Dorsal tubercle

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Dorsal tubercle

Immediately following his regeneration, the Tenth Doctor noted a "slight weakness" in the dorsal tubercle of his right hand. (TV: Born Again) Less than 15 hours later, it was this hand which was cut off by a sword wielded by Fadros Pallujikaa, with the Doctor using his residual regenerative energy to grow a new one. (TV: The Christmas Invasion)