title: Functional anatomy of the radial sesamoid bone in the giant panda (Ailuropoda melanoleuca).
abstract: The function of the radial sesamoid bone (RS) in the giant panda (Ailuropoda melanoleuca) was examined by macroscopic study of RS-related bones and muscles. The RS was observed to be connected to the scapholunar and the 1st metacarpal bones. A joint cavity was present between the proximal surface of the RS and the distal area of the scapholunar bone but the RS possessed a fibrous joint connecting it to the proximal radial surface of the 1st metacarpal bone. It is suggested that the RS possesses no substantial abductor-adductor function as the articulation between the RS and the 1st metacarpal bone (FM) seems not to permit flexible movement of the RS. The RS may be a supporting process opposite the digits in the palm when the animal flexes its 5 digits to grip objects, but it is not an active grasping apparatus. In the muscular system, abductor pollicis longus provided strong tendons to the RS as an RS-abductor, whereas the abductor pollicis brevis, opponens pollicis and aponeurosis palmaris were well developed as an RS-adductor muscle group. Observation of RS articulations, however, showed that the muscles do not provide appreciable abduction-adduction actions for the RS.
authors.affiliation: Department of Zoology, National Science Museum, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Endo
authors.forename: N
authors.initials: N
authors.lastname: Sasaki
authors.forename: D
authors.initials: D
authors.lastname: Yamagiwa
authors.forename: Y
authors.initials: Y
authors.lastname: Uetake
authors.forename: M
authors.initials: M
authors.lastname: Kurohmaru
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D002335:Carnivora / Q000033:anatomy & histology* / Q000502:physiology; D005552:Forelimb; D007596:Joints / Q000033:anatomy & histology / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology; D012716:Sesamoid Bones / Q000033:anatomy & histology* / Q000502:physiology