Facts about Proximal interphalangeal joint
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Finger injuries causing proximal interphalangeal joint dislocation occur in approximately 5 percent of all hand trauma cases and represent the most common hand joint dislocation seen in emergency departments.
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Synovial fluid within the proximal interphalangeal joint contains hyaluronic acid at concentrations of 3-4 milligrams per milliliter, which reduces friction during finger movement to approximately one-tenth that of ice on ice.
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During finger extension, the central slip of the extensor digitorum tendon inserts directly onto the base of the middle phalanx to actively straighten the proximal interphalangeal joint against resistance.
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Repetitive flexion and extension of the proximal interphalangeal joint at rates exceeding 60 cycles per minute can cause inflammatory synovitis within 2-3 weeks in susceptible individuals.
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Bouchard's nodes, bony enlargements of the proximal interphalangeal joint, develop in approximately 10 percent of the general population and represent osteophyte formation from osteoarthritis.
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Swan neck deformity, a hyperextension of the proximal interphalangeal joint combined with flexion at the distal interphalangeal joint, occurs in approximately 25 percent of rheumatoid arthritis patients.
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Volar plate cartilage in the proximal interphalangeal joint bears loads up to 3 times body weight during forceful gripping, making it susceptible to degenerative wear patterns.
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Osteoarthritis most commonly affects proximal interphalangeal joints in the hands, accounting for approximately 70 percent of hand arthritis cases in older adults.
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Collateral ligaments of the proximal interphalangeal joint measure approximately 2-3 millimeters in thickness and provide critical lateral stability during hand gripping activities.
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The proximal interphalangeal joint allows approximately 100 degrees of flexion in human fingers, enabling precise gripping and fine motor control.