Sequence of action of the diaphragm and quadratus lumborium during quiet breathing

2010

The Anatomical Record

Many physiological parameters scale with body size. Regarding limb muscles, it has been shown that the demands for relatively faster muscles, less postural work, and greater heat production in small mammals are met by lower proportions of Type I and conversely higher proportions of Type II fibers. To investigate possible adaptations of the perivertebral musculature, we investigated the proportion, spatial distribution, and cross-sectional area (csa) of the different muscle fiber types in the laboratory and harvest mouse. Serial cross sections from the posterior thoracic to the lumbo-sacral region were prepared and Type I, IIA, and IIB fibers identified using enzymehistochemistry. The general distribution of Type I and IIB fibers, as well as the more or less equal distribution of IIA fibers, resembles the pattern found in other mammals. However, the overall proportion of Type I fibers was very low in the laboratory mouse and particularly low in the harvest mouse. Muscular adaptations to a small body size were met primarily by increased Type IIA fiber proportions. Thereby, not all muscles or muscle regions similarly reflected the expected scaling effects. However, our results clearly show that body size is a critical factor when fiber-type proportions are compared among different sized mammals. Anat Rec, 293:446-463, 2010. V V C 2010 Wiley-Liss, Inc.

“…This is consistent with the more cranial muscle bundles stabilizing the ribs during inhalation (Boyd et al, 1965) (see above).…”

Section: Type II Fiber Proportions-special Role Of Intermediate Fibersupporting

confidence: 84%

Section: Fiber Types In Perivertebral Muscles Of Micesupporting

confidence: 71%

Section: Fiber Types In Perivertebral Muscles Of Micementioning

confidence: 99%

See 1 more Smart Citation

Distribution Pattern of Muscle Fiber Types in the Perivertebral Musculature of Two Different Sized Species of Mice

Hesse

Fischer

2010

The Anatomical Record

“…Rib stabilization and possibly widening of the pleural cavity during inhalation may be provided by the quadratus lumborum muscle based on its activation pattern as has been shown in rabbits [171]. The homology of this muscle has been subject of controversy [i.e., partially subvertebralis, [172], intercostalis system: intertransversarii muscles, [112], levatores costarum muscles, [173]].…”

Section: Evolution Of Axial Muscle Function and Morphologymentioning

confidence: 99%

Evolution of the axial system in craniates: morphology and function of the perivertebral musculature

2011

Front Zool

The axial musculoskeletal system represents the plesiomorphic locomotor engine of the vertebrate body, playing a central role in locomotion. In craniates, the evolution of the postcranial skeleton is characterized by two major transformations. First, the axial skeleton became increasingly functionally and morphologically regionalized. Second, the axial-based locomotion plesiomorphic for craniates became progressively appendage-based with the evolution of extremities in tetrapods. These changes, together with the transition to land, caused increased complexity in the planes in which axial movements occur and moments act on the body and were accompanied by profound changes in axial muscle function. To increase our understanding of the evolutionary transformations of the structure and function of the perivertebral musculature, this review integrates recent anatomical and physiological data (e.g., muscle fiber types, activation patterns) with gross-anatomical and kinematic findings for pivotal craniate taxa. This information is mapped onto a phylogenetic hypothesis to infer the putative character set of the last common ancestor of the respective taxa and to conjecture patterns of locomotor and muscular evolution. The increasing anatomical and functional complexity in the muscular arrangement during craniate evolution is associated with changes in fiber angulation and fiber-type distribution, i.e., increasing obliqueness in fiber orientation and segregation of fatigue-resistant fibers in deeper muscle regions. The loss of superficial fatigue-resistant fibers may be related to the profound gross anatomical reorganization of the axial musculature during the tetrapod evolution. The plesiomorphic function of the axial musculature -mobilization- is retained in all craniates. Along with the evolution of limbs and the subsequent transition to land, axial muscles additionally function to globally stabilize the trunk against inertial and extrinsic limb muscle forces as well as gravitational forces. Associated with the evolution of sagittal mobility and a parasagittal limb posture, axial muscles in mammals also stabilize the trunk against sagittal components of extrinsic limb muscle action as well as the inertia of the body's center of mass. Thus, the axial system is central to the static and dynamic control of the body posture in all craniates and, in gnathostomes, additionally provides the foundation for the mechanical work of the appendicular system.

“…2001). The m. quadratus lumborum is active synchronously to the second third of the inspiration cycle and supports the inspiration process by widening the pleural cavity in addition to the dilation by diaphragm contraction in the first third of the cycle (Boyd et al. 1965).…”

Section: Distribution Pattern Of Muscle Fibre Typesmentioning

confidence: 99%

Characteristics of paravertebral muscles - fibre type distribution pattern in the pika, Ochotona rufescens (Mammalia: Lagomorpha)

2005

J Zoological System

The evolution of the locomotor apparatus in vertebrates is marked by major reorganizations in trunk's musculature. The hypothesized functions of mammalian back muscles in the literature are discussed under consideration of the distribution and proportion of oxidative, type-I-fibres, oxidativeglycolytic, type-IIa-fibres and glycolytic, type-IIb-fibres in paravertebral muscles of a small mammal. The fibre type distribution was examined from a complete series of histological sections maintaining topographical relationships between the muscles as well as within the muscle, in order to establish the overall distribution pattern. The deep and short muscles showed the highest percentage of oxidative fibres. The larger, superficial paravertebral muscles contained the highest percentage of glycolytic fibres. Two muscles were intermediate in their proportion of fibre types. All epaxial muscles together can be interpreted as an antigravity muscle-complex counteracting enduringly against the rebound tendency caused by gravitation, comparable with antigravity muscles in limbs. A gradient from deep to superficial, or a clear regionalization of oxidative muscle fibres in central deep regions around a large intramuscular tendon was found in the m. spinalis and the m. quadratus lumborum, respectively. Concepts of the function of human back muscles as those of A. Bergmark (1989: Acta Orthop. Scand. 230, 1) or S.G.T. Gibbons & M.J. Comerford (2001: Orthop. Division Rev.March/April, 21) were exposed to be more general within mammals. Functional specializations of different muscles and muscle parts are discussed under the consideration of evolutionary reorganization of the paravertebral musculature in tetrapods.Along the cranio-caudal axis, the percentage of oxidative fibres was decreased in caudal direction within the same muscles, whereas the proportion of glycolytic fibres was increased. Therefore, classifications of muscles as ÔglycolyticÕ or ÔoxidativeÕ based on biopsies or analyses of single cross-sections may result in wrong interpretations. Changes in the proportions of the fibre type distribution pattern were mostly due to oxidative and glycolytic fibre types, whereas the percentage of oxidative-glycolytic fibres had only minor influence. A significant positive correlation between the cross-sectional area of the single fibre and its percentage in the area investigated were observed for oxidative fibres, whereby the size was positive correlated to the proportion of the oxidative fibres.