muscles of thenar and hypothenar

muscles of thenar and hypothenar
Short Muscles of the Thumb
The short muscles of the thumb are the abductor pollicis
brevis, the flexor pollicis brevis, the opponens pollicis, and
the adductor pollicis (Figs. 9.59, 9.62, and 9.67). The first
three of these muscles form the thenar eminence.
Opposition of the Thumb
It should be noted that the opponens pollicis muscle pulls
the thumb medially and forward across the palm so that
the palmar surface of the tip of the thumb may come into
contact with the palmar surface of the tips of the other fingers.
It is an important muscle and enables the thumb to
form one claw in the pincer-like action used for picking
up objects. This complex movement involves a flexion of
the carpometacarpal and metacarpophalangeal joints and
a small amount of abduction and medial rotation of the
metacarpal bone at the carpometacarpal joint.
Abduction of the Thumb
Abduction of the thumb may be defined as a movement
forward of the thumb in the anteroposterior plane. It
takes place at the carpometacarpal joint and the metacarpophalangeal
joint.
Adduction of the Thumb
This movement can be defined as a movement backward
of the abducted thumb in the anteroposterior plane.
It restores the thumb to its anatomic position, which is flush
with the palm. The adductor pollicis is the muscle
that, in
association with the flexor pollicis longus and the opponens
pollicis muscles, is largely responsible for the power of the
pincers grip of the thumb. Adduction of the thumb occurs
at the carpometacarpal and at the metacarpophalangeal