feet

Question 1

purpose of ankles

Answer 1

allows the foot to take up any position in space and It helps the foot adapt to any irregularities of ground

Question 2

purpose of feet

Answer 2

has to be pliable to absorb stress and rigid enough to withstand large propulsive forces. The entire body is affected by the mechanics of the foot, through its influence on the ankle, hip, knee, pelvis and vertebral column

Question 3

mechanical concepts behind arches

Answer 3

keystone–> medial= navicular is keystone. Lateral= cuboid and talus supported by plantar fascia and spring lig
windlass–> weight bears, shock absorbs, increases leverage, support arch twisting, allows movement. Attaches anterior to posterior
beams–> plantar fascia and lugs
staples–> ligaments and bones fixing together (cuneiforms, metatarsal, tarsal)
Suspension—> peroneus longus (stirrup)

Question 4

2nd class lever

Answer 4

the load is in the middle between the fulcrum and the effort. This type of lever is found in the ankle area. When standing on tiptoe, the ball of the foot acts as the fulcrum, the weight of the body acts as the load and the effort comes from the contraction of the gastrocnemius muscle.

Question 5

roll and slide

Answer 5

talocrural–> The talus rolls within the mortise during dorsiflexion and plantarflexion. During dorsiflexion, the talus rolls anteriorly and it glides posteriorly. While with plantarflexion, the talus rolls posteriorly and glides anteriorly.
subtalar–> the calcaneus rolls into inversion and it glides/slides laterally. And during eversion, the calcaneus rolls into eversion and it glides/slides medially.
midtarsal–> the concave navicular moves on the convex talus and hence the roll and glide is in the same direction of movement. The calcaneocuboid joint is a saddle joint so the direction changes depending on the movement. During flexion-extension, the cuboid is concave and the calcaneus is convex; Hence, the roll and glide occurs in the same direction as the talonavicular joint. During abduction-adduction, however, the cuboid is convex and the calcaneus is concave, and therefore the roll and glide occurs in the opposite direction
MTP and IP–> Glide and roll is in the same direction as the movement for the MTP joints, as the concave base of the phalanx moves on the convex head of the metatarsal. The same is true for the IP joints, where glide and roll is in the same direction, as the concave distal phalanx moves on the convex proximal phalanx

Question 6

ground reaction forces

Answer 6

adaption:
The transverse arch= formed by the intercuneiform and cuneocuboid joint coplex
Stable second ray= reinforced by the recessed second tarsometatarsal joint
first ray= Combined plantar flexion and eversion of left tarsometatarsal joint allows the forefoot to better conform to the surface of uneven surfaces

Question 7

neuromusular intelligence

Answer 7

-Central control, local control, corrective measures, feedback loops
-Extrapyramidal system – control muscle tone and posture. They maintain postural equilibrium via active adaptation. Eg- Hip shift on walking
-Basal Ganglia – smooth out motor behaviour and inhibit unwanted movements.
-Sensory feedback is via visual, vestibular and proprioceptive mechanisms
-“Predictive or anticipatory postural control is critical for successful execution of any voluntary movement whether it is episodic or rhythmic” Patla 2002

Question 8

structural relationships

Answer 8

-The longitudinal arches (med and lat) act like a twisting flexible ruler.
-Increased twist on med arch leads to inversion, whilst decrease twist leads to eversion.
-This control on med arch allows small joints of foot to be stabilised during propulsion and intrinsic muscles to produce leverage during propulsion.
-This is supported by long and short plantar ligaments and action of Tibialis anterior and posterior.
-The lateral arch relies on the ‘keystone’ role of the cuboid for stability.