Ankle Biomechanics

Question 1

Name some functions of the ankle.

Answer 1

Shock Absorption
A rigid lever for push-off
Adapts to uneven terrain

Question 2

What type of joint is the distal Tibiofibular Joint?

Answer 2

Syndesmosis joint

Question 3

How is the distal Tibiofibular joint connected?

Answer 3

Articular capsule

Anterior & Posterior tibiofibular ligaments

Question 4

What is the Talocrural joint?

Answer 4

Articulation between the distal tibia & fibula with the trochlea of the talus

Question 5

What type of joint is the Talocrural Joint?

Answer 5

Uniaxial hinge joint

Question 6

How many degrees of freedom does the talocrural joint have?

Answer 6

1 (Plantar and Dorsal Flexion)

Question 7

Where is the axis of rotation for the talocrural joint?

Answer 7

10 degrees offset in the frontal plane

6 degrees offset in the horizontal plane

Question 8

What are the 3 fibers for the deltoid ligament?

Answer 8

Tibionavicular fibers
Tibiocalcaneal fibers
Tibiotalar fibers

Question 9

What does the Tibionavicular fibers restrict?

Answer 9

(restricts talocrural eversion, PF, & anterior slide of talus)
(restricts talonavicular eversion & abduction

Question 10

What do the Tibiocalcaneal Fibers restrict?

Answer 10

Talocrural and subtalar eversion

Question 11

What do the Tibiotalar fibers restrict?

Answer 11

Talocrural eversion, DF, and posterior slide of the talus

Question 12

Name some of the lateral ligaments of the talocrural joint

Answer 12

Anterior talofibular ligament (ATFL)
Calcaneofibular Ligament
Posterior talofibular ligament

Question 13

What does the ATFL restrict?

Answer 13

Talocrural PF, anterior slide of talus, inversion, and adduction.

Question 14

What does the Calcaneofibular ligament restrict?

Answer 14

Talocrural DF, posterior slide of talus, and inversion
Subtalar inversion (mostly stretched during DF)

Question 15

What does the posterior talofibular ligament restrict?

Answer 15

Talocrural DF, posterior slide of talus, inversion, and abduction

Question 16

Which ligament is the weakest in the lateral region, and is mostly related to inversion ankle sprains?

Answer 16

ATFL

Question 17

What type of joint is the subtalar joint?

Answer 17

Diarthrodial synovial joint

Question 18

What is the articulations with the Subtalar joint?

Answer 18

Calcaneus and talus

Question 19

What is the main action of the Subtalar joint?

Answer 19

Supination (inversion), and pronation (eversion)

Question 20

What is pronation?

Answer 20

Dorsiflexion, Abduction, Eversion

Question 21

What is supination?

Answer 21

Plantarflexion, Adduction, Inversion

Question 22

What does supination allow?

Answer 22

A rigid push-off during gait, (medial sole showing)

Question 23

What does pronation allow?

Answer 23

Shock absorption with ground reaction forces (lateral sole showing)

Question 24

What path does the subtalar joint take and where is the axis of rotation?

Answer 24

Curvilinear path
Approximately 42 degrees from the horizontal plane
Approximately 23 degrees from the sagittal plane

Question 25

Name the ligaments associated with the subtalar joint

Answer 25

Cervical talocalcaneal ligament | Interosseous talocalcaneal ligament

Question 26

What does the cervical talocalcaneal ligament restrict?

Answer 26

Inversion | binds the calcaneus to the talus

Question 27

What does the interosseous talocalcaneal ligament restrict?

Answer 27

Limits Eversion | binds the calcaneus to the talus

Question 28

What is the articulations with the Transverse Tarsal joint?

Answer 28

Calcaneocubiod & talonavicular joints

Question 29

What type of joint is the Transverse Tarsal joint?

Answer 29

Synovial saddle joint

Question 30

What are the axis of motion in the transverse tarsal joint?

Answer 30

Longitudinal (inversion/eversion) 15 degrees upward from transverse plane, 9 degrees from longitudinal reference Oblique (flexion/extension) 52 degrees upward from transverse plane, 50-57 degrees from the frontal plane

Question 31

What does the spring ligament do?

Answer 31

Supports the medial longitudinal arch | Prevents excessive medial and plantar movement of the talus

Question 32

What does the medial longitudinal arch consist of?

Answer 32

Calcaneous, Talus, Navicular, Cuniforms, and Medial metatarsals

Question 33

What's the keystone of the medial longitudinal arch?

Answer 33

Talonavicular joint?

Question 34

What supports the medial longitudinal arch?

Answer 34

Plantar Fascia, Spring ligament Short & long plantar ligaments tibialis posterior muscle

Question 35

What is Pes planus?

Answer 35

``` dropped arch (overstretched plantar fascia) Commonly connected to overpronation & excess rearfoot varus ```

Question 36

During stance phase, what happens to the arch?

Answer 36

decreased arch, increased rear foot pronation w/ increased weight bearing

Question 37

During the swing phase, what happens to the arch?

Answer 37

Increased arch, decreased rear foot pronation (so supination), w/ decreased weight bearing

Question 38

What happens with over pronation of the foot?

Answer 38

Hip-increased IR, flexion, adduction Knee-Increased valgus stress Rearfoot- increased pronation Mid/Forefoot- supination (inversion)

Question 39

What happens when you correct over pronation?

Answer 39

Better storing of elastic energy (better push off) Able to grip surface better Decreased stress transmission to other joints

Question 40

What type of joint is the tarsometatarsal joint?

Answer 40

Plane synovial joint (gliding movements)

Question 41

Which TMT is most mobile and least mobile?

Answer 41

2nd and 3rd TMT highly immobile | 1st TMT most mobile (helps transfer force at push-off)

Question 42

What type of joint is the MTP joint?

Answer 42

Condyloid synovial joint (biaxial joints) | 2 degrees of freedom

Question 43

What is turf toe?

Answer 43

Hyperextension of first MTP joint

Question 44

What type of joint is the IP joints?

Answer 44

Synovial hinge joint (Concave on Convex) | 1 degree of freedom

Question 45

What is the Plantar Fascia

Answer 45

Fibrous band that goes from medial plantar tuberosity to MTP plantar plates

Question 46

What tightens the plantar fascia?

Answer 46

toe extension

Question 47

What's the windlass effect?

Answer 47

When Plantar fascia is tight, it inverts calcaneous and elevates arch, helps supinate subtalar joint

Question 48

Where's the tarsal tunnel, and what can happen here?

Answer 48

Posterior & inferior to medial malleolus, can cause tibial nerve entrapment

Question 49

What all runs through the tarsal tunnel

Answer 49

``` Tibialis posterior Flexor Digitorum Longus Posterior Tibial Artery & Vein Tibial Nerve Flexor Hallucis Longus ```

Question 50

What doe the intrinsic muscles of the foot do?

Answer 50

Control arch during midstance of gait Help lift the arch during the later phases of gait Stabilize the forefoot during terminal stance

Question 51

What happens during inversion ankle sprain?

Answer 51

Tear of ligaments of ankle (ATFL most common, followed by CFL) Happens with PF & inversion

Question 52

How are ankle sprains graded?

Answer 52

1: Ligament damage, with no instability 2: Ligaments having partial tear, ATFL partial tear, CFL stretches 3: Rupture of of ATFL & CFL ligaments, with partial tear of posterior talofibular & Tibiofibular ligaments

Question 53

What is a foot drop?

Answer 53

Inability to DF foot Damage to fibular nerve, (stroke/brain injury, spine problems, muscle disorders) Treated with bracing, orthotics, physical therapy

Question 54

What is hallux valgus?

Answer 54

``` 1st metatarsal is adducted phalanges abducted hypermobile 1st metatarsal increased pronation of the foot bunions can form ```