Tibia

The shin bone, the larger and more medial of the two leg bones, carrying body weight from the knee to the ankle.

At a glance

English: Tibia
Latin (TA2): Tibia
System: Bone
Region: Lower limb
Side: Paired, left and right
Muscles on it: Soleus

About the tibia

The tibia, or shin bone, is the larger and more medial of the two bones of the leg below the knee. It carries almost all of the body's weight from the femur down to the talus. Only the fibula lies beside it, and the two are bound together by an interosseous membrane and joints at either end.

The upper end is broad and flattened into two condyles whose upper surfaces form the tibial plateau. Each holds a shallow facet for a femoral condyle, deepened in life by the menisci. Between the facets rises the intercondylar eminence, with areas in front and behind for the cruciate ligaments and the horns of the menisci. A small facet under the back of the lateral condyle meets the head of the fibula. In front, below the plateau, is the tibial tuberosity, where the patellar ligament ends.

The shaft is triangular in section. Its sharp anterior border and broad medial surface lie straight under the skin as the shin, with no muscle covering them. The posterior surface carries the soleal line, a slanting ridge for soleus, and the lateral border is the attachment of the interosseous membrane. Lower down, the bone widens to the ankle. Its distal surface sits on the talus, its medial malleolus projects downwards to form the inner bump of the ankle, and a notch on its lateral side holds the lower end of the fibula.

Because so much of it is just under the skin, the tibia is the long bone most often broken through an open wound. Fractures confined to the tibia include the toddler's fracture of the shaft in young children, the bumper fracture of the plateau and the Segond avulsion at the lateral condyle, which is linked with anterior cruciate ligament tears. Ankle injuries often involve both leg bones, as in bimalleolar and trimalleolar fractures. The shaft has a limited blood supply in its lower part, which helps explain why fractures there can be slow to heal. Repeated overload can cause shin splints or stress fractures along the medial border.

Function and supply

Function: Bears the body's weight across the knee and ankle and gives attachment to the quadriceps through the patellar ligament, to the hamstrings and to the leg muscles.
Nerve supply: Periosteum supplied by branches of the nerves of the leg, mainly the tibial and saphenous nerves; the tibial nerve runs behind the bone.
Blood supply: A nutrient artery from the posterior tibial artery enters the upper back of the shaft; periosteal vessels from the anterior tibial artery add to it.

Parts of the tibia

Each number is marked on the model. Press one, here or on the model, to see it named in place.

Anterior border of tibiaMargo anterior tibiaeThe sharp ridge down the front of the shaft from the tibial tuberosity to the front of the medial malleolus. It lies just under the skin as the shin and is easily bruised.
Anterior intercondylar areaArea intercondylaris anteriorThe broad, rough region in front of the intercondylar eminence on the tibial plateau. The anterior horns of the menisci and the anterior cruciate ligament attach here.
Articular facet of medial malleolusFacies articularis malleoliThe smooth, cartilage-covered inner face of the medial malleolus. It meets the medial side of the talus and helps hold the ankle joint stable.
Articular surface of medial condyleFacies articularis condyli medialisThe oval, slightly hollowed upper facet of the medial condyle, larger than the lateral one. It meets the medial condyle of the femur, with the medial meniscus between them.
Body of tibiaCorpus tibiaeThe shaft of the bone, triangular in cross-section with anterior, medial and interosseous borders. Its lower third is narrowest and has the poorest blood supply.
Fibular articular facetFacies articularis fibularisA small, flat, rounded facet under the back of the lateral condyle. It meets the head of the fibula at the proximal tibiofibular joint, which allows only slight gliding.
Fibular notchIncisura fibularisA hollow on the outer face of the lower end of the tibia. The lower end of the fibula sits in it, bound by strong ligaments at the distal tibiofibular joint.
Inferior articular surface of tibiaFacies articularis inferior tibiaeThe smooth, four-sided lower surface that rests on the top of the talus. It is wider in front than behind and forms the roof of the ankle joint.
Intercondylar areaArea intercondylarisThe rough strip between the two articular surfaces of the plateau, divided by the intercondylar eminence. The cruciate ligaments and the horns of both menisci attach to it.
Intercondylar eminenceEminentia intercondylarisA raised ridge between the articular facets of the plateau, closer to the back than the front. It bears two small tubercles and can be pulled off in a tibial spine avulsion.
Interosseous border of tibiaMargo interosseus tibiaeThe thin lateral border of the shaft facing the fibula. The interosseous membrane attaches along it, and it splits below to outline the fibular notch.
Lateral condyle of tibiaCondylus lateralis tibiaeThe outer half of the expanded upper end of the tibia. It carries the lateral articular facet above and the fibular facet beneath its back, and a small slip of biceps femoris attaches to it.
Lateral intercondylar tubercleTuberculum intercondylare lateraleThe outer of the two small peaks on the intercondylar eminence. With its medial partner it helps stop the femur sliding sideways on the plateau.
Lateral surface of tibiaFacies lateralis tibiaeThe face of the shaft between the anterior and interosseous borders. Tibialis anterior arises from its upper part, and the lower part turns forwards and is crossed by the extensor tendons.
Malleolar groove of tibiaSulcus malleolaris tibiaeA broad groove on the back of the medial malleolus. It carries the tendons of tibialis posterior and flexor digitorum longus as they pass to the foot.
Medial border of tibiaMargo medialis tibiaeThe rounded border between the medial and posterior surfaces, from the medial condyle to the back of the medial malleolus. Soleus and the deep fascia attach to it, and pain along it is typical of shin splints.
Medial condyle of tibiaCondylus medialis tibiaeThe inner half of the expanded upper end, larger than the lateral condyle. Semimembranosus inserts into a groove on its back.
Medial intercondylar tubercleTuberculum intercondylare medialeThe inner of the two small peaks on the intercondylar eminence. It is the taller of the pair and sits beside the medial articular facet.
Medial malleolusMalleolus medialisThe strong, blunt projection at the lower inner end of the tibia, forming the bony bump on the inside of the ankle. The deltoid ligament attaches to it, and it is often broken in ankle injuries.
Medial surface of tibiaFacies medialis tibiaeThe broad, smooth face of the shaft lying straight under the skin on the inside of the shin. Its upper part receives the tendons of sartorius, gracilis and semitendinosus, which form the pes anserinus.
Posterior intercondylar areaArea intercondylaris posteriorThe roughened area behind the intercondylar eminence. The posterior horns of the menisci and the posterior cruciate ligament attach here.
Posterior malleolusMalleolus posteriorThe back edge of the lower end of the tibia, projecting slightly downwards behind the talus. It is a named piece in trimalleolar ankle fractures.
Posterior surface of tibiaFacies posterior tibiaeThe back of the shaft, between the medial and interosseous borders. It is crossed above by the soleal line and gives origin to the deep calf muscles, tibialis posterior and flexor digitorum longus.
Soleal lineLinea musculi soleiA rough ridge running obliquely down and inwards across the upper back of the shaft. Soleus arises from it, and popliteus inserts on the triangle above it.
Superior articular surface of lateral condyleFacies articularis superior condyli lateralisThe nearly round, upper facet of the lateral condyle, slightly hollowed from side to side. It meets the lateral femoral condyle with the lateral meniscus between them.
Superior articular surfaces of tibiaFacies articulares superiores tibiaeThe two cartilage-covered upper facets of the plateau, one on each condyle. Together they carry the femoral condyles and transmit the load of the body through the knee.
Tibial plateauPlanum tibiaeThe broad, flattened top of the tibia formed by the upper surfaces of both condyles. It is the weight-bearing floor of the knee and can be split or crushed in a plateau fracture.
Tibial tuberosityTuberositas tibiaeA raised, roughened bump on the front of the upper tibia below the condyles. The patellar ligament inserts on it, and in growing children it is the site of Osgood-Schlatter disease.
Tubercle of iliotibial tractTuberculum tractus iliotibialisA smooth, flat bump on the front of the lateral condyle of the tibia, also called Gerdy's tubercle. The iliotibial tract attaches here.

Anthromica

See the tibia where it really sits, with every layer of the body around it.

Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
English and Latin. Every structure named the way your exam names it.
Quiz until it sticks. Short drills on the structures you keep missing.

Open it in Anthromica

Free to start. No card.

At a glance

About the tibia

Function and supply

Related structures

See the tibia where it really sits, with every layer of the body around it.