M. Nicaise

Cross‐sectional anatomy and comparative ultrasonography of the equine medial femorotibial joint and its related structures

REASONS FOR PERFORMING STUDY Injuries of the equine stifle are frequent causes of hindlimb lameness. Ultrasonography is useful for the diagnosis of many soft tissue lesions but, until recently, its application to the equine stifle has been limited to a description of normal and abnormal structures. A comparative study using gross anatomical sections to identify all structures visible on ultrasonographic images of the equine stifle has not previously been reported. OBJECTIVES To provide a comprehensive comparative cross-sectional atlas of the normal equine medial femorotibial (MFT) joint and its related structures using ultrasonography. METHODS The stifle joints of 15 cadaver limbs were examined ultrasonographically using a systematic approach. Ten different scanning planes were defined. The lateral and medial femorotibial and the femoropatellar joints were injected with pigments of different colours. Each leg was frozen (10 in extension and 5 in flexion) and cut into slices corresponding to the different scanning planes. According to the different ultrasonographic reference images, 10 representative anatomical images were selected and digitised. RESULTS All bony and soft tissue structures were identified on the anatomical sections and subsequently located on the corresponding ultrasonographic images, except the caudal meniscotibial ligaments. Visualisation of the cruciate ligaments was a challenge due to their position and oblique orientation. CONCLUSIONS Ultrasonography is a very useful technique for imaging both soft tissue and bony structures of the MFT joint and its related structures, although a protocol is required to perform a systematic and standardised ultrasonographic examination. Good anatomical knowledge is mandatory for identification of the different structures. POTENTIAL RELEVANCE This study should contribute to 1) knowledge of the ultrasonographic anatomy of the equine MFT joint and its related structures, 2) use of a protocol for a standardised ultrasonographic examination and 3) the ability to recognise abnormal structures.

Numerical Vertebral Variations and Transitional Vertebrae in the Goat

This study of 185 vertebral columns of male and female goats describes the gross variation in numbers of segmental vertebrae and the occurrence of a variety of transitional vertebrae. The variations in number and gross anatomical organization of transitional vertebrae are discussed and a hypothesis presented to explain their occurrence.

Morphological Study of the Development of the Disseminate Prostate in Intact and Castrated Male Pigs Aged Two to Six Months

The light-microscopical and ultrastructural differentiation of the disseminate prostate was studied in 12 boars and 8 barrows, ranging in age from 8 to 28 and 12 to 27 weeks, respectively. The barrows had been castrated at the age of 8 weeks. In young boars the prostate is organized in an inner zone and an outer zone. The glandular tubules of the latter are more differentiated than those in the inner zone. Sexual maturation in the prostate is characterized by almost complete reduction of the inner zone and concomitant enlargement of the outer zone. This differentiation of the inner zone occurs progressively and is manifested by a higher density of the glandular tubules, by a decrease in the number of basal cells and by an increase in the secretory tubular cells containing more microvilli, organelles and secretory vesicles. A few weeks after castration, the characteristic morphology of the undifferentiated inner zone is found throughout the entire glandular layer. The number of glandular tubules in barrows has decreased, and their cells show minimal secretory activity, nuclear indentations and a decrease in their organelles. A further castration effect is vacuolization of the perinuclear cytoplasm in numerous glandular cells.

Structure of the Prostate and the Pelvic Urethra in Barrows and the Changes Induced by Diethylstilbestrol

The anatomical and light microscopical structures of the pelvic urethra with the surrounding prostate were investigated in male pigs, which were castrated early in life and examined at slaughter weight. The general structure was regular in the caudal part, but was irregular in the cranial part. In the prostate each lobule contained a cell-rich stroma, which surrounded several glandular tubules and a few prostate ductules. The tubules were lined by low columnar cells and some reserve cells, the ductules by a low two-layered epithelium and the urethra by a transitional epithelium. Small differences in the gland structure and urethral epithelium were observed between the cranial and caudal part. Subcutaneous injection of diethylstilbestrol provoked metaplasia of the epithelium of the urethra and the ducts, while the peroral administration of diethylstilbestrol in combination with methyltestosterone resulted in an increased number of glandular tubules.

Morphology of the Vesicular and Bulbourethral Glands in Barrows and the Changes Induced by Diethylstilboestrol

The macroscopic and light microscopic structure of the vesicular and bulbourethral glands was investigated in male pigs, which were castrated early in life and examined at slaughter weight. The vesicular glands showed a constant morphological pattern while in the bulbourethral glands an individual variation was observed in the number of mucous acini and the amount of interstitial tissue. In spite of this variation in the normal structure, the latter gland as well as the vesicular gland showed reliable changes after treatment with diethylstilboestrol.