Thetibia (/ˈtɪbiə/;pl.:tibiae/ˈtɪbii/ ortibias), also known as theshinbone,shankbone or simply theshin, is the larger, stronger, and anterior (frontal) of the twobones in theleg below theknee invertebrates (the other being thefibula, behind and to the outside of the tibia); it connects the knee with theankle. The tibia is found on themedial side of the leg next to the fibula and closer to themedian plane. The tibia is connected to the fibula by theinterosseous membrane of leg, forming a type offibrous joint called asyndesmosis with very little movement. The tibia is named for the flutetibia. It is the second largest bone in thehuman body, after thefemur. The leg bones are the strongestlong bones as they support the rest of the body.
Inhuman anatomy, the tibia is the second largest bone after thefemur. As in other vertebrates the tibia is one of two bones in the lower leg, the other being thefibula, and is a component of the knee and ankle joints. The tibia together with the fibula make up the front part of the leg, between the knee and the ankle, known as theshin.
Theossification or formation of the bone starts from three centers, one in the shaft and one in each extremity.
The tibia is categorized as along bone and is as such composed of adiaphysis and twoepiphyses. The diaphysis is the midsection of the tibia, also known as theshaft or body. While the epiphyses are the two rounded extremities of the bone; anupper (also known as superior or proximal) closest to thethigh and alower (also known as inferior or distal) closest to thefoot. The tibia is most contracted in the lower third and the distal extremity is smaller than the proximal.
Upper surface of right tibia. (Anterior is at top.)Knee
The proximal or upper extremity of the tibia is expanded in the transverse plane with amedial andlateral condyle, which are both flattened in the horizontal plane. The medial condyle is the larger of the two and is better supported over theshaft. The upper surfaces of the condylesarticulate with the femur to form the tibiofemoral joint, the weightbearing part of the knee joint.[1]
The articular surfaces of both condyles are concave, particularly centrally. The flatter outer margins are in contact with the menisci. The medial condyles superior surface is oval in form and extends laterally onto the side ofmedial intercondylar tubercle. The lateral condyles superior surface is more circular in form and its medial edge extends onto the side of thelateral intercondylar tubercle. The posterior surface of the medial condyle bears a horizontal groove for part of the attachment of thesemimembranosus muscle, whereas the lateral condyle has a circular facet for articulation with thehead of the fibula.[1]
The superior articular surface presents two smooth articularfacets.
Themedial facet, oval in shape, is slightly concave from side to side, and from before backward.
Thelateral, nearly circular, is concave from side to side, but slightly convex from before backward, especially at its posterior part, where it is prolonged on to the posterior surface for a short distance.
The central portions of these facets articulate with the condyles of thefemur, while their peripheral portions support themenisci of theknee joint, which here intervene between the two bones.
Between the articular facets in theintercondylar area, but nearer the posterior than the anterior aspect of the bone, is theintercondyloid eminence (spine of tibia), surmounted on either side by a prominent tubercle, on to the sides of which the articular facets are prolonged; in front of and behind the intercondyloid eminence are rough depressions for the attachment of theanterior andposterior cruciate ligaments and the menisci.
Theanterior surfaces of the condyles are continuous with one another, forming a large somewhat flattened area; this area is triangular, broad above, and perforated by large vascular foramina; narrow below where it ends in a large oblong elevation, thetuberosity of the tibia, which gives attachment to thepatellar ligament; abursa intervenes between the deep surface of the ligament and the part of the bone immediately above the tuberosity.
Posteriorly, the condyles are separated from each other by a shallow depression, theposterior intercondyloid fossa, which gives attachment to part of theposterior cruciate ligament of theknee-joint. The medial condyle presents posteriorly a deep transverse groove, for the insertion of the tendon of thesemimembranosus.
Itsmedial surface is convex, rough, and prominent; it gives attachment to themedial collateral ligament.
The lateral condyle presents posteriorly a flat articular facet, nearly circular in form, directed downward, backward, and lateralward, for articulation with the head of the fibula. Itslateral surface is convex, rough, and prominent in front: on it is an eminence, situated on a level with the upper border of the tuberosity and at the junction of its anterior and lateral surfaces, for the attachment of theiliotibial band. Just below this a part of theextensor digitorum longus takes origin and a slip from the tendon of thebiceps femoris is inserted.
The shaft or body of the tibia is triangular in cross-section and forms three borders: an anterior, medial, and lateral or interosseous border. These three borders form three surfaces: the medial, lateral, and posterior.[2]
Theanterior crest or border, the most prominent of the three, commences above at thetuberosity, and ends below at the anterior margin of themedial malleolus. It is sinuous and prominent in the upper two-thirds of its extent, but smooth and rounded below; it gives attachment to thedeep fascia of the leg.
Themedial border is smooth and rounded above and below, but more prominent in the center. It begins at the back part of the medial condyle, and ends at the posterior border of the medial malleolus; its upper part gives attachment to the tibial collateral ligament of the knee-joint to the extent of about 5 cm., and insertion to some fibers of thepopliteus muscle. From its middle third some fibers of thesoleus andflexor digitorum longus muscles take origin.
Theinterosseous crest or lateral border is thin and prominent, especially its central part, and gives attachment to theinterosseous membrane; it commences above in front of the fibular articular facet, and bifurcates below, to form the boundaries of a triangular rough surface, for the attachment of the interosseous ligament connecting the tibia and fibula.
Themedial surface is smooth, convex, and broader above than below; its upper third, directed forward and medialward, is covered by theaponeurosis derived from the tendon of thesartorius, and by the tendons of theGracilis andSemitendinosus, all of which are inserted nearly as far forward as the anterior crest; in the rest of its extent it issubcutaneous.
Thelateral surface is narrower than the medial; its upper two-thirds present a shallow groove for the origin of the Tibialis anterior; its lower third is smooth, convex, curves gradually forward to the anterior aspect of the bone, and is covered by the tendons of theTibialis anterior,Extensor hallucis longus, andExtensor digitorum longus, arranged in this order from the medial side.
Theposterior surface presents, at its upper part, a prominent ridge, the popliteal line, which extends obliquely downward from the back part of the articular facet for the fibula to the medial border, at the junction of its upper and middle thirds; it marks the lower limit of the insertion of thePopliteus, serves for the attachment of the fascia covering this muscle, and gives origin to part of theSoleus,Flexor digitorum longus, andTibialis posterior. The triangular area, above this line, gives insertion to the Popliteus. The middle third of the posterior surface is divided by a vertical ridge into two parts; the ridge begins at the popliteal line and is well-marked above, but indistinct below; the medial and broader portion gives origin to the Flexor digitorum longus, the lateral and narrower to part of theTibialis posterior. The remaining part of the posterior surface is smooth and covered by the Tibialis posterior,Flexor digitorum longus, andFlexor hallucis longus. Immediately below the popliteal line is the nutrient foramen, which is large and directed obliquely downward.
Lower extremity of right tibia seen from the frontLower extremity of right tibia seen from the back
The distal end of the tibia is much smaller than the proximal end and presents five surfaces; it is prolonged downward on its medial side as a strong pyramidal process, themedial malleolus. The lower extremity of the tibia together with the fibula andtalus forms theankle joint.
Theinferior articular surface is quadrilateral, and smooth for articulation with the talus. It is concave from before backward, broader in front than behind, and traversed from before backward by a slight elevation, separating two depressions. It is continuous with that on the medial malleolus.
Theanterior surface of the lower extremity is smooth and rounded above, and covered by the tendons of the Extensor muscles; its lower margin presents a rough transverse depression for the attachment of the articular capsule of the ankle-joint.
Theposterior surface is traversed by a shallow groove directed obliquely downward and medialward, continuous with a similar groove on the posterior surface of the talus and serving for the passage of the tendon of theFlexor hallucis longus.
Thelateral surface presents a triangular rough depression for the attachment of the inferior interosseous ligament connecting it with the fibula; the lower part of this depression is smooth, covered with cartilage in the fresh state, and articulates with the fibula. The surface is bounded by two prominent borders (theanterior and posterior colliculi), continuous above with theinterosseous crest; they afford attachment to the anterior and posterior ligaments of the lateral malleolus.
The part of the ankle joint known as the talocrural joint, is asynovialhinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus. The articulation between the tibia and the talus bears more weight than between the smaller fibula and the talus.[citation needed]
Plan of ossification of the tibia. From three centers.Epiphysial lines of tibia and fibula in a young adult. Anterior aspect.
The tibia isossified from threecenters: aprimary center for thediaphysis (shaft) and a secondary center for eachepiphysis (extremity). Ossification begins in the center of the body, about the seventh week of fetal life, and gradually extends toward the extremities.
The center for the upper epiphysis appears before or shortly after birth at close to 34 weeks gestation; it is flattened in form, and has a thin tongue-shaped process in front, which forms thetuberosity; that for the lower epiphysis appears in the second year.
The lower epiphysis fuses with the tibial shaft at about the eighteenth, and the upper one fuses about the twentieth year.
Two additional centers occasionally exist, one for the tongue-shaped process of the upper epiphysis, which forms the tuberosity, and one for themedial malleolus.
The tibia has been modeled as taking an axial force during walking that is up to 4.7 bodyweight. Itsbending moment in the sagittal plane in the late stance phase is up to 71.6 bodyweight times millimetre.[7]
The structure of the tibia in most othertetrapods is essentially similar to that in humans. The tuberosity of the tibia, a crest to which thepatellar ligament attaches in mammals, is instead the point for the tendon of thequadriceps muscle in reptiles, birds, and amphibians, which have nopatella.[9]
^abcdDrake, Richard L.; Vogl, A. Wayne; Mitchell, Adam W. M. (2010).Gray´s Anatomy for Students (2nd ed.). Churchill Livingstone/Elsevier. pp. 558–560.ISBN978-0-443-06952-9.[page needed]
^abcdDrake, Richard L.; Vogl, A. Wayne; Mitchell, Adam W. M. (2010).Gray´s Anatomy for Students (2nd ed.). Churchill Livingstone/Elsevier. pp. 584–588.ISBN978-0-443-06952-9.
^Bojsen-Møller, Finn; Simonsen, Erik B.; Tranum-Jensen, Jørgen (2001).Bevægeapparatets anatomi [Anatomy of the Locomotive Apparatus] (in Danish) (12th ed.). Munksgaard Danmark. pp. 364–367.ISBN978-87-628-0307-7.
^McCormick, Frank; Nwachukwu, Benedict U.; Provencher, Matthew T. (2012)."Stress Fractures in Runners".Clinics in Sports Medicine.31 (2):291–306.doi:10.1016/j.csm.2011.09.012.PMID22341018. Retrieved2025-10-04.tibial shaft is the most common location for stress fractures in athletes. ... Whereas high-risk stress fractures are so classified based on their tendency for incomplete healing or fracture completion...
^Romer, Alfred Sherwood; Parsons, Thomas S. (1977).The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 205.ISBN0-03-910284-X.
.jpg)
.jpg)
