Kinesiology of the Ankle:
By Dr. Brent Brookbush, DPT, PT, MS, CPT, HMS, IMT
From the Course:
Additional Courses
- Lesson 16: Ankle Joint Actions and Muscles (Introductory Course)
- Ankle Joint Anatomy: Talocrural, Subtalar, and Tibiofibular Joints (Advanced Course)
Definitions:
- Prime Mover : The muscle that can produce the most force for a joint action. Generally, this is the muscle that will generate the most force during a joint action when exerting force against an external load.
- Agonist : Muscles that perform a joint action, including the prime mover and synergists. That is, unlike the terms prime mover and synergist, agonist refers to all of the muscles that can perform a joint action.
- Synergist : Synergists are muscles that assist the prime mover in performing a joint action. By definition, all agonists that are not the prime mover are synergists.
- Antagonist : Muscles that oppose the agonists (including the prime mover and synergists) for a given joint action. That is, all of the muscles that can perform the opposing joint action.
- Neutralizer : During a joint action, neutralizers are muscles that oppose the unwanted or ancillary joint motions that result from the force generated by the prime mover and/or synergists.
- Fixator : Fixators are muscles that act to reduce or prevent movement of joints proximal to the joint in motion.
- Stabilizer : The role of a stabilizer is to improve arthrokinematics by maintaining optimal alignment of joint surfaces during joint actions. Most often, these muscles are the most intrinsic muscles of a joint. For example, the muscles of the rotator cuff of the shoulder.
Kinesiology of the Ankle Joint
Ankle Plantar Flexion
- Prime Mover: Soleus , gastrocnemius
- Synergists: Fibularis longus, fibularis brevis , tibialis posterior , flexor hallucis longus, flexor digitorum longus , plantaris
- Antagonists: Tibialis anterior , extensor digitorum longus, extensor hallucis longus, fibularis tertius
- Neutralizers: The tibialis posterior and medial gastrocnemius neutralize the eversion force created by the soleus , lateral gastrocnemius and the fibularis muscles .
- Stabilizers: Fibularis longus , fibularis brevis , fibularis tertius , tibialis posterior , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, extensor digitorum longus
- Fixators: Medial and lateral stabilizers of the knee, quadriceps , musculature of the foot
Ankle Dorsi Flexion
- Prime Mover: Tibialis anterior
- Synergists: Extensor digitorum longus, extensor hallucis longus, fibularis tertius
- Antagonists: Soleus , gastrocnemius , fibularis longus, fibularis brevis , tibialis posterior , flexor hallucis longus, flexor digitorum longus , plantaris
- Neutralizers: The fibularis tertius and extensor digitorum longus neutralize inversion force created by tibialis anterior and extensor hallucis longus . The toe flexors stabilize the toe extension force created by extensor hallucis longus, and extensor digitorum longus .
- Stabilizers: Fibularis longus, fibularis brevis , fibularis tertius , tibialis posterior , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, extensor digitorum longus
- Fixators: Medial and lateral stabilizers of knee, quadriceps , popliteus , musculature of the foot.
Ankle Inversion
- Prime Mover: Tibialis anterior , tibialis posterior
- Synergists: Medial gastrocnemius , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, plantaris
- Antagonists: Soleus , lateral gastrocnemius , fibularis longus, fibularis brevis , fibularis tertius, extensor digitorum longus , plantaris
- Neutralizers: Careful balance between groups is important to prevent unwanted ancillary motion. It is difficult to name specific neutralizers, as inversion rarely occurs in isolation.
- Stabilizers: Fibularis longus, fibularis brevis , fibularis tertius , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, extensor digitorum longus
- Fixators: Medial and lateral stabilizers of knee, quadriceps , popliteus , musculature of the foot.
Ankle Eversion
- Prime Mover: Fibularis longus, fibularis brevis
- Synergists: Fibularis tertius , soleus , lateral gastrocnemius , extensor digitorum longus
- Antagonists: Tibialis anterior , tibialis posterior , medial gastrocnemius , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus
- Neutralizers: Careful balance between groups is important to prevent unwanted ancillary motion. It is difficult to name specific neutralizers, as eversion rarely occurs in isolation.
- Stabilizers: Fibularis tertius , tibialis anterior , tibialis posterior , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, extensor digitorum longus
- Fixators: Medial and lateral stabilizers of knee, quadriceps , popliteus , musculature of the foot.
Ankle Dorsi Flexion and Inversion
- Prime Mover: Tibialis anterior
- Synergists: Extensor hallucis longus
- Antagonists: Soleus , lateral gastrocnemius , fibularis longus, fibularis brevis , plantaris
- Medial gastrocnemius , tibialis posterior , flexor hallucis longus, flexor digitorum longus , extensor digitorum longus, fibularis tertius
- Neutralizers:In this analysis we could view those muscles that act as synergists in one, but not both joint actions as neutralizers of excessive motion. In this case those muscles would be:
- Invertors: Medial gastrocnemius , tibialis posterior , flexor hallucis longus, flexor digitorum longus
- Dorsi Flexors: Extensor digitorum longus, fibularis tertius
- Stabilizers: Fibularis longus, fibularis brevis , fibularis tertius , tibialis posterior , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, extensor digitorum longus
- Fixators: Medial and lateral stabilizers of knee, quadriceps , popliteus , musculature of the foot.
Ankle Plantar Flexion and Eversion
- Prime Mover: Soleus , lateral gastrocnemius
- Synergists: Fibularis longus, fibularis brevis , plantaris
- Antagonists: Tibialis anterior , extensor hallucis longus
- Neutralizers: In this analysis we could view those muscles that act as synergists in one, but not both joint actions as neutralizers of excessive motion. In this case those muscles would be:
- Evertors: Fibularis tertius, extensor digitorum longus
- Plantar flexors: Medial gastrocnemius , tibialis posterior , flexor hallucis longus, flexor digitorum longus
- Stabilizers: Fibularis longus, fibularis brevis , fibularis tertius , tibialis posterior , flexor hallucis longus, flexor digitorum longus , extensor hallucis longus, extensor digitorum longus
- Fixators: Medial and lateral stabilizers of knee, quadriceps , popliteus , musculature of the foot.
© 2011 Brent Brookbush
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