Results 231 to 240 of about 3,484,749 (296)

Human evolution and the obstetrical dilemma: The pelvic floor hypothesis

open access: yesThe Anatomical Record, EarlyView.
Abstract Human childbirth is mechanically difficult because a large‐headed, broad‐shouldered fetus must pass through a comparatively narrow, twisted bony birth canal. Traditional explanations of this “obstetrical dilemma” emphasize the role of bipedal locomotion in inhibiting the evolution of a wider, more spacious pelvis.
Barbara Fischer, Ekaterina Stansfield
wiley   +1 more source

Balancing mechanics and metabolism: Elevational variation in the microanatomy of hummingbird flight muscle

open access: yesThe Anatomical Record, EarlyView.
Abstract Factors varying along elevational gradients impose strong aerodynamic and physiological constraints on powered flight, yet the internal microanatomical variation associated with elevational context in animals under such conditions remains poorly understood.
Juan Camilo Ríos‐Orjuela   +5 more
wiley   +1 more source

Compassionate Leadership in Healthcare: A Concept Analysis Using the Walker and Avant Method. [PDF]

open access: yesJ Healthc Leadersh
Gardashkhani S   +3 more
europepmc   +1 more source

Pelvic breadth and juvenile locomotor energetics: Implications for the obstetrical dilemma hypothesis across human growth in past and present humans

open access: yesThe Anatomical Record, EarlyView.
Abstract The obstetrical dilemma hypothesis (ODH) proposes an evolutionary trade‐off between obstetric requirements and locomotor performance. However, whether external pelvic breadth measures influence walking energetics during human growth remains poorly understood.
Guillermo Zorrilla‐Revilla   +4 more
wiley   +1 more source

The “costly son” hypothesis: Sons exacerbate obstetrical dilemmas in humans and other mammals

open access: yesThe Anatomical Record, EarlyView.
Abstract Human childbirth has often been considered uniquely difficult among mammals, yet recent evidence suggests that obstructed labor and fetopelvic disproportion are widespread across placental mammals. Here, we propose the “costly son” hypothesis: because male offspring are typically larger at birth, they impose greater obstetric risk on mothers ...
Nicole D. S. Grunstra   +1 more
wiley   +1 more source

Anatomy and variation in the paraphyletic Mosasaurus lemonnieri assemblage from the Craie phosphatée de ciply, Belgium

open access: yesThe Anatomical Record, EarlyView.
Abstract Nineteenth century excavations of the Ciply‐Malogne Phosphatic Chalk Formation in Hainaut, Belgium, yielded over 50 partial mosasaur skeletons, the majority of which were referred to the species Mosasaurus lemonnieri Dollo, 1889. In the years since, this taxon has experienced a complicated taxonomic history, and its exceptional hypodigm has ...
Henry S. Sharpe   +3 more
wiley   +1 more source

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