Joints
Subtalar joint
Talus on calcaneus, with an axis running obliquely through the foot. That is why inversion and eversion never occur purely in one plane but always as supination and pronation: a combination of inversion, adduction and plantar flexion against eversion, abduction and dorsiflexion.
- Joint type
- Compound joint with one oblique axis, one degree of freedom
- Latin name
- Articulatio subtalaris
Movements, axes and normal values
| Movement | Plane | Axis | Normal range | End feel |
|---|---|---|---|---|
| Inversion (part of supination) | compound | oblique subtalar axis, about 42 degrees to the transverse plane | 0-35 degrees | hard-elastic |
| Eversion (part of pronation) | compound | oblique subtalar axis | 0-15 degrees | hard (calcaneus against the fibula) |
- Close-packed position
- Full supination
- Resting (loose-packed) position
- Midway between inversion and eversion, in slight plantar flexion
- Capsular pattern
- Inward tilt of the heel more limited than outward, with a hard stop; the forefoot stays out of the assessment.
- Arthrokinematics
- Three facets between talus and calcaneus that glide and tilt at the same time. In the closed chain the talus turns medially during pronation and the tibia follows in internal rotation: this is how the position of the foot translates up to the knee.
- Stability
- Interosseous talocalcaneal ligament in the sinus tarsi, the cervical ligament and the lateral ankle ligaments.
- Palpation
- The sinus tarsi as a hollow just anterior and distal to the lateral malleolus; tenderness there fits sinus tarsi syndrome.
- Clinical
- Overpronation with consequences up to the knee and hip; sinus tarsi syndrome after an inversion trauma; tarsal coalition in a stiff, painful foot in adolescents.
- Source
- Kapandji, Physiologie articulaire deel 2; Neumann, Kinesiology of the Musculoskeletal System