Tibia

The tibia (English pronunciation: /ˈtɪbɪə/), shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates (the other being the fibula), and connects the knee with the ankle bones. The tibia is named for the Greek aulos flute, also known as a tibia. It is commonly recognized as the strongest weight bearing bone in the body.

In humans

The tibia is found next to the fibula. It is the second largest bone in the human body, the largest being the femur. The tibia articulates with the femur superiorly, the fibula laterally and with the talus inferiorly.

[edit]Gender differences

In the male, its direction is vertical, and parallel with the bone of the opposite side. In the female, it has a slightly oblique direction downward and laterally, to compensate for the greater obliqueness of the femur. Studies are inconclusive, however.

[edit]Structure

It is prismoid in form, expanded above, where it enters into the knee-joint, contracted in the lower third, and again enlarged but to a lesser extent towards the ankle joint.

The superior tibiofibular articulation is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula. The inferior tibiofibular articulation (tibiofibular syndesmosis) is formed by the rough, convex surface of the medial side of the lower end of the fibula, and a rough concave surface on the lateral side of the tibia. The tibia is connected to the fibula by an interosseous membrane, forming a type of joint called a syndesmoses. The forward flat part of the tibia is called the fibia, often confused with the fibula.

[edit]Blood supply

The tibia derives its arterial blood supply from two sources:^[1]

1. the nutrient artery (main source)
2. periosteal vessels derived from the anterior tibial artery

[edit]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.^[2]

[edit]In 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 thepatellar ligament attaches in mammals, is instead the insertion point for the tendon of the quadriceps muscle in reptiles, birds, and amphibians, which have no patella.^[3]

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