Week 7 - Early stance phase mechanics Flashcards
What are three ways in which pronation can be considered abnormal?
Magnitude of pronation, duration of pronation, and timing of pronation
When excessive pronation occurs, the talus adducts and plantar flexes excessively. What does this do to surrounding structures?
Tenses the spring ligaments and plantar fascia. Impairs windlass mechanism
What structures can be affected by increased eversion of the calcaneus associated with excessive pronation?
Sustentaculum tali of the calcaneus is unable to support the head of the talus as it moves anteriorly. Causes the lateral 3-5 toes to abduct, irritates the plantar fascia
How does adduction of the talus affect the tibia? How does this affect gait?
Puts it into internal rotation. The more adducted it goes, the more tibia internally rotates. External rotation of the tibia is delayed, stopping the foot from resupinating for toe-off
As pronation occurs, the tibia internally rotates. How does this internal rotation affect the femur/hip? The knee?
Movement of the tibial plateau under the femoral condyles can cause stress to the medial meniscus, medial joint capsule, and pes anserine bursa. Can affect patellar tracking as well.
What is considered to be abnormal supination?
When a foot is unable to pronate during stance phase, typically a more rigid cavus foot
What is happening up the chain with a normal lateral heel strike?
Lateral heel contact, STJ supinated, ankle dorsiflexed but beginning to plantar flex, hip flexed/internally rotating, knee extended/internally rotating,
What is the loading response phase?
Early midstance, when weight is accepted. Heel strike to forefoot load
What are some potential reasons we may see a central heel strike?
Forefoot varus causing prolonged pronation, rearfoot valgus causing calcaneal eversion, PTTD causing prolonged pronation, genu valgum causing excessive tibial internal rotation
What are some potential reasons we could see an excessive lateral heel strike?
A rigid rearfoot varus, rigid forefoot valgus causing compensatory RF inversion, clubfoot (rigid RF varus), tibial/genu varum
What are some potential causes for a forefoot contact/lack of heel strike?
Pes equinus foot structure, knee injury causing lack of knee extension, severe LLD
What could cause a delayed heel strike?
Pes equinus, ankle dorsiflexion restriction
What could cause flat foot contact?
Excessive knee flexion, short stride length, shuffle gait, inability to dorsiflex the ankle
What could cause a low heel strike?
Limited ankle dorsiflexion, tibialis anterior weakness, excessive knee or hip flexion
What are some things that could cause excessive rearfoot eversion?
Rigid forefoot varus, pes equinus, STJ hypermobility, rearfoot valgus
