Feet

Question 1

Mechanical concepts involved with the foot and ankle

Answer 1

Structural shape allows for adaptation to ground reaction forces

Talocrural joint is an example of a second class lever

Concave/convex, roll and slide concept of the talocrural joint

Form and force closure in the talocrural joint

Windlass, keystone, staples and beam, mid foot mechanics concepts

Question 2

Mechanical concepts behind the arches of the foot

Answer 2

Structural shape allows for adaptation to ground reaction forces

Keystone:
– talus

Staples:
– small ligaments joining the tarsals and other foot bones together

Beam:
– tendon of flexor hallicus longus

Suspension:
– supplied by the peroneus longus

How the arches of the foot are maintained:
- peroneus longus:
— comes all the way down the lateral border underneath the foot and attached onto the medial cuneiform

• tibial anterior:
  — comes all the way down and attaches to the medial border

— these both help to maintain the arches within the foot as it creates a stirrup

Question 3

Roll and slide concept

Answer 3

Concave- tibia

Convex- talus

Concave on convex

They will roll and slide in opposite directions

Pivot point- mid talus

In both the plantar and dorsi flexion of the foot, the tibia and talus passively allow movement from the foot

Plantar flexion:
– tibia slides anteriorly on superior talus
– talus rolls posteriorly on calcaneum

Dorsi flexion:
– tibia slides posteriorly on superior talus
– talus rolls anteriorly on calcaneum

Question 4

2nd class lever

Question 5

Neuromuscular intelligence, balance and equilibrium

Answer 5

Central control:
– there is a control from the brain and the spinal cord which can play a part in gait
—- the central control decides how or where we want to walk or what movements needs to be done, this gets sent to the basal ganglia to ensure the movement is smooth. This will then go down into the peripheries as we get into sensory feedback

Local control:
– the spinal nerves as they descend into peripheral nerves have a relationship with the muscles and ligaments allowing the muscles to be innervated to contract

Corrective measures

Feedback loops:
– corrective mechanisms are apart of this, how we correct our walking, e.g: from ground reaction forces and different terrains how we adapt to that

Extrapyramidal system:
– happens around the medulla oblongata
– it controls the muscle tone and posture
– they maintain postural equilibrium via active adaptation.
—- e.g: hip shift on walking

Basal ganglia:
– smooths out the motor behaviour and inhibit unwanted movements

Predictive or anticipatory postural control:
– feed forward loop
– critical for successful execution of any voluntary movement whether it is episodic or rhythmic
—- anticipatory load of putting the joints into the correct position for the desired movement

Question 6

Movers vs stabilisers

Answer 6

Movers:
– gastrocnemius
– tibial anterior
– tibialis posterior
– flexor digitorum group
– extensor digitorum group

Stabilisers:
– capsules
– deltoid ligament
– spring ligament
– retinaculum
– soleus
– peroneal group
– sinus tarsi ligaments (interosseous talocalcaneal ligament and cervical ligament)