The pneumatization of the humerus in the common fowl and the associated activity of theelin

Bremer, John Lewis

doi:10.1002/ar.1090770209

Cited by 33 publications

(34 citation statements)

References 17 publications

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“…D and E were prepared as barium-latex preparations (modified protocol from Sedlmayr and Witmer, 2002) studies on birds with pneumatic postcrania reveal that nutrient vessels share (i.e., co-occupy) foramina with pneumatic diverticula to gain access to the medullary space (e.g., Gallus gallus, OUVC 9419, 9420; Stuthio camelus, OUVC 9665). This is consistent with observations that diverticula of the pulmonary system first gain access to the interior of bones by utilizing preexisting vascular foramina (e.g., Bremer, 1940b).…”

Section: Osteological Correlates Of Different Soft-tissue Systemssupporting

confidence: 91%

“…Prominent vertebral fossae pierced by foramina result from invasion of bone by pneumatic diverticula. Diverticula, lined with simple cuboidal to columnar epithelium, pass through the cortical surface and spread throughout the medullary space (Bremer, 1940b;Hogg, 1984a). The bony morphology resulting from diverticular invasion varies enormously in shape, size, and texture ( Fig.…”

Section: Osteological Correlates Of Different Soft-tissue Systemsmentioning

confidence: 99%

“…It is also common in birds for distinct diverticular networks to anastomose with one another, such that those pneumatizing neural arches are continuous with those of the centra. The exact mechanism by which pneumatic diverticula induce bone resorption and interact with one another within a given bone requires further study (e.g., Bremer, 1940b;Ikarashi et al, 1996;Hönig et al, 2002).…”

Section: Osteological Correlates Of Different Soft-tissue Systemsmentioning

confidence: 99%

“…Previous workers (e.g., Cope, 1877;Marsh, 1877;Seeley, 1901;Mü ller, 1908;Romer, 1966;Currey and Alexander, 1985;Carrano and O'Connor, 2005) have emphasized the densityreducing effect of skeletal pneumatization in fossil archosaurs. From studies of extant birds, pneumatization proceeds by the replacement of trabecular bone and marrow with air sac diverticula (Bremer, 1940b;King and Kelly, 1956;King, 1957;Schepelmann, 1990;Brackmann, 1991), resulting in a significant reduction in the density of a given bone. From an energetics perspective, then, the cost of transport for a pneumatic bone will be less than for an apneumatic bone of the same volume.…”

Section: Nonpulmonary Roles Of Postcranial Pneumaticitymentioning

confidence: 99%

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Postcranial pneumaticity: An evaluation of soft-tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs

2006

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Postcranial pneumaticity has been reported in numerous extinct sauropsid groups including pterosaurs, birds, saurischian dinosaurs, and, most recently, both crurotarsan and basal archosauriform taxa. By comparison with extant birds, pneumatic features in fossils have formed the basis for anatomical inferences concerning pulmonary structure and function, in addition to higher-level inferences related to growth, metabolic rate, and thermoregulation. In this study, gross dissection, vascular and pulmonary injection, and serial sectioning were employed to assess the manner in which different soft tissues impart their signature on the axial skeleton in a sample of birds, crocodylians, and lizards. Results from this study indicate that only cortical foramina or communicating fossae connected with large internal chambers are reliable and consistent indicators of pneumatic invasion of bone. As both vasculature and pneumatic diverticula may produce foramina of similar sizes and shapes, cortical features alone do not necessarily indicate pneumaticity. Noncommunicating (blind) vertebral fossae prove least useful, as these structures are associated with many different soft-tissue systems. This Pneumaticity Profile (PP) was used to evaluate the major clades of extinct archosauriform taxa with purported postcranial pneumaticity. Unambiguous indicators of pneumaticity are present only in certain ornithodiran archosaurs (e.g., sauropod and theropod dinosaurs, pterosaurs). In contrast, the basal archosauriform Erythrosuchus africanus and other nonornithodiran archosaurs (e.g., parasuchians) fail to satisfy morphological criteria of the PP, namely, that internal cavities are absent within bone, even though blind fossae and/or cortical foramina are present on vertebral neural arches. An examination of regional pneumaticity in extant avians reveals remarkably consistent patterns of diverticular invasion of bone, and thus provides increased resolution for inferring specific components of the pulmonary air sac system in their nonavian theropod ancestors. By comparison with well-preserved exemplars from within Neotheropoda (e.g., Abelisauridae, Allosauroidea), the following pattern emerges: pneumaticity of cervical vertebrae and ribs suggests pneumatization by lateral vertebral diverticula of a cervical air sac system, with sacral pneumaticity indicating the presence of caudally expanding air sacs and/or diverticula. The identification of postcranial pneumaticity in extinct taxa minimally forms the basis for inferring a heterogeneous pulmonary system with distinct exchange and nonexchange (i.e., air sacs) regions. Combined with inferences supporting a rigid, dorsally fixed lung, osteological indicators of cervical and abdominal air sacs highlight the fundamental layout of a flow-through pulmonary apparatus in nonavian theropods.

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Section: Osteological Correlates Of Different Soft-tissue Systemssupporting

confidence: 91%

Section: Osteological Correlates Of Different Soft-tissue Systemsmentioning

confidence: 99%

Section: Osteological Correlates Of Different Soft-tissue Systemsmentioning

confidence: 99%

Section: Nonpulmonary Roles Of Postcranial Pneumaticitymentioning

confidence: 99%

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Postcranial pneumaticity: An evaluation of soft-tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs

2006

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“…It has been postulated that pneumatic structures form in unstressed areas of the bone (Bremer 1940;Witmer 1997) and that pneumatic bones would have a mechanical advantage in allowing the bone material to be concentrated far away from the centre of rotation (Hunter 1774;Currey & Alexander 1985). The mechanical basis of pneumatization in sauropod cervical vertebrae up to 1.3 m or more in length has not been studied previously using biomechanical approaches (Lovelace et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Mechanical implications of pneumatic neck vertebrae in sauropod dinosaurs

et al. 2009

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The pre-sacral vertebrae of most sauropod dinosaurs were surrounded by interconnected, air-filled diverticula, penetrating into the bones and creating an intricate internal cavity system within the vertebrae. Computational finite-element models of two sauropod cervical vertebrae now demonstrate the mechanical reason for vertebral pneumaticity. The analyses show that the structure of the cervical vertebrae leads to an even distribution of all occurring stress fields along the vertebrae, concentrated mainly on their external surface and the vertebral laminae. The regions between vertebral laminae and the interior part of the vertebral body including thin bony struts and septa are mostly unloaded and pneumatic structures are positioned in these regions of minimal stress. The morphology of sauropod cervical vertebrae was influenced by strongly segmented axial neck muscles, which require only small attachment areas on each vertebra, and pneumatic epithelia that are able to resorb bone that is not mechanically loaded. The interaction of these soft tissues with the bony tissue of the vertebrae produced lightweight, air-filled vertebrae in which most stresses were borne by the external cortical bone. Cervical pneumaticity was therefore an important prerequisite for neck enlargement in sauropods. Thus, we expect that vertebral pneumaticity in other parts of the body to have a similar role in enabling gigantism.

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New Contributions on the So-Called Otosclerosis of Chickens

Altmann¹

1944

Archives of Otolaryngology - Head and Neck Surgery

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The pneumatization of the humerus in the common fowl and the associated activity of theelin

Cited by 33 publications

References 17 publications

Postcranial pneumaticity: An evaluation of soft-tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs

Postcranial pneumaticity: An evaluation of soft-tissue influences on the postcranial skeleton and the reconstruction of pulmonary anatomy in archosaurs

Mechanical implications of pneumatic neck vertebrae in sauropod dinosaurs

New Contributions on the So-Called Otosclerosis of Chickens

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