Subtalar Joint Flashcards
What kind of joint is the Subtalar Joint
Functional synovial joint (Bones are not directly joined, they share a synovial cavity)
How many articular surfaces does the Subtalar joint have
Consists of 2 articular facets lined with hyaline cartilage
Concave Posterior Calcaneal Facet + Convex Posterior Talar Surface
Which ligaments stabilise the Subtalar Joint
Medial:
Anterior Tibiotalar Ligament
Posterior Tibiotalar Ligament
Tibiocalcaneal Ligament
TibioNavicular Ligament
Lateral:
Posterior Talofibular Ligament
Anterior Talofibular Ligament
Calcaneofibular Ligament
What is the Sustentaculam Tali
It is a Horizontal shelf arising from the anteromedial aspect of the calcaneus.
Its inferior portion has a groove for the Tendon of the Flexor Hallucis Longus
Define Subtalar Joint Neutral
Forefoot locked on the rearfoot with maximum pronation of the Midtarsal.
The foot is neither Pronated or Supinated
What happens to the Tarsal bones when the foot is in a pronated state?
The joints between the Tarsal bones open increasing the mobility, this allows for shock absorption and weight acceptance.
The foot is said to be unlocked
What happens to the Tarsal bones when the foot is in a supinated state?
The Joints between the tarsal bones close making them more rigid, this allows for push off and propulsion.
The foot is said to be locked
Explain closed chain Supination of the Subtalar Joint?
Talus Dorsiflexes
Tibial External rotation (Talar Abduction)
Calcaneus Inverts
How does Subtalar Supination influence the alignment of the axes of the Midtarsal Joint
The axes move into a non parallel position locking the Midtarsal and making the foot a more rigid lever
This occurs during the Midstance and Terminal Stance phases of walking cycle
Explain closed chain Pronation of the Subtalar Joint?
Talus Plantar flexes
Tibial Internal rotation (Talar Adduction)
Calcaneus Everts
How does Subtalar Pronation influence the alignment of the axes of the Midtarsal Joint
The axes move into a more parallel position unlocking the Midtarsal and making the foot more flexible to adapt to different surfaces
This occurs during the Initial Contact and Loading response phases of the walking cycle
What is the position of the Subtalar joint axis in degress (Transverse plane)
The subtalar joint axis is considered to be 42 degrees from the transverse plane
What is the position of the subtalar joint axis in degrees (Sagital plane)
The subtalar joint axis is considered to be 16 degrees from the sagital plane
What is the Clinical significance of a medially deviated Subtalar joint axis
In order to minimise pronation we have to apply a force to the medial side of the rearfoot axis
If the Subtalar joint axis in the transverse plane is medially deviated there is less space to apply that force
if axis is medial, a greater force from an orthoses will be needed to supinate the pronated foot
