Q:Information: - 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. - In humans, the calcaneus (from the Latin "calcaneus" or "calcaneum", meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. - The foot (plural 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 up of one or more segments or bones, generally including claws or nails. - A joint or articulation (or articular surface) is the connection made between bones in the body which link the skeletal system into a functional whole. They are constructed to allow for different degrees and types of movement. Some joints, such as the knee, elbow, and shoulder, are self-lubricating, almost frictionless, and are able to withstand compression and maintain heavy loads while still executing smooth and precise movements. Other joints such as sutures between the bones of the skull permit very little movement (only during birth) in order to protect the brain and the sense organs. The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis. Joints are classified both structurally and functionally. - The skull is a bony structure that forms the head of the skeleton in most vertebrates. It supports the structures of the face and provides a protective cavity for the brain. The skull is composed of two parts: the cranium and the mandible. In the human these two parts are the neurocranium and the viscerocranium or facial skeleton that includes the mandible as its largest bone. The skull forms the anterior most portion of the skeleton and is a product of cephalisationhousing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In the human these sensory structures are part of the facial skeleton. - The fibula or calf bone is a leg bone located on the lateral side of the tibia, with which it is connected above and below. It is the smaller of the two bones, and, in proportion to its length, the slenderest of all the long bones. Its upper extremity is small, placed toward the back of the head of the tibia, below the level of the knee joint, and excluded from the formation of this joint. Its lower extremity inclines a little forward, so as to be on a plane anterior to that of the upper end; it projects below the tibia, and forms the lateral part of the ankle-joint. - Fibrous joints are connected by dense connective 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 are called sutures. Such immovable joints are also referred to as synarthroses. - A leg is a weight bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element capable of changing length and rotating about an omnidirectional "hip" joint. - The ankle , or the talocrural region , is the region where the foot and the leg meet . The ankle includes three joints : the ankle joint proper or talocrural joint , the subtalar joint , and the Inferior tibiofibular joint . The movements produced at this joint are dorsiflexion and plantarflexion of the foot . In common usage , the term ankle refers exclusively to the ankle region . In medical terminology , '' ankle '' ( without qualifiers ) can refer broadly to the region or specifically to the talocrural joint . The main bones of the ankle region are the talus ( in the foot ) , and the tibia and fibula ( in the leg ) . 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 that between the smaller fibula and the talus . - In human anatomy, the subtalar joint, also known as the talocalcaneal joint, is a joint of the foot. It occurs at the meeting point of the talus and the calcaneus. - A bone is a rigid organ that constitutes part of the vertebrate skeleton. Bones support and protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have a complex internal and external structure. They are lightweight yet strong and hard, and serve multiple functions. - The tibia (plural tibiae or tibias), also known as the 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 it connects the knee with the ankle bones. The tibia is found on the medial side of the leg next to the fibula, and closer to the median plane or centre-line. The tibia is connected to the fibula by the interosseous membrane of the 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 next to the femur. The leg bones are the strongest long bones as they support the rest of the body. After reading the paragraphs above, we are interested in knowing the entity with which 'ankle' exhibits the relationship of 'instance of'. Find the answer from the choices below. Choices: - anatomical structure - anatomy - articulation - bearing - bone - bony structure - brain - complex - fibrous joint - fibula - function - head - human - humans - joint - limb - locomotive - meeting - organ - part - plane - point - sense - side - skull - structure - tissue - two - variety
A:
anatomical structure