Calcaneus: The largest of the TARSAL BONES which is situated at the lower and back part of the FOOT, forming the HEEL.Subtalar Joint: Formed by the articulation of the talus with the calcaneus.Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Talus: The second largest of the TARSAL BONES. It articulates with the TIBIA and FIBULA to form the ANKLE JOINT.Foot Deformities, Acquired: Distortion or disfigurement of the foot, or a part of the foot, acquired through disease or injury after birth.Achilles Tendon: A fibrous cord that connects the muscles in the back of the calf to the HEEL BONE.Nerve Fibers: Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.Muscle Fibers, Skeletal: Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.Heel: The back (or posterior) of the FOOT in PRIMATES, found behind the ANKLE and distal to the TOES.Ankle Joint: The joint that is formed by the inferior articular and malleolar articular surfaces of the TIBIA; the malleolar articular surface of the FIBULA; and the medial malleolar, lateral malleolar, and superior surfaces of the TALUS.Muscle Fibers, Fast-Twitch: Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.Tarsal Joints: The articulations between the various TARSAL BONES. This does not include the ANKLE JOINT which consists of the articulations between the TIBIA; FIBULA; and TALUS.Foot: The distal extremity of the leg in vertebrates, consisting of the tarsus (ANKLE); METATARSUS; phalanges; and the soft tissues surrounding these bones.Clubfoot: A deformed foot in which the foot is plantarflexed, inverted and adducted.Muscle Fibers, Slow-Twitch: Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.Muscle Contraction: A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.Muscles: Contractile tissue that produces movement in animals.Fractures, Bone: Breaks in bones.Tarsal Bones: The seven bones which form the tarsus - namely, CALCANEUS; TALUS; cuboid, navicular, and the internal, middle, and external cuneiforms.Dietary Fiber: The remnants of plant cell walls that are resistant to digestion by the alimentary enzymes of man. It comprises various polysaccharides and lignins.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Bone Density: The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.Hindlimb: Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)Intra-Articular Fractures: Fractures of the articular surface of a bone.Osteoblastoma: A benign, painful, tumor of bone characterized by the formation of osteoid tissue, primitive bone and calcified tissue. It occurs frequently in the spine of young persons. (From Dorland, 27th ed; Stedman, 25th ed)Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Fractures, Closed: Fractures in which the break in bone is not accompanied by an external wound.Bone Cysts: Benign unilocular lytic areas in the proximal end of a long bone with well defined and narrow endosteal margins. The cysts contain fluid and the cyst walls may contain some giant cells. Bone cysts usually occur in males between the ages 3-15 years.Muscular Atrophy: Derangement in size and number of muscle fibers occurring with aging, reduction in blood supply, or following immobilization, prolonged weightlessness, malnutrition, and particularly in denervation.Deer: The family Cervidae of 17 genera and 45 species occurring nearly throughout North America, South America, and Eurasia, on most associated continental islands, and in northern Africa. Wild populations of deer have been established through introduction by people in Cuba, New Guinea, Australia, New Zealand, and other places where the family does not naturally occur. They are slim, long-legged and best characterized by the presence of antlers. Their habitat is forests, swamps, brush country, deserts, and arctic tundra. They are usually good swimmers; some migrate seasonally. (Walker's Mammals of the World, 5th ed, p1362)Tendons: Fibrous bands or cords of CONNECTIVE TISSUE at the ends of SKELETAL MUSCLE FIBERS that serve to attach the MUSCLES to bones and other structures.Osteoporosis: Reduction of bone mass without alteration in the composition of bone, leading to fractures. Primary osteoporosis can be of two major types: postmenopausal osteoporosis (OSTEOPOROSIS, POSTMENOPAUSAL) and age-related or senile osteoporosis.Muscle Denervation: The resection or removal of the innervation of a muscle or muscle tissue.Mineral Fibers: Long, pliable, cohesive natural or manufactured filaments of various lengths. They form the structure of some minerals. The medical significance lies in their potential ability to cause various types of PNEUMOCONIOSIS (e.g., ASBESTOSIS) after occupational or environmental exposure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p708)Tendon Transfer: Surgical procedure by which a tendon is incised at its insertion and placed at an anatomical site distant from the original insertion. The tendon remains attached at the point of origin and takes over the function of a muscle inactivated by trauma or disease.Fracture Fixation, Internal: The use of internal devices (metal plates, nails, rods, etc.) to hold the position of a fracture in proper alignment.Flatfoot: A condition in which one or more of the arches of the foot have flattened out.Physical Conditioning, Animal: Diet modification and physical exercise to improve the ability of animals to perform physical activities.Absorptiometry, Photon: A noninvasive method for assessing BODY COMPOSITION. It is based on the differential absorption of X-RAYS (or GAMMA RAYS) by different tissues such as bone, fat and other soft tissues. The source of (X-ray or gamma-ray) photon beam is generated either from radioisotopes such as GADOLINIUM 153, IODINE 125, or Americanium 241 which emit GAMMA RAYS in the appropriate range; or from an X-ray tube which produces X-RAYS in the desired range. It is primarily used for quantitating BONE MINERAL CONTENT, especially for the diagnosis of OSTEOPOROSIS, and also in measuring BONE MINERALIZATION.Felidae: The cat family in the order CARNIVORA comprised of muscular, deep-chested terrestrial carnivores with a highly predatory lifestyle.Isometric Contraction: Muscular contractions characterized by increase in tension without change in length.Foot Injuries: General or unspecified injuries involving the foot.Hindlimb Suspension: Technique for limiting use, activity, or movement by immobilizing or restraining animal by suspending from hindlimbs or tails. This immobilization is used to simulate some effects of reduced gravity and study weightlessness physiology.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)External Fixators: External devices which hold wires or pins that are placed through one or both cortices of bone in order to hold the position of a fracture in proper alignment. These devices allow easy access to wounds, adjustment during the course of healing, and more functional use of the limbs involved.Motor Neurons: Neurons which activate MUSCLE CELLS.Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Cotton Fiber: A TEXTILE fiber obtained from the pappus (outside the SEEDS) of cotton plant (GOSSYPIUM). Inhalation of cotton fiber dust over a prolonged period can result in BYSSINOSIS.Radius: The outer shorter of the two bones of the FOREARM, lying parallel to the ULNA and partially revolving around it.Equinus Deformity: Plantar declination of the foot.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Weight-Bearing: The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.