Table 1 Two synergistic muscle groups reflected on the multivariate patterns among hand entheseal surfaces (21, 22).
MusclesPrimary function (16)Insertion site
analyzed (16, 21, 22)
Muscles coordinated for precision grasping using the thumb and
index finger (21, 5255)
Abductor pollicisAbducts the thumbRadial base of the first
proximal phalanx
Adductor pollicisAdducts the thumbUlnar base of the first
proximal phalanx
First dorsal
interosseus
Abducts the second
finger
Radial base of the
second proximal
phalanx
First palmar
interosseus
Draws the second finger
toward the third
finger
Ulnar base of the
second proximal
phalanx
Flexor pollicis brevisFlexes the first
metacarpophalangeal
joint
Radial base of the first
proximal phalanx
Opponens pollicisAbducts, rotates, and
flexes the thumb
Radial diaphysis of
the first metacarpal
Muscles coordinated for producing sustained power grasping (21, 5355)
Abductor digiti
minimi
Abducts the fifth fingerUlnar base of the fifth
proximal phalanx
Extensor carpi
ulnaris
Extends the wrist and
adducts hand
Ulnar base of the fifth
metacarpal
Extensor pollicis
brevis
Extends the thumbDorsal base of the first
proximal phalanx
Flexor digiti minimiFlexes the fifth fingerUlnar base of the fifth
proximal phalanx
Flexor pollicis
longus
Flexes the first distal
phalanx
Palmar diaphysis of the
first distal phalanx