[The first ray of the hand and the foot of the primates (I). Descriptive anatomy].

Dissection of the first ray and the connecting structures of the hand and the foot of simian primates, conserved by freezing or embalming and observation of 325 skeletal pieces of specimens of the Museum of Natural History of Paris. The trapezometacarpal articulation is a saddle joint with a trapezial concavity according to its great oblique axis directed at 45 degrees with respect to a sagittal plan for the whole of the simian primates, with a trapezoidal concavity according to a great axis directed in a sagittal plan for the loridae, the galagonidae and the daubentonidae and with a counter fort supported by a mediopalmar apophysis or a sesamoid bone for the lemurpides. The whole of the mediopalmar ligaments is inserted distally on the medial tubercle at the basis of the first metacarpus. This insertion was fibrocartilaginous for the gorilla. The mediopalmar ligaments are very more developed than the laterodorsal ligaments in all the hominidae and the catarhinious. The both groups are equivalent for the platyrhinious and the prosimious. An intracapsular ligament may reinforce the laterodorsal by the lemoridae. The cuneometatarsal articulation presents a sagittal great axis. It was in fact a spiral trochoid joint with a cuneiform convexity in all the simian primates except for the humans. In this late case, the articular surface was less high, more narrow, with less marked relief. The form of this articulation is that of a saddle with a sagittal concavity in the prosimious with a strong lateral and palmar cuneiform tuberosity and a big lateral opposite apophysis at the basis of the first metatarsus. The tendon of the long lateral fibular muscle and one fascicle of the tendon of the anterior tibialis is fixed on the both side of the basis of the first metatarsus, except for human beings in which the tendon was undivided and was principally inserted of the navicular bone. The disposition of the cuneometatarsal ligaments is similar to that of the trapezometacarpal ligaments. The distal insertions of the lateral ligaments are fibrocarlilaginous in the cerpopithecidae. All the metacarpophalangeal and metatarsophalangeal are condylar, except for the metacarpophalangeal of the humans which looks like bicondylar; the interphalangeal articulations are bicondylar. The ligamentous devices include the glenoidal and collateral ligaments with their metacarpal- and metatarsophalangeal fascicles and their interphalangeal and phalangeoglenoidal fascicles.