Erb's paralysis : brief and easy handout

Erb’s paralysis : it is also known as upper trunk plexus injury.

Cause of injury:  Upper trunk is ruptured due to forceful widening of the angle between the head and shoulder . traction of the arm during child birth and or by fall on the shoulder causes widening of angle between the head and shoulder. The root value of upper trunk is C5,6 .

In this paralysis, nerve roots involved: Mainly C5 and partly C6.

Muscles paralysed: Mainly biceps, deltoid,brachilais and brachioradialis.Partly supraspinatus, infraspinatus and supinator

Deformity: The deformity is known as "Policeman's tip hand" or "Porter's tip hand".

Loss of function:

Motor loss:

Arm: Hangs by the side, it is adducted due to paralysis of deltoid muscle. It is also medially rotated due to paralysis of supraspinatus, infraspinatus  and teres minor muscles

Forearm: Extended and pronated due to paralysis of biceps brachii.

Sensory loss:

The sensory loss of this clinical condition is minimal, only along the outer aspect of arm due to involvement of roots of C6 spinal nerve.