SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
is located on the cranial aspect of the limb, lying between the tibialis cranialis and
extensor digitorum longus muscles. Proximally, the peroneus tendon is roughly
oval in shape and it flattens distally until it divides into two branches to insert
laterally on the calcaneus and fourth tarsal bone and medially on the third tarsal
bone and MT3. The tibialis cranialis muscle lies deep to the peroneus tertius and
inserts in two branches on the proximal end of the metatarsal bone and, as the
cunean tendon, on the first tarsal bone. The bifurcation of the tendon occurs
immediately distal to the bifurcation of the peroneus tertius. There is a sheath at
the point the tendon courses superficially between the branches of insertion of the
peroneus tertius and a bursa beneath the cunean tendon. The superficial digital
flexor muscle lies between the two heads of the gastrocnemius muscle. Its tendon
spirals around the tendon of the gastrocnemius to adopt a superficial location
within the common calcaneal tendon. It has an insertion on the tuber calcis and
then courses distally over the point of the hock. The tendon is echoic and has an
oval shape, except at the point of the hock where it is flattened and crescent
shaped. The gastrocnemius tendon arises from the lateral and medial heads of
the gastrocnemius muscle that are superficial in location. In its mid portion, the
tendon spirals around the SDFT so that it lies deep to the SDFT. It inserts on the
calcaneal tuberosity. Longitudinal and transverse images are made from the
plantar aspect of the limb. The tendon is uniformly echoic with an oval shape on
transverse images. The gastrocnemius bursa is dorsal to the insertion of the
gastrocnemius tendon on the calcaneal tuberosity. The intertendinous portion of
the calcaneal bursa is deep to the SDFT, from the distal fourth of the tibia to the
middle of the tarsus. It is visible between the superficial digital flexor and
gastrocnemius tendons. It connects with the gastrocnemius bursa 100% of the
time medially and 50% of the time laterally. The superficial calcaneal bursa lies
superficial to the SDFT and is variable in its presence. The tarsal sheath can be
imaged surrounding the DDFT along the medial aspect of the hock and in the
proximal metatarsal region. The tarsal sheath is also a thin echogenic structure that
is difficult to distinguish from the DDFT unless there is fluid contained within the
sheath.
The collateral ligaments are multiple; there are one long and 3 short lateral
and medial collateral ligaments. The long lateral collateral ligament originates on the
lateral malleolus of the tibia and inserts on the distolateral calcaneus, fourth tarsal
bone, MT4 and MT3. The 3 short lateral collateral ligaments are partially fused at
their origin dorsal to the groove for the lateral digital extensor tendon on the lateral
malleolus of the tibia. The superficial short lateral collateral ligament inserts on the
calcaneus and tibial tarsal bone just distal to the coranoid process of the calcaneus.
The middle short lateral collateral ligament inserts on the tibial tarsal bone dorsal to
the superficial lateral collateral ligament. The deep short lateral collateral ligament
inserts more dorsally on the tibial tarsal bone approaching its lateral margins. The
long medial collateral ligament originates on the medial malleolus of the tibia and
extends distally to its insertion on the distal tibial tuberosity of the tibial tarsal bone,
the medial surface of the small tarsal bones and the proximal portion of MT2 and
MT3. The 3 short medial collateral ligaments extend from the craniomedial aspect of
the medial malleolus of the tibia under the long collateral ligament to their insertions.
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