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One of the carpal bones of the wrist.
It is situated between the hand and forearm on the thumb side of the wrist-lateral or radial side.
The scaphoid is situated between the proximal and distal rows of carpal bones.
It forms the radial border of the carpal tunnel.
The largest bone of the proximal row of wrist bones.
Its long axis is from above downward, lateralward, and forward.
The scaphoid bone It is approximately the size and shape of a medium cashew.
It articulates with five bones:
radius proximally
trapezoid bone and trapezium bone distally
capitate and lunate medially
80% is covered in articulations cartilage.
The palmar surface of the scaphoid is concave.
The palmar surface forms a tubercle, giving attachment to the transverse carpal ligament.
The proximal surface is triangular articulates with the radius and adjacent carpal bones, namely the lunate, capitate, trapezium and trapezoid.
The lateral surface gives attachment to the radial collateral ligament.
The medial surface has two facets, articulating with the lunate bone, and an inferior concave facet, articulating alongside the lunate with the head of the capitate bone.
The dorsal surface of the bone is narrow, but allows ligaments to attach.
The scaphoid bone receives its blood supply primarily from lateral and distal branches of the radial artery, via palmar and dorsal branches.
The middle and distal scaphoid bone receive adequate blood supply, but the proximal portion of the bone relies on retrograde flow supplied by the palmar branch.
The carpal bones working as a unit to provide a bony superstructure for the hand, and it is involved in movement of the wrist.
Along with the lunate, it articulates with the radius and ulna to form the major bones involved in movement of the wrist.
It serves as a link between the two rows of carpal bones.
It can be palpated at the base of the anatomical snuff box, and also in the palma hand/wrist.
Fractures of the scaphoid are the most common of the carpal bone injuries.
It has connections with the two rows of carpal bones.
The scaphoid bone has limited circulation and can be slow to heal .
Fractures of the scaphoid must be recognized and treated quickly.
The prompt treatment by immobilization or surgical fixation increases the likelihood of the bone healing in anatomic alignment, avoiding mal-union or non-union.
Delay of treatment may compromise healing.
The non-union of a fracture leads to post-traumatic osteoarthritis of the carpus.
The proximal segment of the scaphoid bone has tenuous blood supply and can be responsible for non-union.
Non-union fractures can result in loss of blood supply to the proximal pole, which can result in avascular necrosis of the proximal segment.
Scapholunate instability can occur when the ligament connecting the scaphoid to the lunate bone and other surrounding ligaments are disrupted, increasing the distance between the scaphoid and lunate bones is increased.
Isolated nondisplaced fracture of the carpal scaphoid bone is a frequently seen injury in the emergency department.
Approximately 7% of scaphoid fractures are not visible on initial radiographs.