Surgical Anatomy--FRACTURE OF LOWER END OF RADIUS: _Colles" fracture_; _Chauffeur"s fracture_; _Smith"s fracture_; _Longitudinal fracture_; _Separation of epiphysis_--FRACTURE OF LOWER END OF ULNA: _Shaft_; _Styloid process_; _Separation of epiphysis_--FRACTURE OF CARPAL BONES--DISLOCATION: _Inferior radio-ulnar joint_; _Radio-carpal joint_; _Carpal bones_; _Carpo-metacarpal joint_--SPRAINS--INJURIES OF FINGERS: _Fractures_; _Dislocations_; _Mallet finger_.
INJURIES IN THE REGION OF THE WRIST
These include fractures of the lower ends of the bones of the forearm and separation of their epiphyses; sprains and dislocations of the inferior radio-ulnar, and of the radio-carpal articulations; and fractures and dislocations of the carpus.
#Surgical Anatomy.#--The most important landmarks in the region of the wrist are the styloid processes of the radius and ulna. The tip of the radial styloid is palpable in the "anatomical snuff-box" between the tendons of the long and short extensors of the thumb, and it lies about half an inch lower than the ulnar styloid. The ulnar styloid is best recognised on making deep pressure a little below and in front of the head of the ulna, which forms the rounded subcutaneous prominence seen on the back of the wrist when the hand is p.r.o.nated.
The tubercle of the navicular (scaphoid) and the greater multangular (trapezium) can be felt between the radial styloid and the ball of the thumb, a little below the radial styloid; and the pisiform and hook of the hamatum (unciform) are palpable, slightly below and in front of the ulnar styloid.
In examining an injured wrist, the different bony points should be located, and their relative positions to one another and to the adjacent joints noted; and the shape, position, and relations of any unnatural projection or depression observed, using the wrist on the other side as the normal standard for comparison. The power and range of movement--active and pa.s.sive--at the various joints should also be tested.
FRACTURE OF THE LOWER END OF THE RADIUS
#Colles" Fracture.#--This injury, which was described by Colles of Dublin in 1814, is one of the commonest fractures in the body, and is especially frequent in women beyond middle age. It is almost invariably the result of a fall on the palm of the hand, in the three-quarters p.r.o.nated position, the force being received on the ball of the thumb, and transmitted through the carpus to the lower end of the radius which is broken off, the lower fragment being driven backwards.
The fracture takes place through the cancellated extremity of the bone, within a half to three-quarters of an inch of its articular surface (Fig. 45). It is usually transverse, but may be slightly oblique from above downwards and from the radial to the ulnar side. In a considerable proportion of cases it is impacted, and not infrequently the lower fragment is comminuted, the fracture extending into the radio-carpal joint.
[Ill.u.s.tration: FIG. 43.--Colles" Fracture showing radial deviation of hand.]
[Ill.u.s.tration: FIG. 44.--Colles" Fracture showing undue prominence of ulnar styloid.]
When impaction takes place, it is usually reciprocal, the dorsal edge of the proximal fragment piercing the distal fragment, and the palmar edge of the distal fragment piercing the proximal. The periosteum is usually torn and stripped from the palmar aspect of the fragments, while it remains intact on the dorsum.
In the majority of cases the styloid process of the ulna is torn off by traction exerted through the medial ulno-carpal (internal lateral) ligament, and in a considerable proportion there is also a fracture of one of the carpal bones.
The resulting _displacement_ is of a threefold character: (1) the distal fragment is displaced backwards; (2) its carpal surface is rotated backwards on a transverse diameter of the forearm; while (3) the whole fragment is rotated so that the radial styloid comes to lie at a higher level than normal.
[Ill.u.s.tration: FIG. 45.--Radiogram showing the line of fracture and upward displacement of the radial styloid in Colles" Fracture.]
_Clinical Features._--In a typical case there is a prominence on the dorsum of the wrist, caused by the displaced distal fragment, with a depression just above it (Fig. 43); and the wrist is broadened from side to side. The natural hollow on the palmar aspect of the radius is filled up by the projection of the proximal fragment. The carpus is carried to the radial side by the upward rotation of the distal fragment, and the radial styloid is as high, or even higher, than that of the ulna. The lower end of the ulna is rendered unduly prominent by the flexion of the hand to the radial side. The fingers are partly flexed and slightly deviated towards the ulnar side; and the patient supports the injured wrist in the palm of the opposite hand, and avoids movement of the part. Occasionally the median nerve is bruised or torn, causing motor and sensory disturbances in its area of distribution.
The general outline of the wrist and hand has been compared not inaptly to that of "an inverted spoon." p.r.o.nation and stipulation are lost, the joint is swollen, and there is tenderness on pressure, especially over the line of fracture. Tenderness over the position of the ulnar styloid may indicate fracture of that process, although it is sometimes present without fracture. No attempt should be made to elicit crepitus in a suspected case of Colles" fracture as the manipulations are painful, and are liable to increase the displacement.
_Treatment._--It cannot be too strongly insisted upon that success in the treatment of Colles" fracture with displacement and impaction depends chiefly upon complete and accurate reduction, and to enable this to be effected a general anaesthetic is almost essential. The surgeon grasps the patient"s hand, as if shaking hands with him, and, resting the palmar surface of the wrist on his bent knee, makes traction through the hand, and counter-extension through the forearm, with lateral movements, if necessary, to undo impaction. When the fragments are freed from one another, the wrist is flexed, and the hand carried to the ulnar side, while the lower fragment is moulded into position by the thumb of the surgeon"s disengaged hand. When reduction is complete, the deformity disappears, and the two styloid processes regain their normal positions relative to one another.
As there is no tendency to re-displacement and no risk of non-union, no retentive apparatus is required, but, if it adds to the patient"s sense of security, a bandage or a poroplastic wristlet may be applied.
In severe cases, however, anterior and posterior splints, similar to those used for fracture of both bones of the forearm, or a dorsal splint padded so as to flex the wrist to an angle of 45, but somewhat narrower, may be employed. The hand and forearm are in any case supported in a sling.
To avoid the stiffness that is liable to follow, ma.s.sage and movement of the wrist and fingers should be carried out from the first, the range of movement being gradually increased until the function of the joints is perfectly restored. If splints are used, they should be discarded in a week, and the patient is then encouraged to use the wrist freely.
The various special splints recommended for the treatment of Colles"
fracture, such as Carr"s, Gordon"s, the "pistol splint," and many others, are all designed to correct the deformity as well as to control the fragments. It has already been pointed out that if reduction is complete there is no deformity to correct, and if it is not complete the deformity cannot be corrected by any form of splint.
_Unreduced Colles" Fracture._--When union has been allowed to take place without the displacement having been reduced, an unsightly deformity results. In young subjects whose occupation is likely to be interfered with, and in women for aesthetic reasons, the fracture is reproduced and the displacement of the lower fragment corrected. This is conveniently done by means of Jones" wrench, which grasps the distal fragment and affords sufficient leverage to break the bone.
#Chauffeur"s Fracture.#--A fracture of the lower end of the radius frequently occurs from the recoil of the crank, "by back firing," in starting the engine of a motor-car. The injury may be produced either by direct violence, the handle as it recoils striking the forearm, or by indirect violence, from forcible hyper-extension of the hand while grasping the handle. The fracture may pa.s.s transversely through the lower end of the radius, as in Colles" fracture, but is more often met with two or three inches above the wrist (Fig. 46). It is treated on the same lines as Colles" fracture.
[Ill.u.s.tration: FIG. 46.--Radiogram of Chauffeur"s Fracture.]
A fracture of the lower end of the radius _with forward displacement of the carpal fragment_, was first described by R. W. Smith of Dublin (_Colles" fracture reversed_, or #Smith"s fracture#) (Fig. 47). It is nearly always due to forcible flexion, as from a fall on the back of the hand. Like Colles" fracture, it may be transverse or slightly oblique, impacted, or comminuted. The deformity is characterised by an elevation on the dorsum running obliquely upwards from the ulnar to the radial side of the wrist, and caused by the head of the ulna, which remains in position, and the distal end of the proximal fragment. Below this, over the position of the distal radial fragment, is a gradual slope downwards on to the dorsum of the hand. Anteriorly there is a prominence in the flexure of the wrist, and the distal fragment may be felt under the flexor tendons. The hand deviates to the radial side, and thereby still further increases the prominence caused by the lower end of the ulna. The radial styloid is displaced forward, upward, and to the radial side, and the ulnar styloid may be torn off.
[Ill.u.s.tration: FIG. 47.--Radiogram of Smith"s Fracture.
(Sir George T. Beatson"s case.)]
When the deformity is not well marked, this injury may be mistaken for forward dislocation of the wrist, for fracture of both bones low down, or for sprain of the joint.
The _treatment_ is carried out on the same lines as in Colles"
fracture.
_Longitudinal fractures_ of the lower end of the radius opening into the joint usually result from the hand being crushed by a heavy weight or in machinery. They are often compound and comminuted.
#Separation of the lower epiphysis# of the radius, which is on the same level as that of the ulna and lies above the level of the synovial membrane of the wrist-joint, is comparatively common between the ages of seven and eighteen, especially in boys, and is caused by the same forms of violence as produce Colles" fracture.
Although clinically the appearances in these two injuries bear a general resemblance to one another, separation of the epiphysis may usually be identified by the directly transverse line of the dorsal and palmar projections, the folding of the skin observed in the palmar depression, the absence of abduction of the hand and the ease with which m.u.f.fled crepitus can be elicited (E. H. Bennett). The deformity is readily reduced, and the fragments are easily retained in position.
This injury is often complicated with fracture of the shaft or styloid process of the ulna, or with dislocation of the radio-ulnar joint, and it is not infrequently compound, the lower end of the shaft being driven through the skin on the palmar aspect immediately above the wrist. Impairment of growth in the radius seldom occurs; when it does, it results in a valgus condition of the hand (Fig. 48), calling for resection of the lower end of the ulna.
[Ill.u.s.tration: FIG. 48.--Ma.n.u.s Valga following separation of lower radial epiphysis in childhood.
(Mr. H. Wade"s case.)]
The _treatment_ is the same as for Colles" fracture.
#Fracture of the Lower End of the Ulna.#--The lower end of the _shaft_ of the ulna is seldom fractured alone. The _styloid process_, as has already been pointed out, is frequently broken in a.s.sociation with Colles" and other fractures of the lower end of the radius.
Separation of the _lower epiphysis_ of the ulna sometimes occurs, and in rare cases results in arrest of the growth of the bone, leading to a varus condition of the hand and bending of the radius. Sometimes the separated epiphysis fails to unite, and although this gives rise to no disability, it is liable to lead to errors in the interpretation of skiagrams.
The _treatment_ is similar to that for the corresponding injuries of the radius.
Simultaneous separation of the _epiphysis of both radius and ulna_ sometimes occurs, and, as a result of severe violence, may be compound, the lower ends of the diaphyses projecting through the skin on the palmar aspect above the wrist.
#Fracture of Carpal Bones.#--The use of the Rontgen rays has shown that fracture of individual carpal bones is commoner than was previously supposed, and that many cases formerly looked upon as severe sprains are examples of this injury.
The _navicular_ (scaphoid) and _lunate_ (semilunar) are those most commonly fractured, usually by indirect violence, by forced dorsiflexion from a fall on the extended hand. The clinical features are: localised swelling on the radial side of the wrist, increase in the antero-posterior diameter of the carpus, marked tenderness in the anatomical snuff-box when the hand is moved laterally, especially in the direction of adduction, and, rarely, crepitus. The median nerve is sometimes over-stretched or partly torn. In many cases, however, the symptoms are so obscure that an accurate diagnosis can only be made by the use of the X-rays (Fig. 49). Codman recommends taking pictures of the navicular by placing the two wrists of the patient in adduction, and of the lunate, in abduction.
[Ill.u.s.tration: FIG. 49.--Radiogram showing Fracture of Navicular (Scaphoid) Bone.]
The _treatment_ of simple fractures consists in ma.s.sage and movement.
Codman and Chase recommend excision of the proximal half of the fractured bone, through a dorsal incision to the lateral side of the extensor digitorum communis. When the fracture is compound, the loose fragments should be removed.
DISLOCATIONS IN THE REGION OF THE WRIST
Dislocation may occur at the inferior radio-ulnar, the radio-carpal, mid-carpal, inter-carpal, or carpo-metacarpal joints, but the strong ligaments of these articulations, the comparatively free movement at the various joints, and the relative weakness of the lower end of the radius whereby it is so frequently fractured, render dislocation a rare form of injury.
Dislocation of the #inferior radio-ulnar# articulation may complicate fracture of the lower end of the radius, or accompany sub-luxation of the head of the radius. The head of the ulna usually pa.s.ses backward.