Biomechanics

 1.Effect of first metatarsal primus elevatus?  decreases hallux dorsiflexion
2.Patient has a steppage gait type, what nerve is damaged? Deep peroneal nerve, this gait is seen with CMT, guillain-barre, and foot drop patients.
3.What joint has equal motion in two planes? subtalar joint
4.What is foot structure if you lost common peroneal nerve?  Equinovarus
5.If lower STJ axis closer to floor, you get more motion in which plane  Frontal plane
6.What is metatarsal primus elevatus associated with?   Hallux Limitus
7.What is function of Morton’s extension?   limit first MPJ motion and redistribute forces (solid plate extending under hallux
8.Highest lift you can put in a shoe?  1/4 inch, if you add more it will significanlty alter gait
9.What diagnosis do you suspect in a spastic, adducted, scissor gait? Cerebral Palsy
10.What is the best position to place the foot in order to see the appropriate subtalar joint inversion ROM? maximally dorsiflexed and inverted
11.When performing neutral suspension casting for orthotics, what position should the foot be? Minimal DF. for neutral STJ positioning
12. A 12 year old complains of severe heel pain. You see radiographs and diagnose of calcaneal apophysitis, what treatment do you give?
  • NSAIDS
  • RICE
  • eliminate activity
  • heel lifts
  • streching
  • strapping
13. True or False: You can give a heel steroid injection for calcaneal apophysitis? FALSE
14.If a patient has a callus sub 2nd metatarsal, what is the underlying cause?

a. forefoot varus
b. forefoot valgus
c. rearfoot valgus 

forefoot valgus, hypermobile 1st ray, hallux amputation, keller osteotomy
15.A 3 year old boy presents with a waddling gait and toruble getting up from his seat, what condition does he have?  muscular dystorphy
16.Child walks on his toes and his ankle joint is stiff, there is clonus. What is diagnosis? Spastic equinus
17. Patient is a healthy runner, they notice that their foot arch is flattening and have pain in the medial arch, what is the diagnosis? PTTD – posterior tibial tendon dysfunction
Degress of freedom at ankle joint? MPJ joint?  ankle – one axis so 1 degree of freedom

MPJ an MTJ are 2 axis so 2 degrees of freedom

Planes and Axis of Motion

Sagittal plane? vertical line dividing into right and left sections
Frontal plane? vertical line dividing into front and back sections. Passes center of gravity
Transverse plane? horizontal line divides into upper and lower halves
Define axis an imaginary line which all motions takes place
Single vs triplane joint motion? single- plane of motion is perpendicular to axis of motion

triplane-motion depends on degree of angle at joint axis

Motion of knee joint? Frontal plane axis – controls 140 flexion and 120 extension

Longitudial plane axis – 30 internal and 40 external rotation

Motion of ankle joint? The axis is lateral, plantar, posterior -> medial, dorsal, anterior.

Allows ROM 20-30 dorsiflexion and 30-50 planterflexion

Motion of subtalar joint? Oblique axis for triplanar(pronation and supination)

Axis deviated 42 transverse plane and 16 sagittal plane

Motion of midtarsal joint? Longitudial axis – passes 150 transverse plane and 9 sagittal plane and allows 4-6 ROM of inversion/eversion

 

Motion of first ray? axis angles 45 to frontal and sagittal plane. Allows triplanar motion at 1:1 ratio.

As first ray dorsiflexes it inverts 1. When plantarflexes it everts 1.

How many axis at MPJs? has 2- a transverse and vertical

Gait Cycle

1.What does one whole gait cycle consist of?  heel contact of the support limb to heel contact of that same limb again
2.What are the two phase of a gait cycle?  1) stance 58-62%
2) swing 38-42%
3.What periods does the stance phase of a gait cycle consist of? Contact period, midstance period, and propulsion period
4.What physical/anatomical events occur from the start to the end of the contact period? starts with heel contact and ends with fore foot loading
5.What physical/anatomic events occur from the start of the midstance period to its end? starts with forefoot loading and ends at heel off
6.What portion of the stance cycle is the propulsion period?  33%
7.What is the order of the four moments of gait of a normal gait cycle?  Heel contact, forefoot loading, heel off, toe off
8.What are the anatomical relations of the body during the beginning of contact period?  -Hip is internally rotated and flexed
-Ankle Joint is dorsiflexed
-STJ is supinated
9.During heel contact to forefoot loading of the contact period?  -Hip and leg continue to internally rotate and moves from flexed to extended
-Ankle begins to plantarflex (brings forefoot to ground)
-STJ pronates
-Lateral side of foot bares weight
-1st ray plantar flexes
10.At the beginning of midstance?  -Hip begins to externally rotate
-Hip continues to extend
-AJ is plantar flexed
-STJ is pronated
11.From forefoot loading to heel off during midstance period of gait?  -Entire leg externally rotates
-hip joint is in full extension
-ankle joint dorsiflexes (close kinetic chain)
-STJ supinates to NP by the end
-Heel leaves ground
12.At the beginning of heel off?  -Hip is still externally rotated
-Hip is still extended
-AJ is fully plantarflexed
-STJ is neurtral
13.From heel off to toe off during propulsion period of the gait?  -Hip continues to externally rotate
-Hip begins to flex
-Ankle joint plantar flexes
-STJ supinates
14.Between toe off and heel contact of the swing phase?  -hip internally rotates
-hip continues flexion
-ankle joint rapidly dorsiflexes
-STJ supinates
15.What happens to the MTJ during midstance period?  MTJ locks because the STJ supinates
16.When is the ground reactive force (GFR) greater than the body weight during the gait cycle?  at forefoot loading and just after heel off
17.When the STJ supinates in CKC, what does the talus do?  dorsiflex and abducts