Last revised by Andrew Murphy on 31 Jul 2022

The tibia (plural: tibiae) is the largest bone of the leg and contributes to the knee and ankle joints. (shin- or shank-bone are lay terms). It is medial to and much stronger than the fibula, exceeded in length only by the femur.

The broad weight-bearing surface of the proximal tibia consists of the medial and lateral condyles, each having an articular concave surface and internal intercondylar tubercles projecting superiorly into the knee. The intercondylar area separates the medial and lateral plateau and is divided into the anterior and posterior areas. The anterior intercondylar area houses the attachment of the anterior cruciate ligament, anterior horn of medial meniscus and a small part of the anterior horn of lateral meniscus. The posterior intercondylar area inclines down and back, exhibits a medial intercondylar tubercle for the posterior cornu of the medial meniscus and a smooth tapering ridge for attachment of the posterior cruciate ligament. The tibial tuberosity is a bony projection of the area where the anterior condylar surface merges. It receives the patellar tendon attachment and is separated from the skin by the subcutaneous infrapatellar bursa. Gerdy's tubercle is located at the anterolateral aspect of the proximal tibia, where the iliotibial band (ITB) attaches.

The diaphysis of the tibia is triangular in cross section and has medial, lateral and posterior surfaces, separated by the anterior, lateral (interosseous) and medial borders. The shaft is thinnest at the junction of middle and distal thirds.

The slightly expanded end of the tibia is rotated laterally (tibial torsion) and has five surfaces; anterior, posterior, medial, lateral and distal. The lateral surface exhibits a triangular notch which attaches to the fibula.

  • proximal
    • tibiofemoral
    • proximal tibiofibular
  • distal
    • tibiotalar
    • distal tibiofibular

At the medial malleolus, three tendons pass posteriorly (in order of anterior to posterior): tibialis posterior, flexor digitorum longus and flexor hallucis longus.

The nutrient artery (a branch of the posterior tibial artery) enters through the nutrient foramen at the level of soleal line and is the major arterial supply for the tibia. The proximal metaphysis receives supply from the genicular arterial anastomosis, and the periosteum via the anterior tibial artery as it branches to form the periosteal arteries. Arterial anastomosis at ankle supplies the distal end of tibia. 

The tibia is proximally innervated by branches supplying the knee joint, and distally by those supplying the ankle. The periosteum of the diaphysis receives nerve twigs from the overlying muscles attaching to the tibia.

The tibia ossifies from three centers; one in the diaphysis and one at each of the proximal and distal epiphysis.

The diaphyseal ossification center appears at the seventh week antenatally. The proximal ossification center appears at birth and fuses in the sixteenth year in females and the eighteenth year in males. The distal ossification center appears at the first year of life and joins the shaft at the fifteenth year in females, and the seventeenth year in males.

The medial malleolus is merely an extension from the distal epiphysis and ossifies at seventh year of life.

ADVERTISEMENT: Supporters see fewer/no ads