Tibia Bot Ng 7.4 Download
Giorgina Calvello
The tibia (/ˈtɪbiə/; pl.: tibiae /ˈtɪbii/ or tibias), 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 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 called a syndesmosis with very little movement. The tibia is named for the flute tibia. It is the second largest bone in the human body, after the femur. The leg bones are the strongest long bones as they support the rest of the body.
In human anatomy, the tibia is the second largest bone next to the femur. 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 tibia is categorized as a long bone and is as such composed of a diaphysis and two epiphyses. The diaphysis is the midsection of the tibia, also known as the shaft 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 and a lower (also known as inferior or distal) closest to the foot. The tibia is most contracted in the lower third and the distal extremity is smaller than the proximal.
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 shaft. The upper surfaces of the condyles articulate with the femur to form the tibiofemoral joint, the weightbearing part of the kneejoint.[1]
The medial and lateral condyle are separated by the intercondylar area, 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, which both articulates with and is anchored to the lower extremity of the femur. The intercondylar eminence divides the intercondylar area into an anterior and posterior part. The anterolateral region of the anterior intercondylar area are perforated by numerous small openings for nutrient arteries.[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 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, whereas the lateral condyle has a circular facet for articulation with the head of the fibula.[1]Beneath the condyles is the tibial tuberosity which serves for attachment of the patellar ligament, a continuation of the quadriceps femoris muscle.[1]
Between the articular facets in the intercondylar area, 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 anterior and posterior cruciate ligaments and the menisci.
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 intervenes between the deep surface of the ligament and the part of the bone immediately above the tuberosity.
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 takes origin and a slip from the tendon of the biceps 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]The forward flat part of the tibia is called the fibia, often confused with the fibula.[3][failed verification]
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. From its middle third some fibers of the soleus and flexor digitorum longus muscles take origin.
The interosseous crest or lateral border is thin and prominent, especially its central part, and gives attachment to the interosseous 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.
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 medial malleolus. The lower extremity of the tibia together with the fibula and talus forms the ankle joint.
In the knee the tibia forms one of the two articulations with the femur, often referred to as the tibiofemoral components of the knee joint.[5][6]; it is the weightbearing part of the knee joint.[2]The tibiofibular joints are the articulations between the tibia and fibula which allows very little movement.[citation needed]The proximal tibiofibular joint is a small plane joint. The joint is formed between the undersurface of the lateral tibial condyle and the head of fibula. The joint capsule is reinforced by anterior and posterior ligament of the head of the fibula.[2]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.[2]
The part of the ankle joint known as the talocrural joint, is a synovial hinge 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]
The tibia is ossified from three centers: 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 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.[8]
Fractures of the tibia can be divided into those that only involve the tibia; bumper fracture, Segond fracture, Gosselin fracture, toddler's fracture, and those including both the tibia and fibula; trimalleolar fracture, bimalleolar fracture, Pott's fracture.
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.[9]
There are several ways to classify tibia and fibula fractures. Below are some of the most common tibia and fibula fractures that occur in children. Sometimes they may also involve the fracture of the growth plate (physis) located at each end of the tibia.
These fractures occur in the knee end of the tibia and are also called tibial plateau fractures. Depending on the exact location, a proximal tibial fracture may affect the stability of the knee as well as the growth plate. Common proximal tibial fractures include:
These fractures occur at the ankle end of the tibia. They are also called tibial plafond fractures. One of the common types in children is the distal tibial metaphyseal fracture. This is a fracture in the metaphysis, the part of tibia before it reaches its widest point.
These fractures are usually transverse (across) or oblique (slanted) breaks in the bone. Distal tibial metaphyseal fractures usually heal well after setting them without surgery and applying a cast. However, there is a risk of full or partial early closure of the growth plate. This may lead to a growth arrest in the form of leg length discrepancy or other deformity.
An open fracture occurs when the bone or parts of the bone break through the skin. This type of fracture usually results from high-energy trauma or penetrating wounds. Open fractures of the tibia are common among children and adults.
The treatment of an open tibial fracture starts with antibiotics and a tetanus shot to address the risk of infection. Then the injury is cleaned to remove any debris and bone fragments. Surgery may also be needed depending on the wound size, amount of tissue damage and any vascular (circulation) problems. Open reduction and internal fixation is the surgery that can be used to reposition and physically connect the bones in an open fracture.
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