Architectural and histochemical diversity within the quadriceps femoris of the brown lemur (Lemur fulvus)

Abstract

Physiologically related features of muscle morphology are considered with regard to functional adaptation for locomotor and postural behavior in the brown lemur (Lemur fulvus). Reduced physiological cross-sectional area, estimated maximum excursion of the tendon of insertion, length of tendon per muscle fasciculus, and areal fiber type composition were examined in the quadriceps femoris in order to assess the extent of a "division of labor" among four apparent synergists. Each of these four muscles in this prosimian primate displays a distinguishing constellation of morphological features that implies functional specialization during posture and normal locomotion (walk/run, galloping, leaping). Vastus medialis is best suited for rapid whole muscle recruitment and may be reserved for relatively vigorous activities such as galloping and leaping (e.g., small cross-sectional area per mass, long excursion, predominance of fast-low oxidative fibers, relatively little tendon per fasciculus). In theory, rectus femoris could be employed isometrically in order to store elastic strain energy during all phasic activities (e.g., large cross-sectional area per mass, short excursion, predominance of fast-high oxidative fibers, large amount of tendon per fasciculus). Vastus intermedius exhibits an overall morphology indicative of a typical postural muscle (e.g., substantial cross-sectional area, short excursion, predominance of slow-high oxidative fibers, large amount of tendon per fasciculus). The construction of vastus lateralis reflects an adaptation for high force, relatively high velocity, and resistance to fatigue (e.g., large cross-sectional area, long excursion, most heterogeneous distribution of fiber types, large amount of tendon per fasciculus); this muscle is probably the primary contributor to a wide range of locomotor behaviors in lemurs. Marked dramatic architectural disparity among the four bellies, coupled with relative overall fiber type heterogeneity, suggests the potential for exceptional flexibility in muscle recruitment within this mass. One interpretation of this relatively complex neuromuscular organization in the brown lemur is that it represents an adaptation for the exploitation of a three-dimensional arboreal environment by rapid quadrupedalism and leaping among irregular and spatially disordered substrates.

Function and Cytochemical Characteristics of Postural Limb Muscles of the Rhesus Monkey: A Telemetered EMG and Immunofluorescence Study

“…These authors, relying on fibre-type data from other prosimians [41], speculated on the fibre content of various heads of the lemur quadriceps femoris. The speculations were subsequently confirmed histochemically by Anapol and Jungers [19], who found that vastus intermedius was 82% type I fibres whereas all the other heads were greater than 90% type II fibres.…”

“…Armstrong et al [78] found a 'small but consistent' trend along these lines in three heterogeneous muscles of the dog. Such was also found to be the case for the heads of the quadriceps femoris in Eulemur fulvus [19], the human soleus and vastus lateralis [31], and the equine gluteus medius [14,35]. Burke [4] was also quick to point out that type I fibres of the homogeneous cat soleus are about the same size as the large type IIb fibres of that animal's gastrocnemius.…”

“…This would not seem to be merely an effect of low body weight, since mice as small as the house shrew do have type I fibres in their triceps surae [20,22]. On the other hand, Petter and Jouffroy [21] pointed out that the percentage of type I fibres in the knee and ankle extensors of the lightest primate species, Microcebus murinus (50-70 g) is much lower than in heavier primates (see Ariano et al [41], Sickles and Pinkstaff [43], Anapol and Jungers [19], Acosta and Roy [50]). Finally, the slow loris, whose postural repertoire includes not only pronograde standing, but also clinging and hanging in the widest variety of positions, lacks the strong contrast of the percentage of type I fibres between postural and nonpostural extensor heads; the three vasti, as well as soleus and gastrocnemius lateralis, are composed of 50-80% slow fibres and are totally lacking in type IIb fibres [45].…”

Dimensions and moment arms of the hind- and forelimb muscles of common chimpanzees (Pan troglodytes)

“…However, much less literature is available for chimpanzees, and no study of ape muscle function has directly measured muscle PCSAs or the moment arms of the muscles about the joints [although note that Anapol and Jungers (1986) and Babcock (1994) have published data for lemurs and galagos, respectively, and Yamazaki (1985) made single estimates of the moment arms of some chimpanzee muscles]. Doran (1992a,b) and Hunt (1994) have published extensive data on the frequencies of the different locomotor modes exhibited by free ranging chimpanzees, and Hunt (1990Hunt ( , 1992Hunt ( , 1994 in particular has attempted to relate morphological characteristics of the appendicular skeleton of chimpanzees to behaviour and ecology.…”

Histochemistry profile of the biceps brachii muscle fibres of capuchin monkeys (Cebus apella, Linnaeus, 1758)

“…In contrast, small species with the ability for fast movement have a high proportion of fibres of fast contraction speed in most of their muscles (Ariano et al, 1973;Sickles and Pinkstaff, 1981a;Jouffroy et al, 2003). Studies in primates have shown that the population of the fibre type in the muscle varies according to the predominant way of locomotion of each species (Ariano et al, 1973;Plaghki et al, 1981;Sickles and Pinkstaff, 1981a, b;Moriyama, 1983;Anapol and Jungers, 1986;Petter and Jouffroy, 1993;Jouffroy et al, 1999).…”