382 THE MUSCLES OF THE DOG 
which are homologous with those of the same digit in the forelimb. These are 
the abductor hallucis, adductor hallucis, and flexor hallucis brevis. 
The principal burs and synovial sheaths of the muscles of the leg and foot are as follows: 
The tibialis anterior has a bursa under its tendon at the tarsus. A pouch of the synovial membrane 
of the stifle joint underlies the tendon of origin of the extensor digitalis longus, and is partially 
reflected upon the superficial face of the tendon; the tendons of insertion are provided with a 
synovial sheath which begins at the end of the muscular part and extends to the proximal part of 
the metatarsus. The tendons of the lateral digital extensor and peroneus brevis have a common 
synovial sheath at the distal end of the leg and proximal part of the tarsus. The tendon of the 
peroneus longus has a synovial sheath which begins an inch or more above the lateral malleolus 
(in a good-sized dog) and extends about to the middle of the tarsus; another sheath envelops the 
tendon to the point where it bends round to the plantar surface of the hock; a bursa lies between 
the tendon and the joint capsule and fourth tarsal bone, and communicates with the joint cavity. 
A bursa underlies the terminal part of the tendon of the peroneus brevis. There is a bursa in 
front of the distal part of the tendon of the gastrocnemius; it extends an inch or more (in large 
dogs) above the tuber calcis. A bursa underlies the superficial flexor tendon at the tarsus; in large 
dogs it extends about an inch above and below the tuber calcis. The tendon of the tibialis posterior 
has a synovial sheath at the distal end of the leg. The tendon of the flexor digitalis longus has a 
synovial sheath which begins a little above the medial malleolus and extends to the junction with 
the tendon of the flexor hallucis. The tarsal sheath of the flexor hallucis begins (in large dogs) 
about an inch and a half above the level of the medial malleolus and extends to the distal end of 
the tarsus; it communicates with the tibio-tarsal joint cavity. The synovial apparatus in the 
distal part of the limb resembles that of the forelimb. 
