Lecture 9 - Subtalar Joint (STJ) Flashcards

1
Q

What articulations form the STJ?

What is it’s anatomical shape?

A

Articulation of talus & calcaneus

Convex/ concave shaped joint=
saddle shaped & very strong,

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2
Q

List the 3 ligaments of the STJ

A

Talocalcaneal
Lateral Talocalcaneal [cervical]
Posterior Talocalconeal

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3
Q

Where is the STJ Axis?

A

Tri-planar axis, large individual variation: average 42° from TP & 16° from SP
(With 10 degrees of rotation)

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4
Q

List STJ Motion

A

pronation/ supination in foot

Converts TP plane motion of tibia to FP motion in foot

ROM: 20°inversion & 10° eversion

Frontal plane motion measurable [2:1]

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5
Q

Normal gait requires how many degrees of STJ motion?

A

6°- 12° of ROM

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6
Q

Why is STJ important?

A
  • Pronation produces pliable foot to adapt to ground & shock absorption during gait
  • Supination turns foot into rigid lever for propulsion & support
  • Compensates for abnormal forefoot/ rearfoot
  • STJ motion is interdependent with MTJ motion (STJ pronation increases MTJ motion & vice versa)
  • Forces medial to STJ (GRF/muscle) produce supination & forces lateral to STJ produce pronation
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7
Q

What is STJ neutral?

A

•Theorised position where STJ neither supinated or pronated
•2:1 ratio of inversion:eversion or supination:pronation from this position
-Pros vs cons 2:1 ratio: low reducibility amongst ppl & everyone different
•Neutral position is where foot functions most efficiently
•Varies person to person

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8
Q

How is STJ neutral clinically measured?

A

Talar head palpation

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9
Q

What is the motion of STJ in gait?

A
  • Subject to controversy
  • Pronates at heel contact & supinates at propulsion
  • Root suggests foot achieves STJ Neutral position at heel lift
  • Orthotic treatment aim/ backbone is to align STJ to neutral
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10
Q

What is the OKC motion of STJ in pronation & supination?

non weight bearing

A

DEAb
(DF, eversion & abduction) of calcaneus
in pronation

PlAd
(PF & Adduction) of calcaneus
in supination

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11
Q

What is the CKC motion of STJ in pronation & supination?

weight bearing

A

PAd of talus & Eversion of calcaneus in pronation

DAb of talus, Inversion of calcaneus in supination

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