Anatomical and radiographic study of the scapula in juveniles and adults of Tamandua mexicana (Xenarthra: Myrmecophagidae)

Tamandua mexicana is a mammal of the superorder Xenarthra geographically located between Mexico and Peru that remains insufficiently studied. These species are characterized by their movement, resting, and eating of termites and ants in arboreal and terrestrial environments, and therefore, their thoracic limbs have been adapted morphologically to move in these environments. Tamandua mexicana is a species constantly threatened by different causes, and their thoracic limbs can be affected in the scapular and shoulder regions as a result; therefore, specific anatomical knowledge of the scapula allows for better clinical procedures, surgical approaches, radiological diagnosis and muscular reconstructions in extinct species of anteaters. The main objective of this study was to report the anatomical and radiographic features of the scapula in juvenile and adult specimens of T. mexicana. Gross dissections and radiographic study were performed in six cadavers. The scapula had large differences compared with other mammals, such as two spines, a foramen for the suprascapular nerve, a long acromion, a cranial transverse scapular ligament and caudolateral fossa for the origin of the muscles teres major, tensor fasciae antebrachii and subscapular. In juvenile specimens, a scapular cartilage, an acromial cartilage, craniomedial and caudolateral coracoscapular ligaments forming the foramen for the suprascapular nerve, and progressive ossification of those ligaments and the cranial transverse scapular ligament were observed. These findings were corroborated by radiography; therefore, these characteristics change with age. The bony reliefs of the scapula of T. mexicana corroborate the specialization of the shoulder in this species.     

ECHOGRAPHIC EXAMINATION OF THE STIFLE JOINT AFFECTED BY CRANIAL CRUCIATE LIGAMENT RUPTURE IN THE DOG

Ultrasound is a useful technique for the study of normal and pathologic stifle joints, in particular for soft tissue examination. The aim of this study was to evaluate sonography for examination of stifle joints affected by cranial cruciate ligament rupture. Forty-two medium to giant breed dogs were studied. Tibial compression radiography was performed. A 7.5 MHz transducer with an incorporated 2 cm thick standoff was employed. Sagittal and midsagittal images were collected. The stifle was positioned in maximum flexion during sonography. Sonographic findings were compared with pathologic findings at surgery. Ultrasound was useful in evaluating the presence of fibrous tissue within the joint due to repair processes. It was observed in 70% of stifles with radiographic evidence of chronic osteoarthritis. In 19.6% of the joints it was possible to identify the ruptured cranial cruciate ligament. Ultrasound was not an accurate test for cruciate rupture evaluation, but was specific for the soft tissue pathologic changes which were observed consequent to joint instability.     

LATERAL COLLATERAL LIGAMENT AVULSION OF THE HUMERORADIAL JOINT IN A HORSE

This report describes traumatic avulsion of the lateral collateral ligament of the humeroradial joint in a horse. The history and diagnostic procedures are included with relevant radiographs and ultrasonographs. The poor prognosis associated with this injury is due to degenerative joint disease.     

RADIOGRAPHIC ASSESSMENT OF CRANIAL CRUCIATE LIGAMENT RUPTURE IN THE DAIRY COW

Case records and radiographs of 37 dairy cows presented to the University of Illinois Veterinary Medicine Teaching Hospital with a diagnosis of cranial cruciate ligament rupture were reviewed. Signalment, history, duration of lameness prior to clinical presentation, and physical examination findings were evaluated. Survey radiographs were examined and radiographic lesions were documented. Individual cows were classified into groups (A, B, C) based on the severity of radiographic lesions, with Group A cows having minimal radiographic lesions. Cows in Groups A and B had radiographic lesions similar to Class I in beef bulls reported in another study.^3,4 An attempt was made to relate the severity of radiographic lesions with age and duration of lameness. Group A animals tended to be younger cows (x?= 4.58 years) with a short duration of lameness. Group B cows were older (x?= 7.87 years) with a somewhat longer duration of lameness. Group C cows were slightly younger (x?= 7.30 years) than Group B cows; however, their duration of lameness was much longer (x?= 57.2 weeks vs 6.35 weeks for Group B and 2.54 weeks for Group A). The pathogenesis of cranial cruciate ligament rupture and its associated lameness appeared to differ in dairy cows from beef bulls. The majority of animals in this study had radiographic lesions of mild to moderate severity (Groups A and B). In contrast, based on previous work, beef bulls had a greater tendency to be similar to our Group C designation. Beef bulls became lame with cranial cruciate ligament rupture only after severe lesions of degenerative joint disease had already occurred. It has been stated that lameness associated with cranial cruciate ligament rupture in the beef bull is, therefore, secondary to degenerative joint disease. In contrast, the syndrome in dairy cows, as evidenced here, differs, since they often presented with cranial cruciate ligament rupture with little or no radiographic evidence of degenerative joint disease.     

N-甲基-N-亚硝基脲(MNU)对家蚕毒性的半致死剂量调查

N-甲基-N-亚硝基脲(MNU)是一种能诱导生物体产生随机点突变的烷化剂。为了完善利用MNU诱导家蚕突变的实验体系,用MNU处理家蚕品种大造的5龄第3天幼虫、化蛹第5天蛹、羽化当天的雄蛾及产后4～6 h的受精卵,通过Bliss法计算MNU对家蚕的半致死剂量(LD50)。结果显示MNU对不同发育时期家蚕的LD50值存在一定的差异:MNU对家蚕5龄第3天幼虫雌雄个体的LD50分别为28.735、20.157μg/头;对化蛹第5天蛹雌雄个体的LD50分别为56.466、54.672μg/头;对羽化当天的雄蛾的LD50为273.94μg/头;对产后4～6 h的受精卵的LD50为7 288.8μg/mL。实验数据表明,家蚕幼虫对MNU的毒性耐受能力差,蛾和卵的耐受能力较强;雌性个体对MNU毒性的耐受能力比雄性个体更强。     

Bilateral Dorsal Subluxation of the Proximal Interphalangeal Joint of the Hind Limb in a Mare: Case Report

Subluxation of the proximal interphalangeal joint is a rare and little studied condition in horses. We describe the case of a 12-year-old mare with bilateral dorsal subluxation of the proximal interphalangeal joint of the hind feet. Tenectomy of the medial digital flexor was performed in both limbs, and the patient showed signs of recovery within 14 days. Goniometry of the proximal interphalangeal joints 10 months after surgery showed diminution of 5° for the proximal interphalangeal axis of the left hind limb. However, no change was found for the joint angle of the right limb. Even so, the patient's gait and radiographic results were normal, and clinical abnormalities such as joint clicking and swelling were no longer observed.     

Ultrasonographic Evaluation of the Distal Extremity

Despite the increasing use of magnetic resonance imaging (MRI), ultrasound remains a valuable tool to diagnose injuries that cause distal extremity lameness in the horse. The key to a successful examination is a strong knowledge of anatomy in combination with proper ultrasonographic technique and the patience and dedication to learn these skills. Similar to all imaging modalities, it is equally important to recognize and consider the limitations of ultrasound in this region so that findings can be interpreted appropriately. Ultrasound can be used to diagnose injuries to the deep digital flexor tendon (DDFT), straight distal sesamoidean ligament and branches of the superficial digital flexor tendon using standard pastern ultrasonographic technique. The addition of newer techniques to image the DDFT at the level of P2, the navicular bursa and the collateral sesamoidean ligament can enhance the diagnostic utility of ultrasound in horses with distal extremity lameness. Although visibility is limited, ultrasound can be used to diagnose collateral ligament injuries of the coffin joint in many affected horses. Transcuneal imaging may be useful in some horses to detect abnormalities of the distal sesamoidean impar ligament and navicular bone, but evaluation of the DDFT is limited. Ultrasound should be considered in all horses with distal extremity lameness, regardless of the ability to perform advanced imaging procedures. Information gained is often complementary to other imaging modalities and may provide the basis for recheck examination purposes.