IDENTIFICATION OF AN OSSICLE ASSOCIATED WITH THE PALMAR ASPECT OF THE CARPUS IN THE HORSE

An ossicle associated with the palmar aspect of the carpus is described in five horses. The size of the ossicle varied from 3 x 4 mm to approximately 12 x 10 mm. The ossicles were located at the junction of the proximal and distal rows of carpal bones, between the palmaromedial aspect of the fourth carpal bone and the ulnar carpal bone. In 3 horses they were bilateral, in one horse unilateral, and only one limb was examined in the remaining horse. In all horses it was an incidental finding and not regarded to be a pathologic entity.     

COMPUTED TOMOGRAPHIC ARTHROGRAPHY OF THE INTERCARPAL LIGAMENTS OF THE EQUINE CARPUS

Injuries of the intercarpal ligaments are an important cause of lameness in performance horses. The purpose of this prospective cadaver study was to determine whether computed tomography (CT) arthrography would be a feasible method for visualizing and characterizing intercarpal ligaments in the horse. One cadaver limb from each of eight nonlame horses was collected immediately after euthanasia. For each limb, overlapping 2.0 mm CT images were acquired before and after injection of iodinated contrast medium into the antebrachiocarpal joint, middle carpal joint, and carpal sheath. Spin echo magnetic resonance imaging (MRI) sequences were acquired in three planes using a 1.5 Tesla MRI scanner in three limbs. Following MRI, colored resin was injected into the synovial structures of these three limbs, limbs were frozen, and anatomic sections were obtained in three planes. Findings from CT arthrograms were compared to findings from precontrast CT, MRI, anatomic slices, and arthroscopy. Medial and lateral palmar intercarpal ligaments, radiocarpal and transverse intercarpal ligaments, and palmar carpal ligament were visible in CT arthrograms of all limbs. The proximal and distal entheses of all ligaments were readily identifiable. Findings indicated that CT arthrography is feasible for visualizing intercarpal ligaments and may be a useful adjunct imaging technique for diagnosing lameness due to suspected carpal ligament injury in horses.     

ULTRASONOGRAPHIC APPEARANCE OF CANINE PARVOVIRAL ENTERITIS IN PUPPIES

The ultrasonographic appearance of the gastrointestinal tract of puppies suffering from parvoviral enteritis was characterized. Forty puppies between 6 and 24 weeks of age with confirmed canine parvoviral enteritis were examined ultrasonographically within 24 h of admission. Sonographic findings included fluid‐filled small intestines in 92.5% of subjects, and stomach and colon in 80% and 62.5% of subjects, respectively. Generalized atony was present in 30 subjects and weak peristaltic contractions indicative of functional ileus observed in the remaining 10 subjects. The duodenal and jejunal mucosal layer thicknesses were significantly reduced when compared with normal puppies with mean duodenal mucosal layer measuring 1.7 mm and jejunal mucosal layer 1.0 mm. Additionally, a mucosal layer with diffuse hyperechoic speckles was seen in the duodenum (15% of subjects) and the jejunum (50% of subjects). The luminal surface of the duodenal mucosa was irregular in 22.5% of subjects and the jejunal mucosa in 42.5% of subjects. In all of these subjects, changes were accompanied by generalized indistinct wall layering. Small intestinal corrugations were seen within the duodenum in 35% of subjects and within the jejunum in 7.5%. A mild amount of anechoic free peritoneal fluid was observed in 26 subjects and was considered within normal limits and a moderate amount of anechoic free peritoneal fluid was observed in six subjects. The jejunal lymph node size was within normal limits. None of the above changes are pathognomonic for canine parvoviral enteritis but finding them in combination is highly suggestive.     

ECTRODACTYLY (SPLIT-HAND DEFORMITY) IN THE DOG

Radiographs of 14 dogs with ectrodactyly of the forelimb were evaluated and the defect classified according to the site of division of the longitudinal axis of the paw. The majority of separations occurred between metacarpal bones one and two, although separations were also noted between metacarpal bones two and three, two and four, and three and four. Other lesions noted in affected limbs included digit contracture, digit aplasia, metacarpal hypoplasia and metacarpal fusions. Bilateral involvement was noted in only one of 14 cases. No breed or sex predisposition was found and there was equal involvement of the left and right limbs.     

奶牛正常腕关节的超声影像学的研究

采用7．5MHz的线扫探头对4只奶牛尸体腕关节和6头奶牛的8个腕关节的正常结构进行了超声检查。一般骨骼的回声为光环或光线，关节囊呈明显的液性暗区，腱质呈实性强回声。桡腕关节囊、腕间关节囊及囊内绒毛可见。腕关节的腕桡侧伸肌腱、臂二头肌腱、指浅屈肌腱和指深屈肌腱都可清楚地看到，腕关节外侧由于腱比较细，加上侧副韧带多，在声像图上较难辨别其结构，腕关节内侧超声声像图不清楚。     

RADIOLOGIC ANATOMIC VARIATION OF THE CARPUS IN HORSES WITH CARPAL LAMENESS AND CONTROL HORSES

Our purpose was to describe the variation of the radiologic appearance of the carpus of horses of different breeds, discipline, and gender with lameness related to the carpus and control horses, with particular reference to the ulnar carpal bone. Two hundred and eighty‐six sets of carpal radiographs from 222 horses were analyzed. Breed, gender, discipline, and cause of lameness were recorded. Chi square tests were used to test for associations between radiologic findings and gender, breed and discipline, to test for associations between different radiologic findings, and to test for associations between radiologic findings and causes of lameness. Bonferroni correction was applied when necessary. The shape of the ulnar carpal bone and most of the anatomic variants, with the exception of the first carpal bone and a radiolucent area in the second carpal bone, were not breed or gender related. Radiolucent areas and associated fragments on the palmaromedial aspect of the ulnar carpal bone can be an incidental finding in horses from all disciplines.     

A RADIOGRAPHIC STUDY OF THE DEVELOPMENT OF THE SHEEP CARPUS FROM BIRTH TO 18 MONTHS OF AGE

Osseous development of the carpus of six clinically normal lambs was studied radiographically from birth to 18 months of age with the aim of forming a standard radiographic evaluation and reference for the sheep carpus.
Radiographic data consisted of 200 radiographs. Dorsopalmar and lateromedial projections were made daily during the first week, then weekly until the sixth month, and finally monthly until 18 month of age. Ten radiographs were selected to illustrate normal development of the carpus.
The distal ulnar epiphysis reached the ulnar carpal bone at the third week, but remained separate from the ulnar diaphysis until six months of age. The ulnar epiphysis was radiographically fused with the ulnar diaphysis at thirteen months of age.     

MAGNETIC RESONANCE IMAGING SCORING OF AN EXPERIMENTAL MODEL OF POST‐TRAUMATIC OSTEOARTHRITIS IN THE EQUINE CARPUS

Magnetic resonance imaging (MRI) is the most sensitive imaging modality to detect the early changes of osteoarthritis. Currently, there is no quantifiable method to tract these pathological changes over time in the horse. The objective of this experimental study was to characterize the progression of MRI changes in an equine model of post‐traumatic osteoarthritis using a semiquantitative scoring system for whole‐organ evaluation of the middle carpal joint. On day 0, an osteochondral fragment was created in one middle carpal joint (OCI) and the contralateral joint (CON) was sham‐operated in 10 horses. On day 14, study horses resumed exercise on a high‐speed treadmill until the completion of the study (day 98). High‐field MRI examinations were performed on days 0 (preosteochondral fragmentation), 14, and 98 and scored by three blinded observers using consensus agreement. Images were scored based on 15 independent articular features, and scores were compared between and within‐groups. On days 14 and 98, OCI joints had significantly (P ≤ 0.05) higher whole‐organ median scores (29.0 and 31.5, respectively), compared to CON joints (21.5 and 20.0, respectively). On day 14, OCI joints showed significant increases in high‐signal bone lesion scores, and osteochondral fragment number and size. On day 98, high‐signal bone lesion, low‐signal bone lesion, osteophyte formation, cartilage signal abnormality, subchondral bone irregularity, joint effusion, and synovial thickening scores were significantly increased in OCI joints. Study results suggest that the MRI whole‐organ scoring system reported here may be used to identify onset and progression of pathological changes following osteochondral injury.     

ULTRASONOGRAPHY OF THE DORSAL AND LATERAL ASPECTS OF THE EQUINE CARPUS: TECHNIQUE AND NORMAL APPEARANCE

The normal ultrasonographic appearance of the dorsal and lateral soft tissue structures and anatomic landmarks of the equine carpus useful in clinical imaging are described.
Both limbs of 5 cadavers and 5 clinically sound adult horses were imaged using a 7.5 MHz sector transducer. At the dorsal aspect of the carpus and distal radius, the extensor carpi radialis- and the common digital extensor tendon and their tendon sheaths were easily identified. These two tendons are the most prominent structures in this region. Smaller and more difficult to identify are the tendon and tendon sheath of the extensor carpi obliquus-, the lateral digital extensor- and the ulnaris lateralis muscle. The ultrasonographic appearance and course through the carpal region of the tendons and tendon sheaths mentioned are described. Other soft tissue structures examined include the lateral collateral ligament, the carpal joint capsule and the distal articular cartilage of the radius. Ultrasonographic findings correlated well with gross anatomy in the cadavers limbs.