The venous communication between the gastrocnemius muscle heads

This investigation establishes the venous communication between the gastrocnemius muscle heads. Fourteen fresh (with the exception of one) cadaveric specimens were examined. Anastomotic veins were dissected along the raphe after perfusion of each muscle with 0.1 % methylene blue solution. A distally based musculocutaneous perforating vein of the medial head was the site of perfusion in 13 specimens, whereas one specimen received injection through the accompanying vein of the medial sural cutaneous nerve. Additional perfusion of dye from different sites was required in two specimens. Communicating veins were dissected in all 14 muscles. Direct anastomotic veins were detected in eight specimens; whereas in six the accompanying vein of the medial sural cutaneous nerve that had been included proved to be the intermediate pathway of venous communication between the muscle heads. Obstructive valves were encountered in most cases; nevertheless anastomotic veins were always recognized. The role of valves and the clinical implications are discussed.     

The inferiorly based gastrocnemius muscle flap: anatomic aspects

The arterial communication between the gastrocnemius muscle heads through their lowest anastomotic arteriole bundle alone was examined in specimens from 14 fresh cadavers. In 3 specimens, the larger vessels in close vicinity to the lowest vessels were preserved as well. Distinct communication between the arterial networks of the heads was demonstrated in all cases after injecting dyes through both sural arteries or into the lateral sural artery and the lowest anastomotic arteriole in 11 and 3 specimens, respectively. Therefore, it seems that one head can be adequately supplied from the contralateral one through their lowest anastomotic arteriole(s); nevertheless, the location of this vessel varies significantly and cannot be detected preoperatively. Measurements demonstrated that although this vessel is not found at a constant level, it is invariably detected in the lower third of the medial gastrocnemius head's length and, in 93 percent of cases, in the lower fourth. Thus, rough preoperative planning becomes feasible. Given that the venous communication between the heads has been documented as well, the authors think that an inferiorly based flap of the medial gastrocnemius head for defects of the middle third of the tibia might be both reliable and applicable; however, for reasons of safety, the muscle heads should remain attached along their lower third.     

The medial sural artery perforator free flap.

The medial sural artery supplies the medial gastrocnemius muscle and sends perforating branches to the skin. The possible use of these musculocutaneous perforators as the source of a perforator-based free flap was investigated in cadavers. Ten legs were dissected, and the topography of significant perforating musculocutaneous vessels on both the medial and the lateral gastrocnemius muscles was recorded. A mean of 2.2 perforators (range, 1 to 4) was noted over the medial gastrocnemius muscle, whereas in only 20 percent of the specimens was a perforator of moderate size noted over the lateral gastrocnemius muscle. The perforating vessels from the medial sural artery clustered about 9 to 18 cm from the popliteal crease. When two perforators were present (the most frequent case), the perforators were located at a mean of 11.8 cm (range, 8.5 to 15 cm) and 17 cm (range, 15 to 19 cm) from the popliteal crease. A series of six successful clinical cases is reported, including five free flaps and one pedicled flap for ipsilateral lower-leg and foot reconstruction. The dissection is somewhat tedious, but the vascular pedicle can be considerably long and of suitable caliber. Donor-site morbidity was minimal because the muscle was not included in the flap. Although the present series is short, it seems that the medial sural artery perforator flap can be a useful flap for free and pedicled transfer in lower-limb reconstruction.     

Blood supply of the bed nucleus of the stria terminalis in rat

Summary The topographical distribution of the blood vessels in the bed nucleus of the stria terminalis (NIST) has been mapped in rats. Arteries and veins were visualized in red and blue by using a double-ink perfusion technique. Arteries supplying the NIST arise from the anterior cerebral artery directly or through the anterior communicating and interhemispheric arteries. Only a few, dorsal branches derive from the medial cerebral artery through thalamostriatal arteries. According to their terminal branches, NIST arteries can be divided into five groups: medial, ventral, lateral, septal and dorsal, which have only a relatively small overlap in their territories. About 90% of veins from the NIST drain into the major basal veins. Medial branches run into the perioptic and interhemispheric veins, while the ventral branches and the large lateral vein drain directly into the anterior cerebral vein. A small proportion of NIST veins run dorsalward into the vena cerebri magna via thalamostriatal veins.     

Gastrocnemius fascicle length changes with two-joint passive movements

Predicting muscle fascicle length changes during passive movements may lead to a better understanding of muscle function. The purpose of this study was to experimentally compare fascicle length changes in the gastrocnemius during two-joint passive movements with a previously derived kinematic model based on anatomical measures from a cadaver. The ratio of passive ankle to knee motion was manipulated to generate medial gastrocnemius fascicle elongation and lateral gastrocnemius fascicle shortening. Ultrasound images from both heads of the gastrocnemius fascicles were acquired at 10 degrees knee flexion increments and compared with this kinematic model. Our results suggest that the two-joint kinematic model from which we originally based our knee and ankle movements did not adequately reflect fascicle length changes during any of the movement conditions in this study. From our data, we propose that for every degree of ankle motion the medial and lateral gastrocnemius changes 0.42 mm and 0.96 mm, respectively, whereas changes of 0.14 mm and 0.22 mm are observed for the medial and lateral gastrocnemius, respectively, during knee movements.     

The anatomic basis for the platysma skin flap

Meticulous anatomic dissection of the vasculature of the superficial anterolateral neck indicates that the platysma and overlying skin are supplied by direct cutaneous arteries measuring 0.5 mm in diameter. The small arteries are branches of the postauricular and occipital arteries in the upper lateral neck, the facial and submental arteries in the upper medial neck, the superior thyroid artery in the middle of the neck, the subclavian artery in the lower medial neck, and the transverse or superficial cervical arteries in the lateral aspect of the neck. These vessels traverse the undersurface of the platysma muscle to provide blood flow to the overlying skin. As opposed to this direct cutaneous system, the myocutaneous blood supply perforating through the sternocleidomastoid is scant. The platysma skin flap will survive if the blood supply from at least one region is preserved. In addition, it may be beneficial to include the external jugular and/or the communicating veins in the flap. By following these guidelines, the platysma flap has been successfully used for facial reconstruction in 7 of 8 consecutive patients.     

The role of the endothelium in the development of functional hyperemia of the skeletal muscles]

Experiments on anesthesized dogs demonstrated that gastrocnemius muscle vessels working hyperemia substantially decreased after chemical destruction of endothelium by saponin, inhibition of endothelium-derived relaxing factor synthesis by gossypol and inhibition of quanylate cyclase by methylene blue. Reaction was not decreased after cyclooxygenase inhibition by indomethacin. The endothelium-derived relaxing factor predecessor--L-arginine essentially increased working hyperemia. We concluded that endothelium plays an important role in reaction of working hyperemia by endothelium-derived relaxing factor release.     

Anatomy and Biomechanical Properties of the Plantar Aponeurosis: A Cadaveric Study

Objectives

To explore the anatomy of the plantar aponeurosis (PA) and its biomechanical effects on the first metatarsophalangeal (MTP) joint and foot arch.

Methods

Anatomic parameters (length, width and thickness of each central PA bundle and the main body of the central part) were measured in 8 cadaveric specimens. The ratios of the length and width of each bundle to the length and width of the central part were used to describe these bundles. Six cadaveric specimens were used to measure the range of motion of the first MTP joint before and after releasing the first bundle of the PA. Another 6 specimens were used to evaluate simulated static weight-bearing. Changes in foot arch height and plantar pressure were measured before and after dividing the first bundle.

Results

The average width and thickness of the origin of the central part at the calcaneal tubercle were 15.45 mm and 2.79 mm respectively. The ratio of the length of each bundle to the length of the central part was (from medial to lateral) 0.29, 0.30, 0.28, 0.25, and 0.27, respectively. Similarly, the ratio of the widths was 0.26, 0.25, 0.23, 0.19 and 0.17. The thickness of each bundle at the bifurcation of the PA into bundles was (from medial to lateral) 1.26 mm, 1.04 mm, 0.91 mm, 0.84 mm and 0.72 mm. The average dorsiflexion of the first MTP joint increased 10.16° after the first bundle was divided. Marked acute changes in the foot arch height and the plantar pressure were not observed after division.

Conclusions

The first PA bundle was not the longest, widest, or the thickest bundle. Releasing the first bundle increased the range of motion of the first MTP joint, but did not acutely change foot arch height or plantar pressure during static load testing.     

Radial fibre proportions in human knee joint menisci. Measurement by scanning optical microscopy

The proportions of medial and lateral knee joint menisci represented by radially orientated collagen (COL) were measured in 42 specimens from 24 hospital patients examined post-mortem. Images of the fibre bundles were obtained by the 488-nm laser confocal scanning of hydrated, fixed radial blocks taken from the anterior, middle and posterior regions of the menisci after staining with picro-Sirius red. Measurements of the percentage of each image occupied by fluorescent, doubly refractile COL were made by means of a Kontron IBAS image analyser, after interactive segmentation. In areas adjoining the outer, lateral parts of both the medial and lateral menisci, the proportion of all samples identified as radial COL was 7.56 +/- 0.28%. The corresponding figure for areas near the inner, medial edges of the menisci was 17.80 +/- 0.80%. However, no relationship was demonstrable between age and sex and meniscal radial fibre optical density, and there was no difference between the proportion of radial fibres in the anterior, middle or posterior regions.     

The blood supply of the reverse temporalis muscle flap: anatomic study and clinical implications

Although the reverse temporalis muscle flap has been used clinically, the exact vascular connection between the superficial and deep temporal vessels has not been clearly defined. The purpose of this study was to investigate the vascular territory of the reverse temporalis muscle supplied by the superficial temporal vessels. Six cadaver heads were studied using a colored lead oxide injection through the superficial temporal artery. The specimens were examined macroscopically and radiographically. The reverse temporalis muscle flap was then applied to a clinical case presenting with traumatic anterior skull base defect communicating with the nasal cavity. The cadaver specimens demonstrated that the superficial temporal artery formed an average 1.3 +/- 0.2 cm in width of dense vascular zone, which was located within 1.8 cm below the superior temporal line. The dense vascular network further perfused the anterior and posterior deep temporal arteries and the muscular branch of the middle temporal artery to supply the temporalis muscle. The mean perfused area of the temporalis muscle was 83 percent, ranging from 79 to 89 percent, in five cadaver heads. One cadaver revealed only 55 percent of perfused area in the absence of the muscular branch of the middle temporal artery. The consistent area without perfusion was located in the distal third of the posterior portion of the reverse temporalis muscle. In clinical cases, the reverse temporalis muscle flap was used successfully to obliterate the anterior skull base defect without evidence of muscle flap necrosis. The exact blood supply to the distal third of the posterior portion of the reverse temporalis muscle flap needs to be investigated further in vivo. Particular attention was paid to the inclusion of the muscular branch of the middle temporal artery in this flap to augment the blood supply to the temporalis muscle.     

Innervation pattern of the deep extensor abdominal muscle in the crayfish species Astacus astacus

The deep extensor abdominal muscle consisting of one medial and two lateral muscle bundles together with the nerve innervating the muscles of crayfish species Astacus astacus, was prepared. Light microscopic investigations of methylene blue stained preparations showed that the nerve innervating the deep extensor abdominal muscle consists of five distinct axons. The five axons were stained separately with lucifer yellow and the innervation pattern of the axons was determined. To confirm the histological results the axons were also stimulated with a suction electrode to elicit excitatory postsynaptic currents on the muscle membrane which were detected using a macro patch electrode. The muscle is innervated by a common excitatory and a common inhibitory axon branching over all three muscle bundles and sending additionally a branch to the L1-bundle of the next posterior segment, and by two axons specific for the two lateral muscle bundles. The axon specific for the innervation of the L1-bundle sends also a branch to the L1-bundle of the next posterior segment. In addition there is one excitatory axon which directly innervates the medial muscle bundle of the next posterior segment branching in most of the cases also to the medial bundle of the segment where it originates.Abbreviations DEAM deep extensor abdominal muscle - EPSC excitatory postsynaptic current - IPSC inhibitory postsynaptic current - L lateral - M medial - GABA -aminobutyric acid     

Vasospasm and platelet deposition in human arteries: effects of topical methylene blue

Vasodilation of small blood vessels is controlled in part by the endothelium-derived relaxing factor (EDRF), which also inhibits platelet adhesion. Methylene blue (MB), which is occasionally applied directly to blood vessels during microsurgery to provide orientation and prevent torsion, is an irreversible inhibitor of the effects of endothelium-derived relaxing factor and may thereby augment both vasospasm and platelet responses. We have investigated the effects of the extravascular adventitial application of methylene blue on platelet deposition to human placental arteries (HPA) in the presence and absence of surgically induced vasospasm. A trend toward increased platelet deposition to human placental arteries was seen in each group but did not reach significance. The degree of platelet deposition to control human placental arteries suggests that the effects of methylene blue on platelet deposition may be dwarfed by the effects of surgical trauma and ischemia.     

Distally based sural fasciomuscular flap: anatomic study and application for filling leg or foot defects

Since 1995, the authors have created 32 distally based superficial sural artery flaps based on the vascular axis of the sural nerve. The creation of the first 18 flaps permitted the authors to view perforators that issued from the gastrocnemius muscles to the vascular axis of the sural nerve. This led to the development of an anatomic study involving 25 cadaveric dissections to establish a relationship between the gastrocnemius muscles and the vascular axis of the sural nerve, with two to three constant and direct perforators from the gastrocnemius to the neurovascular axis. In this article, the technique for harvesting this new muscular flap is described. Between June of 1997 and March of 1998, three patients underwent flap operations. Two fasciomyocutaneous flaps and one fasciomuscular flap were created and were followed by uncomplicated postoperative courses in terms of flap viability and donor sites. In all cases, the flap created was designed to fill bone defects of the leg (one case) or of the foot (two cases). The results were considered to be excellent and stable over time, with follow-up periods ranging from 9 months to 18 months in duration.     

Contractile function of single muscle fibers after hindlimb suspension

The purpose of this investigation was to determine how muscle atrophy produced by the hindlimb suspension (HS) model alters the contractile function of slow- and fast-twitch single muscle fibers. After 2 wk of HS, small bundles of fibers were isolated from the soleus and the deep and superficial regions of the lateral and medial heads of the gastrocnemius, respectively. The bundles were placed in skinning solution and stored at -20 degrees C until studied. Single fibers were isolated and suspended between a motor arm and force transducer, the functional properties were studied, and subsequently the fiber type was established by myosin heavy chain (MHC) analysis on 1-D sodium dodecyl sulfate polyacrylamide gel electrophoresis. After HS, slow-twitch fibers of the soleus showed a significant reduction in fiber diameter (68 +/- 2 vs. 41 +/- 1 micron) and peak tension (1.37 +/- 0.01 vs. 0.99 +/- 0.06 kg/cm2), whereas the maximal shortening speed (Vmax) increased [1.49 +/- 0.11 vs. 1.92 +/- 0.14 fiber lengths (FL)/s]. A histogram showed two populations of fibers: one with Vmax values identical to control slow-twitch fibers and a second with significantly elevated Vmax values. This latter group frequently contained both slow and fast MHC protein isoforms. The pCa-force relation of the soleus slow-twitch fibers was shifted to the right; consequently, the free Ca2+ required for the onset of tension and for 50% of peak tension was significantly higher after HS. Slow-twitch fibers isolated from the gastrocnemius after HS showed a significant reduction in diameter (67 +/- 4 vs. 44 +/- 3 microns) and peak tension (1.2 +/- 0.06 vs. 0.96 +/- 0.07 kg/cm2), but Vmax was unaltered (1.70 +/- 0.13 vs. 1.65 +/- 0.18 FL/s). Fast-twitch fibers from the red gastrocnemius showed a significant reduction in diameter (59 +/- 2 vs. 49 +/- 3 microns) but no change in peak tension or Vmax. Fast-twitch fibers from the white superficial region of the medial head of the gastrocnemius were unaffected by HS. Collectively, these data suggest that the effects of HS on fiber function depend on the fiber type and location. Both slow-twitch type I and fast-twitch type IIa fibers atrophied; however, only slow-twitch fibers showed a decline in peak tension, and the increase in Vmax was restricted to a subpopulation of slow-twitch soleus fibers.     

Architecture of the human gastrocnemius muscle and some functional consequences

Measurements were performed on the m. gastrocnemius of eight human cadavers in order to describe, in some detail, the architecture of the muscle and its heads. The fibres of the lateral head contain more sarcomeres than those of the medial head. The effect of this difference on the length-force curve of the muscle, calculated with a planimetric muscle model, is diminished by the effect of the difference of fibre angle with respect to the line of pull of the muscle. Within the heads some variation of the number of sarcomeres of the proximal and distal fibres occurs in all muscles. In the lateral head the distal fibres contain fewer sarcomeres than the proximal fibres. In the medial head this is also found in some heads, while others show the reverse. In the lateral head the longer fibres have smaller angles of attachment to the tendon plate and vice versa, while in the medial heads this relationship is only found occasionally. Some variation in the number of sarcomeres is found in the fibres of one bundle. The effects of variations in the number of sarcomeres on the length-force curve are probably insignificant at greater muscle lengths, but may have some importance for the individual with relatively small muscle lengths.     

Phenotype of distinct primary sensory afferent subpopulations and caspase-3 expression following axotomy

Specific sensory neuronal subpopulations show contrasting responses to peripheral nerve injury, as shown by the axotomy-induced death of many cutaneous sensory neurons whilst muscular sensory afferents survive an identical insult. We used a novel combination of retrograde neuronal tracing with immunohistochemistry and laser microdissection techniques, in order to describe the neurochemistry of medial gastrocnemius (muscular sensory afferents) and sural (cutaneous sensory afferents) branches of the rat sciatic nerve and relate this to the pro-apoptotic caspase-3 gene expression following nerve transection. Our results demonstrated distinctions in medial gastrocnemius and sural neuron populations with the most striking difference in the respective proportions of isolectin B4 (IB4) staining neurons (3.7 V 32.8%). The mean neuronal area of the medial gastrocnemius (MG) neurons was larger than that of the sural (SUR) neurons (1,070.8 V 646.2 μm2) and each phenotypic group was significantly smaller in sural neurons than in MG neurons. At 1 week post-axotomy, MG neurons markedly downregulated caspase-3, whilst SUR neurons upregulated caspase-3 gene expression; this may be attributable to the differing IB4-positive composition of the subpopulations. These findings provide further clarification in the understanding of two distinct neuronal populations used increasingly in nerve injury models.     

中国水蛇脑动脉的初步观察

取已帮血管单注射的中国水蛇头部标本浸于10％HNO3中12小时,剥去脑颅各骨,可看到左右脑动脉之间有很多交通支相连,令左颈总动态血液通过这些交通支达到右侧脑部以及右侧头部各组织器官。脑动脉另一个特点是具有中脑动脉环。     

Data in favor of possible olfactory function of the antennal nerve and lateral lobe of protocerebrum of larva of the dragonfly Aeschna grandis

Using staining with methylene blue of larvae of dragonflies of the genus Aeschna sp. (2000 animals) the antennal nerve was shown to be connected with the lateral lobe of protocerebrum with a septum, through which sensory fibers enter the lobe. Near the lateral lobe of the antennal nerve, two enlargements are found, which contain motor neurons of antennal muscle as well as the incoming sensory fibers of antennal receptors and descending lateral bundles of fibers of lobes of mushroom bodies. In the lateral lobe of protocerebrum there is revealed arborization of neurons with terminal apparatuses similar to endings of the descending neuron of the glomerular antennal tract of the domestic fly.     

Comparative anatomy of rabbit and human achilles tendons with magnetic resonance and ultrasound imaging

We sought to describe the comparative anatomy of the Achilles tendon in rabbits and humans by using macroscopic observation, magnetic resonance imaging, and ultrasonography. The calcaneus-Achilles tendon-gastrocnemius-soleus complexes from 18 New Zealand white rabbits underwent ultrasound (US) and magnetic resonance (MR) imaging and gross anatomic sectioning; these results were compared with those from a cadaveric gastrocnemius-soleus-Achilles tendon-calcaneus specimen from a 68-y-old human male. The medial and lateral gastrocnemius muscle tendons merged 5.2 +/- 0.6 mm proximal to the calcaneal insertion macroscopically, at 93% of their course, different from the gastrocnemius human tendons, which merged at 23% of their overall course. The rabbit flexor digitorum superficialis tendon, corresponding to the flexor digitorum longus tendon in human and comparable in size with the gastrocnemius tendons, was located medial and anterior to the medial gastrocnemius tendon proximally and rotated dorsally and laterally to run posterior to the Achilles tendon-calcaneus insertion. In humans, the flexor digitorum longus tendon tracks posteriorly to the medial malleolus. The soleus muscle and tendon are negligible in the rabbit; these particular comparative anatomic features in the rabbit were confirmed on the MR images. Therefore the rabbit Achilles tendon shows distinctive gross anatomical and MR imaging features that must be considered when using the rabbit as a research model, especially for mechanical testing, or when generalizing results from rabbits to humans.     

Angiosomes of the brachial plexus: an anatomical study

This anatomical study analyzed the neurovascular relationships of the brachial plexus. Ten fresh cadaveric brachial plexuses were examined after injection of the arterial system. The vascular anatomical features of the brachial plexus were documented with microdissection after lead oxide/gelatin injection. The specimens were analyzed by using radiography (including digital subtraction techniques) and light-microscopic, macroscopic, and digital photography. Four angiosomes, based on the subclavian, axillary, vertebral, and dorsal scapular arteries, were observed. As noted in previous angiosome studies, connections between angiosome territories lay within tissues, in this case, nerve trunks. Nutrient vessels penetrated nerve trunks at points of branching within the brachial plexus, with a Y-shaped mode of division on entry. The vascular supply was markedly rich, often with true anastomotic connections occurring within the nerves. There was much variation in supply, depending on the vascular anatomical features of the subclavian artery.