Some histochemical properties of the fiber types in the pectoralis muscle of an emu (Dromaius novaehollandiae)

Abstract

The muscle fibers of the cranial slip of M. pectoralis pars thoracica of an emu (Dromaius novaehollandiae) were studied histochemically for intracellular lipid, succinic dehydrogenase, myofibrillar adenosine triphosphatase, and acetylcholinesterase. It was concluded that the muscle consisted of approximately 28% slow-tonic and 72% fast-twitch glycolytic fibers. The tonic fibers were considered to be characteristic of a postural muscle, and the fast-twitch glycolytic fibers to reflect the inability of the muscle to engage in sustained activity. The general absence of slow-tonic fibers from the pectoralis of other avian species so far studied may be attributed to inadequate sampling of the deeper regions of the muscle.

Slow tonic muscle fibers in the thyroarytenoid muscles of human vocal folds; a possible specialization for speech

“…For example, in birds the shoulder muscles, such as the ALD muscles, connect the wings to the trunk and contain a high proportion of STF. These muscles are believed to contract in a tonic fashion when the bird is flying to stabilize the shoulder joint (Simpson, 1979; Rosser and George, 1984). During gliding and soaring these muscles lock the wings into position for extended periods (Loughna et al, 1990).…”

An exceptionally high density of muscle spindles in a slow‐tonic pigeon muscle

“…Mature avian appendicular muscles typically consist of variable proportions of fast-twitch glycolytic, fast-twitch oxidative-glycolytic, and slow-tonic extrafusal fiber types which have different properties and functions (see Rosser and George, 1984). Muscle spindles are thought to monitor the length of extrafusal fibers, and the density of muscle spindles to be an indication of the function of a muscle since high spindle densities are characteristic of muscles which maintain posture or initiate fine movements (Olkowski and Manocha, 1973;Barker, 1974).…”

The Anatomical Record Stretches Its Legs and Pumps Its Arms in Part II of Our Special Issue Examining Behavioral Adaptations in Muscle Functional Morphology

“…As has long been the case, many comparative and evolutionary thoughts have appeared in our journal. These have included studies by: Howell () assessing the phylogenetic relationships of the muscular system; Campell () on the comparative anatomy of the dorsal interosseous muscles; Kerr's () comparative study on the homologies of thigh muscles in various vertebrates; English and Letbetter's () histochemical study of the cat gastrocnemius muscle; Rosser and George's () study on the fiber types in the pectoralis muscle of emus; Suzuki's () study on the myofiber types in house shrew limb muscles; Sciote and Rowlerson's () study on fiber types in limb and jaw muscles in the opossum; Paul's () comparative assessment of muscle length and fiber architecture in leg muscles of a number of mammalian species; Aversi‐Ferreira et al () comparative and evolutionary study of forearm extensors; Diogo and Molnar's () comparative and evolutionary study of tetrapod hindlimb muscles; and Kowashima and colleagues (Kawashima et al, ) comparative study of shoulder girdle modifications in pangolins and armadillos, and on evolutionary transformations in the palmaris longus muscle in flying squirrels (Kawashima et al, ). And the list can go on and on……”

“…Many other luminaries who shined light on muscle biology published in The Anatomical Record throughout our 112-year history. Included in these are found work from the laboratories of two of the AAA's presidents, Barry Joseph Anson (President 1958(President -1959 of Northwestern University Medical School and John E. Pauly (President 1983-1984 of the University of Arkansas for Medical Sciences. Anson was a prot eg e of the great Leslie B. Arey (also an AAA President, 1953-1954 and, like Arey a true Renaissance scholar who published over 300 papers on many topics.…”