subclavian artery, and the nerves are sought for
as they emerge from under cover of the scalenus anterior, and are then
traced until the seat of injury is found. In the case of the first
dorsal nerve, it may be necessary temporarily to resect the clavicle.
The usual after-treatment must be persisted in until recovery ensues,
and care must be taken that the paralysed muscles do not become
over-stretched. The prognosis is less favourable in the supra-clavicular
lesions than in those below the clavicle, which nearly always recover
without surgical intervention.

In the _brachial birth-paralysis_ met with in infants, the lesion is due
to over-stretching of the plexus, and is nearly always of the
Erb-Duchenne type. The injury is usually unilateral, it occurs with
almost equal frequency in breech and in vertex presentations, and the
left arm is more often affected than the right. The lesion is seldom
recognised at birth. The first symptom noticed is tenderness in the
supra-clavicular region, the child crying when this part is touched or
the arm is moved. The attitude may be that of the Erb-Duchenne type, or
the whole of the muscles of the upper limb may be flaccid, and the arm
hangs powerless. A considerable proportion of the cases recover
spontaneously. The arm is to be kept at rest, with the affected muscles
relaxed, and, as soon as tenderness has disappeared, daily massage and
passive movements are employed. The reaction of degeneration can rarely
be satisfactorily tested before the child is three months old, but if it
is present, an operation should be performed. After operation, the
shoulder should be elevated so that no traction is exerted on the
affected cords.

#The long thoracic nerve# (nerve of Bell), which supplies the serratus
anterior, is rarely injured. In those whose occupation entails carrying
weights upon the shoulder it may be contused, and the resulting
paralysis of the serratus is usually combined with paralysis of the
lower part of the trapezius, the branches from the third and fourth
cervical nerves which supply this muscle also being exposed to pressure
as they pass across the root of the neck. There is complaint of pain
above the clavicle, and winging of the scapula; the patient is unable to
raise the arm in front of the body above the level of the shoulder or to
perform any forward pushing movements; on attempting either of these the
winging of the scapula is at once increased. If the scapula is comp