The functional anatomy of the shoulder of the savannah monitor lizard (Varanus exanthematicus)

The excursions of the scapulocoracoid and forelimb and the activity of 18 shoulder muscles were studied by simultaneous cineradiography and electromyography in Savannah Monitor lizards (Varanus exanthematicus) walking on a treadmill at speeds of 0.7–1.1 km/hour. During the propulsive phase, the humerus moves anteroposteriorly 40–55° and rotates a total of 30–40°. Simultaneously, the coracoid translates posteriorly along the tongue-and-groove coracosternal joint by a distance equivalent to about 40% the length of the coracoid. Biceps brachii, coraco-brachialis brevis and longus, the middle and posterior parts of the latissimus dorsi and pectoralis, serratus anterior, serratus anterior superficialis, subscapularis, supracoracoideus, and triceps usually become active during the late swing phase and continue activity throughout most or all of propulsion. The anterior part of the latissimus dorsi is active during the transition from propulsive to swing phases. Brachialis, deltoideus scapularis, levator scapulae, the anterior part of pectoralis, scapulo-humeralis posterior, and subcoracoideus are active primarily during the swing phase; they are occasionally active during propulsion. Deltoideus clavicularis, scapulo-humeralis posterior, sternocoracoideus, and the posterior part of the trapezius are biphasic, with activity in both the propulsive and swing phases. A number of shoulder muscles in Varanus exanthematicus and Didelphis virginiana (the Virginia opossum) are similar in attachments, in activity patterns with respect to phases of the step cycle, and in apparent actions. These similarities are interpreted as a pattern inherited from the ancestors of higher tetrapods. The sliding coracosternal joint permits an increase in step length without demanding greater excursion at the shoulder and elbow joints.     

Gliding flight in the American Kestrel (Falco sparverius): An electromyographic study

Electromyographic (EMG) activity was studied in American Kestrels (Falco sparverius) gliding in a windtunnel tilted to 8 degrees below the horizontal. Muscle activity was observed in Mm. biceps brachii, triceps humeralis, supracoracoideus, and pectoralis, and was absent in M. deltoideus major and M. thoracobrachialis (region of M. pectoralis). These active muscles are believed to function in holding the wing protracted and extended during gliding flight. Quantification of the EMG signals showed a lower level of activity during gliding than during flapping flight, supporting the idea that gliding is a metabolically less expensive form of locomotion than flapping flight. Comparison with the pectoralis musculature of specialized gliding and soaring birds suggests that the deep layer of the pectoralis is indeed used during gliding flight and that the slow tonic fibers found in soaring birds such as vultures represents a specialization for endurant gliding. It is hypothesized that these slow fibers should be present in the wing muscles that these birds use for wing protraction and extension, in addition to the deep layer of the pectoralis. © 1993 Wiley-Liss, Inc.     

Anatomy and histochemistry of spread-wing posture in birds. I. Wing drying posture in the double-crested cormorant,Phalacrocorax auritus

Spread-wing postures of birds often have been studied with respect to the function of behavior, but ignored with regard to the mechanism by which the birds accomplish posture. The double-crested cormorant, Phalacrocorax auritus, was used as a model for this study of spread-wing posture. Those muscles capable of positioning and maintaining the wing in extension and protraction were assayed histochemically for the presence of slow (postural) muscle fibers. Within the forelimb of Phalacrocorax, Mm. coracobrachialis cranialis, pectoralis thoracicus (cranial portion), deltoideus minor, triceps scapularis, and extensor metacarpi radialis pars dorsalis and ventralis were found to contain populations of slow-twitch or slow-tonic muscle fibers. These slow fibers in the above muscles are considered to function during spread-wing posture in this species. J Morphol 233:67–76, 1997. © 1997 Wiley-Liss, Inc.     

Capillarity and fibre types in locomotory muscles of wild mallard ducks (Anas platyrhynchos)

Six locomotory muscles from wild mallard ducks (Anas platyrhynchos) were analysed by histochemical methods. Special care was taken in sample procedure in order to describe the heterogeneity found throughout each muscle. Capillarity and fibre-type distributions were correlated to the functional implications and physiological needs of each muscle. Comparisons between our results and similar previous reports on dabbling and diving ducks are also discussed. Muscles from the leg presented the most heterogeneous fibre-type distributions, which are correlated to the wide range of terrestrial and aquatic locomotory performances shown by these animals. More specialized muscles such as pectoralis, used almost exclusively for flapping flight, had more homogeneous fibretype distributions, whereas muscles from the wing presented a high proportion of glycolytic fibres probably recruited during non-steady flapping flight. Deep muscle pectoralis zones and parts of the gastrocnemius which are closer to the bone are remarkable for their high capillarity indices and oxidative capacities, which suggests that these parts are recruited during sustained flapping flight and swimming. However, two different strategies for achieving these high oxygen needs are evident, indicating that the fibre cross-sectional area plays an important role in the modulation of the oxygen supply to the muscle cells.Abbreviations AChE acetylcholinesterase - cap mm^-2 number of capillaries per square millimeter - CD capillary density - C/F capillary-to-fibre ratio - EMR muscle extensor metacarpialis radialis - FCSA fibre cross-sectional area - FD fibre density - FG fast glycolytic - FOG fast oxidative glycolytic - GLE muscle gastrocnemius lateralis (pars externa) - GPDH -glycerophosphate dehydrogenase - ITC muscle iliotibialis cranialis - m-ATPase myofibrillar adenosine triphosphatase - OFA oxidative fibre area - OFN oxidative fibre number - PEC muscle pectoralis - SCH muscle scapulohumeralis caudalis - SDH succinate dehydrogenase - SO slow oxidative - TSC muscle scapulotriceps or triceps scapularis     

The functional anatomy of the shoulder in the European starling (Sturnus vulgaris)

The excursions of wing elements and the activity of eleven shoulder muscles were studied by cineradiography and electromyography in European starlings (Sturnus vulgaris) flying in a wind tunnel at speeds of 9–20 m s^?1. At the beginning of downstroke the humerus is elevated 80–90° above horizontal, and both elbow and wrist are extended to 90° or less. During downstroke, protraction of the humerus (55°) remains constant; elbow and wrist are maximally extended (120° and 160°, respectively) as the humerus passes through a horizontal orientation. During the downstroke-upstroke transition humeral depression ceases (at about 20° below horizontal) and the humerus begins to retract. However, depression of the distal wing continues by rotation of the humerus and adduction of the carpometacarpus. Humeral retraction (to within about 30° of the body axis) is completed early in upstroke, accompanied by flexion of the elbow and carpometacarpus. Thereafter the humerus begins to protract as elevation continues. At mid-upstroke a rapid counterrotation of the humerus reorients the ventral surface of the wing to face laterad; extension of the elbow and carpometacarpus are initiated sequentially. The upstroke-downstroke transition is characterized by further extension of the elbow and carpometacarpus, and the completion of humeral protraction. Patterns of electromyographic activity primarily coincide with the transitional phases of the wingbeat cycle rather than being confined to downstroke or upstroke. Thus, the major downstroke muscles (pectoralis, coracobrachialis caudalis, sternocoracoideus, subscapularis, and humerotriceps) are activated in late upstroke to decelerate, extend, and reaccelerate the wing for the subsequent downstroke; electromyographic activity ends well before the downstroke is completed. Similarly, the upstroke muscles (supracoracoideus, deltoideus major) are activated in late downstroke to decelerate and then reaccelerate the wing into the upstroke; these muscles are deactivated by mid-upstroke. Only two muscles (scapulohumeralis caudalis, scapulotriceps) exhibit electromyographic activity exclusively during the downstroke. Starlings exhibit a functional partitioning of the two heads of the triceps (the humerotriceps acts with the pectoralis group, and does not overlap with the scapulotriceps). The biphasic pattern of the biceps brachii appears to correspond to this partitioning.     

Anatomy and histochemistry of spread-wing posture in birds. 2. Gliding flight in the California Gull,Larus californicus: A paradox of fast fibers and posture

Gliding flight is a postural activity which requires the wings to be held in a horizontal position to support the weight of the body. Postural behaviors typically utilize isometric contractions in which no change in length takes place. Due to longer actin-myosin interactions, slow contracting muscle fibers represent an economical means for this type of contraction. In specialized soaring birds, such as vultures and pelicans, a deep layer of the pectoralis muscle, composed entirely of slow fibers, is believed to perform this function. Muscles involved in gliding posture were examined in California gulls (Larus californicus) and tested for the presence of slow fibers using myosin ATPase histochemistry and antibodies. Surprisingly small numbers of slow fibers were found in the M. extensor metacarpi radialis, M. coracobrachialis cranialis, and M. coracobrachialis caudalis, which function in wrist extension, wing protraction, and body support, respectively. The low number of slow fibers in these muscles and the absence of slow fibers in muscles associated with wing extension and primary body support suggest that gulls do not require slow fibers for their postural behaviors. Gulls also lack the deep belly to the pectoralis found in other gliding birds. Since bird muscle is highly oxidative, we hypothesize that fast muscle fibers may function to maintain wing position during gliding flight in California gulls. J. Morphol. 233:237–247, 1997. © 1997 Wiley-Liss, Inc.     

Flightlessness in the Galápagos cormorant (Compsohalieus [Nannopterum] harrisi): heterochrony, giantism and specialization

A study of flightlessness in the Galápagos cormorant (Compsohalieus [Nannopterum] harrisi) was undertaken using study skins and skeletons of C. harrisi and eight flighted confamilials; in addition, four skin specimens and disassociated skeletal elements of the extinct spectacled cormorant (C. perspicillatus) of Beringia, reputed by some to have been flightless, were studied. Anatomical specimens of C. penicillatus and C. harrisi were dissected for myological comparisons. Flightless C. harrisi is 1.6 to 2.2 times as heavy as its extant flighted congeners; males averaged 3958 g and females averaged 2715 g in total body weight. Estimates of body weight for C. perspicillatus based on femur length approximated 3900 g. Wing lengths of C. harrisi were smaller than those of any other cormorant, averaging 190 mm and 170 mm for males and females, respectively. Wing-loadings (g body mass.cm^-2 wing area) of flighted cormorants ranged from 1.0 to 1.7. Estimated wing-loadings, incorporating approximate wing areas, were 2.0 and 5.1 g.cm^-2 for C. perspicillatus and C. harrisi, respectively; the former suggests that C. perspicillatus was probably capable of laboured flight. The small wings of C. harrisi result from an c. 50% shortening of remiges, accompanied by reduced asymmetry of vane widths and increased rounding of the tips, and significant reductions in lengths of wing bones, particularly the radius and ulna. Numbers of primary and secondary remiges in C. harrisi remain unchanged. Multivariate morphometries revealed that sexual dimorphism in external and skeletal dimensions is significantly greater in C. harrisi than in flighted cormorants. Canonical analysis of six external measurements indicated that C. harrisi is distinguished primarily by its relatively short wings. Skeletal peculiarities of C. harrisi were diverse, including conformational changes in the sternum, furcula, coracoid, humerus, ulna, radius, carpometacarpus and patella. Mensural comparisons confirmed substantial reductions in elements of the pectoral girdle of C. harrisi, particularly the sternal carina, as well as the alar skeleton, especially the radius and ulna. Differential shortening of the wing elements resulted in significant differences in proportions within the wing skeleton. These unique skeletal proportions of C. harrisi, in addition to its great overall size, combine to produce an immense multivariate skeletal distance between C. harrisi and all confamilials. Sexual dimorphism in skeletal dimensions, in both total and size-corrected data, was 2–3 times greater in C. harrisi than in other phalacrocoracids sampled. Most pectoral muscles of C. harrisi were absolutely or relatively smaller than those of C. penicillatus, in spite of its larger body size. No muscles or parts thereof were lacking in the pectoral limb of C. harrisi, but a number of qualitative differences distinguished the musculature of the flightless species, including: an exceptionally tough skin involving a well-developed M. pectoralis pars abdominalis and M. latissimus dorsi interscapularis; a thin, medially obsolete and laterally extensive M. pectoralis pars thoracica; a weakly developed M. rhomboideus profundus consisting of a variably tendinous fascia invested with three fasciculi of muscle fibres; an extraordinarily thick, extensive M. obliquus externus abdominis, which, together with a unique cnemio-costal slip of smooth muscle, restricts the metapatagium through an anchoring of M. serratus superficialis metapatagialis; and the presence of a unique alular muscle named here as M. levator alulae. Fusions of the tendons of origin and insertion, respectively, of M. flexor digiti superficialis and M. flexor digiti profundus in C. harrisi, muscles derived from a common muscle primordium, and the retention of a carpometacarpal tendon of M. flexor carpi ulnaris cranialis constitute strong evidence of pectoral paedomorphosis in C. harrisi. Mensural comparisons quantified the reduction of pectoral muscles in C. harrisi and indicated that these reductions were especially pronounced in the distal musculature. Morphological characteristics of Phalacrocoracidae, together with the exploitation of localized marine food resources and weakly developed seasonal movements of Compsohalieus, may have predisposed the founding population of C. harrisi to flightlessness. Anatomical changes in C. harrisi are exceeded in degree among foot-propelled diving birds by those of only a few fossil flightless birds (e.g. Hesperomis, Chendytes). Many of the morphological peculiarities of C. harrisi are paedomorphic, although several are not attributable to developmental heterochrony. These morphological characters of flightless C. harrisi are considered with respect to locomotion, feeding ecology, reproduction and demography of the species, and are compared with those of other flightless carinates.     

Die vorderextremitat von opisthocomus cristatus (vieillot)

Ohne Zusammenfassung

Zeichenerklärung der Abbildungen

Abb. 1-6 Skelett an.v. Angulus dorsalis - ap.tb.med. Apex tuberculi medialis - b.p. Knochenplatte der Phal.l dig. 2 - c.l. Crus laterale tuberculi medialis - c.m. Crus mediale tuberculi medialis - col.tr. Collum troehleae - ep.a. Caput articulare - cr.lat. Crista lateralis - cr.med. Crista medialis - dig.d. Digitus 3 (Medius) - dig.4. Fraglicher Rest eines vierten Fingers, mit dem dritten verwachsen - ep.l. Epicondylus lateralis - ep.m. Epicondylus medialis - fiss. Fissura metacarpi - foss. Fossa pneumo-anconaea - fov. Fovea supratrochlearis ventralis - inc.coll. Incissura collaris - i.c. Impressio coraeo-brachialis ant - i.p. Impressio pectoralis - k. Knochenöse an der Phal. 2 dig. 2 - l.a.h. Linea anconaei humeralis dorsalis - l.d.v. Linea deltoidis ventralis - l.l.d. Linea latissimus dorsi anterioris - o. Olecranon - pl. Planum ulnare ventrale - p.ms. Processus muscularis metacarpi II - p.spc.l. Processus supracondyloideus later - r.m. Radialhöcker des Metacarpus I - s. Sesambein - s.anc.l. Sulcus anconaeus lateralis - s.anc.m. Sulcus anconaeus medialis - s.d.c. Sulcus tendinis Musculi extensoris digitorum communis - s.r. Sulcus extensoris metacarpi radialis - tbdat. Tuberculum lateralis - tb.med. Tuberculum medialis - tb.ms. Tuberculum muscularis zur Insertion des Musculus extensor metacarpi uln - tb.r. Tuberculum radialis - tb.u. Tuberculum ulnaris - tr.r. Trochlea radialis - tr.u. Trochlea ulnaris - v.itr. Vallis intertrochlearis Abb. 8-10 Nerven a.h. Nervus anconaeus humeralis - a.sc. Nervus anconaeus scapularis - ab.ind. Nervus abductor indicis - ab.p. Nervus abdoctor pollicis - ad.p. Nervus adductor pollicis - b. Nervus biceps - br.inf. Nervus brachialis inferior - cbr.a. Nervus coraco-brachialis anterior - cbr.p. Nervus coracobrachialis posterior - cut.b Nervus cutaneus brachii - d.min. Nervus deltoides minor - d.mj. Nervus deltoides major - d.ppt. Nervus deltoides propatagialis - ect.r. Nervus ectepicondylo-radialis - ect.u. Nervus ectepicondylo-ulnaris - e.c.u. Nervus extensor carpi ulnaris - e.d.c. Nervus extensor digitorum communis - e.i.b. Nervus extensor indicis brevis - e.i.l. Nervus extensor indicis longus - e.m.r. Nervus extensor metacarpi radialis - ent.r.s. Nervus entepicondylo-radialis sublimis - Int.r.p Nervus entepicondylo-radialis profund - e.p.b. Nervus extensor pollicis brevis - e.p.l. Nervus extensor pollicis longus - f.c.u. Nervus flexor carpi ulnaris - f.d.III. Nervus flexor digiti III - f.d.p. Nervus flexor digitorum profundus - f.d.s. Nervus flexor digitorum sublimis - f.p. Nervus flexor pollicis - i.d. Nervus interosseus dorsalis - i.p. Nervus interosseus palmaris - lat.d. Nervus latissimus dorsi - m. Nervus metapatagialis - p. Nervus pectoralis - prop.i. Nervus propatagialis inferior - prop.s. Nervus propatagialis superior - sbc.l. Nervus subscapularis internum et coracoideum - sbc.2. Nervus subscapularis externum - sch. Nervus seapulo-humeralis - spc. Nervus supracoracoideus - u.m.d. Nervus ulni-metacarpalis dorsalis - u.m.v. Nervus ulni-metacarpalis ventralis Abb. 11-32 Muskeln Abkürzungen: a. Musculus anconaeus - ab.ind. Musculus abductor indicis - ab.p. Musculus abductor pollicis - ad.p. Musculus adductor pollicis - a.h. Musculus anconaeus humeralis - a.sc. Musculus anconaeus scapularis - b. Musculus biceps brachii - b.ppt. Musculus biceps propatagialis - br.inf. Musculus brachialis inferior - cbr.a. Musculus coraco-brachialis anterior - cbr.p. Musculus coraco-brachialis posterior - d.min. Musculus deltoides minor - d.mj. Musculus deltoides major - d.ppt. Musculus deltoides propatagialis - ect.r. Musculus ectepicondylo-radialis - ect.u. Musculus ectepicondylo-ulnaris - e.c.u. Musculus extensor carpi ulnaris - e.d.c. Musculus extensor digitorum communis - e.i.b. Musculus extensor indicis brevis - e.i.l. Musculus extensor indicis longus - El. Elastica - E.S. Expansor secundariorum - e.m.r.b. Musculus extensor metacarpi radialis brevis - e.m.r.l. Musculus extensor metacarpi radialis longus - ent.r.s. Musculus entepicondylo-radialis sublimis - ent.r.p. Musculus entepicondylo-radialis profundus - e.p.b. Musculus extensor pollicis brevis - e.p.l. Musculus extensor pollicis longus - f.c.u. Musculus flexor carpi ulnaris - f.d.III. Musculus flexor digiti III - f.d.p. Musculus flexor digitorum profundus - f.d.s. Musculus flexor digitorum sublimis - f.p. Musculus flexor pollicis - i.d. Musculus interosseus dorsalis - i.p. Musculus interosseus palmaris - lat.d.a. Musculus latissimus dorsi anterior - lat.d.p. Musculus latissimus dorsi posterior - L.ch. Ligamentum coraco-humerale - p. Musculus pectoralis thoracicus - p.ppt. Musculus pectoralis propatagialis - Prop. b. Propatagialis brevis - Prop.l. Propatagialis longus - sbc.c. Musculus subcoraco-scapularis coracoideum - sbc.e. Musculus subcoraco-scapularis externum - sbc.i. Musculus subcoraco-scapularis internum - sch. Musculus scapulo-humeralis (posterior) - spc. Musculus supra coracoideus - s.s.a. Musculus serratus superficialis anterior - T.m. Tendo matapatagialis - u.m.d. Musculus ulni-metacarpalis dorsalis - u.m.v. Musculus ulni-metacarpalis ventralis     

Mechanics of the avian propatagium: Flexion-extension mechanism of the avian wing

The supporting elements of the avian propatagium were examined in intact birds and as isolated components, using static force-length measurements, calculated models, and airflow observations. The propatagial surface supported between Lig. propatagiale (LP) and brachium-antebrachium is equally resistant to distortion over the range of wing extension used in flight. The lengths LP assumes in flight occur across a nearly linear, low-stiffness portion of the force-length curve of its extensible pars elastica. In an artificial airflow, intact wings automatically extend; their degree of extension is roughly correlated with the airflow velocity. Comparisons between geometric models of the wing and the passive force-length properties of LPs suggest that the stress along LP blances the drag forces acting to extend the elbow. The mechanical properties (stiffness) of the LP vary and appear to be tuned for flight-type characteristics, e.g., changes in wing extension during flight and drag. Lig. limitants cubiti and LP combine to limit elbow extension at its maximum, a safety device in flight preventing hyperextension of the elbow and reduction of the propatagium's cambered flight surface. Calculations using muscle and ligament lengths suggest that M. deltoideus, pars propatagialis, via its insertions onto both the propatagial ligaments, controls and coordinates propatagial deployment, leading edge tenseness, and elbow/wing extension across the range of wing extensions used in flight. The propatagial ligaments and M. deltoideus, pars propatagialis, along with skeleto-ligamentous elbow/carpus apparatus, are integral components of the wing's extension control mechanism. © 1995 Wiley-Liss, Inc.     

Anatomy and histochemistry of spread-wing posture in birds. 3. Immunohistochemistry of flight muscles and the "shoulder lock" in albatrosses

As a postural behavior, gliding and soaring flight in birds requires less energy than flapping flight. Slow tonic and slow twitch muscle fibers are specialized for sustained contraction with high fatigue resistance and are typically found in muscles associated with posture. Albatrosses are the elite of avian gliders; as such, we wanted to learn how their musculoskeletal system enables them to maintain spread-wing posture for prolonged gliding bouts. We used dissection and immunohistochemistry to evaluate muscle function for gliding flight in Laysan and Black-footed albatrosses. Albatrosses possess a locking mechanism at the shoulder composed of a tendinous sheet that extends from origin to insertion throughout the length of the deep layer of the pectoralis muscle. This fascial "strut" passively maintains horizontal wing orientation during gliding and soaring flight. A number of muscles, which likely facilitate gliding posture, are composed exclusively of slow fibers. These include Mm. coracobrachialis cranialis, extensor metacarpi radialis dorsalis, and deep pectoralis. In addition, a number of other muscles, including triceps scapularis, triceps humeralis, supracoracoideus, and extensor metacarpi radialis ventralis, were found to have populations of slow fibers. We believe that this extensive suite of uniformly slow muscles is associated with sustained gliding and is unique to birds that glide and soar for extended periods. These findings suggest that albatrosses utilize a combination of slow muscle fibers and a rigid limiting tendon for maintaining a prolonged, gliding posture.     

Beziehungen zwischen Körperbau und Lebensweise bei Blenniidae (Pisces) des Roten Meeres

The muscle and skeleton anatomy of the pectoral, pelvic, and anal fins are described in 3 Salariin Blenniidae: Salarias fasciatus (sublittoral), Istiblennius edentulus (eulittoral), Alticus kirkii (supralittoral). In A. kirkii these organs are adapted to a climbing habit on the steep rocks beyond the water. The results are compared with those found in Periophthalmus.

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Abbildungserklärungen B Basale - Cl Cleithrum - Co Coracoid - Creld Crista cleithri dorsalis - Crele Crista cleithri externa - H Haken an den Lepidotrichen der Ventralia - Lep Lepidotrichen - Pel Postcleithrum - Prsv Processus spinae ventralis - Pt Posttemporale - Rad Radiale - Scl Supracleithrum - SCl Symphyse des Cleithrum - Scp Scapula - abpr M. abductor profundus - adpr M. adductor profundus - arre M. arrector externus - arri M. arrector internus - cord M. coraco-radialis - dep M. depressor (Analis) - dprrd M. depressor radiorum (Pectoralia) - er M. erector - extpr M. extensor proprius - fls M. flexor superficialis - inc M. inclinator - levs M. levator superficialis - mes M. mesoventralis - rtrd M. retractor dorsalis - rtris M. retractor ischii - rtrv M. retractor ventralis Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Functional Morphology of the Forelimb of the Nine-Banded Armadillo (<Emphasis Type="Italic">Dasypus novemcinctus</Emphasis>): Comparative Perspectives on the Myology of Dasypodidae

The nine-banded armadillo, Dasypus novemcinctus, is a member of the family Dasypodidae, which contains all extant species of armadillos and represents the most diverse group of xenarthran mammals by their speciation, form, and range of scratch-digging ability. This study aims to identify muscle traits that reflect specialization for fossorial habit by observing forelimb structure in D. novemcinctus and comparing it among armadillos using available myological data. A number of informative traits were observed in D. novemcinctus and among Dasypodidae, including the absence of m. rhomboideus profundus, the variable presence of a m. articularis humeri and m. coracobrachialis, two heads of m. triceps brachii with scapular origin, and a lack of muscle mass devoted to antebrachial supination. Muscle mass and myosin heavy chain (MHC) isoform content were also quantified from our forelimb dissections. New osteological indices are additionally calculated and reported for D. novemcinctus. Collectively, the findings emphasize muscle mass and power output for limb retraction and specialization of the distal limb for sustained purchase of soil by strong pronation and carpal/digital flexion. Moreover, the myological traits assessed here provide a valuable resource for interpretation of muscle architecture specializations among digging mammals and future reassessment of armadillo phylogeny.     

Preliminary electromyographical analysis of brachiation in gibbon and spider monkey

In order to refine the concept of brachiation as a locomotor mode and to examine the complex relationship between locomotor behavior and muscle morphology, we have undertaken a telemetered electromyographic (EMG) analysis of muscle recruitment in brachiating gibbons (Hylobates lar) and spider monkeys (Ateles belzebuth andAteles fusciceps) Electrical activity patterns were determined for both support and swing phases in the following muscles: cranial pectoralis major, caudal pectoralis major, middle deltoideus, short head of biceps brachii, flexor digitorum superficialis, latissimus dorsi, and dorsoepitrochlearis. Our experimental findings reinforce earlier behavioral observations that brachiation is not a discrete, stereotyped locomotor activity. EMG patterns differed most between gibbon and spider monkey in those muscles that exhibit markedly disparate morphologies in the two genera-pectoralis major (both portions) and the short head of biceps brachii. Additional recruitment differences appear related to consistent species-specific differences in the timing and mechanics of both support and swing phases, and probably to the role of the prehensile tail as a fail-safe mechanism in the spider monkey.     

Comments on the evolution of the jaw adductor musculature of snakes

The aim of this study is to provide a general view of the adductor musculature of the alethinophidian snakes. The aponeurotic system present in anilioid snakes is here described as being also present in colubroid and booid snakes. Although modified in various groups, this aponeurotic system retains the same topographical pattern in the anilioids, booids and colubroids, and is thus hypothesized to be homologous. An analysis of the aponeurotic system and related muscular bundles within the alethinophidian snakes is given. A new terminology is proposed for the jaw adductor muscles where the muscles levator anguli oris and adductor mandibulae externus superficialis (proper) of snakes (sensu Lakjer, 1926; Haas, 1962) retain these names even if this fails to reflect the presumed homologies with the bundles of the same name in lizards (see Rieppel, 1988b); the fibres originating from the temporal tendon in the Anilioidea, and presumed to form a bundle of composite nature (Rieppel, 1980b), are named the M. adductor mandibulae externus temporalis (lost by the Macrostomata); the M. adductor mandibulae externus medialis is a composite muscle in the Anilioidea (Rieppel, 1980b) which give rise to two different muscles in the ‘booids’, the M. adductor mandibulae externus medialis, pars anterior and the M. adductor mandibulae externus profundus, the former being secondarily lost by the Caenophidia which retains only fibres homologues of the 3b and 3c heads of the profundus layer of lizards; the so-called M. adductor mandibular externus profundus of snakes (sensu Lackjer, 1926; Haas, 1962) is also a composite muscle in the Anilioidea (Rieppel, 1980b), in the alethinophidians it is essentially made of fibres homologous with the posterior pinnate part of the medialis layer of lizards, and is here named the M. adductor mandibulae externus medialis, pars posterior. As a result from this analysis it follows that: (1) the Macrostomata are characterized by the downward extension of the fibres forming the M. adductor mandibulae externus medialis, pars anterior and the loss of the M. adductor mandibulae externus temporalis: (2) the Xenopeltidae are set apart from the remaining macrostomatan snakes by the retention of the M. levator anguli oris and of a well developed lateral sheet of the quadrate aponeurosis; (3) the ‘booids’ form a monophyletic group comprising only the Boidae and Bolyeriidae (with the exclusion of the Xenopeltidae and Tropidophiidae) which is characterized by a differentiated M. adductor mandibulae externus medialis, pars anterior inserting on the lateral surface of the compound bone via its own aponeurosis; (4) the Tropidophiidae are set apart from all other snakes by the peculiar course of their lateral head vein; however, they belong to the Caenophidia as they show a facial carotid artery which passes dorsally to the mandibular and maxillary branches of the trigeminus; (5) a possible additional character in favour of an Acrochordoidea + Colubroidea monophyletic unit may be given by the pattern of innervation of the jaw adductor muscles in these two taxa; (6) a new interpretation of the compressor glandulae muscular complex of Atractaspis resulted in a morphologically similar pattern to that of the viperids; the phylogenetic implications of such similarity are discussed in detail.     

Hind limb myology of the common hippopotamus,Hippopotamus amphibius (Artiodactyla: Hippopotamidae)

Based on morphological traits, hippos have traditionally been classified with pigs and peccaries in the suborder Suiformes. However, molecular data indicate that hippos and cetaceans are sister taxa. This study analyses muscle characters of the common hippo hind limb in order to clarify the phylogenetic relationships and functional anatomy of hippos. Several muscles responsible for propelling the body through water are robust and display extensive fusions, including mm. semimembranosus, semitendinosus, biceps femoris and gluteus superficialis. In addition, common hippos retain long flexor and extensor tendons for each digit, reflecting the fact that all four toes are weight‐bearing. These flexor tendons, together with the well‐developed intrinsic muscles of the pes, serve to adduct the digits, preventing splaying of the toes when walking on soft terrain. Lastly, common hippos retain a number of primitive features, including the presence of m. articularis coxae, a well‐developed m. obturator internus, superficialis and profundus tendons to all digits, mm. flexor digitorum brevis, abductor digiti V, lumbricalis IV, adductores digitorum II and V, and two mm. interossei per digit. Pygmy hippos share these features. Thus, hippopotamids retain muscles that have been lost in the majority of artiodactyls, including other suiforms. These and previously reported findings for the forelimb support the molecular data in indicating an early divergence of the Hippopotamidae from the rest of the Artiodactyla. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 661–682.     

Cellular and molecular investigations into the development of the pectoral girdle

The forelimbs of higher vertebrates are composed of two portions: the appendicular region (stylopod, zeugopod and autopod) and the less prominent proximal girdle elements (scapula and clavicle) that brace the limb to the main trunk axis.We show that the formation of the muscles of the proximal limb occurs through two distinct mechanisms. The more superficial girdle muscles (pectoral and latissimus dorsi) develop by the “In–Out” mechanism whereby migration of myogenic cells from the somites into the limb bud is followed by their extension from the proximal limb bud out onto the thorax. In contrast, the deeper girdle muscles (e.g. rhomboideus profundus and serratus anterior) are induced by the forelimb field which promotes myotomal extension directly from the somites. Tbx5 inactivation demonstrated its requirement for the development of all forelimb elements which include the skeletal elements, proximal and distal muscles as well as the sternum in mammals and the cleithrum of fish. Intriguingly, the formation of the diaphragm musculature is also dependent on the Tbx5 programme. These observations challenge our classical views of the boundary between limb and trunk tissues. We suggest that significant structures located in the body should be considered as components of the forelimb.     

Histochemical Characterization and Distribution of Fiber Types in the Pectoralis Muscle of the Ostrich (Struthio camelus) and Emu (Dromaius novaehollandiae)

The muscle fibers of the pectoralis (M. pectoralis pars thoracicus) of a male and a female ostrich (Struthio camelus) and a male and a female emu (Dromaius novaehollandiae) were studied histochemically for succinate dehydrogenase and myofibrillar adenosine triphosphatase. Slow-tonic (ST), fast-twitch oxidative-glycolytic (FOG) and fast-twitch glycolytic (FG) fibers were approximately equal in number and distribution in the emu pectoralis examined. In the ostriches, both predominantly FG and approximately equal areas, were present. ST fibers were significantly (P ≤ 0.05) larger than the similarly (P ≥ 0.05) sized FG and FOG fibers in the female ostrich and emus. In the male ostrich ST fibers were smaller (P ≤ 0.05) than FG fibers, neither of which were significantly (P ≥ 0.05) different from FOG fibers. The ratites have the greatest percentage and widest distribution of ST fibers found in any avian pectoralis studied to date. This could represent the ancestoral avian pectoralis, neoteny or an effect of flightlessness. ST fibers are used in the maintenance of posture, which is probably the main role of the pectoralis in the emu. The predominantly FG areas of the ostrich are indicative of an additional function, namely, behavioural display. Sexual dimorphism in the ostrich pectoralis is strongly suggested.     

Localization of neuropeptide Y-immunoreactive cells and fibres in the brain of the Japanese quail

Summary In the present study, we have demonstrated, by means of the biotin-avidin method, the widespread distribution of neuropeptide Y (NPY)-immunoreactive structures throughout the whole brain of the Japanese quail (Coturnix coturnix japonica). The prosencephalic region contained the highest concentration of both NPY-containing fibres and perikarya. Immunoreactive fibres were observed throughout, particularly within the paraolfactory lobe, the lateral septum, the nucleus taeniae, the preoptic area, the periventricular hypothalamic regions, the tuberal complex, and the ventrolateral thalamus. NPY-immunoreactive cells were represented by: a) small scattered perikarya in the telencephalic portion (i.e. archistriatal, neostriatal and hyperstriatal regions, hippocampus, piriform cortex); b) medium-sized cell bodies located around the nucleus rotundus, ventrolateral, and lateral anterior thalamic nuclei; c) small clustered cells within the periventricular and medial preoptic nuclei. The brainstem showed a less diffuse innervation, although a dense network of immunopositive fibres was observed within the optic tectum, the periaqueductal region, and the Edinger-Westphal, linearis caudalis and raphes nuclei. Two populations of large NPY-containing perikarya were detected: one located in the isthmic region, the other at the boundaries of the pons with the medulla. The wide distribution of NPY-immunoreactive structures within regions that have been demonstrated to play a role in the control of vegetative, endocrine and sensory activities suggests that, in birds, this neuropeptide is involved in the regulation of several aspects of cerebral functions.Abbreviations AA archistriatum anterius - AC nucleus accumbens - AM nucleus anterior medialis - APP avian pancreatic polypeptide - CNS centrai nervous system - CO chiasma opticum - CP commissura posterior - CPi cortex piriformis - DIC differential interferential contrast - DLAl nucleus dorsolateralis anterior thalami, pars lateralis - DLAm nucleus dorsolateralis anterior thalami, pars medialis - E ectostriatum - EW nucleus of Edinger-Westphal - FLM fasciculus longitudinalis medialis - GCt substantia grisea centralis - GLv nucleus geniculatus lateralis, pars ventralis - HA hyperstriatum accessorium - Hp hippocampus - HPLC high performance liquid chromatography - HV hyperstriatum ventrale - IF nucleus infundibularis - IO nucleus isthmo-opticus - IP nucleus interpeduncularis - IR immunoreactive - LA nucleus lateralis anterior thalami - LC nucleus linearis caudalis - LFS lamina frontalis superior - LH lamina hyperstriatica - LHRH luteinizing hormone-releasing hormone - LoC locus coeruleus - LPO lobus paraolfactorius - ME eminentia mediana - N neostriatum - NC neostriatum caudale - NPY neuropeptide Y - NIII nervus oculomotorius - NV nervus trigeminus - NVI nervus facialis - NVIIIc nervus octavus, pars cochlearis - nIV nucleus nervi oculomotorii - nIX nucleus nervi glossopharyngei - nBOR nucleus opticus basalis (ectomamilaris) - nCPa nucleus commissurae pallii - nST nucleus striae terminalis - OM tractus occipitomesencephalicus - OS nucleus olivaris superior - PA palaeostriatum augmentatum - PBS phosphate-buffered saline - POA nucleus praeopticus anterior - POM nucleus praeopticus medialis - POP nucleus praeopticus periventricularis - PP pancreatic polypeptide - PYY polypeptide YY - PVN nucleus paraventricularis magnocellularis - PVO organum paraventriculare - R nucleus raphes - ROT nucleus rotundus - RP nucleus reticularis pontis caudalis - Rpc nucleus reticularis parvocellularis - RPgc nucleus reticularis pontis caudalis, pars gigantocellularis - RPO nucleus reticularis pontis oralis - SCd nucleus subcoeruleus dorsalis - SCv nucleus subcoeruleus ventralis - SCNm nucleus suprachiasmaticus, pars medialis - SCNl nucleus suprachiasmaticus, pars lateralis - SL nucleus septalis lateralis - SM nucleus septalis medialis - Ta nucleus tangentialis - TeO tectum opticum - Tn nucleus taeniae - TPc nucleus tegmenti pedunculo-pontinus, pars compacta - TSM tractus septo-mesencephalicus - TV nueleus tegmenti ventralis - VeL nucleus vestibularis lateralis - VLT nucleus ventrolateralis thalami - VMN nucleus ventromedialis hypothalami A preliminary report of this study was presented at the 15th Conference of European Comparative Endocrinologists, Leuven, Belgium, September 1990     

Increase of CGRP Expression in Motor Endplates Within Fore and Hind Limb Muscles of the Degenerating Muscle Mouse (<Emphasis Type="Italic">Scn8a</Emphasis><Superscript><Emphasis Type="Italic">dmu</Emphasis></Superscript>)

The distribution of calcitonin gene-related peptide (CGRP) was examined in skeletal muscles of fore and hind limb as well as in oral and cranio-facial regions of the degenerating muscle (dmu) mouse, which harbours a null mutation in the voltage-gated sodium channel gene Scn8a. In limb, oral and cranio-facial muscles of wild type mice, only a few motor endplates contained CGRP-immunoreactivity. However, many CGRP-immunoreactive motor endplates appeared in the triceps brachii muscle, the biceps brachii muscle, the brachialis muscle, and the gastrocnemius muscle of dmu mice. CGRP-immunoreactive density of motor endplates in the skeletal muscles was also elevated by the mutation. In these muscles, the atrophy of muscle fibers could be detected and the density of cell nuclei in the musculature increased. In the flexor digitorum profundus muscle, the flexor digitorum superficialis muscle, and the soleus muscle as well as in oral and cranio-facial muscles, however, the distribution of CGRP-immunoreactivity was barely affected by the mutation. The morphology of muscle fibers and the distribution of cell nuclei within them were also similar in wild type and dmu mice. In the lumbar spinal cord of dmu mice, CGRP-immunoreactive density of spinal motoneurons increased. These findings suggest that the atrophic degeneration in some fore and hind limb muscles of dmu mice may increase CGRP expression in their motoneurons.     

Anatomy of the propatagium: The great horned owl (Bubo virginianus)

Skinfolds and feathers form the profile of the avian airfoil. The wing of birds has a nearly flat profile from shoulder to carpus, without the presence of the propatagium. The propatagium is the largest skinfold of the wing; it fills the angle formed by the partially flexed elbow, and with its feathers forms a rounded leading edge and dorsally cambered profile added to the cranial aspect of the wing. The propatagium is variably deployed, relative to elbow extension, in flight; support for its cambered shape is maintained by multilayered collagenous and elastic tissue networks suspended between leading edge and dorsal antebrachium. The leading edge ligament (Lig. propatagiale) courses from deltopectoral crest to carpus and, with its highly distensible center section, supports the leading edge of the propatagium across a range of wing extensions. The elbow extension limiting ligament (Lig. limitans cubiti) courses from deltopectoral crest to proximal antebrachium and limits maximum elbow extension. M. deltoideus, pars propatagialis inserts on the proximal end of the common origin of the propatagial ligaments and, by way of the insertions of the two ligaments, coordinates (1) automatic flexion / extension actions of the elbow and wrist, (2) propatagial deployment, and (3) tension along the length of Lig. propatagiale supporting the leading edge. © 1994 Wiley-Liss, Inc.