Fracture Thumb

In an effort to establish basic differences between Georgia soft kaolinites (clay feels soft and friable) and Georgia hard kaolinites (breaks with a conchoidal fracture and crumbles with difficulty between thumb and finger) Hinckley (1961) analyzed over three hundred samples. Although this is an empirical division it effectively divides... 

The first secondary transition below Tg, the so called fj-relaxation, is practically important. This became evident after Struik s (1978) finding that polymers are brittle below Tp and establish creep and ductile fracture between Tp and Tg. The p-relaxation is characteristic for each individual polymer, since it is connected with the start of free movements of special short sections of the polymer chain. In view of more recent data of Tp Boyer s relation, Eq. (6.29), is very approximate and fails completely for amorphous polymers with high Tg s (e.g. aromatic polycarbonates and polysulphones). Some rules of thumb may be given for a closer approximation. 

Knowing the penetration depth and fracture angle, one can calculate the horizontal clearance that will produce a clean cut. The rule of thumb of using 9% 10% metal thickness for horizontal clearance, when processing mild cold-rolled steel, is the result of this calculation. 

The Thumb 291 Paediatric Skier s Thumb 292 Dislocation of the Thumb MCP Joint 292 Fractures of the Thumb Metacarpal Base 293... 

These are rare injuries. If associated with fractures of the metacarpal base, the dislocations are analogous to Bennett s fractures of the thumb (Sandzen 1973). Post-reduction these injuries tend to redislocate, and often require stabilisation (Graham and Waters 2001). 

Fig. 19.25. Avulsion fracture of the ulnar collateral ligament at the thumb metacarpophalangeal joint...

Fractures of the head and shaft of the thumb metacarpal are similar to those seen in the other digits in terms of treatment. Fractures of the base of the metacarpal, however, deserve special attention due to their potential impact on thumb function (Graham and Waters 2001). Four categories are described. Type A fractures are extra-articular fractures of the shaft, usually in the proximal third of the metacarpal with a transverse or oblique orientation (Fig. 19.28). There is often apex lateral angulation, with medial impaction. Good remodelling can be expected due to the proximity to the physis. 

TypeD fractures are intra-articular Salter-Harris 111 or IV injuries of the proximal thumb metacarpal, resembling the adult Bennett s fracture (Fig. 19.32). These injuries are fortunately not common, as they can be very difficult to treat. Open reduction and internal fixation are often required... 

Fig. 19.28. Type A fracture ofthe thumb metacarpal proximal third...

Fig. 19.29. Type B fracture of the thumb metacarpal base with a medial metaphyseal spur...

Fig. 19.31. Type C fracture of the thumb metacarpal base, lateral view reveals marked displacement...

Fig. 19.32. Small Salter-Harris 111 fracture at the base of the thumb metacarpal, type D fracture...

Kozin SH (2006) Fractures and dislocations along the pediatric thumb ray. Hand Clin 22 19-29 Kramhoft M, Bodtker S (1988) Epidemiology of distal forearm fractures in Danish children. Acta Orthop Scand 59 557-559... 

The two-phase structure is critical to impact modification. Impact energy is absorbed during fracture when a propagating crack meets a rubbery domain and fracture energy is dispersed by deformation of the rubbery material (28). As a rule of thumb, an average particle size of about 1 pm must be achieved to provide low-temperature impact. 

Any fracture, other than to the fingers, thumbs or toes... 

Any fracture other than to fingers, thumbs or toes >- Any amputation... 

As already stated, the extensor pollicis longus tendon (third compartment of the extensor tendons) is a thin tendon that reflects over the medial aspert of the Lister tubercle before reaching the dorsum of the hand. Because of mechanical friction and its small size, the extensor poUicis longus is frequently affected by tenosynovitis that presents with local pain over the Lister tubercle and, less commonly, with local crepitus during thumb movements. This condition can be assodated with previous fractures of the distal radius... 

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