Which of the following parts of the brachial plexus is involved in Klumpke's paralysis?

Ans. C. Lower trunkKlumpke's paralysis - It is caused by the hyperabduction of the arm, which may occur when one falls on an outstretched hand or an arm is pulled into machinery or during delivery (extended arm in a breech presentation).It involves the lower trunk of brachial plexus. The nerve roots involved in this injury are C8 and T1 and sometimes C7 .The clinical features are as follows: -Claw hand, due to paralysis of the flexors of the wrist and fingers (C6 ,C7 , and C8 ), and all intrinsic muscles of the hand (C8 and T1 ).a. Loss of sensations along the medial border of the forearm and hand (T1 ).b. Horner's syndrome, (characterized by partial ptosis, miosis, anhydrosis, and enophthalmos) due to involvement of sympathetic fibres supplying head and neck, which leave the spinal cord through T1 .