Anatomy & Biomechanics Flashcards

What is the primary function of the plantar fascia during the push-off phase of gait?

Answer: Windlass mechanism to raise the medial longitudinal arch

The windlass mechanism tightens the plantar fascia as the toes dorsiflex, raising the arch and storing energy for propulsion.

In a transtibial amputation, which residual limb muscle imbalance is most common without surgical correction?

Answer: Plantarflexion contracture from gastrocnemius dominance

Loss of the tibialis anterior's antagonist leads to an unopposed gastrocnemius pull, promoting plantarflexion contracture.

Which structure provides the primary static restraint against anterior tibial translation in the knee?

Answer: Anterior cruciate ligament

The ACL is the primary restraint preventing anterior translation of the tibia on the femur.

Ground reaction force (GRF) passes posterior to the knee joint during which phase of normal gait, producing a flexion moment?

Answer: Loading response

During loading response the GRF passes posterior to the knee, creating an external flexion moment resisted by the quadriceps.

The subtalar joint axis is oriented approximately how relative to the transverse and sagittal planes?

Answer: 42° from transverse, 16° from sagittal

The subtalar axis averages 42° of inclination from the transverse plane and 16° of deviation medially from the sagittal plane.

Which bony landmark serves as the primary weight-bearing contact point of the calcaneus during standing?

Answer: Calcaneal tuberosity (medial and lateral processes)

The medial and lateral processes of the calcaneal tuberosity form the weight-bearing base of the heel during static standing.