Hershey Manual - Ch 32 Biomechanics

Front 1

Malleolar torsion

Back 1

13-18 ext rotated

Front 2

Ankle joint ROM

Back 2

-10 DF with knee extended
-gastrocs are tight with less then 10 degrees in flex and extension
-20 degrees PF
-note that these degrees are from neutral or past 90 degrees

Front 3

STJ ROM

Back 3

-total of 30
-20 inversion
-10 eversion

Front 4

when the STJ is in neutral, the calcaneal bisection should be paralell to what, and perpendicular to what

Back 4

-parallel to bisection of lower 1/3 of the leg
-perpendicular to the supporting surface

Front 5

how much dorsal and plantar excursion should the 1st ray (met and cuneiform) have

Back 5

-equal amounts up and down (5mm) from a level equal with the 2nd met

Front 6

how much dorsal and plantar excursion should the 5th ray have

Back 6

-equal excursion dorsal and plantar from a level of the central 3 mets

Front 7

upon WB, where should the bisection of the posterior surface of the calcaneus lie

Back 7

-vertical

Front 8

what should the relationship of the forefoot and rearfoot be to each other

Back 8

paralell to each other

Front 9

what if the ankle DF is less then 10 when the knee is flexed or extended

Back 9

-there is an osseous or soleus equinus

Front 10

ankle dorsiflexion is only less then 10 with extension

Back 10

gastroc equinus

Front 11

STJ neutral

Back 11

-point that divides the medial 2/3 of motion from the lateral 1/3 of motion

Front 12

STJ ROM

Back 12

-30 total (20 inversion, 10 eversion)
-minimum of 8-12 for normal ambulation

Front 13

how much movt should the 1st ray have and how to you test that

Back 13

-5 mm above and 5 mm below the lesser mets
-stabilize mets 2-5 and grasp the 1st met head and move it up and down

Front 14

what is normal malleolar torsion

Back 14

13-18 externally rotated

Front 15

normal hip rotation

Back 15

-45 internal and 45 external
-total ROM 90

Front 16

what is angle of gait and what is its norm

Back 16

-number of degrees that the foot is deviated from the line of progression of gait
-7-10 abducted from the line of progression

Front 17

what is NCSP and what is RCSP

Back 17

-NCSP is the angular relationship b/w the bisection of the calcaneus and the ground when STJ is in neutral
-RCSP is degrees the calcaneus bisector deviates from perpendcular with the groun when the STJ is in a relaxed state and the pt is standing in angle and base of gait

Front 18

symptoms of RF varus (calc is inverted relative to the ground when STJ is in neutral)

Back 18

-callus plantar 4th and 5th met heads
-tailors bunion
-haglunds deformity
-inversion ankle sprains
-adductovarus of 4th, 5th
-mild HAV

Front 19

symptoms of RF valgus (calcaneus is everted relative to the ground when STJ is neutral)

Back 19

-callus plantar 2nd met head (occasionally)
-fatigue muscles
-arch pain
-HAV deformity

Front 20

symptoms of FF varus

Back 20

-callus plantar 2,4, and/or 5th met head
-muscle fatigue
-tailors bunion
-adductovarus of 4th, 5th
-HAV
-plantar fascitis/heel spur

Front 21

adductovarus is common effect of what foot deformities

Back 21

-RF and FF varus
-equinus

Front 22

symptoms of FF valgus (PF 1st ray)

Back 22

-callus 1st and 5th met heads
-tibial sesamoiditis
-lateral knee strain
-flexion contracture of lesser digits

Front 23

symptoms of met primus elevatus (1st ray has a resting position above the plane of the lesser mets)

Back 23

-callus 2nd met and hallux IPJ
-dorsal bunion
-hallux limitus/rigidus

Front 24

symptoms of equinus

Back 24

-corn of 5th toe
-adductovarus of 4th and 5th
-HAV deformity
-plantar fascitis/heel spur
-neuroma symptoms
-contracture of all the digits (extensor substitution)

Front 25

what is extensor substitution

Back 25

-occurs when the anterior muscles are weak
-the EDL is then recruited to raise the foot in swing phase
-the EDL then overpowers the lumbricals that normally equalize the EDL pull and you get digital contractures

Front 26

what is flexor substitution

Back 26

-occurs when there is a weakness in the major calf muscles (Gastrocnemius and Soleus muscles), and other tendons, including those that flex the toes
-Flexor Digitorum Longus tendons) are recruited to help the foot in heel-off. Because of their overuse, the flexor tendons to the toes overpower the extensors, and hammertoes may develop.

Front 27

what is the MC cause of hammertoes

Back 27

-flexor stabilization
-This occurs in patients who excessively pronate
-the FDL is recruited to stabilize the foot. But because the muscle attaches to the toes by way of a tendon, it begins to overpower the small muscles (Interosseous muscles) that stabilize the toes, and the toes contract.
-Adductovarus rotation of the fourth and fifth toes, (where the toes rotate on their sides), is commonly seen with this condition.

Front 28

what is the relationship b/w axis of motion and plane of motion

Back 28

-axis of motion is always perpendicular to the plane in which the motion takes place
-the motion takes place in one plane and hte axis lies in the other two planes

Front 29

the greater the amount of degrees b/w an axis of motion and a cardinal body plane, what will happen to the amount of motion that occurs in that body plane

Back 29

-motion will increase

Front 30

range of DF and PF of the ankle

Back 30

20-30 DF
30-50 PF
-only 10 DF from neutral needed for walking

Front 31

what joint has triplanar motion (pronation and supination)

Back 31

STJ (its axis lies oblique to all three plane)
MTJ (bc it has two axes)
1st ray
5th ray
ankle

Front 32

where is the axis of the STJ located and where does it run

Back 32

-42 from transverse and frontal
-16 from sagittal
-enters the heel and exits out the dorsal talar neck

Front 33

STJ has an axis that is oblique to all three planes giving it triplane motion, how does the MTJ have triplane motion

Back 33

-the MTJ has two axes (oblique and longitudinal)

Front 34

what plane of motion does the oblique axis of MTJ move in, the longitudinal axis?

Back 34

-oblique axis permits motion in transverse and sagittal (ab/add and DF/PF)
-longitudinal axis permits motion in frontal plane (eversion/inversion)

Front 35

what bones does the 1st ray consist of

Back 35

-1st met and medial cuneiform

Front 36

which joint has a 1:1 ratio of sagital and frontal plane motion

Back 36

-eventhough the 1st ray is triplanar, most of its motion is in the sag and frontal
-when it DF 1 degree, it also inverts 1 degree
-when it PF 1 degree, it also everts 1 degree

Front 37

the 2nd, 3rd and 4th rays, as well as digital IPJ allow motion in what plane

Back 37

-they are all uniplanar and produce purely sagittal plane motion

Front 38

how many axes do the MPJ have

Back 38

-two (transverse and sagittal)

Front 39

how is the first MPJ a hinge (ginglymus) and an arthrodial joint (sliding)

Back 39

-it acts as a hinge joint for the first 25 of DF
-then acts as a sliding joint with the 1st met PF and MPJ dorsiflexing after the intial 25 degrees

Front 40

what does degrees of freedom of a joint mean

Back 40

-it refers to the numbers of axes of a joint
-the ankle and most foot joints have one DOF
-the MPJ and MTJ each have 2 axes and thus 2 DOF

Front 41

what bones does the 5th ray consist of

Back 41

-the 5th met
-unlike the 1st ray consisting of 1st met and medial cuneiform

Front 42

what planes of motion does the 5th ray permit movt in

Back 42

-mainly the sagital and frontal (very little transverse)

Front 43

Antetorsion of the femur is about 35-40 degrees at birth and untwists to 12 by adulthood, what if the adult remains in antetorsion

Back 43

-pigeontoed

Front 44

what is normal tibial torsion in an adult and how is it measure

Back 44

-18-23 external
-measured by malleolar torsion which is 5 degrees less

Front 45

if a infant has abnormal tibial torsion due to osseous (not soft tissue) deformity, how can you treat it

Back 45

-it is rigid osseous deformity so you can use serial above the knee casting followed by maintenance with a Ganley splint or D-B bar

Front 46

what does a reverse tailors sitting postion manifest in a child

Back 46

-medial femoral torsion (anteversion)
-can cause knock knee

Front 47

stance phase is the largest part of the gait cycle, what happens here

Back 47

-heel strike and foot hits supinated
-foot flat (pronation is shock absorber due to internal leg rotation)
-midstance
-heel lift
-toe off (resupination as rigid lever due to ext leg rotation)

Front 48

as the gait progresses from the heel to the ankle to the forefoot what happens to the hip and knee

Back 48

-when the ankle PF when the foot moves from heel contact to midstance the knee and hiip are flexed
-as the ankle starts to PF to toe off, the hip and knee extend to accelerate the WB leg into swing phase

Front 49

summarize the action of the anterior muscles during gait

Back 49

-the TA, EDL and PT are active at toe off and DF the foot
-remain active during swing
-show peak activity at heel strike to deccelerate the foot as it strikes the ground

Front 50

summarize the action of the posterior muscles during gait

Back 50

-TP, soleus, gastroc, plantaris, FHL, FDL
-fire during contact and terminate during propulsion to acheive heel off

Front 51

Formula for calculated neutral calc position

Back 51

=eversion -TROM/3 ; a positive number is valgus or neutral, negative is varus or neutral. This is STJ neutral, add tibial component for NCSP

Hint 51

A a

Front 52

Calculate neutral position if eve is 10 and inver is 20

Back 52

Zero

Front 53

Minimal STJ ROM needed for ambulation

Back 53

8-12

Front 54

Calculate neutral position of the hip if: IR = 55, ER = 35

Back 54

=IR – TROM/2; 55-90/2 = 10 Internal

Front 55

From neutral position how much does the hip rotate Int and ext if IR = 55, ER = 35

Back 55

TROM/2 = 45 in this case, so from neutral position the hip rotates 45 degrees in each direction

Front 56

From neutral position how much does the hip rotate Int and ext if IR = 10, ER = 40

Back 56

TROM/2 = 25 in this case, so from neutral position the hip rotates 25 degrees in each direction

Front 57

Calculate neutral position of the hip if: IR = 10, ER = 40

Back 57

=IR – TROM/2; 10-50/2 = 15 External

Front 58

How does FF supinatus differ from FF varus

Back 58

FF supinatus is a fixed position of the FF, where the FF is max pronated and locked about both MTJ axes caused by ST adaptation

Front 59

What is the relationship between an axis of motion and a cardinal body plane

Back 59

the greater the distance (up to 90 degrees) between an axis of motion and a cardinal body plane, the greater the amount of motion that will occur in that body plane

Front 60

If an axis is oblique to all THREE body planes, what type of motion does this allow for

Back 60

triplanar (pronation and supination) P: ab/evr/DF. Sup: add/inv/PF

Front 61

Calculate STJ neutral position if: Maximum calc inversion right (12) ,left (15); maximum calc eversion right (6), left (3), with tibial varum 1 degree bilaterally.

Back 61

Formula: TROM/3 – evr (Right 0, Left 3 varus)

Front 62

Calculate NCSP if: Maximum calc inversion right (12) ,left (15); maximum calc eversion right (6, left (3), with tibial varum 1 degree bilaterally

Back 62

Formula: neutral position (from TROM/3 – evr) plus any tibial component. So Right has NCSP of 0 + 1 varus = 1 varus, left has NCSP of 3 RF varus + 1 varus = 4 RF varus

Front 63

Calculate RCSP if: Maximum calc inversion right (12) ,left (15); maximum calc eversion right (6), left (3), with tibial varum 1 degree bilaterally

Back 63

since this yields a RF varus (RSCP) of 3 degrees on the right and 4 degrees on the left, this individual will compensate at the STJ to bring the calc to perpendicular to the ground using all STJ pronatory ROM, since pronation is 1/3 of the TROM of 18 degrees, you have 6 degrees available which will bring the NCSP of both sides to ) degrees.

Front 64

Calculate STJ neutral position, NCSP and RCSP if: Calc inv Right 16, Left (15), calc eversion right (2), left (3); tibial varum Right (3), left (2)

Back 64

STJ neutral: Right 4 inv, Left 3 inv. NCSP: Right 7 varus, Left 5 varus. RCSP Right 1 varus, Left 0,with the STJ still having 1 more degree of compensation remaining on the left

Front 65

How do you calculate STJ neutral position

Back 65

with the formula TROM/3-eversion (positive is varus, negative is valgus)

Front 66

How do you calculate NCSP

Back 66

adjust your STJ neutral position with the amount of tibial varum that is present

Front 67

How do you calculate RCSP

Back 67

adjust your NCSP with the amount of compensation you have available with pronation, remembering that you have 1/3 of the TROM available for pronation compensation

Front 68

What is the relationship of the oblique and longitudinal MTJ axis at maximum supination

Back 68

the axes are divergent, they are parallel in pronation