Fracture of the Shaft of the usually occurs below the middle of the bone. Falls on the hand or elbow are frequent causes. The fracture may be across or aslant, and presents all the usual signs of fracture, un natural mobility, deformity, loss of function, and crepitation when the ends are brought into contact with one another. The displacement is effected by muscular action drawing the lower fragment to the inner side. Riding is also pre sent, and shortening.
The Treatment (Fig. 37) is practically the same as that for fractures of the upper end.
The outer splint, however, need not go over the shoulder, but where the break is in the neighbourhood of the lower end it may be moulded round the elbow.
Fractures of the Lower End of the Arm are various kinds of fracture in this region. In one form there is a break across just above the joint; in ;mother the ture extends into the joint, the break ing both across the bone and running down Fracture.
Kind of fall—fall on elbow.
Projection behind of great mass, consisting of olecra non process or ulna grasping condyles of arm-bone. Projection in front — small, broken end of shaft, not pushed deep down into elbow.
Motion increased.
Crepitation (grating) present on extension.
Length of upper arm shortened.
Length of forearm increased.
Reduction easy and not permanent.
Treatment for this fracture is also similar to that described under fractures of upper end of humerus, the outer splint being here moulded round the elbow-joint behind. The prominences of the joint should be carefully padded. The passive movement of the joint should be begun in about three weeks.
Splitting of the Condyles (p. 62) may be easily recognized by causing the elbow to be bent and stuck out behind. Then stand behind the middle into the joint, so as to separate the processes, or condyles, that project on each side, front one another; while in a third form the epiphysis—the end not yet united to the shaft —is separated from the rest of the bone. A fall upon the elbow will readily produce this fracture.
Signs.—Deformity—the bones of the fore arm, with the lower fragment., are, by muscles at the back of the arm, pulled upwards behind the upper fragment which projects in front, the two fragments riding on one another. The size of the joint from behind forwards is thus greatly increased and changed in shape, as may be seen by comparison with the arm of the other side. The projection in front is found to
have a ragged edge, and the measurement from the top of the shoulder to the end of the arm bone is less on the injured than on the sound side. On the other hand, the measurement front the knuckle of the middle finger to the end of the lump behind the upper arm is greater than the measurement of the forearm bones on the sound side, because to the forearm bones is added the length of the lower fragment retained in their grasp. Let an assistant hold the upper arm, let the operator place his knee in the elbow, grasp the wrist and pull the forearm round his knee. This easily reduces the fracture, and when it is reduced grating can be felt. As soon as the wrist is let go, the deformity returns. This is a fracture liable to be mistaken for dis location at the elbow-joint. The differences are shown in the following table:— Dislocation.
Kind of fall—fall on hand, arm being bent Projection behind—olecranon alone.
Projection In front—articulating end of humerus—con dyles—pushed far down.
Motion diminished.
Crepitation absent.
Length of upper arm nat [watt Length of forearm normal. Reduction difficult, but permanent.
the patient and place one thumb on the projec tion of the humerus on one side, and the other thumb on the condyle of the other side, and press. If the condyles move on one another, splitting has occurred. The treatment is as above; or the joint may be entirely surrounded by a mould.
Fractures of the Forearm occur at the upper end, or at the shaft of radius or ulna (p. 62), or of both together, and at the lower end.
Fracture of the Olecranon (p. is the fracture that occurs at the upper end, the olecranon being the process of the ulna that grasps the arm-bone behind, and forms the point of the elbow or " funny-bone." It is usually due to a fall on the elbow.
Signs.—It is easily distinguished. The chief muscle of the back of the arm—the triceps—is attached at its lower end to this process, and consequently when the connection between the ulna and the olecranon is severed the triceps has nothing to oppose it and pulls the point of the elbow up on the back of the upper arm. The point of the elbow is, therefore, gone, and a hollow is in its place. The person can bend the arm, but has great pain and inability to straighten it. The olecranon can be felt up in its unusual position and can be pushed down.