1st Ray, 1st MPJ, and Lesser Rays Flashcards Preview

Biomechanics > 1st Ray, 1st MPJ, and Lesser Rays > Flashcards

Flashcards in 1st Ray, 1st MPJ, and Lesser Rays Deck (23)
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1
Q

What is the axis of the 1st ray?

A

45 deg from frontal plane

45 deg from sagittal plane

2
Q

what is the direction of the 1st ray axis as it courses across the foot?

A

proximal-medial-dorsal

to distal-lateral-plantar

3
Q

What is the total ROM of the 1st ray?

A

10mm
(5mm- dorsiflexion)
(5mm-plantarflexion)

4
Q

what is considered a hypermobile joint?

A

total ROM over 15-20mm

5
Q

what is the function of the 1st ray in gait?

A

plantarflexion of 1st ray during midstance and propulsion necessary for proper 1st MPJ function allowing dorsiflexion in toe-off

6
Q

what are the requirements for `proper 1st ray function?

A
supinated STJ (locked) 
stable MTJ (supination of OA)
7
Q

which muscle stabilizes the lesser tarsus and 1st met against ground allowing plantarflexion of 1st ray?

A

peroneus longus

8
Q

what is the biggest plantar flexor muscle?

A

abductor hallucis

9
Q

what is the function of the 1st MPJ?

A

dorsiflexion allows smooth, effective propulsion of the body during toe-off

10
Q

how many centers of motion are within the 1st metatarsal head?

A

4

11
Q

describe the types of motion the 1st MPJ exhibits.

A
  • rolling motion
  • sliding motion w/ 1st ray plantarflexion
  • compression at end ROM
12
Q

how much dorsiflexion and plantarflexion can you get for 1st MPJ?

A

dorsiflexion- 60 to 65 deg

plantarflexion- 5 to 10 deg

13
Q

proper 1st MPJ function during gait requires what?

A
  1. stability and plantarflexion of the 1st ray
  2. normal sesamoid function
  3. normal function of 1st MPJ muscle stabilizers
14
Q

what is the function of 1st MPJ in gait? (from midstance to toe-off)

A

hinge motion- for first 20 deg

arthroidal motion- occurs at 20 deg

15
Q

what is position 1 on the 1st met head for?

A

rolling motion (this is hinge motion)

16
Q

what is position 2 and 3 on the 1st met head for?

A

sliding motion (tangential motion)

17
Q

what is position 4 on the 1st met head for?

A

compression from velocity

18
Q

which positions will you use if you are walking in a leisurely gait?

A

positions 1,2,3

19
Q

which positions are you using if you are running?

A

will use 1-4!

20
Q

As there is an increase in _____, more positions are exposed on the 1st met head

A

plantarflexion

21
Q

where is the axis of motion for 2nd,3rd, and 4th rays?

A

proximal to tarsometatarsal joint

22
Q

what is the motion that occurs about the 2nd-4th rays?

A

pure dorsiflexion and plantarflexion

23
Q

what is the axis for the 5th ray?

A

20 from transverse

35 from sagittal