Humeral Head: The portion of the upper rounded extremity fitting into the glenoid cavity of the SCAPULA. (from Stedman, 27th ed)Humerus: Bone in humans and primates extending from the SHOULDER JOINT to the ELBOW JOINT.Shoulder Joint: The articulation between the head of the HUMERUS and the glenoid cavity of the SCAPULA.Shoulder Dislocation: Displacement of the HUMERUS from the SCAPULA.Shoulder Fractures: Fractures of the proximal humerus, including the head, anatomic and surgical necks, and tuberosities.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.Arthroplasty, Replacement: Partial or total replacement of a joint.Glenoid Cavity: A depression in the lateral angle of the scapula that articulates with the head of the HUMERUS.Brachial Plexus Neuropathies: Diseases of the cervical (and first thoracic) roots, nerve trunks, cords, and peripheral nerve components of the BRACHIAL PLEXUS. Clinical manifestations include regional pain, PARESTHESIA; MUSCLE WEAKNESS, and decreased sensation (HYPESTHESIA) in the upper extremity. These disorders may be associated with trauma (including BIRTH INJURIES); THORACIC OUTLET SYNDROME; NEOPLASMS; NEURITIS; RADIOTHERAPY; and other conditions. (From Adams et al., Principles of Neurology, 6th ed, pp1351-2)Rotator Cuff: The musculotendinous sheath formed by the supraspinatus, infraspinatus, subscapularis, and teres minor muscles. These help stabilize the head of the HUMERUS in the glenoid fossa and allow for rotation of the SHOULDER JOINT about its longitudinal axis.Paralysis, Obstetric: Paralysis of an infant resulting from injury received at birth. (From Dorland, 27th ed)Osteochondrosis: Any of a group of bone disorders involving one or more ossification centers (EPIPHYSES). It is characterized by degeneration or NECROSIS followed by revascularization and reossification. Osteochondrosis often occurs in children causing varying degrees of discomfort or pain. There are many eponymic types for specific affected areas, such as tarsal navicular (Kohler disease) and tibial tuberosity (Osgood-Schlatter disease).Joint Prosthesis: Prostheses used to partially or totally replace a human or animal joint. (from UMDNS, 1999)Scapula: Also called the shoulder blade, it is a flat triangular bone, a pair of which form the back part of the shoulder girdle.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.Osteonecrosis: Death of a bone or part of a bone, either atraumatic or posttraumatic.Birth Injuries: Mechanical or anoxic trauma incurred by the infant during labor or delivery.Hemiarthroplasty: A partial joint replacement in which only one surface of the joint is replaced with a PROSTHESIS.Shoulder: Part of the body in humans and primates where the arms connect to the trunk. The shoulder has five joints; ACROMIOCLAVICULAR joint, CORACOCLAVICULAR joint, GLENOHUMERAL joint, scapulathoracic joint, and STERNOCLAVICULAR joint.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)Fracture Fixation, Internal: The use of internal devices (metal plates, nails, rods, etc.) to hold the position of a fracture in proper alignment.Acromion: The lateral extension of the spine of the SCAPULA and the highest point of the SHOULDER.Suture Anchors: Implants used in arthroscopic surgery and other orthopedic procedures to attach soft tissue to bone. One end of a suture is tied to soft tissue and the other end to the implant. The anchors are made of a variety of materials including titanium, stainless steel, or absorbable polymers.Cadaver: A dead body, usually a human body.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.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)Arthroscopy: Endoscopic examination, therapy and surgery of the joint.Cartilage Diseases: Pathological processes involving the chondral tissue (CARTILAGE).Periprosthetic Fractures: Fractures around joint replacement prosthetics or implants. They can occur intraoperatively or postoperatively.Joint Instability: Lack of stability of a joint or joint prosthesis. Factors involved are intra-articular disease and integrity of extra-articular structures such as joint capsule, ligaments, and muscles.Head Movements: Voluntary or involuntary motion of head that may be relative to or independent of body; includes animals and humans.Bursitis: Inflammation or irritation of a bursa, the fibrous sac that acts as a cushion between moving structures of bones, muscles, tendons or skin.Arthroplasty: Surgical reconstruction of a joint to relieve pain or restore motion.Shoulder Pain: Unilateral or bilateral pain of the shoulder. It is often caused by physical activities such as work or sports participation, but may also be pathologic in origin.Tendon Injuries: Injuries to the fibrous cords of connective tissue which attach muscles to bones or other structures.Ligaments, Articular: Fibrous cords of CONNECTIVE TISSUE that attach bones to each other and hold together the many types of joints in the body. Articular ligaments are strong, elastic, and allow movement in only specific directions, depending on the individual joint.Femur Head: The hemispheric articular surface at the upper extremity of the thigh bone. (Stedman, 26th ed)Bone Plates: Implantable fracture fixation devices attached to bone fragments with screws to bridge the fracture gap and shield the fracture site from stress as bone heals. (UMDNS, 1999)Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Cartilage, Articular: A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.Recovery of Function: A partial or complete return to the normal or proper physiologic activity of an organ or part following disease or trauma.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.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Rupture: Forcible or traumatic tear or break of an organ or other soft part of the body.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.Joint DiseasesSperm Head: The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.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.Fluoroscopy: Production of an image when x-rays strike a fluorescent screen.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.Bone Screws: Specialized devices used in ORTHOPEDIC SURGERY to repair bone fractures.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.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.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.