Sonography is an important tool for diagnosing diseases of the locomotor system. It
helps to evaluate tendons, ligaments, joint capsules and any free fluid. Knowledge of
the sonographic anatomy is essential to detect any changes.
The aim of this study was to describe the anatomy of the fetlock region in sheep
and goats based on sonographic pictures. Furthermore, reference values of individual
structuressize were collected and compared to each other.
During the first phase, sonographic examination was conducted on the fetlock of six
sheep cadavers and compared to frozen feet sections. In the case of eight feet, the joint
pouches were experimentally filled. During the second phase, the same examination
was conducted on ten living sheep and eight goats. The Toshiba Aplio XG ultrasound
device with a 9 MHz probe was used in the first phase and the Mindray M7 with a 10
MHz probe in the second one.
Clear differentiation of the joint space, the capsule, the articular cartilage, the extensor
tendons, the flexor tendons and the interosseus medius muscle was possible by
means of the sonographic examination. Eleven structures, the joint capsule, the
articular cartilage, the ligg. collateralia lateral & mediale, the superficial digital flexor
tendon, the superficial part and the deep part of the manica flexoria, the deep flexor
tendon in longitudinal and transverse section and the musculus interosseus medius
in longitudinal and transverse section were measured and compared to each other.
No significant differences were observed between the right and left and between the
front and back extremities. Differences between sheep and goats could neither be
neglected nor demonstrated. In the case of goats, a correlation between the age of
the animals and the size of the structures could not be proven. It was shown that a
minimum experimental filling of 3 ml was necessary for imaging a distended fetlock joint cavity.
The clear differentiation of the soft tissue structures by ultrasonography is a valuable
tool for the examination of the fetlock joint. However, more studies are necessary for
demonstrating any pathological aspects.