nerves to the arm & forearm-->they are the median , the ulnar , the radial , the musculocutaneous nerves
effects of their injury are :
the median nerve --> causes ape hand deformity
the ulnar nerve --> causes claw hand
the radial nerve --> causes wrist , finger drop
the musculocutaneous nerve --> causes paralysis in coracobrachialis, brachialis & biceps along with sensory nerve in lateral part of forearm( by affecting lateral cutaneuos nerve of forearm )
all of these nerves and more are branches of the cords of brachial plexus --> which are formed of anterior rami of C5,C6,C7,C8,T1 nerves , which are considered the roots of the brachial plexus
the injury of brachial plexus ( level of c5,c6,c7) causes erb's palsy --> also called porter tip's paralysis
and injury at level of ( c8,T1 ) is known as klumpke's palsy