Feet

Question 1

Purpose of Ankles and Feet

Answer 1

• The ankle allows the foot to take up any position in space.
• It helps the foot adapt to any irregularities of ground.
  The entire body is affected by the mechanics of the foot, through its influence on the ankle, hip, knee, pelvis and vertebral column

Question 2

Foot loading during Gait

Answer 2

Walking - 1.2x BW
Running - 2x BW
Jumping (height of 2 feet) - 5x BW

Question 3

Roll and slide

Answer 3

• Ankle has concave (tibia) on convex (Talus) roll and slide opposite direction, with the pivot point being in the mid talus.
• In both plantar or dorsi flexion, the tibia and talus passively allow movement from the foot. The Tibia slides anteriorly on superior talus. Talus rolls posteriorly on calcaneum. Talocrural joint
• Anticlockwise roll and slide on Dorsiflexion.
  Clockwise roll and slide on Plantar flexion

Question 4

Form closure

Answer 4

uses the shape of one bone in relation to bones to provide stability to the surrounding joints. For mobility to occur further joint compression and stabilisation is required to withstand a vertical load.
* Force closure is the term used to describe the other forces such as the ligaments and muscles acting across the joint to create stability.
* Superior Talus is convex, inferior talus is concave, superior calcaneum is convex.
* This is a form closure.
* The medial and lateral ligaments create Force closure.

Question 5

Key stone

Answer 5

In arches of the foot, talas and cuboid on lateral side. Allows for stability, locks in joints and structures around it but also allows for a lot of movement. Example of form and force closure.

Question 6

Staples

Answer 6

Tiny individual ligaments that link one tarsal bone to another, cuneiforms, navicular and metatarsals.

Question 7

Beam

Answer 7

Plantar ligaments and plantar fascia

Question 8

Suspension

Answer 8

Peroneus longus, connects from head of fibula to underneath the lateral border of the foot to the plantar surface of the medial cuneiform. Acts like a stirrup.

Question 9

What is the point of these arches

Answer 9

Arches of the foot allow for propulsion and ability to walk on different surfaces.

Question 10

How the plantar fascia supports foot function

Answer 10

• The plantar fascia increases the stability during weight bearing and locomotion.
• Acts like a ligament but is less flexible.
• Due to proximity to plantar surface it has greater leverage and shock absorption.
• It has limited flexibility, but by being attached to heel and toes only it stabilises and supports the twisting mechanism of arches.

Question 11

Neurological mechanisms involved – EXAM Q

Answer 11

Always consider;
Central control
Local control
Corrective measures and feedback loops
Extrapyramidal system
Basal Ganglia
Sensory feedback

Question 12

Central control

Answer 12

Brain and spinal cord, some decisions deliciated down to inter neurons there. Dictates and initiates signals sent. Includes motor cortex and cerebellum.

Question 13

Local control

Answer 13

spinal nerves as they descend into Peripheral nerves and their interaction with muscles and ligaments.

Question 14

Corrective measures & feedback loops

Answer 14

• Feedback/forward
• Control muscle tone and posture. They maintain postural equilibrium via active adaptation. Eg- Hip shift on walking

Question 15

Extrapyramidal system and Basal ganglia

Answer 15

• 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

Question 16

Sensory feedback

Answer 16

via visual, vestibular and proprioceptive
mechanisms

Question 17

Talus anatomy

Answer 17

• Articulates directly with tibia and fibula and calcaneus. No muscular attachments, responds passively to everything around it.
• 3 facets, Anterior, middle and posterior
• Convex surface superiorly and a concave surface inferiorly
• Hugely dependent on its ligaments, Interosseous talocalcaneal lig and cervical lig - two that attach the inferior talus to superior calcaneum that we can’t get anywhere near, act the same as the cruciate ligs in the knee. Common football, rugby or hockey injuries, from shearing or traction strain, whole body weight goes forward but boot/studs stay stuck in the ground. Traction through subtalar joint, ankles never really seem to get better.

Question 18

Role of Talus

Answer 18

1. The talus acts as a torque converter, causing rotations of the leg to be converted to inversion and eversion vectors in the foot.
2. This is essential for adaptation of the foot to ground reaction forces and loose pack positioning after heel strike.
3. It locks the structures of the foot and ankle during toe off to create a stable base for weight bearing and propulsion.

Question 19

Structural relationships

Answer 19

how the anatomy supports weight distribution through the foot during walking.

Question 20

Structural relationships - Talocrural joint

Answer 20

• The posterior inferior transverse ligament has a deep portion covered by hyaline cartilage and forms part of the articular surface of talocrural joint.
• The vulnerability of the Talocrural joint is that it has no direct muscle attachments and it’s domed/wedge like shape. It is totally dependent on ligamentous support to prevent anterior/posterior displacement of leg on talus, excessive inversion/eversion (imagine a bosu ball)

Question 21

Structural relationships - Sinus tarsi

Answer 21

The secret ligament: Interosseus talocalcaneal ligament and cervical ligament, this lies in the sinus tarsi. (similar to the cruciate ligaments of the knee)
* The space between the talus and the calcaneus is the sinus tarsi.
* This space is filled with connective and adipose tissue, richly innervated with mechanoreceptors and free nerve endings.
* Important area for proprioception.
* Inferior extensor retinaculum lies over the lateral aspect of the sinus tarsi.

Question 22

Weight distribution through foot during walking
The role of the arches during walking

Answer 22

• 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.

Question 23

Repetitive injuries to the foot

Answer 23

• Morton’s neuroma – Transverse arch drops, Mainly on toes 2-4 plantar nerves that travel between metatarsals have all the weight of the body on them, become sensitised, thicken and cause Morton’s neuroma. Affects people most who are working on their feet all day e.g retail.
• Plantar fasciitis – Most common in middle aged women, diabetics or people who were high heels frequently.
• Heel spur
• Calcified Achilles tendon

Question 24

other injuries to the foot

Answer 24

Systemic - Gout
Congenital – Talipes or club foot
Developmental – Sever’s disease, failure of the growth plate as the Achilles attaches onto it. Normally early or pre Adolescents.
Degenerative – Bunions
Neurological:
* UMNL; stroke
* LMNL; foot drop