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Hamate fractures are uncommon, comprising only 2 % of carpal bone fractures. (http://emedicine.medscape.com/article/97813-overview) Fractures of the hook of the hamate are more common than fractures of the body of the hamate. Hamate hook fractures are likely to be best demonstrated on the carpal tunnel view.
The hamate is the most ulnar carpal bone in the distal row. "The body of the hamate articulates distally with the bases of the 4th and 5th metacarpals, radially with the capitate and proximally with the triquetrum and lunate. The hook of the hamate (hamulus) is the distal border of Guyon's canal, which contains the ulnar artery and nerve. With injury of the hamate one should always assure vascular patency and that sensation is intact in the 5th digit and the ulnar border of the 4th. " (Kevin E. Burroughs)
Fractures of the hook of the hamate are associated with sports injuries (golf, tennis etc) but may also result from a direct blow.
source: unknown"Type I fractures involving the hook of the hamate are the most common and can occur via several different mechanisms.First, repeated microtrauma to the hook during sports involving swinging clubs, bats, or racquets can result in a hook stress fracture. These usually occur in the nondominant hand and account for approximately one third of hamate fractures.Second, direct trauma can be applied during sports when the butt of the club rests on the hamate and the force of the swing is then transmitted directly to the bone.In addition, indirect trauma can be applied to the hook through its muscular and ligamentous attachments.This can occur either when falling on a hyperextended wrist or during power grips.
Type II fractures involving the body of the hamate are less common than type I fractures and always require direct force.4 Most commonly, these fractures occur with a punch-press injury or dorsopalmar compression of the wrist between heavy weights"
Amy Powell, MD, Hamate Fracture, E medicine
Hamate fractures are not always demonstrated well on routine wrist views. A carpal tunnel view should be considered for hook of hamate fractures and a reverse oblique position can demonstrate hamate body fractures well
The PA wrist view demonstrates no obvious fracture
The oblique wrist view is unremarkable
The scaphoid view of the wrist is unremarkable
The lateral view of the wrist demonstrates a fracture of the
body of the hamate
This patient presented to the Emergency Department following an injury to his hand/wrist. The mechanism of injury is unknown.
The PA wrist projection image demonstrates no clearly demonstrated fracture (although the hamate appears suspect) The ulnar aspect of the hamate is irregular on the oblique wrist view image suggesting a hamate fracture. The scaphoid view demonstrates no displaced fracture A coned oblique view centred on the area of interest suggests a hamate fracture
This 34 year old man presented to the Emergency Department following an injury to his hand/wrist. The mechanism of injury is unknown.
The PA wrist projection image demonstrated some irregularity of the ulnar aspect of the hamate The ulnar aspect of the hamate is also irregular on the oblique wrist view image suggesting a hamate fracture. The lateral wrist view somewhat pronated. There appears to be a fracture of the hamate in this view. Care should be taken to ensure that this appearance is not from an os styloideum. Subsequent CT imaging suggested that the appearance is a hamate fracture. Axial CT demonstrated a comminuted fracture of the body of the hamate Coronal CT of the wrist demonstrated a comminuted fracture of the body of the hamate Saggital wrist CT demonstrated the hamate body fracture.
This 40 year old male presented to the Emergency Department following a fall. He was examined and found to have a painful wrist and swelling over the dorsum of his right hand. He was referred for right hand and wrist radiography.
There is a fracture of the ulnar aspect of the hamate.
Old injury to the 5th digit noted.This is an enlarged image demonstrating the hamate fracture. The fracture is intra-articular. The oblique hand projection did not demonstrate the fracture of the hamate. This is an oblique wrist position with tube angulation (similar to a scaphoid projection). The hamate fracture is demonstrated. Off-lateral wrist projections were performed. This was unlikely to demonstrate the fracture given that is was known to be sited at the ulnar aspect of the hamate.
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M.J.Fuller |
Latest page update: made by M.J.Fuller
, Mar 7 2011, 9:27 PM EST
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Keyword tags:
carpal bones
fracture
hamate fracture
hook of the hamate
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