The development of the skeleton of the limbs of the horse

Ewart, J. C.

doi:10.1016/s0368-1742(94)80002-5

Cited by 7 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We find the horse distal forelimb shares features with that of an early horse embryo. Horse embryos at several stages (20, 50, 350 mm) show one, long, cylindrical dominant digit and two splint metacarpal digits, which commence as cartilaginous precursors that ultimately ossify [ 53 ]. Skeletal precursors are evident for digits II, III and IV, and are apparently absent for digits I and V; areas of apoptosis have been visualized surrounding digits II and IV [ 22 ].…”

Section: Discussionmentioning

confidence: 99%

The evolution and anatomy of the horse manus with an emphasis on digit reduction

et al. 2018

View full text Add to dashboard Cite

We revisit digit reduction in the horse and propose that all five digits are partially present in the modern adult forelimb. Osteological descriptions of selected tetradactyl, tridactyl and monodactyl equids demonstrate the evolution of the forelimb. Histological, osteological and palaeontological evidence suggest that the Equus distal forelimb is more complex than traditionally conceived. The current understanding is that the horse distal forelimb consists of one complete digit (III) and two reduced splint metacarpals (II and IV). Metacarpals II and IV each exhibit a ventral ridge, which we suggest represents the undifferentiated digits I and V. These ridges are present in the tridactyl Mesohippus, but are absent in the tetradactyl Hyracotherium. The carpal articulations of the five metacarpals match those of pentadactyl taxa. Distally, the frog, a V-shaped structure on the ventral hoof represents digits II and IV, and the wings and hoof cartilages of the distal phalanx are digits I and V. We relate this revised interpretation of the Equus forelimb to Laetoli footprints, and suggest the Hipparion side impressions are created from the hooves of I and V, rather than from II and IV. We show shades of pentadactyly within the Equus manus.

show abstract

Section: Discussionmentioning

confidence: 99%

The evolution and anatomy of the horse manus with an emphasis on digit reduction

et al. 2018

View full text Add to dashboard Cite

show abstract

“…EOM is a specialized muscle type that controls eyeball movement and differs from other skeletal muscles [16]. Muscular dystrophies rarely involve this group of muscles, suggesting their unique quality [17,18].…”

Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of Extraocular Muscle-Derived Muscle Progenitor Cells from Normal and Graves' Orbitopathy Patients

Park

Nepali

Lew

2020

Stem Cells and Development

View full text Add to dashboard Cite

Mesenchymal stem cells (MSCs) are useful for various purposes, including tissue engineering, regeneration, and gene therapy. MSCs isolated from extraocular muscles (EOMs) can be easily expanded in vitro, and can undergo multilineage differentiations involving adipogenesis, chondrogenesis, osteogenesis, and even neuronal or myogenic differentiation. This study aimed to isolate, characterize, and compare extraocular muscle-derived muscle progenitor cells (EOM-MPCs) from normal subjects and patients with Graves' orbitopathy (GO). EOM was obtained during strabismus surgery. Flow cytometry was conducted to identify CD surface antigens such as CD34, CD45, CD44, CD59, CD73, and CD90. We quantitated various cytokines secreted from MSCs, including interleukin (IL)-1a, IL-2, IL-6, IL-8, IL-10, IL-12, IL17A, tumor necrosis factor (TNF)-a, and interferon (IFN)-g, using a multi-analysis enzyme-linked immunosorbent assay array kit. We performed Oil Red O staining for adipogenesis, Alzarin Red staining for osteogenesis, Alcian blue staining for chondrogenesis, and polymerase chain reaction to measure messenger RNA expression during myogenesis. Our results show that EOM-MPCs from normal subjects and GO patients had similar levels of surface antigen expression and cytokine secretion. There was also no significant difference in the multilineage differentiation of adipocytes, chondrocytes, osteocytes, and myoblasts from EOM-MPCs taken from normal subjects and GO patients. However, hyaluronic acid synthetase 2 expression was higher after induction with tafluprost in EOM-MPCs from GO patients when compared with normal subjects. Together, these results show that EOM-MPCs derived from normal subjects are a good source for stem cell-based therapy for various disorders.

show abstract

“…Particularly wellknown examples of atavisms are the cases of naturally occurring supranumerary digits in horses (Ewart, 1894) and the induced production of teeth in chicks (Kollar and Fisher,'80). Four essential attributes that define atavistic characters are 1) "persistence into adult life," 2) "absence in the parents or recent ancestors," 3) "presence in one or only a few individuals within a population," and 4) "close resemblance to .…”

Section: Discussionmentioning

confidence: 99%

Atavisms and the homology of hyobranchial elements in lower vertebrates

Reilly

Lauder

1988

Journal of Morphology

View full text Add to dashboard Cite

The homology of branchial arch segments in salamanders has been a matter of controversy since the last century. Many investigators term the most medial paired elements of salamander branchial arches "ceratobranchials" and the next distal paired elements "epibranchials." This suggests that the first two segmental elements of the salamander branchial arch are not homologous with elements occupying the same position in ray-finned fishes, Latimeria, "rhipidistians," and lungfishes, in which these bones are called hypobranchials and ceratobranchials, respectively. Three lines of evidence suggest that it is more parsimonious to interpret urodele branchial arch segments as being homologous with those of other vertebrate clades-(1) comparative osteology, (2) comparative myology, and (3) the discovery of cartilaginous structures forming a third segmental unit that we interpret as atavistic epibranchials of the branchial arch in one population of the salamander Notophthalmus viridescens. These structures possess all the defining attributes of atavisms, and illustrate the special role that atavistic features play in resolving questions of homology recognition.

show abstract

The development of the skeleton of the limbs of the horse

Cited by 7 publications

References 0 publications

The evolution and anatomy of the horse manus with an emphasis on digit reduction

The evolution and anatomy of the horse manus with an emphasis on digit reduction

Isolation and Characterization of Extraocular Muscle-Derived Muscle Progenitor Cells from Normal and Graves' Orbitopathy Patients

Atavisms and the homology of hyobranchial elements in lower vertebrates

Contact Info

Product

Resources

About