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Scaphoid fractures occur in three locations: (A) Distal tubercle, (B) waist, and (C) proximal pole. Fractures of scaphoid can occur either with direct axial compression or with hyperextension of the wrist, such as a fall on the palm on an outstretched hand.
Healing of the fracture with a non-anatomic deformity (frequently, a volar flexed "humpback") can also lead to post-traumatic arthritis. Non-unions can result in loss of blood supply to the proximal pole, which can result in avascular necrosis of the proximal segment. Scaphoid fractures may be difficult to diagnose via plain x-ray.
Preiser disease, or avascular necrosis of the scaphoid, is a rare condition where ischemia and necrosis of the scaphoid bone occurs without previous fracture.It is thought to be caused by repetitive microtrauma or side effects of drugs (e.g., steroids or chemotherapy) in conjunction with existing defective vascular supply to the proximal pole of the scaphoid.
The Herbert classification is a system of categorizing scaphoid fractures. [1] Classification ... Proximal pole B4 Fracture dislocation B5 Comminuted fracture: C
Blood enters the scaphoid distally. Consequently, in the event of a fracture the proximal segment of the scaphoid will be devoid of a vascular supply, and will—if action is not taken—avascularly necrose within a sufferer's snuffbox. Due to the small size of the scaphoid and its shape, it is difficult to determine, early on, whether or not ...
The term navicular bone or hand navicular bone was formerly used for the scaphoid bone, [1] one of the carpal bones of the wrist. The navicular bone in humans is located on the medial side of the foot , and articulates proximally with the talus , distally with the three cuneiform bones , and laterally with the cuboid .
Scapholunate advanced collapse is the most common form, followed by scaphoid non-union advanced collapse (SNAC). [3] Other post-traumatic causes such as intra-articular fractures of the distal radius or ulna can also lead to wrist osteoarthritis, but are less common.
Isolated fractures of the capitate comprise only 0.3% and are often non-displaced. This is since the capitate is at the centre of the carpal region and is therefore quite well protected. Capitate fractures occur together with fractures of another carpal bone, the scaphoid. [5] Various mechanisms for fractures of the capitate have been postulated.