Tibia and Fibula Anatomy - PDF

Tibia and Fibula •Tibia • Medial bone of the leg • Second strongest and longest bone in the body • Receives the body weight from the femur and transfers it to the talus •Fibula • Lateral bone of the leg • Quite thin • Does not transmit the body weight in the leg Posterior view Tibia and Fibula...

Tibia and Fibula •Tibia • Medial bone of the leg • Second strongest and longest bone in the body • Receives the body weight from the femur and transfers it to the talus •Fibula • Lateral bone of the leg • Quite thin • Does not transmit the body weight in the leg Posterior view Tibia and Fibula • Both are long bones • Proximal epiphysis Head of fibula Medial and lateral condyles of tibia • Medial and lateral condyles of tibia • Head of the fibula • Shaft • Distal epiphysis shaft • Lateral malleolus of the fibula • Medial malleolus of the tibia • Malleolus = L. for small hammer or mallet • Boney knob on either side of the ankle • Both are subcutaneous and palpable Medial malleolus Lateral malleolus Proximal Tibia Lateral condyle • Lateral condyle • Smaller than the medial condyle • Greater overhang • Anterior: Gerdy’s tubercle Gerdy’s tubercle • Gerdy’s tubercle • Flattened area for insertion of iliotibial band (IT band) • Posterior: • Fibular facet • Articulates with head of the fibula Fibular facet • Tibial tuberosity • Distal to condyles anteriorly Right Tibia • Smooth superiorly • Rough inferiorly • Patellar ligament attachment Proximal Tibia Superior view right tibia • Medial condyle Medial condyle • Larger than the lateral tibial condyle Intercondylar eminence, medial and lateral tubercles • Bears 60% of the weight Head of fibula groove Posterior view, right • Posterior: • Groove for semimembranosus • Medial hamstring muscle • Tendon continues as the oblique popliteal ligament • Also forms fascia superficial to popliteus Fibula • Fibula • Does not articulate with the femur • Not part of the knee joint • Articulates with the tibia: • 1. proximal tibiofibular joint • 2. interosseous membrane • 3. distal tibiofibular joint • Runs parallel to the tibia • Lies posterior, inferior and lateral to it • Function is muscle attachment Fibula Head Neck • Head of the fibula • Circular articular facet on its superomedial aspect • Articulates with the tibia at the proximal tibiofibular joint • Planar synovial joint • Apex (styloid process) of the head of the fibula • Projects posterolateral • Palpable 2 cm distal to knee joint Posterior right • Neck • Thin area just distal to the head Proximal tibiofibular joint (PTFJ) PTFJ Proximal tibiofibular joint (PTFJ) • Fibular head articulates with inferior side of the lateral tibial condyle • synovial joint (arrow) • #13 is the joint capsule which is thickened to form the anterior superior tibiofibular ligament Proximal tibiofibular joint (PTFJ) • Posterior view of the PTFJ on the right (arrow). • #14 is the posterior superior tibiofibular ligament which is the exterior part of the joint capsule. • joint allows a small amount of rotation of the shaft of the fibula • occurs during plantarflexion and dorsiflexion of the ankle joint Middle tibiofibular joint (MTFJ) • shafts of the tibia and fibula are connected over their entire length by the interosseous membrane. • fibrous joint known as a syndesmosis. • Runs from lateral border of tibial shaft to anteriomedial fibula Interosseous membrane • collagen fibers of interosseous membrane are mostly oriented from superomedial to inferolateral. • allows some up and down (superiorinferior) movement of the fibula. • small amount of rotation and proximal-distal movement of the fibula takes place during dorsiflexion and plantarflexion of the ankle Distal Tibia • Articular surfaces of the distal tibia: • Tibial plafond • Inferior aspect of tibia Tibial plafond Comma-shaped facet • Comma shaped articular facet on lateral aspect of the medial malleolus • Both articulate with the talus at the ankle joint Distal Lateral Fibula • Triangular area distally • Subcutaneous • Fibular groove • Posterior aspect of lateral malleolus • Peroneal tendons of the lateral compartment Medial Surface of the Lateral Malleolus • Triangular articular surface for the talus • Located anteriorly • Rough area • Located posteriorly and projects more inferiorly • Attachment of ligaments • Contains the lateral malleolar fossa • You should be able to tell a left fibula from a right fibula Right anterior ankle Distal tibiofibular joint (DTFJ) • joint is often referred to as the tibiofibular syndesmosis. • distal part of the fibula is attached to the fibular notch of the tibia by an interosseous ligament. Distal tibiofibular joint (DTFJ) The fibular notch of the tibia (6) is the area of attachment of the interosseous tibiofibular ligament. The interosseous tibiofibular ligament is attached to the fibula in the area (6) superior to the facet for the talus. Distal tibiofibular joint (DTFJ) • In addition to the direct interosseous ligament between the two bones, there are two ligaments on the surfaces: • anterior inferior tibiofibular ligament (1) • posterior inferior tibiofibular ligament (2). 1 2 3 ligaments of the distal tibiofibular syndesmosis Inferior transverse ligament • inferior transverse ligament (arrow) is a separate band of (and part of) the posterior (inferior) tibiofibular ligament. • It can articulate with the posterolateral corner of the talus. High ankle sprain • A high ankle sprain is a tearing of any or all of the distal tibiofibular ligaments (1). • often referred to as an ankle syndesmosis injury. • In some cases, there may be an avulsion of bone (break and separation) instead of a ligament tear (2). 1 2 High ankle sprain Rotation of the talus (ankle bone) in the ankle mortise (formed by tibia and fibula) can pry the tibia and fibula apart.* *this will be discussed in detail in LEA II High ankle sprain • Torn tibiofibular ligaments allow the bones to separate and move more than normal. (see black arrows) • A fixation screw may be necessary to substitute for the ruptured syndesmosis.