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1.
Distal forelimb specimens of eight skeletally mature horses were imaged using proton density turbo spin echo, T1-weighted spoiled gradient echo, T2*-weighted gradient echo, short tau inversion recovery and T2-weighted fast spin echo sequences with the limb parallel to the main magnetic field, and with angulation of the limb relative to the main magnetic field. The magic angle effect can be identified in the collateral ligaments of the distal interphalangeal joint when imaged in a high-field magnetic resonance (MR) imaging system with a horizontally oriented main magnetic field. This effect has previously been described in the collateral ligaments of the distal interphalangeal joint in a low-field system with a vertically oriented main magnetic field. The curvature of the ligaments places the fibers at the magic angle in both horizontally and vertically orientated main magnetic fields. This effect can be identified on short time of echo sequences and impacts the signal pattern of the ligaments at the level of the middle phalanx with the limb in a neutral position and with angulation of the limb. Magic angle effect should be considered as a possible cause of an asymmetrical signal pattern, depending on the positioning of the limb and the sequences used for imaging, when evaluating the collateral ligaments of the distal interphalangeal joint on images acquired with a high-field MR imaging system that has a horizontally oriented main magnetic field.  相似文献   

2.
The purpose of this study was to describe the appearance of normal bone marrow in seven adult dogs using low-field (0.3 T) magnetic resonance (MR) imaging. The areas imaged included the lumbar spine, pelvis, and femur. T1-weighted, fast spin-echo T2-weighted, and short tau (T1) inversion recovery (STIR) sequences were obtained at all locations. Histopathology was performed on sections from the sixth lumbar vertebral body, the wing of the ilium, and the femur (head and neck, mid-diaphysis, and condyle) for evaluation of cellularity and fat content. The lumbar spine and pelvic marrow MR images were similar in all dogs. The lumbar vertebral bone marrow was uniform, intermediate signal intensity, and isointense to muscle on all sequences. There was variation between dogs in the bone marrow distribution with MR imaging of the femur. In the proximal and mid-diaphysis of the femur there was patchy high-signal intensity on T1- and T2-weighted images, and hypointense foci on the STIR images. The distal femoral metaphysis had a variable pattern ranging from intermediate-to-high signal on T1- and T2-weighted images and intermediate-to-low signal on STIR images. The femoral condyles were uniformly high signal on T1- and T2-weighted images and hypointense on STIR images. Histopathologically there was a normal variation in the bone marrow cellularity. The marrow was normocellular (25–75% cellularity) for all sites examined except the femoral condyles, which were hypocellular (<25% cellularity).  相似文献   

3.
We describe the abnormal magnetic resonance (MR) imaging findings in the deep digital flexor tendon (DDFT) and distal sesamoid bone in horses with radiographic changes compatible with navicular syndrome. Thirteen postmortem specimens were examined using a 1.5-T magnetic field, with spin echo (SE) T1-weighted, turbo SE (TSE) proton density-weighted (with and without fat saturation), and fat saturation TSE T2-weighted sequences. The limbs were then dissected to compare the MR findings with the gross assessment and histologic examination of the DDFT and distal sesamoid bones. Tendonous abnormalities were detected by MR imaging in 12 DDFTs and confirmed at necropsy. Most tendon lesions were located at the level of the distal sesamoid bone and the proximal recess of the podotrochlear bursa. Tendon lesions were classified based on their MR imaging features as core lesions, dorsal lesions, dorsal abrasions, and parasagittal splits. Areas of increased MR signal in the DDFTs were characterized by tendon fiber disturbance and lack of continuity of the collagen fibers, foci of edema, hemorrhages, and formation of lakes containing eosinophilic plasma-like material or amphophilic material of low density. Bone marrow signal alterations in the distal sesamoid bone were seen in all digits. Two main phenomena were responsible for the abnormal signal, respectively, in T1-weighted (decreased signal) and in T2-weighted fat-suppressed images (increased signal): a decrease in the fat marrow content in the trabecular spaces and an increase in the fluid content. Histologic examination revealed foci of bone marrow edema, hemorrhage, necrosis, and fibrosis. Cyst formation and trabecular abnormalities (disorganization, thinning, remodelling) were also observed in areas of abnormal signal intensity. Increased bone density because of trabecular thickening induced a decrease in signal in all sequences.  相似文献   

4.
Collagen fibers oriented at 55° to the static magnetic field (B0) are characterized by an artifactual increase in signal intensity due to the magic angle effect. We hypothesized that there would be increased signal intensity in the collateral ligaments of the distal interphalangeal joint and oblique sesamoidean ligaments when these ligaments were at angles approaching 55° to a horizontal B0 during standing magnetic resonance (MR) imaging. MR imaging was performed on four cadaver forelimbs in a 0.27 T standing system. Transverse and dorsal images were obtained using various sequences, with limbs angled at 0°, 4°, 8°, and 12° to the vertical. Images were analyzed and the angle of each ligament to B0 determined. Mean signal intensity in the ligament and cortex of the adjacent phalanx was measured and ratios calculated. With subjective interpretation, there was increased signal intensity in the collateral ligaments of the distal interphalangeal joint and oblique sesamoidean ligaments over ranges of angles of 60–78° and 57–69°, respectively, to B0. In fast spin echo (FSE) sequences, with a long echo time (72 ms), the effect was less pronounced. FSE sequences can help determine the significance of increased signal intensity within tissues. In spite of limited positions of a limb during standing MR imaging compared with horses under general anesthesia, deviation from a vertical posture sufficient to cause a magic angle effect can still occur in both ligaments tested. Conformation may contribute to the occurrence of the magic angle effect during standing MR imaging. Effort should be made to position horses squarely and to minimize leaning during image acquisition.  相似文献   

5.
Bone marrow lesions (BMLs) (also known as ‘bone bruises’, ‘bone oedema’, ‘bone contusions’ and ‘occult fractures’) within the middle phalanx were diagnosed by standing low field magnetic resonance imaging (MRI) in 7 horses. The lesions were characterised by low signal intensity on T1‐ and T2*‐weighted gradient echo sequences, mildly increased signal intensity on T2 fast spin echo sequences, and high signal intensity on short tau inversion recovery (STIR) sequences. Four distinct patterns of abnormal signal were identified: BML associated with osteoarthritis of either the proximal or distal interphalangeal joints; BML associated with soft tissue injury; BML associated with acute trauma; and BML unassociated with any other injury or lameness (assumed to represent bone response to biomechanical stress). Repeat MRI was undertaken in 4 cases. In most cases the BML resolved with rest and time, although lameness was persistent in 2 horses (one of which had an associated osteoarthritis of the proximal interphalangeal joint).  相似文献   

6.
Increased signal intensity in one of the collateral ligaments of the distal interphalangeal (DIP) joint of sound horses in images acquired using a low-field magnet with vertical orientation of the magnetic field was investigated as a possible manifestation of the magic angle effect. Three isolated equine digits were imaged using the following pulse sequences: (1) spin echo T1, (2) turbo spin echo proton density and T2, and (3) 3D gradient echo T1, in different positions by mildly changing the orientation of the long axis of the digit, in the dorsal plane, relative to the magnetic field. The signal intensity in a ligament was significantly increased when the ligament orientation relative to the magnetic field was 55±10°. The signal intensity was markedly increased in pulse sequences with short echo time (TE) 5.0, 4.9, and 3.9 times increased, respectively, for 3D gradient echo T1, spin echo T1, and turbo spin echo proton density) and to a lesser extent with pulse sequences with a longer TE (1.8 times increased for turbo spin echo T2). These changes are characteristic of the magic angle effect. Because of the anatomic orientation of the collateral ligaments of the DIP joint, a slight deviation of the long axis of the digit in the dorsal plane, from the ideal horizontal position, will induce an increased signal intensity that can be confused with desmitis. Careful positioning of the foot in magnetic resonance imaging systems where B 0 is perpendicular to the long axis of the digit is critical to prevent the occurrence of the magic angle effect.  相似文献   

7.
REASONS FOR PERFORMING STUDY: There have been no previously published case series of horses examined using either scintigraphy or MRI to diagnose collateral ligament injuries not detectable using ultrasonography or radiography, nor have other concurrent soft tissue lesions been described. OBJECTIVES: To describe the clinical features of horses with desmitis of the collateral ligaments of the distal interphalangeal (DIP) joint and to evaluate the results of radiographic, ultrasonographic, scintigraphic and magnetic resonance imaging (MRI) examinations. METHODS: Horses were examined between January 2001 and January 2003 and were selected for inclusion in the study if there was unequivocal evidence of collateral desmitis of the DIP joint based on ultrasonography or MRI. Subject details, case history, results of clinical examination and responses to local analgesic techniques were reviewed. The results of radiographic, ultrasonographic, scintigraphic and MRI examinations were assessed. RESULTS: Eighteen horses were identified with desmitis of a collateral ligament of the DIP joint, 3 horses (Group 1) based on ultrasonography alone, 7 (Group II) with positive ultrasonographic and magnetic resonance images and 8 (Group III) with no lesion detectable using ultrasonography, but lesions identified using MRI. Seventeen horses had forelimb injuries and one a hindlimb injury. The medial collateral ligament was injured most frequently (13 horses). In the majority of horses, no localising clinical signs were seen. Lameness was invariably worse in circles compared with straight lines. Lameness was improved by palmar digital analgesia in 16 horses (87%), but only 6 were nonlame. Intra-articular analgesia of the DIP joint produced improvement in lameness in 6/15 horses (40%). In 16 horses, no radiographic abnormality related to the DIP joint or collateral ligament attachments was identified. Eight of 14 horses (57%) had focal, moderately or intensely increased radiopharmaceutical uptake (IRU) at the site of insertion of the injured collateral ligament on the distal phalanx. Alteration in size and signal in the injured collateral ligament was identified using MRI. In addition, 5 horses had abnormal mineralisation and fluid in the distal phalanx at the insertion of the ligament. Eleven horses had concurrent soft tissue injuries involving the deep digital flexor tendon, distal sesamoidean impar ligament, navicular bursa or collateral ligament of the navicular bone. CONCLUSIONS AND POTENTIAL RELEVANCE: Collateral desmitis of the DIP joint should be considered as a cause of foot lameness. Although some injuries are detectable ultrasonographically, false negative results occur. Focal IRU at the ligament insertion on the distal phalanx may be indicative of injury in some horses. MRI is useful for both characterisation of the injury and identification of any concurrent injuries. Further follow-up information is required to determine factors influencing prognosis.  相似文献   

8.
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9.
Standing low‐field magnetic resonance imaging (MRI) was used to image the feet of 21 horses affected by keratomas. The animals had variable clinical histories including acute, chronic or recurrent lameness. Of the 21 horses, only 14 (66%) had radiological changes suggestive of keratoma. Standing low‐field MRI revealed a smoothly demarcated hoof wall lesion in all horses, with deformity of the adjacent surface of the distal phalanx in 15 cases. The signal characteristics of the keratomas varied, with most showing either hypointensity or heterogeneous mixed signal intensity in T1‐ and T2*‐weighted images and hypointensity in STIR sequences. An intermediate or high STIR signal intensity was present in the trabecular bone of the adjacent region of the distal phalanx in 5 cases. Surgical debridement was performed in 16 horses. Recurrence was common, especially in cases where the lesion was ill‐defined; the prior MRI appearance of these cases tended to be of heterogeneous signal intensity.  相似文献   

10.
There is a large spectrum of radiological variants of the distal phalanx that can be seen in both sound and lame horses. Osteitis of the distal phalanx implies active inflammation, a diagnosis that can only be made supported by nuclear scintigraphy, magnetic resonance imaging or computed tomography. Osteitis of the distal phalanx as a primary cause of lameness is relatively unusual, but may be the result of acute or chronic bone trauma or be associated with adjacent laminar disruption. Bone trauma may also be seen in association with moderate to extensive uniaxial or biaxial ossification of the cartilages of the foot. Bone lesions also occur in association with osteoarthritis of the distal interphalangeal (DIP) joint or at, or adjacent to, the insertion of one of the collateral ligaments of the DIP joint.  相似文献   

11.
Palmar foot pain is a common cause of lameness. Magnetic resonance imaging (MRI) has the potential to detect damage in all tissues of the equine foot, but an understanding of the differences in magnetic resonance (MR) images between feet from horses with and without palmar foot pain is required. This study aimed to describe MR findings in feet from horses with no history of foot-related lameness, and to compare these with MR findings in horses with lameness improved by palmar digital local analgesia. Thirty-four limbs from horses euthanized with a clinical diagnosis of navicular syndrome (ameness >2 months duration, positive response to palmar digital nerve blocks and absence of other forelimb problems) (Group L), and 25 feet from age-matched horses with no history of foot pain (Group N) were examined. For each anatomic structure, MR signal intensity and homogeneity, size, definition of margins, and relationships with other structures were described. Alterations in MR signal intensity and homogeneity were graded as mild, moderate, or severe and compared between Groups L and N. Results revealed that there were significant differences in MR images between Groups N and L. Multiple moderate-severe MR signal changes were present in 91% of limbs from Group L and moderate (none were graded severe) in 27% of limbs from Group N. In most Group L limbs, more than three structures and frequently six to eight structures were abnormal. Concomitant abnormalities involved most frequently the deep digital flexor tendon, distal sesamoidean impar ligament, navicular bone, collateral sesamoidean ligament, and navicular bursa (with significant associations in severity grade between these structures), sometimes with involvement of the distal interphalangeal joint and/or its collateral ligaments. It was concluded that findings on MR images were different between horses with and without foot pain, and that pain localized to the foot was associated with MR changes in a variety of structures, indicating that damage to several structures may occur concurrently and that MR imaging was useful for evaluation of foot pain.  相似文献   

12.
We report the use of low-field standing magnetic resonance imaging in the standing horse for the diagnosis of osseous lesions in the metacarpophalangeal (MCP) or metatarsophalangeal (MTP) joint that were not apparent using standard radiography. Thirteen horses were studied and all had thickening of the subchondral bone plate and abnormal signal intensity in the adjacent spongiosa in either the condyles of metacarpal/metatarsal III or the proximal phalanx or both. Abnormalities were characterized by diffuse decreased signal intensity on T1-weighting adjacent to the subchondral bone and within the spongiosa in at least two imaging planes; in the absence of increases in signal intensity in fat-suppressed images, this change was interpreted as bone sclerosis. Nine horses also had a diffuse decreased signal intensity on T2*-weighting in the same areas and five had a diffuse increase in signal intensity in fat-suppressed images in conjunction with a decrease in signal intensity on T1- and T2*-weighted images; the increase in signal intensity in fat-suppressed images was interpreted as fluid accumulation. Five horses had a focal area of change in signal intensity within the subchondral bone with apparent loss of definition between the subchondral bone and the articular cartilage. Eleven horses were available for follow up, of which eight were sound and three remained lame. We conclude that lameness originating from the MCP or MTP joint may be associated with osseous damage in horses of any signalment in the absence of radiographic changes.  相似文献   

13.
Osseous cyst‐like lesions (OCLLs) were diagnosed by standing low‐field magnetic resonance (MR) imaging in 9 mature horses (age range 6–17 years). All horses had been subjected to a routine lameness evaluation (including standard foot radiographs) with no diagnosis being reached prior to MR imaging. The duration of lameness ranged from one month to one year. OCLLs were diagnosed in 12 feet. The site of the lesions included the distal phalanx in 11 feet (subchondral bone in 4, insertion of collateral ligaments of the distal interphalangeal joint in 4, insertion of the distal sesamoidean impar ligament in 3) and the subchondral bone of the distal aspect of the middle phalanx in one foot. OCLLs were characterised by discrete spherical or elliptical areas of high or intermediate signal in all MR sequences. In most cases the lesion was surrounded by a rim of bone with abnormally low signal.  相似文献   

14.
The purpose of this study was to describe the normal magnetic resonance (MR) imaging characteristics of the palmar structures of the equine podotrochlear apparatus by means of retrospective evaluation of MR imaging studies of 16 cadaver limbs. The articular aspect of the distal sesamoid bone was not evaluated in this study. Equine digits were imaged with a human knee radiofrequency coil in a 1.5 T magnetic field, using spin echo (SE) T1-weighted, turbo spin echo proton density (TSE PD)-weighted with and without fat saturation (FS), and FS TSE T2-weighted sequences. The limbs were dissected after imaging to validate the absence of gross abnormalities of the flexor aspect of the distal sesamoid bone, of the deep digital flexor tendon, and the distal impar sesamoidean ligament. Seven deep digital flexor tendons were subjected to histologic examination to exclude any microscopic tendon pathology. The anatomic structures of the podotrochlear apparatus were easily identified on MR images. Compact bone of the flexor cortex of the distal sesamoid bone had low intensity signal on all sequences. In 11 digits an increased signal was seen within the thickness of the sagittal eminence of the flexor cortex in SE T1-weighted images and in TSE PD-weighted images without FS. Trabecular bone had a granular appearance and high signal in SE T1-weighted sequences and TSE images without FS. The deep digital flexor tendon had low signal on FS T2-weighted images, while on short echo time sequences (T1- and PD-weighted sequences), the tendon signal varied depending on the relative orientation between its fibers and the static magnetic field. Seven tendons had stippled appearance due to small intratendonous foci of slightly increased signal on transverse T1-weighted images. MR imaging provides a thorough evaluation of the anatomical structure of the podotrochlear apparatus: A good knowledge of the MR imaging appearance and anatomy and an awareness of potential pitfalls will improve diagnostic specificity for the detection of pathologic changes.  相似文献   

15.
Emaciated human patients have changes in the fat content in medullary bone that are consistent with serous atrophy of the bone marrow histologically. Serous atrophy has been identified at postmortem examination in horses; however, the magnetic resonance (MR) characteristics have not been documented. Herein we describe the abnormalities of the bone marrow and medullary bone detected by low‐field and high‐field MR imaging of the distal limbs of three emaciated horses. These low‐ and high‐field MR imaging abnormalities are characterized by a decrease in signal intensity on T1‐weighted images in combination with an increase in signal intensity on short tau inversion recovery images in all areas of trabecular bone in the distal limbs, in the absence of lameness. Serous atrophy was confirmed microscopically in two horses. Appreciating the sensitivity of MR imaging for detection of bone marrow changes may assist in assessment of fat atrophy in welfare cases where starvation is suspected.  相似文献   

16.
The purpose of this study was to determine the magnetic resonance (MR) imaging characteristics of bone marrow in the pelvis and femur of normal, young dogs. Six greyhounds were imaged at 4, 8, 12, and 16 months of age. Sagittal images of the femur and dorsal images of the pelvis were obtained with T1-weighted, fast spin echo (FSE) T2-weighted, and short tau (T1) inversion recovery (STIR) sequences. On T1-weighted images areas with high signal intensity, similar to fat, included the femoral heads, mid-diaphysis of the femur, femoral condyles, and the body of the ilium. T2-weighted images were characterized by uniform intermediate signal intensity (less than fat, but greater than muscle) in the femoral head, high signal intensity, similar to fat, in the mid-diaphysis of the femur and ilial body, and intermediate to high signal intensity in the femoral condyle. By 16 months high signal intensity was seen in the diaphysis and distal metaphysis on both T1- and T2-weighted images. On STIR images the femoral head had intermediate to low signal intensity, compared with muscle. The mid-diaphysis of the femur was of low signal intensity, similar to fat, and the body of the ilium had mixed signal intensity at all ages. The femoral condyle had inhomogenous, intermediate to low signal intensity at 4 months, but was of uniform low signal intensity at 8-16 months.  相似文献   

17.
REASONS FOR PERFORMING STUDY: Nuclear scintigraphy is commonly used as a diagnostic aid for foot pain, but there is limited information about different patterns of radiopharmaceutical uptake (RU) and their correlation with the results of other imaging modalities. OBJECTIVES: To describe patterns of RU in horses with foot pain. MATERIALS AND METHODS: Scintigraphic images of the feet of 264 horses with front foot pain were analysed subjectively and using region of interest analysis. Magnetic resonance images of all feet were analysed prospectively; the navicular bones were reassessed retrospectively and assigned a grade. A Spearman rank correlation test was used to test for a relationship between the scintigraphic grade of the navicular bone and magnetic resonance imaging (MRI) grade. Sensitivity and specificity of scintigraphy for detection of lesions in the deep digital flexor tendon (DDFT), the collateral ligaments (CL) of the distal interphalangeal (DIP) joint and the navicular bone were determined. RESULTS: Increased radiopharmaceutical uptake (IRU) was detected in: a) the navicular bone (36.6%); b) pool phase images in the DDFT (13.0%); and c) at the insertion of the DDFT on the distal phalanx (14.3%). There was focal IRU at the insertion of the medial or lateral CL of the DIP joint in 9.4% and 1.5% of limbs, respectively. There was IRU in the medial and lateral palmar processes in 7.6% and 3.4% of limbs, respectively. There was a significant positive correlation between the scintigraphy grade and total MRI grade for the navicular bone and no difference between either focal or diffuse IRU and total MRI grade. There was high specificity, but low sensitivity of scintigraphy for detection of MR lesions of the navicular bone, the DDFT and the CLs of the DIP joint. CONCLUSIONS: Positive nuclear scintigraphic results are good predictors of injury or disease of the navicular bone, DDFT and CLs of the DIP joint. However, a negative scintigraphic result does not preclude significant injuries. CLINICAL RELEVANCE: Nuclear scintigraphy is a useful tool in the investigation of foot lameness and may help to determine the significance of MR lesions, especially if >1 lesion is identified that may be contributing to lameness.  相似文献   

18.
Magnetic resonance (MR) imaging is increasingly used in the diagnosis of equine foot pain, but improved understanding of how MR images represent tissue-level changes in the equine foot is required. We hypothesized that alterations in signal intensity and tissue contour would represent changes in tissue structure detected using histologic evaluation. The study objectives were to determine the significance of MR signal alterations in feet from horses with and without lameness, by comparison with histopathologic changes. Fifty-one cadaver feet from horses with a history of lameness improved by palmar digital analgesia (n = 32) or age-matched control horses with no history of lameness (n = 19) were stored frozen before undergoing MR imaging and subsequent histopathological examination at standard sites (deep digital flexor tendon, navicular bone, distal sesamoidean impar ligament, collateral sesamoidean ligament, and navicular bursa). Using MR images, signal intensity and homogeneity, size, definition of anatomic margins, and relationships with other structures were described. Alterations were graded as mild, moderate, or severe for each structure. For each anatomic site examined histologically the structures were described and scored as no changes, mild, moderate, or severe abnormalities, also taking into account adhesion formation within the navicular bursa detected on macroscopic examination. Alterations in MR signal intensity were related to changes at the tissue level detected by histologic examination. A sensitivity and specificity comparison of MR imaging with histologic examination was used to evaluate the significance of MR signal alterations for detection of moderate-to-severe lesions of the deep digital flexor tendon (DDFT), navicular bone, distal sesamoidean impar ligament (DSIL), collateral sesamoidean ligament (CSL) and navicular bursa. Agreement between the MR and histologic grading was assessed for each structure using a weighted kappa agreement. Direct comparison between histology and MR imaging for individual limbs revealed that signal alterations on MR imaging did represent tissue-level changes. These included structural damage, fibroplasia, fibrocartilaginous metaplasia, and hemosiderosis in ligaments and tendons; trabecular damage, osteonecrosis, fibroplasia, cortical defects, and increased vascularity in bone; and fibrocartilage defects. MR imaging had a high sensitivity and specificity for most structures. MR imaging had high specificity for lesions of the DDFT, CSL and navicular bursa, quite high specificity for lesions of the medulla of the navicular bone and its proximal aspect, with moderate specificity for the DSIL, and distal, dorsal and palmar aspects of the navicular bone, and was sensitive for detection of abnormalities in all structures except the dorsal aspect of the navicular bone. When MR and histologic grades alone were compared, there was good agreement between MR and histologic grades for the navicular bursa, DDFT, navicular bone medulla and CSL; moderate-to-good agreement in grades of the distal and palmar aspects of the navicular bone; fair to moderate in grades of the DSIL, and poor agreement for the dorsal and proximal aspects of the navicular bone. The results of this study support our hypothesis and indicate the potential use and limitations of MR imaging for visualization of structural changes within osseous and soft tissue structures of the equine foot.  相似文献   

19.
REASONS FOR PERFORMING STUDY: Causes of palmar foot pain and the aetiopathogenesis of navicular disease remain poorly understood, despite the high incidence of foot-related lameness. HYPOTHESES: Abnormalities of the collateral sesamoidean ligaments (CSLs), distal sesamoidean impar ligament (DSIL), deep digital flexor tendon (DDFT), navicular bone, navicular bursa, distal interphalangeal (DIP) joint or collateral ligaments (CLs) of the DIP joint may contribute to palmar foot pain. METHODS: Feet were selected from horses with a history of unilateral or bilateral forelimb lameness of at least 2 months' duration that was improved by perineural analgesia of the palmar digital nerves, immediately proximal to the cartilages of the foot (Group 1, n = 32); or from age-matched control horses (Group 2, n = 19) that were humanely destroyed for other reasons and had no history of forelimb foot pain. Eight units of tissue were collected for histology: the palmar half of the articular surface of the distal phalanx, including the insertions of the DDFT and DSIL; navicular bone and insertion of the CSLs; DDFT from the level of the proximal interphalangeal (PIP) joint to 5 mm proximal to its insertion; synovial membrane from the palmar pouch of the DIP joint and the navicular bursa; CLs of the DIP joint and DSIL. The severity of histological lesions for each site were graded. Results were compared between Groups 1 and 2. RESULTS: There was no relationship between age and grade of histological abnormality. There were significant histological differences between groups for lesions of the flexor aspect, proximal and distal borders, and medulla of the navicular bone; the DSIL and its insertion and the navicular bursa; but not for lesions of the CSLs, the dorsal aspect of the navicular bone, distal phalanx and articular cartilage, synovium or CLs of the DIP joint. CONCLUSIONS: Pathological abnormalities in lame horses often involved not only the navicular bone, but also the DSIL and navicular bursa. Abnormalities of the navicular bone medulla were generally only seen dorsal to lesions of the FFC. POTENTIAL RELEVANCE: Adaptive and reactive change may be occurring in the navicular apparatus in all horses to variable degrees and determination of the pathogenesis of lesions that lead to pain and biomechanical dysfunction should assist specific preventative or treatment protocols.  相似文献   

20.
Eight sports horses with unilateral (4) or bilateral (3) forelimb or unilateral hindlimb (1) lameness had subtle radiologic abnormalities of the subchondral bone of the sagittal groove of the proximal phalanx associated with moderate or intense increased radiopharmaceutical uptake. High‐field or low‐field magnetic resonance (MR) imaging confirmed the presence of a fissure fracture or subchondral and trabecular bone trauma. Seven of eight lesions were located approximately midway between the dorsal and palmar cortices of the proximal phalanx; the eighth was sited more dorsally. Two horses underwent follow‐up MR imaging and abnormal signal intensity persisted, with little change.  相似文献   

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