Head: The upper part of the human body, or the front or upper part of the body of an animal, typically separated from the rest of the body by a neck, and containing the brain, mouth, and sense organs.Head and Neck Neoplasms: Soft tissue tumors or cancer arising from the mucosal surfaces of the LIP; oral cavity; PHARYNX; LARYNX; and cervical esophagus. Other sites included are the NOSE and PARANASAL SINUSES; SALIVARY GLANDS; THYROID GLAND and PARATHYROID GLANDS; and MELANOMA and non-melanoma skin cancers of the head and neck. (from Holland et al., Cancer Medicine, 4th ed, p1651)Head Movements: Voluntary or involuntary motion of head that may be relative to or independent of body; includes animals and humans.Femur Head: The hemispheric articular surface at the upper extremity of the thigh bone. (Stedman, 26th ed)Sperm Head: The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.Femur Head Necrosis: Aseptic or avascular necrosis of the femoral head. The major types are idiopathic (primary), as a complication of fractures or dislocations, and LEGG-CALVE-PERTHES DISEASE.Head Injuries, Closed: Traumatic injuries to the cranium where the integrity of the skull is not compromised and no bone fragments or other objects penetrate the skull and dura mater. This frequently results in mechanical injury being transmitted to intracranial structures which may produce traumatic brain injuries, hemorrhage, or cranial nerve injury. (From Rowland, Merritt's Textbook of Neurology, 9th ed, p417)Craniocerebral Trauma: Traumatic injuries involving the cranium and intracranial structures (i.e., BRAIN; CRANIAL NERVES; MENINGES; and other structures). Injuries may be classified by whether or not the skull is penetrated (i.e., penetrating vs. nonpenetrating) or whether there is an associated hemorrhage.Carcinoma, Squamous Cell: A carcinoma derived from stratified SQUAMOUS EPITHELIAL CELLS. It may also occur in sites where glandular or columnar epithelium is normally present. (From Stedman, 25th ed)Head Protective Devices: Personal devices for protection of heads from impact, penetration from falling and flying objects, and from limited electric shock and burn.Humeral Head: The portion of the upper rounded extremity fitting into the glenoid cavity of the SCAPULA. (from Stedman, 27th ed)Pediculus: Lice of the genus Pediculus, family Pediculidae. Pediculus humanus corporus is the human body louse and Pediculus humanus capitis is the human head louse.Lice Infestations: Parasitic attack or subsistence on the skin by members of the order Phthiraptera, especially on humans by Pediculus humanus of the family Pediculidae. The hair of the head, eyelashes, and pubis is a frequent site of infestation. (From Dorland, 28th ed; Stedman, 26th ed)Reflex, Vestibulo-Ocular: A reflex wherein impulses are conveyed from the cupulas of the SEMICIRCULAR CANALS and from the OTOLITHIC MEMBRANE of the SACCULE AND UTRICLE via the VESTIBULAR NUCLEI of the BRAIN STEM and the median longitudinal fasciculus to the OCULOMOTOR NERVE nuclei. It functions to maintain a stable retinal image during head rotation by generating appropriate compensatory EYE MOVEMENTS.Rotation: Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Skull Fractures: Fractures of the skull which may result from penetrating or nonpenetrating head injuries or rarely BONE DISEASES (see also FRACTURES, SPONTANEOUS). Skull fractures may be classified by location (e.g., SKULL FRACTURE, BASILAR), radiographic appearance (e.g., linear), or based upon cranial integrity (e.g., SKULL FRACTURE, DEPRESSED).Neck: The part of a human or animal body connecting the HEAD to the rest of the body.Scalp DermatosesHead Injuries, Penetrating: Head injuries which feature compromise of the skull and dura mater. These may result from gunshot wounds (WOUNDS, GUNSHOT), stab wounds (WOUNDS, STAB), and other forms of trauma.Neck Muscles: The neck muscles consist of the platysma, splenius cervicis, sternocleidomastoid(eus), longus colli, the anterior, medius, and posterior scalenes, digastric(us), stylohyoid(eus), mylohyoid(eus), geniohyoid(eus), sternohyoid(eus), omohyoid(eus), sternothyroid(eus), and thyrohyoid(eus).Eye Movements: Voluntary or reflex-controlled movements of the eye.Head Kidney: A primitive form of vertebrate kidney that is found in adults of some primitive FISHES and in the embryos of more advanced fishes. In some species of fishes it contains phagocytic cells and is also a major site of HEMATOPOIESIS, analogous to the mammalian BONE MARROW.Acceleration: An increase in the rate of speed.Posture: The position or attitude of the body.Optic Disk: The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.Vestibule, Labyrinth: An oval, bony chamber of the inner ear, part of the bony labyrinth. It is continuous with bony COCHLEA anteriorly, and SEMICIRCULAR CANALS posteriorly. The vestibule contains two communicating sacs (utricle and saccule) of the balancing apparatus. The oval window on its lateral wall is occupied by the base of the STAPES of the MIDDLE EAR.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Brain Concussion: A nonspecific term used to describe transient alterations or loss of consciousness following closed head injuries. The duration of UNCONSCIOUSNESS generally lasts a few seconds, but may persist for several hours. Concussions may be classified as mild, intermediate, and severe. Prolonged periods of unconsciousness (often defined as greater than 6 hours in duration) may be referred to as post-traumatic coma (COMA, POST-HEAD INJURY). (From Rowland, Merritt's Textbook of Neurology, 9th ed, p418)Hydra: A genus of freshwater polyps in the family Hydridae, order Hydroida, class HYDROZOA. They are of special interest because of their complex organization and because their adult organization corresponds roughly to the gastrula of higher animals.Brain Injuries: Acute and chronic (see also BRAIN INJURIES, CHRONIC) injuries to the brain, including the cerebral hemispheres, CEREBELLUM, and BRAIN STEM. Clinical manifestations depend on the nature of injury. Diffuse trauma to the brain is frequently associated with DIFFUSE AXONAL INJURY or COMA, POST-TRAUMATIC. Localized injuries may be associated with NEUROBEHAVIORAL MANIFESTATIONS; HEMIPARESIS, or other focal neurologic deficits.Cephalometry: The measurement of the dimensions of the HEAD.Glasgow Coma Scale: A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response.Myosins: A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.Semicircular Canals: Three long canals (anterior, posterior, and lateral) of the bony labyrinth. They are set at right angles to each other and are situated posterosuperior to the vestibule of the bony labyrinth (VESTIBULAR LABYRINTH). The semicircular canals have five openings into the vestibule with one shared by the anterior and the posterior canals. Within the canals are the SEMICIRCULAR DUCTS.Skull: The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Neoplasms, Squamous Cell: Neoplasms of the SQUAMOUS EPITHELIAL CELLS. The concept does not refer to neoplasms located in tissue composed of squamous elements.Otorhinolaryngologic Neoplasms: A general concept for tumors or cancer of any part of the EAR; the NOSE; the THROAT; and the PHARYNX. It is used when there is no specific heading.Hip Joint: The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.Orientation: Awareness of oneself in relation to time, place and person.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Neck Injuries: General or unspecified injuries to the neck. It includes injuries to the skin, muscles, and other soft tissues of the neck.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Otolithic Membrane: A gelatinous membrane overlying the acoustic maculae of SACCULE AND UTRICLE. It contains minute crystalline particles (otoliths) of CALCIUM CARBONATE and protein on its outer surface. In response to head movement, the otoliths shift causing distortion of the vestibular hair cells which transduce nerve signals to the BRAIN for interpretation of equilibrium.Trauma Severity Indices: Systems for assessing, classifying, and coding injuries. These systems are used in medical records, surveillance systems, and state and national registries to aid in the collection and reporting of trauma.Hip Prosthesis: Replacement for a hip joint.Early Intervention (Education): Procedures and programs that facilitate the development or skill acquisition in infants and young children who have disabilities, who are at risk for developing disabilities, or who are gifted. It includes programs that are designed to prevent handicapping conditions in infants and young children and family-centered programs designed to affect the functioning of infants and children with special needs. (From Journal of Early Intervention, Editorial, 1989, vol. 13, no. 1, p. 3; A Discursive Dictionary of Health Care, prepared for the U.S. House of Representatives Committee on Interstate and Foreign Commerce, 1976)Humerus: Bone in humans and primates extending from the SHOULDER JOINT to the ELBOW JOINT.Injury Severity Score: An anatomic severity scale based on the Abbreviated Injury Scale (AIS) and developed specifically to score multiple traumatic injuries. It has been used as a predictor of mortality.Laryngeal Neoplasms: Cancers or tumors of the LARYNX or any of its parts: the GLOTTIS; EPIGLOTTIS; LARYNGEAL CARTILAGES; LARYNGEAL MUSCLES; and VOCAL CORDS.Myosin Subfragments: Parts of the myosin molecule resulting from cleavage by proteolytic enzymes (PAPAIN; TRYPSIN; or CHYMOTRYPSIN) at well-localized regions. Study of these isolated fragments helps to delineate the functional roles of different parts of myosin. Two of the most common subfragments are myosin S-1 and myosin S-2. S-1 contains the heads of the heavy chains plus the light chains and S-2 contains part of the double-stranded, alpha-helical, heavy chain tail (myosin rod).Legg-Calve-Perthes Disease: A particular type of FEMUR HEAD NECROSIS occurring in children, mainly male, with a course of four years or so.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Unconsciousness: Loss of the ability to maintain awareness of self and environment combined with markedly reduced responsiveness to environmental stimuli. (From Adams et al., Principles of Neurology, 6th ed, pp344-5)Elbow Joint: A hinge joint connecting the FOREARM to the ARM.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Combined Modality Therapy: The treatment of a disease or condition by several different means simultaneously or sequentially. Chemoimmunotherapy, RADIOIMMUNOTHERAPY, chemoradiotherapy, cryochemotherapy, and SALVAGE THERAPY are seen most frequently, but their combinations with each other and surgery are also used.Accidents, Traffic: Accidents on streets, roads, and highways involving drivers, passengers, pedestrians, or vehicles. Traffic accidents refer to AUTOMOBILES (passenger cars, buses, and trucks), BICYCLING, and MOTORCYCLES but not OFF-ROAD MOTOR VEHICLES; RAILROADS nor snowmobiles.Sperm Tail: The posterior filiform portion of the spermatozoon (SPERMATOZOA) that provides sperm motility.Osteotomy: The surgical cutting of a bone. (Dorland, 28th ed)Arthroplasty, Replacement, Hip: Replacement of the hip joint.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Cisplatin: An inorganic and water-soluble platinum complex. After undergoing hydrolysis, it reacts with DNA to produce both intra and interstrand crosslinks. These crosslinks appear to impair replication and transcription of DNA. The cytotoxicity of cisplatin correlates with cellular arrest in the G2 phase of the cell cycle.Nystagmus, Pathologic: Involuntary movements of the eye that are divided into two types, jerk and pendular. Jerk nystagmus has a slow phase in one direction followed by a corrective fast phase in the opposite direction, and is usually caused by central or peripheral vestibular dysfunction. Pendular nystagmus features oscillations that are of equal velocity in both directions and this condition is often associated with visual loss early in life. (Adams et al., Principles of Neurology, 6th ed, p272)Pharyngeal Neoplasms: Tumors or cancer of the PHARYNX.Vestibular Nerve: The vestibular part of the 8th cranial nerve (VESTIBULOCOCHLEAR NERVE). The vestibular nerve fibers arise from neurons of Scarpa's ganglion and project peripherally to vestibular hair cells and centrally to the VESTIBULAR NUCLEI of the BRAIN STEM. These fibers mediate the sense of balance and head position.Torticollis: A symptom, not a disease, of a twisted neck. In most instances, the head is tipped toward one side and the chin rotated toward the other. The involuntary muscle contractions in the neck region of patients with torticollis can be due to congenital defects, trauma, inflammation, tumors, and neurological or other factors.DislocationsProspective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Fixation, Ocular: The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.Oropharyngeal Neoplasms: Tumors or cancer of the OROPHARYNX.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Acetabulum: The part of the pelvis that comprises the pelvic socket where the head of FEMUR joins to form HIP JOINT (acetabulofemoral joint).Chromium Alloys: Specific alloys not less than 85% chromium and nickel or cobalt, with traces of either nickel or cobalt, molybdenum, and other substances. They are used in partial dentures, orthopedic implants, etc.Body Patterning: The processes occurring in early development that direct morphogenesis. They specify the body plan ensuring that cells will proceed to differentiate, grow, and diversify in size and shape at the correct relative positions. Included are axial patterning, segmentation, compartment specification, limb position, organ boundary patterning, blood vessel patterning, etc.Video Recording: The storing or preserving of video signals for television to be played back later via a transmitter or receiver. Recordings may be made on magnetic tape or discs (VIDEODISC RECORDING).Xerostomia: Decreased salivary flow.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Vestibular Function Tests: A number of tests used to determine if the brain or balance portion of the inner ear are causing dizziness.Gene Expression Regulation, Developmental: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action during the developmental stages of an organism.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Prosthesis Failure: Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.Radiotherapy: The use of IONIZING RADIATION to treat malignant NEOPLASMS and some benign conditions.Morphogenesis: The development of anatomical structures to create the form of a single- or multi-cell organism. Morphogenesis provides form changes of a part, parts, or the whole organism.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Infant, Newborn: An infant during the first month after birth.Prognosis: A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.Mouth Neoplasms: Tumors or cancer of the MOUTH.Nystagmus, Physiologic: Involuntary rhythmical movements of the eyes in the normal person. These can be naturally occurring as in end-position (end-point, end-stage, or deviational) nystagmus or induced by the optokinetic drum (NYSTAGMUS, OPTOKINETIC), caloric test, or a rotating chair.Boxing: A two-person sport in which the fists are skillfully used to attack and defend.Models, Anatomic: Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Hematoma, Subdural: Accumulation of blood in the SUBDURAL SPACE between the DURA MATER and the arachnoidal layer of the MENINGES. This condition primarily occurs over the surface of a CEREBRAL HEMISPHERE, but may develop in the spinal canal (HEMATOMA, SUBDURAL, SPINAL). Subdural hematoma can be classified as the acute or the chronic form, with immediate or delayed symptom onset, respectively. Symptoms may include loss of consciousness, severe HEADACHE, and deteriorating mental status.Vestibular Diseases: Pathological processes of the VESTIBULAR LABYRINTH which contains part of the balancing apparatus. Patients with vestibular diseases show instability and are at risk of frequent falls.Hip Dislocation: Displacement of the femur bone from its normal position at the HIP JOINT.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Imaging, Three-Dimensional: The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.Aluminum Oxide: An oxide of aluminum, occurring in nature as various minerals such as bauxite, corundum, etc. It is used as an adsorbent, desiccating agent, and catalyst, and in the manufacture of dental cements and refractories.Pancreaticoduodenectomy: The excision of the head of the pancreas and the encircling loop of the duodenum to which it is connected.Facial Injuries: General or unspecified injuries to the soft tissue or bony portions of the face.Radius: The outer shorter of the two bones of the FOREARM, lying parallel to the ULNA and partially revolving around it.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Osteonecrosis: Death of a bone or part of a bone, either atraumatic or posttraumatic.Radius FracturesRadiotherapy Dosage: The total amount of radiation absorbed by tissues as a result of radiotherapy.Athletic Injuries: Injuries incurred during participation in competitive or non-competitive sports.