Tibiofibular joints are articulations between tibia and fibula. Superior tibiofibular joint is articulation between head of fibula and upper tibia.
At ankle, the articulation between tibia and fibula is called inferior tibiofibular joint.
Two bones are connected by interosseous membrane which is also sometimes called middle tibiofibular joint.
Superior Tibiofibular Joint
The superior tibiofibular joint is a synovial joint between the superior aspects of the tibia and fibula .
In this joint flat facet of fibular head articulates with posterolateral aspect of the lateral tibial condyle. It is a plane type synovial joint.
A joint capsule surrounds the joint and attaches to the tibia and fibula at the margin of the articular surface.
Anterior and posterior proximal tibiofibular ligaments strengthen the joint capsule that runs in a from the head of the fibula to the tibial condyle in superomedial direction.
Biceps femoris and lateral collateral ligament provide additional support.Popliteus tendon runs posterior to joint and popliteus bursa separates popliteus tendon from lateral tibial condyle.
Sometimes there may be synovial communication between superior tibiofibular joint and the knee joint (10-60%)
The joint is supplied by branches of inferior lateral genicular and anterior tibial recurrent arteries
Neural supply is by branches of the common fibular nerve and the nerve to the popliteus
Middle Tibiofibular Joint
It is a fibrous joint formed by the interosseus membrane connecting the shafts of the tibia and the fibula. The interosseus membrane is attached to the interosseous borders of the two bones with fibers are directed downwards and laterally.
Interosseous membrane is wide above and narrow below.
Below , it is continuous with the interosseous ligament of the inferior tibiofibular joint.
In upper part, it presents a large opening at the upper end for the passage of the anterior tibial vessels. In lower part, there is a space for the passage of the perforating branch of the peroneal artery.
The membrane is supplied by nerve to popliteus
Tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius, anterior tibial vessels and deep peroneal nerve lie anterior to interosseous membrane whereas tibialis posterior and flexor hallucis longus are posterior.
Inferior Tibiofibular Joint
This is a syndesmosis uniting the lower ends of the tibia and the fibula connected together by strong interosseus ligament.
The interosseous ligament is concealed both in front and behind by the anterior and posterior tibiofibular ligaments.
The posterior tibiofibular ligament is stronger than the anterior. Its lower and deep portion forms the inferior transverse tibiofibular ligament.
Inferior transverse tibiofibular ligament is a strong thick band of yellowish fibres passing transversely from the upper part of the malleolar fossa of the fibula to the posterior border of the articular surface of the tibia, reaching up to the medial malleolus.
Inferior tibiofibular joint is supplied by perforating branch of the peroneal artery, the malleolar branches of the anterior and posterior tibial arteries.
Nerve supply is by deep peroneal, tibial and saphenous nerves.
The slight movements of the lateral malleolus taking place at this joint provide suppleness to the ankle joint.
- Superior tibiofibular joint gets rarely injured as isolated injury. It more commonly commonly occurs in conjunction with other injuries.
- Superior Tibiofibular Joint functions to
- reduce rotational stress
- prevent lateral bending of the tibia
- spread axial loads when standing
- Interossoeus membrane provides additional surfaces for attachment of muscles and binds the tibia and the fibula together. It also resists the downward pull exerted on the fibula by the powerful muscles attached to the bone.
- Inferior tibiofibular joint permits slight movements, so that the lateral malleolus can rotate laterally during dorsiflexion of the ankle.
- The strength of the ligaments of inferior tibiofibular joint is an important factor in maintaining the integrity of the ankle joint.