The metacarpal is adducted, its head forming a marked prominence on the front of the thenar eminence, and the phalanges are displaced backwards, the proximal being dorsiflexed and the distal flexed towards the palm.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson
The paralysis is most marked in the muscles of the thumb, and becomes less towards the ulnar side; the affected muscles atrophy, especially those forming the thenar eminence, and the finer movements of the thumb and fingers are impaired.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson
Muscles of the Hand We will first recall that, in man, the palm of the hand is divided into three regions: a median palmar region, which is occupied by the tendons of the flexors of the digits, the lumbricales, and, deeply, by the interosseous muscles; an external region, or thenar eminence, formed by the muscles destined for the movements of the thumb; an internal region, or hypothenar eminence, which contains the muscles proper to the small digit and the palmar cutaneous muscle.
"Artistic Anatomy of Animals"
Édouard Cuyer