Flexor digitorum [digitalis] superficialis muscle

The flexor digitorum [digitalis] superficialis muscle is located on the pelvic limb, caudally to the tibia. It is present in all domestic animals but not in humans.

Conformation: It consists of an elongated fleshy body followed by a particularly long tendon which divides distally according to the number of toes.

Origin: Lateral supracondylar tuberosity of the femur or supracondylar fossa.

Insertion: On either side of the calcaneal tuberosity, distal metatarsophalangeal joints.

Relations: Located between the two heads of the gastrocnemius muscle, attached to the lateral head. It covers the popliteal muscle and the deep flexors of the digits. Its tendon is part of the composition of the common calcaneal tendon, which bypasses the tendon of the gastrocnemius, attaches to the calcaneal tuberosity and then continues towards the digits, dividing at the plantar face of the metatarsus.

Action: Flexion of the digits, extension and fixation of the tarsus, flexion of the stifle.

Vascularization: Depending on the species, multiple branches of the popliteal artery, saphenous artery, caudal femoral arteries.

Nerve: Tibial nerve

Description: The flexor digitorum [digitalis] superficialis muscle is located on the caudal part of the crus. Its fleshy body, located on the deep side of the lateral head of the gastrocnemius muscle, is fusiform and has a multi-pennate structure. In ungulates, it is less voluminous than in carnivores or rabbits. It is also more fibrous, more or less depending on the species. Its tendon continues at mid-leg level and flattens out to integrate the common calcaneal tendon. It attaches on either side of the calcaneal tuberosity. Therefore carnivores and rabbits have 4 branches, pigs and ruminants have 2 and equids have 1.

Variations:

• In equines, this muscle is quite fibrous, long and thin. It originates in the supracondylar fossa. Its tendon remains singular throughout its course and inserts onto the middle phalanx.