first part of a two-part review of the structures and disorders of the equine tarsus. It describes the principal disorders affecting the soft tissues of the tarsal region and addresses some of the technical aspects in taking radiographic, ultrasonographic and scintigraphic images of the different soft tissue lesions. Where applicable, comments on the diagnostic use of contrast radiography, arthroscopy and tenoscopy are made. In current clinical practice a combination of radiography and ultrasonography is still most frequently used to arrive at a diagnosis.

Comparison of radiography and ultrasonography to detect osteochondrosis lesions in the tarsocrural joint: a prospective study.

REASONS FOR PERFORMING STUDY: Lesions located on the medial malleolus of the tarsocrural joint can be difficult to image radiographically. Ultrasonography allows evaluation of articular cartilage and subchondral bone. OBJECTIVES: To compare dorso30 degrees lateral-plantaromedial-oblique (DL-PIMO) and dorso45 degrees views to detect lesions on the medial malleolus, to validate the use of ultrasonography to show lesions in the tarsocrural joint and to compare its sensitivity to radiography. METHODS: Tarsocrural joints (n=111) with osteochondrosis were evaluated ultrasonographically and radiographically prior to arthroscopic lesion debridement. A complete radiographic examination was made and the best view to detect each lesion recorded. Longitudinal and transverse ultrasonography of the dorsal aspect of the joint was performed and the best scan plane to image each lesion recorded. RESULTS: There were 94 joints with lesions on the distal intermediate ridge of tibia, 24 with lesions on the medial malleolus, and 4 with lesions on the lateral trochlear ridge. The sensitivity of radiography to detect lesions on the medial malleolus and distal intermediate ridge of tibia was 71 and 96%, respectively. Eighty-two percent of lesions on the medial malleolus were better imaged on dorso30 degrees view. The sensitivity of ultrasonography to detect lesions on the medial malleolus and distal intermediate ridge of tibia was 83 and 98%, respectively. Ultrasonography was significantly more sensitive than radiography to detect lesions on the medial malleolus and distal intermediate ridge of tibia. CONCLUSION: Dorso30 degrees lateral-plantaromedial-oblique view was the best to image lesions on the medial malleolus. Ultrasonography was a valuable diagnostic tool to diagnose lesions in the tarsocrural joint and was more sensitive than radiography for lesions located on the medial malleolus and distal intermediate ridge of tibia. CLINICAL RELEVANCE: Radiographic examination should include a dorso30 degrees view for detection of lesions on the medial malleolus and ultrasonography should be considered to diagnose osteochondrosis in the tarsocrural joints.

Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 2: bony disorders.

This is the second part of a two-part review of the structures and disorders of the equine tarsus. In this part the bones of the tarsal region are considered and the technical aspects of taking radiographic, ultrasonographic and scintigraphic images of the different lesions are addressed. The diagnostic use of arthroscopy, computed tomography and magnetic resonance are discussed. In current clinical practice the most frequently used combination to arrive at a diagnosis is still radiography and ultrasonography.

Prevalence of various radiographic manifestations of osteochondrosis and their correlations between and within joints in Dutch warmblood horses.

REASONS FOR PERFORMING STUDY: Osteochondrosis (OC) is the most important orthopaedic developmental disorder in horses and may manifest in several different forms. No detailed study on the prevalence and/or interrelation of these forms is available, even though these data are a prerequisite for conclusive genetic studies. OBJECTIVES: To assess the prevalence of the various manifestations of OC as detected radiographically and to evaluate possible relationships between their occurrence within the same joint and between different joints. METHODS: The FP (femoropatellar), TC (tarsocrural) and MCP/MTP (metacarpophalangeal/metatarsophalangeal) joints of 811 yearlings selected randomly, descending from 32 representative stallions, were radiographed and scored for the presence and grade of osteochondrotic lesions. Results were compared at the sire, animal, joint and predilection site levels. RESULTS: In the FP joint, the percentage of animals showing normal joint contours in all sites was 60.7%. For the TC joint and the combined MCP/MTP joints, these figures were 68.6 and 64.6%, respectively. For all joints combined, the percentage dropped to 30.5%. Sedation improved detection of OC lesions in the FP joint. There was a high correlation between the right and left joints. The correlation between flattened bone contours and fragments was considerably less. CONCLUSIONS: Scoring on a detailed scale is necessary to achieve good insight into the prevalence of OC. Observations on the right and left joints can be combined in further analyses, whereas flattened bone contours and fragments should be evaluated as statistically different disorders. POTENTIAL RELEVANCE: This study provides insight into the prevalences of various manifestations of OC and their relationships, within and between joints. These results form the basis for detailed quantitative and/or molecular genetic studies that should lead to the establishment of breeding indices and/or genetic marker sets for OC.

Is there a relationship between clinical presentation, diagnostic and radiographic findings and outcome in horses with osteoarthritis of the small tarsal joints?

REASONS FOR PERFORMING STUDY: Despite the possibility that sound horses may have radiographic signs consistent with osteoarthritis of the small tarsal joints (OA-STJ), a diagnosis of 'bone spavin' as a cause of lameness is often made based only on radiographic examination. OBJECTIVES: To determine whether severity of radiographic change and response to treatment are correlated with the duration and degree of lameness and the response to intraarticular anaesthesia in horses with OA-STJ. METHODS: A retrospective study of all horses that showed a positive response to intra-articular anaesthesia of the STJ was performed. Details of history, clinical presentation and diagnostic findings were recorded. Radiographs of affected tarsi were evaluated and scored independently by 2 observers. Follow-up was via a telephone questionnaire with the owner. Statistical analysis was used to assess the association between the duration and degree of lameness, the response to intra-articular anaesthesia and radiographic findings. Response to treatment was compared with the findings from the diagnostic work-up. RESULTS: Ninety-one horses were included (61 unilateral and 30 bilateral lameness). Fifty-nine percent of horses had been lame for over 2 months. There was no association between the duration and degree of lameness, or between duration or degree of lameness, intra-articular anaesthesia and radiographic findings. Response to treatment showed a significant positive association with less severe radiographic changes within the tarsometatarsal (TMT) joint. Follow-up was available for 48% of cases, with 52% horses returning to the same level of exercise. CONCLUSIONS: There is no association between the duration and degree of lameness, the response to intra-articular anaesthesia and radiographic findings in horses with OA-STJ. However, horses that improved following treatment tended to have less marked TMT joint pathology. POTENTIAL RELEVANCE: Response to intra-articular anaesthesia should remain the gold standard for diagnosis of OA-STJ. Predicting which cases are likely to improve following treatment remains difficult.

Intra- and interobserver agreement in the interpretation of navicular bones on radiographs and computed tomography scans.

REASONS FOR PERFORMING STUDY: Criteria for the radiographic evaluation of navicular bones in horses have been published to standardise classification of radiographic signs. However, intra- and interobserver agreement have not been established. OBJECTIVE: To determine intra- and interobserver agreement in the evaluation of radiographic and computed tomographic (CT) navicular changes. It was hypothesised that: 1) intraobserver agreement would be better than interobserver agreement; 2) agreement would be better for CT than for radiography; and 3) pathological changes would be recognised with greater certainty with CT. METHODS: Radiographs and CT scans of 60 cadaver navicular bones were evaluated by 3 observers using published criteria. A subset of 30 studies was evaluated twice by one observer. Agreement was tested using the kappa statistic. Certainty about pathological changes was evaluated by giving the observers the option to choose 'not sure'. RESULTS: Agreement varied from poor to almost perfect for radiographic evaluation and from poor to substantial for CT evaluation. For radiographic evaluation mean interobserver agreement was fair, as it was for CT evaluation. For radiographic evaluation mean intraobserver agreement was moderate as it was for CT evaluation. Pathological changes were evaluated with greater certainty on CT scans compared to radiographs; however, this was not associated with improved agreement. CONCLUSIONS: Variations in classification of navicular lesions in radiographic and CT studies were considerable between and within observers and challenge the use of such studies for diagnostic and prognostic purposes. POTENTIAL RELEVANCE: The results of this study allowed the identification of evaluation criteria with sufficient precision to be useful for navicular bone evaluation.

Arthrographic Study of the Communication between the Tarsal Joints in Crioulo Horses.

OBJECTIVE: The aim of the present study is to assess an arthrographic technique based on the access to the equine tarsus via distal intertarsal and on the existence and frequency of communication between distal and tarsocrural joints in the tarsus of Crioulo horses. MATERIALS AND METHODS: Fifty Crioulo horses of both sexes from 3 to 8 years old were included in the experiment. Animals with radiographic signs of tarsal osteoarthritis and joint space loss were excluded from the experiment. Contrast was injected in the distal intertarsal joint and radiographs were taken at two different times - Time 0 (after contrast application) and Time 1 (45 seconds after) to detect any communication between tarsal joints. The recorded results were analysed through chi-squared test. RESULTS: Thirty out of three hundred tarsi were excluded from the experiment since the radiographic images showed loss of the distal intertarsal joint space. Positive contrast was injected in distal intertarsal joint of 70/100 tarsi. There was not any contrast overflow in the 30/70 assessed tarsi. Contrast diffused to the tarsometatarsal joint in 32/70 of the assessed tarsi and reached tarsocrural joints in 8/70 tarsi. The adopted arthrographic technique was effective in data collection and evaluation; however, 52/70 of tarsi showed contrast overflow to the bursa of the cunean tendon. CLINICAL SIGNIFICANCE: The communication between tarsocrural and distal tarsal joints in Crioulo horses was significantly higher, and this finding emphasizes the importance of performing contrasted arthrography before getting to a final diagnostic and defining therapeutic procedures.

Gross osteology and radiology of the pelvic limb of the adult small East African goat.

The aim of this study was to provide the detailed normal gross osteology and radiographic anatomy of the pelvic limb in adult small East African goats as a reference for clinical use, biomedical research and teaching. Radiography of the pelvic limb was performed in five adult small East African goats. Bone specimens of four skeletally mature small East African goats were used for gross osteological study. The ilial wing was wide. The ischiatic tuberosity was prominent and well developed. The acetabulum was rounded. The minor trochanter was located caudomedially, and the femoral trochlea was deep and narrow. The lateral and medial condyles of the femur were approximately of the same size. The tibial tuberosity was prominent, and the cochlea grooves were deep with a pronounced intermediate ridge. The trochlea of the talus was deep. The patella presented a prominent tuberosity on the cranial surface. The metatarsal sesamoid bone was seen in all animals. The observed gross osteology and radiographic anatomy of the pelvic limb of small East African goats was consistent with the presence of strong extensor muscles of the hip, stifle and tarsus for propulsion during terrestrial walking and trotting.

Use of high-field and low-field magnetic resonance imaging to describe the anatomy of the proximal portion of the tarsal region of nonlame horses.

OBJECTIVE To use high-field and low-field MRI to describe the anatomy of the proximal portion of the tarsal region (proximal tarsal region) of nonlame horses. SAMPLE 25 cadaveric equine tarsi. PROCEDURES The proximal portion of 1 tarsus from each of 25 nonlame horses with no history of tarsal lameness underwent high-field (1.5-T) and low-field (0.27-T) MRI. Resulting images were used to subjectively describe the anatomy of that region and obtain measurements of the collateral ligaments of the tarsocrural joint. RESULTS Long and short components of the lateral and medial collateral ligaments of the tarsocrural joint were identified. Various bundles of the short collateral ligaments were difficult to delineate on low-field images. Ligaments typically had low signal intensity in all sequences; however, multiple areas of increased signal intensity were identified at specific locations in most tarsi. This signal intensity was attributed to focal magic angle effect associated with orientation of collagen fibers within the ligaments at those locations. Subchondral bone of the distal aspect of the tibia was uniform in thickness, whereas that of the medial trochlear ridge of the talus was generally thicker than that of the lateral trochlear ridge. In most tarsi, subchondral bone of the talocalcaneal joint decreased in thickness from proximal to distal. CONCLUSIONS AND CLINICAL RELEVANCE Results generated in this study can be used as a reference for interpretation of MRI images of the proximal tarsal region in horses.