Ultrasonographic examination of the stifle region in cattle--normal appearance.

The stifle region of 18 healthy cattle (14 cows, four bull calves) and the stifles of five bovine cadavers were examined using 7.5 MHz linear or convex and 5 MHz sector transducers. The normal ultrasonographic appearance of soft tissues and bony structures was studied.The homogeneously echogenic patellar and collateral ligaments, the combined tendon of the long digital extensor and peroneus tertius muscles, the popliteus tendon, the anechoic articular cartilage of the femoral trochlea, the echogenic menisci and the hyperechoic bone surfaces were imaged successfully in all cattle and cadavers. The boundaries of the joint pouches only became partially identifiable, when small amounts of anechoic fluid were present in the medial and lateral femorotibial joint pouches. After experimental filling in cadavers, the distended synovial cavities were imaged as clearly demarcated, anechoic areas. Measurement values of cross-sectional diameters of the ligaments, tendons and the popliteal lymph node, the width of normal joint pouches, where visible, and articular cartilage thickness are presented. The established results should serve as reference data for ultrasonography of bovine stifle disorders.     

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.     

The normal anatomical, radiographical and ultrasonographic appearance of the carpal region of one-humped camel (Camelus dromedarius)

The macroscopic, radiographic and ultrasonographic anatomy of the carpal region of eight clinically normal camels (Camelus dromedarius) was determined with the help of a 7.5-MHz linear transducer. At the dorsal aspect of the carpus and distal radius, the extensor carpi radialis, extensor digitorum communis and extensor digitorum lateralis tendons were easily identified. The ulnaris lateralis tendon was observed laterally. The extensor carpi obliqus tendon was identified with difficulty. At the palmar aspect, the flexor carpi radialis, the flexor digitorum superficialis and the flexor digitorum profundus tendons were observed. Other soft structures examined include the lateral collateral ligament and the medial collateral ligament. Ultrasonographic findings correlated with gross anatomy in the dissected limbs. The results of the present study serve as reference data for ultrasonographic investigation of disorders of camel carpus.     

MAGNETIC RESONANCE ANATOMY OF THE CARPUS OF THE HORSE DESCRIBED FROM IMAGES ACQUIRED FROM LOW‐FIELD AND HIGH‐FIELD MAGNETS

Cadaver carpi of 30 mature horses with no history of carpal or proximal metacarpal pain were examined using low‐field (0.27 T) and high‐field (1.5 T) magnetic resonance imaging (MRI). Normal MRI anatomy in transverse, sagittal, and dorsal plane images was determined by comparison with anatomical specimens and standard texts. Subchondral bone and cortical bone thickness measurements were obtained from standardised sites. There was variable subchondral bone thickness in the radius and carpal bones; subchondral bone thickness was consistently larger at dorsal compared with palmar sites in the proximal row of carpal bones. The endosteal surface of the subchondral bone was smooth. The shape of the ulnar carpal bone was variable and one or more small osseous fragments were identified palmar to the bone in 5/30 limbs. There was no evidence to suggest that these were pathological fractures or avulsions of the lateral palmar intercarpal ligament. The amount of muscle tissue in the superficial and deep digital flexor tendons in the proximal aspect of the carpus varied, but none was present at the level of the middle carpal joint and distally. Several structures could be evaluated that cannot be imaged using radiography, ultrasonography, or arthroscopy, including the transverse intercarpal ligaments, the radiocarpal ligament, the short palmar carpal ligaments, and the carpometacarpal ligaments. Anatomical variations not previously described were identified, including the layers of the medial aspect of the carpal fascia. Knowledge of the variation in MRI appearance of the carpus of nonlame horses is helpful for interpretation of MR images of lame horses.     

Arthroscopic approaches to the palmar aspect of the equine carpus

OBJECTIVE: To identify sites for arthroscopic access to the palmar aspects of the antebrachiocarpal (AC) and middle carpal (MC) joints, and describe visible carpal bone surfaces for each approach. STUDY DESIGN: Prospective experimental study. ANIMALS: Equine carpi: 16 cadavers, 8 live horses. METHODS: A latex model was used to identify possible sites for arthroscopic access to the palmar aspects of the AC and MC joints. Carpi (n = 24) were examined arthroscopically and arthroscopic access sites and visible carpal bone surfaces were described. RESULTS: Arthroscopic approaches and instrument portals were developed for the medial and lateral aspects of the palmar pouches of the AC and MC joints. The palmar surface of the radial carpal bone and radius, and the dorsal articular surfaces of the accessory carpal bone, could be viewed using palmar approaches to the AC joint. The palmar aspect of the radial, third and second carpal bones (medially) and ulnar and fourth carpal bones (laterally) could be observed using a palmar approach to the MC joint. CONCLUSIONS: Arthroscopic access, using separate medial and lateral portals to the AC and MC joints, allowed assessment of portions of the caudodistal radius, the palmar surfaces of the radial, ulnar, second, third and fourth carpal bones, and the dorsal aspect of the accessory carpal bone. CLINICAL RELEVANCE: Arthroscopic approaches to the palmar aspect of the carpus could be used to remove fracture fragments, and to assess the medial palmar intercarpal ligaments.     

Carpal hyperextension in a Percheron mare caused by a palmar carpal ligament tear

A Percheron mare was presented for acute, severe lameness and marked swelling of the right forelimb after being cast. The mare was initially diagnosed with cellulitis of the forelimb but as her condition improved and the affected limb was able to bear more weight it became apparent that the limb was hyperextended at the level of the carpus. Widening of the palmar aspect of the middle carpal joint was observed radiographically. During ultrasonographic examination, excessive fluid in the carpal sheath and perithecal swelling were noted and tearing of the palmar carpal ligament was suspected. A dynamic brace was fabricated to prevent hyperextension of the carpus. After discontinuation of systemic antibiotics, the mare became febrile and forelimb lameness worsened. Cytology of fluid from the middle carpal joint confirmed joint sepsis and the mare was anaesthetised for arthroscopic examination. A tear in the palmar carpal ligament, characterised by focal fibre disruption and fibrillation, was identified during arthroscopic and tenoscopic examination. Communication between the carpal flexor tendon sheath and middle carpal joint was identified during these procedures. Both the middle carpal joint and carpal flexor tendon sheath were lavaged with physiological saline solution. Post operatively, swelling and lameness slowly resolved. Four months after discharge, the mare was sufficiently sound to be maintained at pasture. Viewed from its lateral aspect, the limb no longer appeared to be hyperextended from the carpus.     

Die anatomischen Verhältnisse am Karpalgelenk des Geparden (Acinonyx jubatus), verglichen mit jenen der Hauskatze (Felis catus)

The anatomy of the carpal joint of the cheetah (Acinonyx jubatus) was examined in seven specimens using dissection and corrosion casts as well as radiography, and compared to well-known data of the domestic cat (Felis catus). It was found that in the cheetah, as in the domestic cat, the intermedioradial, ulnar and accessory carpal bones, as well as the first, second, third and fourth carpal bones and the sesamoid bone of the abductor pollicis longus muscle, develop in a regular manner. The bones had a similar shape and the ligamentous apparatus was comparable, the most striking differences being the connection of all compartments of the joint cavity and the mediocarpal joint, working as a screw joint. The syndesmosis between the intermedioradial and ulnar carpal bones, instead of a synovial connection, is another adaptation for stabilization of the carpus of the cheetah during locomotion. The joint capsule is little spacious and in all three recesses can be differentiated. The first extends proximally palmar the ulnar carpal bone between the styloid process of the ulna and the accessory carpal bone, the second also extends proximally mediopalmar of the intermedioradial bone, and the largest third recess is located on the dorsal surface and extends proximally, laterally to the inserting tendon of the extensor carpi radialis muscle.     

Ultrasonography of the medial palmar intercarpal ligament in the Thoroughbred: technique and normal appearance

REASONS FOR PERFORMING STUDY: Tearing of the medial palmar intercarpal ligament (MPICL) has been recognised as a cause of lameness in the Thoroughbred, but diagnosis is difficult due to the nonspecific clinical signs, and can be achieved only by performing arthroscopy on the mid carpal joint (MCJ). It would be beneficial to be able to image the MPICL using ultrasonography to determine whether pathology is present in the ligament in order to aid diagnosis and prognosis. OBJECTIVES: To determine whether the MPICL could be imaged using ultrasound from the dorsal aspect of the MCJ, and to describe the technique and normal ultrasonographic appearance of the ligament. METHODS: A pilot study was performed using 2 cadaver carpi. Each carpus in turn had the MPICL imaged simultaneously using arthroscopy and ultrasound, with a metallic probe positioned on the dorsal aspect of the ligament to highlight the position of the MPICL. Six further pairs of carpi had the MPICL imaged ultrasonographically followed by dissection of the carpus to evaluate the ligament and relate its anatomy to the ultrasound images. Finally, 15 Thoroughbreds with no history of lameness isolated to the carpus had their MPICLs assessed and measured ultrasonographically. RESULTS: The MPICL could be imaged via the dorsal aspect of the MCJ using standard ultrasound equipment. The body and division into medial and lateral branches could be seen as a distinct, moderately dense granular echogenic structure in the palmar aspect of the joint, with clearly defined margins. CONCLUSIONS: The normal MPICL can be imaged reliably using ultrasound in the Thoroughbred from the dorsal aspect of the MCJ. There is a wide range in the normal width of the lateral aspect of the MPICL, but there is good symmetry between contralateral limbs. POTENTIAL RELEVANCE: This report of the normal ultrasonographic appearance of the ligament will be beneficial in acting as a reference for the detection of pathology using ultrasound.     

Carpal hyperflexion in a growing dog following neural injury to the distal brachium

A three-month-old dobermann was presented with hyperfiexion of the right carpus. The abnormality had evolved over a three-week period, following circumferential soft tissue trauma to the distal brachium. The carpal joint angle measured at the limit of passive extension was 105 degrees compared with 175 degrees for the left carpus, and prevented placement of metacarpal and digital pads on the ground. Neurological examination revealed marked atrophy of the carpal extensors, an absent extensor carpi radialis reflex and moderate atrophy of the carpal flexors. Spontaneous electromyographic activity consistent with denervation was recorded in the carpal extensor and flexor muscles. Surgical exploration of the distal radial nerve disclosed a region of fibrosis enmeshing the deep branch of the radial nerve. Following relief of the entrapped nerve, carpal hyperflexion, muscle atrophy and the extensor carpi radialis reflex deficit gradually resolved over four months. It is suggested that, In the rapidly growing limb, myoneural dysfunction Induced by trauma was the underlying pathophysiological mechanism for carpal hyperflexion.     

Anatomical features of the carpal flexor retinaculum of the horse

This study aims to elucidate the topographical anatomy of the carpal flexor retinaculum or palmar anular carpal ligament (PACL) in the horse. Ten specimen of the carpus of five healthy horses were studied by dissection in layers. Slices of 5 mm in thickness facilitated observation of the soft tissues. The superficial layer of the PACL subdivides into five compartments: one for the palmar nerve and the arterial and venous branches, one for only the radial artery, one for the radial vein, and one for the tendon of the radial carpal flexor muscle, and finally for the deep layer that supports all tendinous structures located palmar to the carpus, as well as the median artery and palmar medial nerve. The sections of the segmented PACL that are affected by carpal canal syndrome may vary with the aetiology of the space-occupying process. Precise anatomical knowledge of the structures may help in understanding the pathological processes and determining the most appropriate therapy.     

Observations on the in vitro behavior of digital tendons

The force/strain behavior of the common and lateral extensor tendons, the extensor branches of the interosseus muscle, and the superficial flexor tendon have been examined in vitro. The flexor tendon acted as a hard-spring with an initial large strain with small load followed by progressively less strain with increasing load, The distal part of the common extensor tendon and the extensor branches behaved in the same manner during dorsiflexion of the fetlock joint/palmar flexion of the coffin joint. The common extensor tendon behaved in a softening manner during palmar flexion of the fetlock and coffin joints while the lateral extensor and the extensor branches behaved in a nearly linear manner.     

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。     

Ultrasonographic examination of the carpal canal in dogs

The aim of this study was to determine the course of the median nerve and its adjacent structures in the carpal canals of 8 healthy dogs by using high-frequency transducers. Before performing ultrasonography, the transverse and posteroanterior diameters as well as the perimeter of the carpus were measured at just proximal to the side of the carpal pad. The anatomical structures were then determined at two levels of the carpal canal, which were named the proximal and distal levels, on the transverse sonograms. The cross-sectional areas, perimeters and the transverse and posteroanterior diameters of the median nerve were measured at these levels. Although all the measurements were larger at the proximal level, significant differences between the proximal and distal levels were determined for the cross-sectional area, the perimeter and the transverse diameter of the median nerve. On the transverse sonogram, the deep digital flexor tendon was seen in almost the center of the carpal canal like a comma shape and also it had a small concavity on the caudal side. The superficial digital flexor tendon was seen as an ovoid shape on the transverse sonograms and it was located nearly at the posterior side of the carpal canal. Both tendons were seen as intermediate-grade echogenic structures. The median artery was located inside of the concavity of the deep digital flexor tendon. Also, the median nerve was seen at the posteromedial side of the median artery. As a result of this study, the cross-sectional areas of the median nerve ranged between 1.01-2.68 mm² at the proximal level and between 0.93-1.91 mm² at the distal level.     

Tenoscopic Anatomy of the Equine Carpal Flexor Synovial Sheath

Objective —To describe the tenoscopic anatomy of the carpal sheath of the flexor tendons (carpal sheath) viewed from a lateral approach.
Study Design —Tenoscopic observation of structures within the carpal sheath subsequently confirmed by dissection.
Animals or Sample Population—12 equine cadaveric forelimbs.
Methods —The limbs were positioned lateral side up with the carpus slightly flexed. After distention of the carpal sheath, a portal for the arthroscope was made approximately 3 cm proximal to the distal radial physis and 2.5 cm caudal to the radius between the tendons of the ulnaris lateralis and lateral digital extensor muscles.
Results —A lateral tenoscopic approach was adequate to identify all structures within the carpal sheath. From proximal to distal, structures identified using this approach were the radial head of the deep digital flexor muscle, accessory ligament of the tendon of the superficial digital flexor muscle, distal radial physis, tendons of the superficial and deep digital flexor muscles, accessory carpal bone, antebrachiocarpal and middle carpal joints, and vincula of the tendon of the deep digital flexor muscle.
Conclusions —A lateral tenoscopic approach offered an easy, repeatable entry into the carpal sheath and allowed good observation of all structures within the sheath except for the medial borders of the tendons of the deep and superficial digital flexor muscles.
Clinical Relevance —Applications of a lateral tenoscopic approach to the carpal sheath include diagnostic procedures, lavage and synovial resection for septic tenosynovitis, desmotomy of the accessory ligament of the tendon of the superficial digital flexor muscle for flexural deformity or tendinitis, and removal of osteochondromas from the distal radial metaphysis.     

Surgical treatment of carpal flexural deformity in 72 horses

Carpal flexural deformities (CFD) are frequently encountered in the horse, with both congenital and acquired forms described. The success of surgical correction of CFD, both in terms of the ability to achieve a straight palmar carpal angle and the impact on future athletic performance, requires further investigation. OBJECTIVE: To report the surgical management and outcome of treatment of flexural deformity of the carpus in 72 horses up to 12 months of age. METHOD: Information was obtained from the medical records of horses surgically treated for CFD and through follow-up contact with owners. At the time of examination each case was graded on the severity of the flexural deformity as grade 1, 2, or 3, in order of ascending severity. Surgical treatment consisted of tenotomy of the ulnaris lateralis and flexor carpi ulnaris muscles. Re-assessment of the palmar carpal angle was made in the immediate postoperative period and again from at least 8 months after surgery via telephone contact with owners and/or breeders. A successful outcome was defined as achievement of a straight palmar carpal angle. Long term outcome was assessed in terms of fullfilment of intended use for horses reaching 3 years of age at the time of the study. RESULTS: A total of 135 surgical procedures were performed on 72 horses. A successful outcome was recorded in 111 limbs (82%). Excluding cases lost to follow-up, surgical correction was more successful in restoring a straight palmar carpal angle in grade 1 limbs (25/25, 100%) compared to grade 2 limbs (78/87, 89%) and grade 3 limbs (8/14, 57%). For those horses that had reached 3 years of age, 26 of 36 Thoroughbreds started in a race (72%) and 12 of 14 non-Thoroughbreds fulfilled their intended use (86%). CONCLUSION: Tenotomy of the ulnaris lateralis and flexor carpi ulnaris tendons for treatment of grade 1 and 2 CFD's has an excellent prognosis for restoration of a straight palmar carpal angle and for intended athletic pursuit of the horse. In cases of grade 3 CFD, the prognosis following surgery is guarded, especially in neonates. Horses treated in this study were up to 12 months of age, indicating that this deformity may not always be self-limiting as previously thought, and treatment may be required for successful resolution of flexural deformity of the carpus in older animals. The results of this study will help veterinarians to make recommendations regarding the surgical treatment of CFDs.     

Incomplete Longitudinal Fracture of the Proximal Palmar Cortex of the Third Metacarpal Bone in Horses

Seven horses, 2 to 4 years of age, were examined because of moderate-to-severe forelimb lameness, mild effusion of the middle carpal joint (3 horses), and pain on palpation of the origin of the suspensory ligament (4 horses). The lameness was abolished by anesthetic infiltration of the middle carpal joint in six horses. In four of them, a high palmar nerve block also abolished the lameness. A linear radiolucency in the proximal end of the third metacarpal bone (McIII) was interpreted as an incomplete longitudinal fracture. In one horse, distinct intramedullary sclerosis limited to the palmar cortex was indicative of an incomplete fracture confined to the palmar cortex. No osteoproliferative lesions were identified on the dorsal cortex of any of the horses. Surgical treatment with cortical screws in lag fashion accompanied by a rest period was successful in one horse. In four horses, rest for at least 3 months resulted in clinical soundness. In two horses, a shorter rest period resulted in recurrence of the lameness even though the horses were sound when put back into training. Careful clinical and radiographic examinations helped differentiate incomplete longitudinal fractures from lesions involving the carpus and proximal aspect of the suspensory ligament.     

奶牛正常跗关节的超声影像学观察

采用７．５ＭＨz的线扫探头对４个奶牛尸体跗关节和６头活体奶牛的８个跗关节的正常结 构进行了超声检查。一般骨骼的回声为光环或光线,关节囊呈明显的液怀暗区,腱质呈实性强回声。跗关节背侧的腓骨第三肌、趾长伸肌和趾内侧伸肌腱均可风到,下方为宽大的胫距关节囊,外侧为腓骨长肌和趾外侧伸肌腱,该腱周围有液性暗区的腱鞘。趾关节内侧超声影像图不清楚,后方是片状的趾浅屈肌和发达的趾深肌腱。     

ULTRASONOGRAPHIC EVALUATION OF CRANIAL CRUCIATE LIGAMENT RUPTURE VIA DYNAMIC INTRA-ARTICULAR SALINE INJECTION

Ultrasonographic examination of both stifle joints of five clinically and radiographically normal adult dogs was performed before and after surgical transection of the cranial cruciate ligament (CrCL). At pre- and postsurgery, the hyperechoic patellar ligament and the infrapatellar fat interfered with sonographic visualization of the CrCL. When the stifle joint, however, was imaged via dynamic intra-articular saline injection, the hyperechoic ligament was visualized because of the separation of the infrapatellar fat and the CrCL and the contrasting effect of anechoic saline. When the stifle joint was imaged by real-time scanning after the transection of the CrCL, flutter of the ligament and an anechoic area between the bone and the CrCL were identified. The increased diameter of the ligament and the increased thickness of the joint space were identified as well. Ultrasonographic examination via dynamic saline injection into the joint space has potential as a diagnostic tool for assessing CrCL rupture.     

Surgical repair of synovial fistulae between a carpal hygroma,the tendon sheath of the extensor carpi radialis and the antebrachiocarpal joint in a horse

This paper reports the diagnosis and repair of synovial fistulae between a carpal hygroma and both the antebrachiocarpal (ABC) joint and the extensor carpi radialis (ECR) tendon sheath of the left carpus in a 7-year-old gelding. The communication was confirmed using contrast radiography. Arthroscopy visualised the synovial fistulae and aided in the surgical repair. The gelding made a full athletic and acceptable cosmetic recovery.