DPM Clinical Biomechanics 3

Question 1

The center of pressure (COP) during normal gait progresses from heel strike to toe-off in which general direction?

Accepted Answer

Lateral heel → lateral midfoot → first and second metatarsals → hallux

Answer

Normal COP progression travels from the lateral heel, across the lateral midfoot, to the first and second metatarsophalangeal region, and exits at the hallux.

Question 2

Which axis of the subtalar joint is most accurately described?

Accepted Answer

42 degrees from the horizontal and 16 degrees from the sagittal plane

Answer

The subtalar joint axis averages 42 degrees of inclination from the horizontal plane and 16 degrees medial deviation from the sagittal plane.

Question 3

A plantarflexed first ray deformity most commonly causes which compensatory mechanism during gait?

Accepted Answer

Pronation of the subtalar joint to unload the first ray

Answer

A plantarflexed first ray causes ground reactive force to drive the first metatarsal up, requiring the STJ to pronate to redistribute load.

Question 4

What does the term 'maximum midtarsal joint pronation' refer to in functional foot orthotic theory?

Accepted Answer

The position where both midtarsal joint axes allow maximum motion simultaneously

Answer

Maximum midtarsal joint pronation occurs when both the longitudinal and oblique axes of the midtarsal joint are parallel, allowing maximum combined motion.

Question 5

According to Kirby's subtalar joint axis location and rotational equilibrium theory, a laterally deviated STJ axis predisposes to which condition?

Accepted Answer

Peroneal tendinopathy and supination instability

Answer

A laterally deviated STJ axis increases the supination moment arm of the peroneal tendons, predisposing to lateral instability and peroneal overload.

(DPM) Doctor of Podiatric Medicine Practice Test

(DPM) Doctor of Podiatric Medicine Practice Test

DPM Clinical Biomechanics 3