Musculus popliteus
The popliteus is a small muscle located behind the stifle. It originates from the lateral femoral condyle and lateral meniscus and inserts on the caudal proximal tibia. Its actions are to internally rotate the tibia, unlock the stifle from full extension, and initiate stifle flexion. It is innervated by the tibial nerve (roughly L5-S1). It is important for releasing the stay apparatus so the limb can flex.
Origin: Lateral femoral condyle and lateral meniscus
Insertion: Caudal proximal tibia
Action: Internally rotates the tibia; unlocks the stifle from extension; initiates stifle flexion
Innervation: Tibial nerve (L5-S1)
Isolated injury is uncommon. Relevant in evaluations of stifle locking or delayed release and in cases of caudal stifle trauma.
## Overview The popliteus muscle helps unlock the stifle from full extension. Weakness or dysfunction contributes to upward fixation of the patella, in which the hind limb momentarily locks in extens
Persistent locking or delayed release of the stifle should be evaluated rather than forced.
## Overview The popliteus muscle helps unlock the stifle from full extension. Weakness or dysfunction contributes to upward fixation of the patella, in which the hind limb momentarily locks in extension. Signs include catching or clicking at the stifle, worse at slow gaits or when tired, and improvement with fitness and hill work. ## Causes Poor quadriceps and popliteus tone, conformation, or immaturity. ## Diagnosis Observation of intermittent locking, especially when the horse is walked slowly or turned. ## Treatment Conditioning, hill work, and in persistent cases medial patellar ligament splitting or desmotomy. ## Recovery and Prognosis Good. Many young horses improve with fitness. ## Prevention Adequate conditioning. Signs include: momentary hind-limb locking in extension; catching or clicking at the stifle; worse at slow gaits or when tired; improves with fitness
Isolated injury is uncommon. Relevant in evaluations of stifle locking or delayed release and in cases of caudal stifle trauma.
Persistent locking or delayed release of the stifle should be evaluated rather than forced.
See the Popliteus on our interactive 3D horse model. Open 3D Model