Klumpke's palsy is due to injury to the following nerves?

The upper trunk (C5 and C6) is the most common area injured and results in the classic Erb palsy. Injury to the lower trunk (C7-T1) produces a Klumpke palsy. Klumpke palsy is characterized by good shoulder function but decreased or absent hand function. Brachial plexus injuries may also cause a Horner syndrome (unilateral miosis, ptosis, and facial anhidrosis) due to disruption of cervical sympathetic nerves.