![]() The description of hamate body fractures was first noted in 1908 and first classified by Milch in 1934 as involving either the hook or the body. In our analysis of hamate body fractures, the most commonly noted mechanism types were punch or axial loading injuries ( n = 52), fall ( n = 22), motor vehicle accident (MVA) ( n = 10), and crush injuries ( n = 4) (Table (Table1 1). Avulsion fracture of the dorsal surface of the hamate body has been observed and is speculated to arise from disruption of the posterior carpal capsule and ligament occurring after sudden tension is placed on the extensor retinaculum and its attachment to the hamate bone, like in a fall onto an outstretched hand. Medial tuberosity fractures typically occur due to blunt trauma to the ulnar aspect of the wrist. Proximal pole hamate fractures result from shear force more commonly seen in conjunction with complex carpal fracture–dislocation patterns and rarely occur in isolation. Various patterns of dorsal coronal fractures as seen on CT wrist (sagittal view) demonstrating the relationship between the 4th metacarpal base and hamate. Hamate dorsal dislocation, avulsion fracture lunate, fracture 4th MC baseįracture hook of hamate, fracture lunate, fracture triquetrum Ĭompartment syndrome, avulsion ligament of 1st MC to trapeziumįracture hook of hamate, subluxation ulnar CMC jointįracture 1st MC, dislocation all CMC joints, dislocation hamate-capitateįracture radius and ulna shaft, fracture trapeziumįracture 4th MC, dislocation 4th and 5th MCįracture hook of hamate, dislocation 4th MC, subluxation 5th MC Vascular supply to the hamate body is derived from a palmar and dorsal pedicle that is primarily derived by branches of the radial artery, though most anatomic studies demonstrate dual blood supply with additional contributions from branches of the ulnar artery. Hypothenar muscle origination from the hamate-metacarpal joint also contributes to motion of the joint. The stability of the hamate is achieved by articulations with the surrounding carpal and metacarpal bones and through several ligamentous, tendonous, and capsular attachments. The hook of hamate forms the distal ulnar border of the carpal tunnel, while the pisohamate ligament forms the roof of Guyon’s canal. The articulations of the hamate with 4th and 5th metacarpals are modified saddle joints that allow for 15 and 30 degrees arc of motion, respectively. The hamate is part of the distal carpal row and articulates proximally with the triquetrum and lunate, distally with the bases of the 4th and 5th metacarpals, and radially with the capitate. The hook extends to the volar surface and serves as an attachment site for multiple ligaments and tendons. The hook, or hamulus, extends to the volar surface and serves as an attachment site for multiple ligaments and tendons and can be palpated over the hypothenar eminence. The hamate is a wedge-shaped bone composed of the body and the hook.
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