Connections of the Leg Bones
1. Bones of the leg
- Tibia (medial, weight-bearing).
- Fibula (lateral, slender, non-weight-bearing).
Connections between tibia & fibula
They are joined at 3 sites:
A. Superior tibiofibular joint
- Type: plane synovial joint.
- Articulation: head of fibula ↔ lateral condyle of tibia.
- Ligaments: anterior & posterior ligaments of the head of fibula.
- Movement: slight gliding.
B. Interosseous membrane
- Strong fibrous sheet connecting the interosseous borders of tibia & fibula.
- Provides attachment for muscles; stabilizes bones.
- Upper opening → anterior tibial vessels pass.
- Lower opening → perforating branch of fibular artery passes.
C. Inferior tibiofibular joint (syndesmosis)
- Type: fibrous syndesmosis.
- Articulation: roughened surfaces of distal tibia ↔ distal fibula.
- Ligaments: anterior & posterior tibiofibular ligaments, interosseous ligament, inferior transverse tibiofibular ligament.
- Importance: forms a mortise for talus at ankle joint.
Ankle Joint (Talocrural Joint)
1. Type
- Hinge-type synovial joint.
- Allows dorsiflexion & plantarflexion.
2. Articular Surfaces
- Tibia: inferior surface (plafond) + medial malleolus.
- Fibula: lateral malleolus.
- Together form a mortise.
- Talus: trochlea of talus (superior surface wider anteriorly than posteriorly).
3. Capsule
- Thin and loose anteriorly & posteriorly → allows movement.
- Strong on sides, attached to articular margins.