Tibia is a long bone, a bone with a shaft and expanded ends, and the main weight-bearing bone of the leg. It lies between the knee and ankle, on the inner side of the fibula, and connects the thigh bone above with the talus of the foot below.
Where is the tibia located?
In anatomy, the leg is the region between the knee and ankle, rather than the whole lower limb. The tibia lies medially, meaning towards the body's midline; the fibula lies laterally, meaning away from that midline. The femur, or thigh bone, is above it.
The front edge of the tibia forms the shin. This edge and much of the inner surface lie immediately beneath the skin, with little intervening soft tissue. Towards the ankle, the tibia forms the medial malleolus, the bony prominence on the inner side of the ankle.
The tibia and fibula are separated along much of their length by a gap bridged by the interosseous membrane. This is a sheet of strong fibrous tissue that connects their shafts and provides attachment for muscles.
What are the main parts and landmarks of the tibia?
The tibia has an upper end, a shaft and a lower end. Its shaft has lateral, medial and posterior surfaces: these face outwards, inwards and backwards respectively. Borders separate these surfaces, with the sharp anterior border forming the familiar ridge of the shin.
At the upper end, the medial and lateral condyles are expanded regions that carry the knee's joint surfaces. Their upper surfaces together form the tibial plateau. Between them is the intercondylar eminence, a raised area with bony projections bordering the attachment regions of knee ligaments.
| Landmark | Location | Main anatomical relationship |
|---|---|---|
| Medial and lateral condyles | Upper end | Carry the surfaces that meet the femur at the knee |
| Tibial tuberosity | Front of the upper tibia | Receives the patellar ligament |
| Anterior border | Front of the shaft | Forms the palpable ridge of the shin |
| Soleal line | Back of the upper shaft | Provides attachment for the soleus muscle |
| Medial malleolus | Inner side of the lower end | Forms the medial wall of the ankle joint |
The tibial tuberosity is a roughened prominence below the knee. The soleal line is an oblique ridge on the posterior surface. At the lower end, a hollow on the lateral side, called the fibular notch, receives the lower fibula.
How does the tibia form part of the knee?
The upper tibia meets the lower femur at the knee joint. Articular cartilage, a smooth covering on joint surfaces, covers the areas where these bones meet. The medial and lateral menisci are curved pads of fibrocartilage, a tough cartilage containing abundant fibres, that sit between the femur and tibia.
The menisci help distribute load and improve the fit between the joint surfaces. The anterior and posterior cruciate ligaments attach in the region between the tibial condyles; these strong fibrous bands connect the tibia and femur and help restrain excessive movement.
The patella, or kneecap, does not articulate directly with the tibia. Instead, the patellar ligament connects the patella to the tibial tuberosity, transmitting the pull of the quadriceps femoris, the muscle group at the front of the thigh that straightens the knee.
How does the tibia connect to the ankle and fibula?
The lower surface of the tibia articulates, or forms a joint, with the talus. The lateral surface of the medial malleolus also meets this bone. Together with the lateral malleolus of the fibula, these surfaces form a socket around the talus at the ankle.
The tibia and fibula connect at both ends. Near the knee, the head of the fibula meets a small joint surface on the lateral tibial condyle. This proximal tibiofibular joint is a synovial joint, meaning its opposing surfaces are separated by a fluid-containing joint cavity.
Near the ankle, their connection is a syndesmosis: a joint held together by fibrous tissue rather than a joint cavity. Ligaments and the lower interosseous membrane hold the lower fibula against the tibia, maintaining the ankle socket.
Which muscles attach to the tibia?
The tibia provides attachment sites for several muscles of the muscular system, which produces movement through muscle contraction. An origin is a muscle attachment that usually remains relatively stable during an action; an insertion is the attachment that usually moves more.
Important attachments include:
- Tibialis anterior originates from the lateral condyle and upper lateral surface of the tibia.
- Soleus originates partly from the soleal line and adjacent medial border.
- Popliteus inserts on the posterior tibia above the soleal line.
- Sartorius, gracilis and semitendinosus insert together on the upper medial surface, forming the pes anserinus, or “goose's foot” arrangement of tendons.
- Semimembranosus inserts on the posterior aspect of the medial condyle.
These attachments link the tibia to movements at the knee, ankle and foot.
What does the tibia do?
As part of the skeletal system, the tibia provides a rigid support that transfers body weight from the femur towards the foot. Its broad upper end receives load at the knee, while its lower end passes that load to the talus.
The tibia also acts as a lever for muscles and anchors ligaments that guide movement. At the knee it participates chiefly in bending and straightening, with some rotation when the knee is bent. At the ankle it helps form the socket within which the talus moves.
How can you find the tibia in the 3D model?
In the 3D model next to the article, locate the left tibia or right tibia between the knee and ankle, medial to the fibula. Select and isolate it, then rotate and zoom to view the selected bone from different angles and at different scales.
You can also hide or fade selected structures, switch layers, or pull parts apart to change the view. To view a section, cut along a sagittal, coronal or transverse plane.