Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels
Material and methods: 51 anatomical specimens of non-human primates were dissected (18 embalmed, 33 fresh). The amplitudes of the medial cuneometatarsal and metatarsophalangeal articulations of the first ray of the foot of the various fresh pieces and those of 26 sleeping subjects have been measured...
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Société Francophone de Primatologie
2015-12-01
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| Series: | Revue de Primatologie |
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| Online Access: | https://journals.openedition.org/primatologie/2278 |
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| author | J Norbert Kuhlmann |
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| description | Material and methods: 51 anatomical specimens of non-human primates were dissected (18 embalmed, 33 fresh). The amplitudes of the medial cuneometatarsal and metatarsophalangeal articulations of the first ray of the foot of the various fresh pieces and those of 26 sleeping subjects have been measured. Many animals have been observed in semi-liberty or in wide aviaries. Also, 436 foot skeletons of primates have been measured and the measurements converted to a percentage relative to the length of the 3rd metacarpal, in order to compare them, despite their difference in size (collections of the Museum d’Histoire Naturelle of Paris)Results: The hallux column is always very developed and often twice longer than that of the pollex. The medial cuneometatarsal articulation offers a major vertical axis. That of Strepsirrhini is strongly concave/ convex. The convexity is seated on the major axis. That of the Simiiformes has a cuneal surface, which forms a dome, with a lateral cut-out. The dome is more prominent in the Catarrhini and Platyrrhini. It is very discreet in the Homo. The morphological and functional differences of the medial cuneometatarsal joint and the modes of hallucidigital prehension help classifying the primates in four categories that do not correspond exactly to the suborders or the parvorders.1) In the Loridae, the Indriidae and the Daubentoniidae, the articular surfaces are concave/ convex and congruent. The joint acts like a hinge, has only one degree of freedom, but a wide angle (125°) and allows only a laterolateral hallicidigital pinch. The fourth toe is the longest.2) In the Loridae and the Cheirogaleidae the articular surfaces are also concave/ convex and congruent, but the joint works like a cardan. It offers therefore two-degrees of freedom. An opposition with the two last toes is only obtained with a maximum opening of the first web space (90 degrees). Very long toes are necessary to obtain the terminoterminal hallucidigital pinch. The fourth is also the longest.3) In non-human Catarrhini, Pitheciinae and Cebinae (Platyrrhini), the articular surfaces are not congruent. A barrier is formed at the dorsal articular pole of the first metatarsus by the second metatarsus and by the anchoring of its base by a thick dorso-lateral cuneometatarsal ligament. It must now be bypassed to allow flexion or extension. Therefore, it forms a crucial pivot, determining a rotation of the first metatarsus, along its longitudinal axis, sometimes in pronation, sometimes in supination. There are three degrees of freedom. The extension and the abduction of the first metatarsus is 40 degrees. The tendon of the lateral fibular muscle acts powerfully on its flexion, but also on its pronation. The tendon of the abductor longus acts on its extension and supination. A wide transverse intermetacarpal ligament unites the first and the second ray of the foot of the Pitheciidae and the Cebinae, but it is very loose and does not hinder the opening of the hallux.4) In the Callitrichinae (Platyrrhini), like in Homosapiens, a particularly thick transversal inter metatarsal ligament in the first commissure unites the first and the second metatarsus and prevents the opposition of the hallux to the other toes. The metatarsophalangeal joint is condylar and relatively unstable. Such instability prohibits fine pinch force. The hyperextension of the joint allows, to a certain degree, to correct the lack of mobility of the cuneometatarsal joint. The length of the four last toes is inversely proportional to the number of degrees of liberty of the cuneometatarsal joint. The longest toe in the Strepsirrhini is the fourth, the one that can realize an halluci-digital termino-terminal pinch. The toes of the Platyrrhini are also long, the third is the longest. The toes of the non-human Catarrhini are shorter. That of the Homosapiens is still much shorter. The second is the longest.Consequences:The morphological and functional differences have been compared to those of the hand. They influence the arboreal and terrestrial walk, analyzed in this article. They are the landmarks, which allow imagining the different stages of the evolution of non-human primates to Homosapiens. The presence of a transverse intermetatarsal ligament between the first and the second ray of the foot of the Platyrrhini and of the Homo is not in favor of the theory of a divergent primitive hallux. It suggests rather that the origin of the human lineage is much more ancient than it is usually thought. |
| format | Article |
| id | doaj-art-9039c715b862429681438f13cc4ad486 |
| institution | Kabale University |
| issn | 2077-3757 |
| language | English |
| publishDate | 2015-12-01 |
| publisher | Société Francophone de Primatologie |
| record_format | Article |
| series | Revue de Primatologie |
| spelling | doaj-art-9039c715b862429681438f13cc4ad4862025-01-30T10:02:05ZengSociété Francophone de PrimatologieRevue de Primatologie2077-37572015-12-01610.4000/primatologie.2278Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuelsJ Norbert KuhlmannMaterial and methods: 51 anatomical specimens of non-human primates were dissected (18 embalmed, 33 fresh). The amplitudes of the medial cuneometatarsal and metatarsophalangeal articulations of the first ray of the foot of the various fresh pieces and those of 26 sleeping subjects have been measured. Many animals have been observed in semi-liberty or in wide aviaries. Also, 436 foot skeletons of primates have been measured and the measurements converted to a percentage relative to the length of the 3rd metacarpal, in order to compare them, despite their difference in size (collections of the Museum d’Histoire Naturelle of Paris)Results: The hallux column is always very developed and often twice longer than that of the pollex. The medial cuneometatarsal articulation offers a major vertical axis. That of Strepsirrhini is strongly concave/ convex. The convexity is seated on the major axis. That of the Simiiformes has a cuneal surface, which forms a dome, with a lateral cut-out. The dome is more prominent in the Catarrhini and Platyrrhini. It is very discreet in the Homo. The morphological and functional differences of the medial cuneometatarsal joint and the modes of hallucidigital prehension help classifying the primates in four categories that do not correspond exactly to the suborders or the parvorders.1) In the Loridae, the Indriidae and the Daubentoniidae, the articular surfaces are concave/ convex and congruent. The joint acts like a hinge, has only one degree of freedom, but a wide angle (125°) and allows only a laterolateral hallicidigital pinch. The fourth toe is the longest.2) In the Loridae and the Cheirogaleidae the articular surfaces are also concave/ convex and congruent, but the joint works like a cardan. It offers therefore two-degrees of freedom. An opposition with the two last toes is only obtained with a maximum opening of the first web space (90 degrees). Very long toes are necessary to obtain the terminoterminal hallucidigital pinch. The fourth is also the longest.3) In non-human Catarrhini, Pitheciinae and Cebinae (Platyrrhini), the articular surfaces are not congruent. A barrier is formed at the dorsal articular pole of the first metatarsus by the second metatarsus and by the anchoring of its base by a thick dorso-lateral cuneometatarsal ligament. It must now be bypassed to allow flexion or extension. Therefore, it forms a crucial pivot, determining a rotation of the first metatarsus, along its longitudinal axis, sometimes in pronation, sometimes in supination. There are three degrees of freedom. The extension and the abduction of the first metatarsus is 40 degrees. The tendon of the lateral fibular muscle acts powerfully on its flexion, but also on its pronation. The tendon of the abductor longus acts on its extension and supination. A wide transverse intermetacarpal ligament unites the first and the second ray of the foot of the Pitheciidae and the Cebinae, but it is very loose and does not hinder the opening of the hallux.4) In the Callitrichinae (Platyrrhini), like in Homosapiens, a particularly thick transversal inter metatarsal ligament in the first commissure unites the first and the second metatarsus and prevents the opposition of the hallux to the other toes. The metatarsophalangeal joint is condylar and relatively unstable. Such instability prohibits fine pinch force. The hyperextension of the joint allows, to a certain degree, to correct the lack of mobility of the cuneometatarsal joint. The length of the four last toes is inversely proportional to the number of degrees of liberty of the cuneometatarsal joint. The longest toe in the Strepsirrhini is the fourth, the one that can realize an halluci-digital termino-terminal pinch. The toes of the Platyrrhini are also long, the third is the longest. The toes of the non-human Catarrhini are shorter. That of the Homosapiens is still much shorter. The second is the longest.Consequences:The morphological and functional differences have been compared to those of the hand. They influence the arboreal and terrestrial walk, analyzed in this article. They are the landmarks, which allow imagining the different stages of the evolution of non-human primates to Homosapiens. The presence of a transverse intermetatarsal ligament between the first and the second ray of the foot of the Platyrrhini and of the Homo is not in favor of the theory of a divergent primitive hallux. It suggests rather that the origin of the human lineage is much more ancient than it is usually thought.https://journals.openedition.org/primatologie/2278primatesanatomyfunctionfirst cuneometatarsal jointmetatarsophalangeal jointphylogeny. |
| spellingShingle | J Norbert Kuhlmann Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels Revue de Primatologie primates anatomy function first cuneometatarsal joint metatarsophalangeal joint phylogeny. |
| title | Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels |
| title_full | Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels |
| title_fullStr | Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels |
| title_full_unstemmed | Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels |
| title_short | Contribution à l’étude de la mobilité de l’hallux et de la phylogénie des primates actuels |
| title_sort | contribution a l etude de la mobilite de l hallux et de la phylogenie des primates actuels |
| topic | primates anatomy function first cuneometatarsal joint metatarsophalangeal joint phylogeny. |
| url | https://journals.openedition.org/primatologie/2278 |
| work_keys_str_mv | AT jnorbertkuhlmann contributionaletudedelamobilitedelhalluxetdelaphylogeniedesprimatesactuels |