The fibula, also known as the calf bone, is one of the two bones located in the lower leg. It is positioned parallel to the tibia, which is commonly referred to as the shin bone. Despite its slender appearance, the fibula plays a crucial role in facilitating leg movement. Although both the tibia and the fibula have similar lengths, the fibula is considerably thinner. This disparity in size underscores the distinct functions of these bones. While the tibia bears the body’s weight and absorbs stress, the fibula serves as a supportive structure for the tibia, ensuring its stability.
Proximal End
The uppermost part of the fibula is located just behind the tibia’s head, positioned beneath the knee. While some medical professionals refer to this area as the head, it is anatomically known as the proximal end. Proximal is a term used in anatomy to describe an object that is closer to the body’s center. The fibula’s head has a quadrate shape with irregular sides, resembling a square but with uneven edges. At the top of the head, a thick and pointed structure called the apex or styloid process is present. Directly below the head, the fibula narrows to form a slender neck.
Shaft
The fibula, a long and slender bone, is divided into two ends, with a thin and elongated section in between known as the shaft. The shaft of the fibula has a triangular shape in cross sections, although it becomes more irregular as it approaches the ankle. Furthermore, as it extends towards the ankle, it also undergoes a slight twist. The shape of the shaft varies slightly from person to person in order to accommodate the attachment sites for muscles. The fibula has three main surfaces and borders: the medial, lateral, and posterior surfaces, as well as the anterior, posterior, and interosseous borders.