The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two

bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...

s in the leg below the

knee In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

vertebrates Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

(the other being the

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is ...

, behind and to the outside of the tibia); it connects the knee with the ankle. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane. The tibia is connected to the fibula by the interosseous membrane of leg, forming a type of

fibrous joint In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull the joints between the bones ar ...

called a syndesmosis with very little movement. The tibia is named for the flute ''

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

''. It is the second largest bone in the

human body The human body is the structure of a Human, human being. It is composed of many different types of Cell (biology), cells that together create Tissue (biology), tissues and subsequently organ systems. They ensure homeostasis and the life, viabi ...

, after the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

. The leg bones are the strongest

long bone The long bones are those that are longer than they are wide. They are one of five types of bones: long, Short bone, short, Flat bone, flat, Irregular bone, irregular and Sesamoid bone, sesamoid. Long bones, especially the femur and tibia, are subj ...

s as they support the rest of the body.

Structure

human anatomy The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body. It comprises a he ...

, the tibia is the second largest bone next to the

. As in other vertebrates the tibia is one of two bones in the lower leg, the other being the fibula, and is a component of the knee and ankle joints. The

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

or formation of the bone starts from three centers, one in the shaft and one in each extremity. The tibia is categorized as a

and is as such composed of a diaphysis and two epiphyses. The diaphysis is the midsection of the tibia, also known as the

shaft Shaft may refer to: Rotating machine elements * Shaft (mechanical engineering), a rotating machine element used to transmit power * Line shaft, a power transmission system * Drive shaft, a shaft for transferring torque * Axle, a shaft around whi ...

or body. While the epiphyses are the two rounded extremities of the bone; an upper (also known as superior or proximal) closest to the

thigh In human anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone ...

and a lower (also known as inferior or distal) closest to the

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...

. The tibia is most contracted in the lower third and the distal extremity is smaller than the proximal.

Upper extremity

Condyles of tibia

The proximal or upper extremity of the tibia is expanded in the transverse plane with a medial and lateral condyle, which are both flattened in the horizontal plane. The medial condyle is the larger of the two and is better supported over the

. The upper surfaces of the condyles articulate with the femur to form the tibiofemoral joint, the weightbearing part of the kneejoint. The medial and lateral condyle are separated by the

intercondylar area The intercondylar area is the separation between the medial and lateral condyle on the upper extremity of the tibia. The anterior and posterior cruciate ligaments and the menisci attach to the intercondylar area. The intercondyloid eminence i ...

, where the cruciate ligaments and the menisci attach. Here the medial and lateral intercondylar tubercle forms the intercondylar eminence. Together with the medial and lateral condyle the intercondylar region forms the

tibial plateau Tibial may refer to: * Tibia bone * Tibial nerve * Anterior tibial artery * Posterior tibial artery * Anterior tibial vein * Posterior tibial vein The posterior tibial veins are veins of the leg in humans. They drain the posterior compartment of ...

, which both articulates with and is anchored to the

lower extremity of the femur The lower extremity of femur (or distal extremity) is the lower end of the femur (thigh bone) in human and other animals, closer to the knee. It is larger than the upper extremity of femur, is somewhat cuboid in form, but its transverse diameter is ...

. The intercondylar eminence divides the intercondylar area into an

anterior Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and posterior part. The anterolateral region of the anterior intercondylar area are perforated by numerous small openings for nutrient arteries. 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 of medial intercondylar tubercle. The lateral condyles superior surface is more circular in form and its medial edge extends onto the side of the lateral intercondylar tubercle. The posterior surface of the medial condyle bears a horizontal groove for part of the attachment of the

semimembranosus muscle The semimembranosus muscle () is the most medial of the three hamstring muscles in the thigh. It is so named because it has a flat tendon of origin. It lies posteromedially in the thigh, deep to the semitendinosus muscle. It extends the hip joint ...

, whereas the lateral condyle has a circular facet for articulation with the

head of the fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is ...

. Beneath the condyles is the

tibial tuberosity The tuberosity of the tibia or tibial tuberosity or tibial tubercle is an elevation on the proximal, anterior aspect of the tibia, just below where the anterior surfaces of the lateral and medial tibial condyles end. Structure The tuberosity o ...

which serves for attachment of the patellar ligament, a continuation of the quadriceps femoris muscle.

Facets

The superior articular surface presents two smooth articular facets. * The medial facet, oval in shape, is slightly concave from side to side, and from before backward. * The lateral, 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 the

, while their peripheral portions support the menisci of the

joint, which here intervene between the two bones.

Intercondyloid eminence

Between the articular facets in the

, but nearer the posterior than the anterior aspect of the bone, is the intercondyloid 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 the

and posterior cruciate ligaments and the menisci.

Surfaces

The ''anterior 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, the tuberosity of the tibia, which gives attachment to the patellar ligament; a

bursa ( grc-gre, Προῦσα, Proûsa, Latin: Prusa, ota, بورسه, Arabic:بورصة) is a city in northwestern Turkey and the administrative center of Bursa Province. The fourth-most populous city in Turkey and second-most populous in the ...

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, the posterior intercondyloid fossa, which gives attachment to part of the posterior cruciate ligament of the knee-joint. The medial condyle presents posteriorly a deep transverse groove, for the insertion of the tendon of the semimembranosus. Its ''medial surface'' is convex, rough, and prominent; it gives attachment to the medial 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. Its ''lateral 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 the iliotibial band. Just below this a part of the

extensor digitorum longus The extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg. Origin and insertion It arises from the lateral condyle of the tibia; from the upper three-quarters of the anterior surface of the body of t ...

takes origin and a slip from the tendon of the

biceps femoris The biceps femoris () is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group. Structure It has two heads of origin: *the ''long h ...

is inserted.

Shaft

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. The forward flat part of the tibia is called the fibia, often confused with the fibula.

Borders

The anterior crest or border, the most prominent of the three, commences above at the

tuberosity In the skeleton of humans and other animals, a tubercle, tuberosity or apophysis is a protrusion or eminence that serves as an attachment for skeletal muscles. The muscles attach by tendons, where the enthesis is the connective tissue between the ...

, and ends below at the anterior margin of the

medial malleolus A malleolus is the bony prominence on each side of the human ankle. Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the promine ...

. It is sinuous and prominent in the upper two-thirds of its extent, but smooth and rounded below; it gives attachment to the

deep fascia Deep fascia (or investing fascia) is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments. This fibrous connective tissue interpenetrates and surrounds the m ...

of the leg. The medial 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 the

popliteus muscle The popliteus muscle in the leg is used for unlocking the knees when walking, by laterally rotating the femur on the tibia during the closed chain portion of the bipedal gait cycle, gait cycle (one with the foot in contact with the ground). In op ...

. From its middle third some fibers of the soleus and

flexor digitorum longus muscles The flexor digitorum longus muscle is situated on the tibial side of the leg. At its origin it is thin and pointed, but it gradually increases in size as it descends. It serves to flex the second, third, fourth, and fifth toes. Structure The fle ...

take origin. The interosseous crest or lateral border is thin and prominent, especially its central part, and gives attachment to the

interosseous membrane An interosseous membrane is a thick dense fibrous sheet of connective tissue that spans the space between two bones, forming a type of syndesmosis joint. Interosseous membranes in the human body: * Interosseous membrane of forearm * Interosseous ...

; 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.

Surfaces

The medial surface is smooth, convex, and broader above than below; its upper third, directed forward and medialward, is covered by the

aponeurosis An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join musc ...

derived from the tendon of the sartorius, and by the tendons of the Gracilis and Semitendinosus, all of which are inserted nearly as far forward as the anterior crest; in the rest of its extent it is subcutaneous. The lateral 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 the

Tibialis anterior The tibialis anterior muscle is a muscle in humans that originates along the upper two-thirds of the lateral (outside) surface of the tibia and inserts into the medial cuneiform and first metatarsal bones of the foot. It acts to dorsiflex and inve ...

, Extensor hallucis longus, and

Extensor digitorum longus The extensor digitorum longus is a pennate muscle, situated at the lateral part of the front of the leg. Origin and insertion It arises from the lateral condyle of the tibia; from the upper three-quarters of the anterior surface of the body of t ...

, arranged in this order from the medial side. The posterior 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 the

Popliteus The popliteus muscle in the leg is used for unlocking the knees when walking, by laterally rotating the femur on the tibia during the closed chain portion of the gait cycle (one with the foot in contact with the ground). In open chain movements ...

, serves for the attachment of the fascia covering this muscle, and gives origin to part of the Soleus, Flexor digitorum longus, and

Tibialis posterior The tibialis posterior muscle is the most central of all the leg muscles, and is located in the deep posterior compartment of the leg. It is the key stabilizing muscle of the lower leg. Structure The tibialis posterior muscle originates on the i ...

. 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 the

. The remaining part of the posterior surface is smooth and covered by the Tibialis posterior, Flexor digitorum longus, and

Flexor hallucis longus The flexor hallucis longus muscle (FHL) is one of the three deep muscles of the posterior compartment of the leg that attaches to the plantar surface of the distal phalanx of the great toe. The other deep muscles are the flexor digitorum longus an ...

. Immediately below the popliteal line is the nutrient foramen, which is large and directed obliquely downward.

Lower extremity

Tibia - inferior epiphysis (anterior view)

Tibia - inferior epiphysis (posterior view)

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, the

. The lower extremity of the tibia together with the fibula and talus forms the ankle joint.

Surfaces

The inferior 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. The anterior 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. The posterior 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 the

. The lateral 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 (the

and posterior colliculi), continuous above with the interosseous crest; they afford attachment to the anterior and posterior ligaments of the lateral malleolus. The medial surface -- see

for details.

Fractures

Ankle fractures of the tibia have several classification systems based on location or mechanism: *

Medial malleolus A malleolus is the bony prominence on each side of the human ankle. Each leg is supported by two bones, the tibia on the inner side (medial) of the leg and the fibula on the outer side (lateral) of the leg. The medial malleolus is the promine ...

Herscovici classification The Herscovici classification is a system of categorizing medial malleolus fractures of the distal tibia based on level. __TOC__ Classification {, class="wikitable" , - ! Type ! Description , - , A , Avulsion fracture of the anterior collicul ...

* Posterior malleolus - Haruguchi classification *Mechanism - Lauge-Hansen classification

Blood supply

The tibia is supplied with blood from two sources: A nutrient artery, as the main source, and periosteal vessels derived from the anterior tibial artery.

Joints

The tibia is a part of four joints; the knee, ankle,

superior Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake ...

and inferior tibiofibular joint. In the knee the tibia forms one of the two articulations with the

, often referred to as the ''tibiofemoral components'' of the knee joint.; it is the weightbearing part of the knee joint. The tibiofibular joints are the articulations between the tibia and fibula which allows very little movement. The

proximal tibiofibular joint The proximal tibiofibular articulation (also called superior tibiofibular joint) is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula. The contiguous surfaces of the bones present flat, oval facets covere ...

is a small

plane joint A plane joint (arthrodial joint, gliding joint, plane articulation) is a synovial joint which, under physiological conditions, allows only gliding movement. Plane joints permit sliding movements in the plane of articular surfaces. The opposed sur ...

. The joint is formed between the undersurface of the

lateral tibial condyle The lateral condyle is the lateral portion of the upper extremity of tibia. It serves as the insertion for the biceps femoris muscle (small slip). Most of the tendon of the biceps femoris inserts on the fibula. See also * Gerdy's tubercle * Medi ...

and the

head of fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity is ...

. The joint capsule is reinforced by

and

posterior ligament of the head of the fibula The posterior ligament of the head of the fibula is a part of the knee. It is a single thick and broad band, which passes obliquely upward from the back of the head of the fibula to the back of the lateral condyle of the tibia. It is covered by t ...

. The distal tibiofibular joint (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the distal end of the fibula, and a rough concave surface on the lateral side of the tibia. The part of the ankle joint known as the talocrural joint, is a synovial

hinge joint A hinge joint (ginglymus or ginglymoid) is a bone joint in which the articular surfaces are molded to each other in such a manner as to permit motion only in one plane. According to one classification system they are said to be uniaxial (having ...

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.

Development

The tibia is ossified from three

centers Center or centre may refer to: Mathematics * Center (geometry), the middle of an object * Center (algebra), used in various contexts ** Center (group theory) ** Center (ring theory) * Graph center, the set of all vertices of minimum eccentrici ...

: a primary center for the diaphysis (shaft) and a secondary center for each epiphysis (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 the

; 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 the

Function

Muscle attachments

Strength

The tibia has been modeled as taking an axial force during walking that is up to 4.7 bodyweight. Its bending moment in the sagittal plane in the late stance phase is up to 71.6 bodyweight times millimetre.

Clinical significance

Fracture

Fracture Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...

s of the tibia can be divided into those that only involve the tibia;

bumper fracture A bumper fracture is a fracture of the lateral tibial plateau caused by the bumper of a car coming into contact with the outer side of the knee when a person is standing. Specifically, it is caused by a forced valgus applied to the knee. This ca ...

Segond fracture The Segond fracture is a type of avulsion fracture (soft tissue structures pulling off fragments of their bony attachment) from the lateral tibial plateau of the knee, immediately below the articular surface of the tibia (see photo). Clinical ...

Gosselin fracture The Gosselin fracture is a V-shaped fracture of the distal tibia which extends into the ankle joint and fractures the tibial plafond into anterior and posterior fragments. The fracture was described by Leon Athanese Gosselin, chief of surgery at ...

toddler's fracture Toddler's fractures are bone fractures of the Anatomical terms of location#Proximal and distal, distal (lower) part of the shin bone (tibia) in toddlers (aged 9 months-3 years) and other young children (less than 8 years). The fracture is found i ...

, and those including both the tibia and

;

trimalleolar fracture A trimalleolar fracture is a fracture of the ankle that involves the lateral malleolus, the medial malleolus, and the distal posterior aspect of the tibia, which can be termed the posterior malleolus. The trauma is sometimes accompanied by lig ...

bimalleolar fracture A bimalleolar fracture is a fracture of the ankle that involves the lateral malleolus and the medial malleolus. Studies have shown that bimalleolar fractures are more common in women, people over 60 years of age, and patients with existing comorbi ...

Pott's fracture Pott's fracture, also known as Pott's syndrome I and Dupuytren fracture, is an archaic term loosely applied to a variety of bimalleolar ankle fractures. The injury is caused by a combined abduction external rotation from an eversion force. This ...

Society and culture

Judaism Judaism ( he, ''Yahăḏūṯ'') is an Abrahamic, monotheistic, and ethnic religion comprising the collective religious, cultural, and legal tradition and civilization of the Jewish people. It has its roots as an organized religion in the ...

, the tibia, or shankbone, of a goat is used in the

Passover Seder plate The Passover Seder plate ( he, קערה, ''ke'ara'') is a special plate containing symbolic foods eaten or displayed at the Passover Seder. The purpose of the Passover Seder plate is to show all the foods that perpetuate and emphasize the ideas ...

Other animals

The structure of the tibia in most other tetrapods is essentially similar to that in humans. The tuberosity of the tibia, a crest to which the patellar ligament attaches in mammals, is instead the point for the tendon of the quadriceps muscle in reptiles, birds, and amphibians, which have no

patella The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as m ...

Additional images

File:Right tibia - close up - animation.gif, Shape of right tibia File:Human tibia.stl, 3D image File:Braus 1921 292.png, Longitudinal section of tibia showing interior File:Gray345.png, Right knee-joint. Anterior view. File:Gray347.png, Right knee joint from the front, showing interior ligaments File:Gray348.png, Left knee joint from behind, showing interior ligaments File:Gray356.png, Left talocrural joint File:Gray357.png, Coronal section through right talocrural and talocalcaneal joints File:Slide3Bubu.JPG, Dorsum of Foot. Ankle joint. Deep dissection File:Slide2bubu.JPG, Dorsum of Foot. Ankle joint. Deep dissection File:Slide2tat.JPG, Ankle joint. Deep dissection. Anterior view File:Gray258.png, Bones of the right leg. Anterior surface File:Gray259.png, Bones of the right leg. Posterior surface File:Slide2coco.JPG, Dorsum of Foot. Ankle joint. Deep dissection. File:Slide4CEC3.JPG, Ankle joint. Deep dissection. File:Slide5CEC4.JPG, Ankle joint. Deep dissection. File:Slide7CEC6.JPG, Ankle joint. Deep dissection. File:Slide8CEC7.JPG, Ankle joint. Deep dissection. File:Tibia Anatomy by Jason Christian.webm, Tibia Anatomy

References

{{Authority control Bones of the lower limb Long bones