Three developmental compartments involved in rib formation

Abstract

When the thoracic somitic mesoderm was separated from the neural tube and the notochord with a piece of aluminum foil in two-day chick embryos, seven days after the operation ribs lacked their proximal part. The embryos were rescued by co-transplanting the notochord, the ventral half of neural tube, or QT6 cells transformed with Shh, on the somite side of the aluminum foil insert. Thus, proximal rib development depends on the notochord and the ventral neural tube, an effect which might be mediated through Shh secreted by these axial tissues. On the other hand, when the thoracic somitic mesoderm was separated from the surface ectoderm by a piece of polyethylene terephthalate film, the distal parts of the ribs were missing, suggesting that distal rib development depends on surface ectoderm. In these embryos, expression of Pax3 was weak and perturbed showing that the dermomyotome developed abnormally. It is not clear whether the development of distal rib is mediated by the dermomyotome, or the ectoderm. It has previously been shown that sternal rib development depends on lateral plate mesoderm. As to the distal rib, it is considered to be composed of two parts. Thus, the rib is composed of three developmental compartments, in agreement with a recently presented classification of somite derivatives as primaxial and abaxial.

Expansion of the Rib Head: A Novel Computed Tomographic Feature of Supernumerary Intrathoracic Ribs

“…On the other hand, the development of distal parts of the ribs depends on the interaction between dorsal parts of sclerotomes and the surface ectoderm. During embryonic development, any abnormal signal that disturbs the interaction is believed to cause congenital anomalies of the rib [1]. As in our cases, the abnormal signal that results in supernumerary intrathoracic rib originating from the head or proximal part also causes some changes in parts that have the same embryonic origin.…”

“…They may originate from a vertebral body or the proximal or distal part of a rib. In most cases, they are asymptomatic, but they may be associated with developmental abnormalities of the ribs and vertebrae [1]. Diagnosis is important to prevent further investigation or intervention.…”

The relevance of the first ribs of the El Sidrón site (Asturias, Spain) for the understanding of the Neandertal thorax

“…Our results suggest they are smaller, possibly even below the modern human range [erroneously reported in preliminary findings of Bastir et al (2013a)]. Smaller ribs could also fit with reduced size of the thoracic vertebrae in Neanderthals (Gorjanovic Kramberger, 1906;Arensburg, 1991;Gómez-Olivencia et al, 2013a;Gómez-Olivencia et al, 2013b) accounting for their shared developmental background (Aoyama et al, 2005) and common function in the costo-vertebral joints (De Troyer et al, 2005).…”

Body wall morphogenesis: Limb-genesis interferes with body wall-genesis via its influence on the abaxial somite derivatives

“…This figure was drawn from the lateral view of eight-day-old chick embryo, right side. The ribs consist of three compartments based on their development (Aoyama et al, 2005): proximal rib (pr), vertebro-distal rib (vdr) and sterno-distal rib (sdr). The other terminology, except the intercostal muscles, follows that of Yasuda (2002): uncinate process of the rib (puc), vertebrae (vt), scapula (sc), coracoid (cr), sternum (st), ensiform process of sternum (ep), ilium (il), pubis (pb), ischium (is).…”