Dimensional and dynamic features of mammalian gastrocnemius muscle

Attempts were made to determine how behavior of the separate heads of the rat gastrocnemius muscle are related to give responses characteristic of the whole muscle. The lateral head is heavier and shows greater isometric twitch tension than the medial head; the sum of the twitch tensions approximates values for whole muscle. Isometric tetanus tensions of the two heads are of equal magnitude; their sum is only 68% of the value for whole muscle, the deficit being due to loss of mechanical advantage by being separated. Maximum rates of isometric twitch and tetanus tension development and decay are slower in the medial than in the lateral head. The sum of the rates of twitch development approximates the value for whole muscle; the sum of rates of tetanic tension development is 65% of the value for whole muscle, this deficit also being due to loss of mechanical advantage. The medial head has a longer latent period and twitch contraction time and a greater degree of twitch fusion than the lateral head. Load-velocity curves of separate heads are similar and resemble the responses of two halves of a single muscle split lengthwise.

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Endothelial modulation of skeletal muscle blood flow andV˙o 2 during low- and high-intensity contractions

Journal of Applied Physiology ◽

10.1152/japplphysiol.01152.2000 ◽

2002 ◽

Vol 92 (2) ◽

pp. 461-468 ◽

Cited By ~ 14

Author(s):

Cheryl E. King-VanVlack ◽

J. D. Mewburn ◽

C. K. Chapler ◽

P. H. MacDonald

Keyword(s):

Skeletal Muscle ◽

Blood Flow ◽

Methyl Ester ◽

Gastrocnemius Muscle ◽

Muscle Blood Flow ◽

Tension Development ◽

Anesthetized Dogs ◽

Isometric Twitch ◽

Oxide Synthase

In the present study, we determined whether endothelin (ET)-1 contributed to the observed reduction in muscle blood flow (Q˙) during contractions with nitric oxide synthase (NOS) inhibition and whether muscle O2 uptake (V˙o 2) would be affected by the decrease in muscle Q˙ with NOS inhibition at different contraction intensities. Muscle Q˙,V˙o 2, O2 extraction ratio (OER), and tension development (TD) were studied in the in situ gastrocnemius muscle preparation in anesthetized dogs. A decrease in the V˙o 2-to-TD ratio (V˙o 2/TD) was used as an indicator of O2 limitation. Three contraction protocols were used: 1) isometric twitch contractions at 2 twitches (tw)/s, 2) the same contractions at 4 tw/s, and 3) pretreatment with an ETA-receptor antagonist (BQ-123) before 2 tw/s contractions. The muscle was stimulated to contract, and measures were obtained at steady state (∼5–8 min). NOS inhibition ( N ω-nitro-l-arginine methyl ester) was then induced, and measures were repeated at 2, 5, 10, and 15 min. During 2 tw/s contractions, NOS inhibition reduced Q˙with and without ETA-receptor blockade. In both groups, OER increased in response to the fall in Q˙, with the result being no change in V˙o 2/TD. NOS inhibition also decreased Q˙ during 4 tw/s contractions, but OER did not increase, resulting in a reduction inV˙o 2/TD 5 and 15 min after N ω-nitro-l-arginine methyl ester. These data indicated that 1) a reciprocal increase in ET-1 during NOS inhibition does not influence active hyperemia in skeletal muscle, and 2) during 4 tw/s contractions, the ischemia with NOS inhibition was associated with either an O2 limitation or an alteration in the efficiency of muscle contractions.

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The twisted structure of the fetal calcaneal tendon is already visible in the second trimester

Surgical and Radiologic Anatomy ◽

10.1007/s00276-020-02618-0 ◽

2020 ◽

Author(s):

Paweł Szaro ◽

Grzegorz Witkowski ◽

Bogdan Ciszek

Keyword(s):

Soleus Muscle ◽

Gastrocnemius Muscle ◽

Layer By Layer ◽

Second Trimester ◽

Calcaneal Tendon ◽

Medial Head ◽

Plantaris Tendon ◽

Layer Method ◽

Congenital Disabilities ◽

Lateral Head

Abstract Introduction The progress in morphological science results from the greater possibilities of intra-pubic diagnosis and treatment of congenital disabilities, including the motor system. However, the structure and macroscopic development of the calcaneal tendon have not been investigated in detail. Studies on the adult calcaneal tendon showed that the calcaneal tendon is composed of twisted subtendons. This study aimed to investigate the internal structure of the fetal calcaneal tendon in the second trimester. Materials and methods Thirty-six fetuses fixed in 10% formaldehyde were dissected using the layer-by-layer method and a surgical microscope. Results The twisted structure of the calcaneal tendon was revealed in all specimens. The posterior layer of the calcaneal tendon is formed by the subtendon from the medial head of the gastrocnemius muscle. In contrast, the anterior layer is formed by the subtendon from the lateral head of the gastrocnemius muscle. The subtendon from the soleus muscle constitutes the anteromedial outline of the calcaneal tendon. The lateral outline of the calcaneal tendon is formed by the subtendon originating from the medial head of the gastrocnemius muscle. In contrast, the medial outline is formed by the subtendon from the soleus muscle. In most of the examined limbs, the plantaris tendon attached to the tuber calcanei was not directly connected to the calcaneal tendon. Conclusions The twisted structure of the subtendons of the fetal calcaneal tendon is already visible in the second trimester and is similar to that seen in adults.

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Gastrocnemius Flap for Proximal Leg Reconstruction

Operative Plastic Surgery ◽

10.1093/med/9780190499075.003.0085 ◽

2019 ◽

pp. 863-872

Author(s):

Howard N. Langstein ◽

Elaina Y. Chen ◽

Nicholas A. Wingate

Keyword(s):

Operative Technique ◽

Gastrocnemius Muscle ◽

Myocutaneous Flap ◽

Muscle Flap ◽

Medial Head ◽

Gastrocnemius Flap ◽

Lateral Head

The gastrocnemius muscle flap has long been known as a workhorse flap for leg reconstruction given its reliability and ease of harvest. Its utility is varied, but it is especially useful for deep wounds of the proximal third of the leg with exposed vital structures or hardware. This chapter describes the preoperative markings and operative technique for the standard harvest of the medial head of the gastrocnemius muscle, with variations such as island muscle flap, lateral head of gastrocnemius muscle flap, and gastrocnemius myocutaneous flap. Alternatives such as propeller flaps are discussed as well. The gastrocnemius flap is one of many reliable and versatile flaps that plastic surgeons have in their armamentarium of options to reconstruct any defect of the leg.

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Extensibility of Gastrocnemius Muscle at Rest and During Contraction

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1957.191.1.193 ◽

1957 ◽

Vol 191 (1) ◽

pp. 193-199

Author(s):

J. D. Thomson

Keyword(s):

Isometric Tension ◽

Medial Head ◽

Cross Section Area ◽

Section Area ◽

Slow Rise ◽

Low Tension ◽

Resting Muscle ◽

Whole Muscle ◽

Parallel Resistance ◽

Lateral Head

The medial head of rat gastrocnemius shows greater static and semidynamic passive tension (per cm2 cross-section area) than the lateral head. Regarded as two resistances in parallel, resistance of lateral and medial heads together (1.16 and 4.71 mm/sec., 1–5 mm stretch) approximate resistance of whole muscle. Resting muscle shows a slow rise and low tension at 0.29 mm/sec., a rapid rise and higher tension at 1.16 mm/sec., and declining tension rise and level with faster stretches. The lateral head yields more readily than the medial head. The lateral head controls whole muscle's reaction to stretch at rest. Tetanized (15 cps) muscle shows a linear, faster tension rise with faster stretches. Excess (over isometric) tension, related to resting stretch tension, shows a decline with stretch (yielding). The amount of excess tension increases with speed of stretch. The lateral head shows less excess tension rise than the medial head. The medial head controls whole muscle's reaction to stretch during isometric tetanus.

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Twitch and Tetanic Tension during Culture of Mature Xenopus laevis Single Muscle Fibres

Archives of Physiology and Biochemistry ◽

10.1076/apab.109.5.410.11825 ◽

2001 ◽

Vol 109 (5) ◽

pp. 410-417 ◽

Cited By ~ 6

Author(s):

R.T. Jaspers ◽

H.M. Feenstra ◽

M.B.E. Lee-de Groot ◽

P.A. Huijing ◽

W.J. van der Laarse

Keyword(s):

Xenopus Laevis ◽

Muscle Fibres ◽

Single Muscle ◽

Tetanic Tension

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Obturator Nerve Transfer to the Branch of the Tibial Nerve Innervating the Gastrocnemius Muscle for the Treatment of Sacral Plexus Nerve Injury

Neurosurgery ◽

10.1227/neu.0000000000001166 ◽

2015 ◽

Vol 78 (4) ◽

pp. 546-551 ◽

Cited By ~ 4

Author(s):

Gang Yin ◽

Huihao Chen ◽

Chunlin Hou ◽

Jianru Xiao ◽

Haodong Lin

Keyword(s):

Nerve Injury ◽

Gastrocnemius Muscle ◽

Tibial Nerve ◽

Nerve Transfer ◽

Obturator Nerve ◽

Surgical Reconstruction ◽

Sacral Plexus ◽

Medial Head ◽

Anterior Branch ◽

The Mean

Abstract BACKGROUND: Lower-limb function is severely impaired after sacral plexus nerve injury. Nerve transfer is a useful reconstructive technique for proximal nerve injuries. OBJECTIVE: To investigate the clinical effectiveness and safety of transferring the ipsilateral obturator nerve to the branch of the tibial nerve innervating the medial head of the gastrocnemius muscle to recover knee and ankle flexion. METHODS: From 2007 to 2011, 5 patients with sacral plexus nerve injury underwent ipsilateral obturator nerve transfer as part of a strategy for surgical reconstruction of their plexuses. The mean patient age was 31.4 years (range, 19-45 years), and the mean interval from injury to surgery was 5.8 months (range, 3-8 months). The anterior branch of the obturator nerve was coapted to the branch of the tibial nerve innervating the medial head of the gastrocnemius muscle by autogenous nerve grafting. RESULTS: Patient follow-up ranged from 24 to 38 months. There were no complications related to the surgery. Three patients recovered to Medical Research Council grade 3 or better in the medial head of the gastrocnemius muscle. Thigh adduction function was not affected in any patient. CONCLUSION: Knee and ankle flexion can be achieved by transferring the anterior branch of the obturator nerve to the branch of the tibial nerve innervating the medial head of the gastrocnemius muscle, which is useful for balance. This procedure can be used as a new method for treating sacral plexus nerve injury.

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Length dependence of staircase potentiation: interactions with caffeine and dantrolene sodium

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y99-143 ◽

2000 ◽

Vol 78 (4) ◽

pp. 350-357 ◽

Cited By ~ 10

Author(s):

Dilson E Rassier ◽

Brian R MacIntosh

Keyword(s):

Skeletal Muscle ◽

Gastrocnemius Muscle ◽

Repetitive Stimulation ◽

Mammalian Skeletal Muscle ◽

Optimal Length ◽

Dantrolene Sodium ◽

Length Dependence ◽

Before And After ◽

Isometric Twitch

In skeletal muscle, there is a length dependence of staircase potentiation for which the mechanism is unclear. In this study we tested the hypothesis that abolition of this length dependence by caffeine is effected by a mechanism independent of enhanced Ca2+ release. To test this hypothesis we have used caffeine, which abolishes length dependence of potentiation, and dantrolene sodium, which inhibits Ca2+ release. In situ isometric twitch contractions of rat gastrocnemius muscle before and after 20 s of repetitive stimulation at 5 Hz were analyzed at optimal length (Lo), Lo - 10%, and Lo + 10%. Potentiation was observed to be length dependent, with an increase in developed tension (DT) of 78 ± 12, 51 ± 5, and 34 ± 9% (mean ± SEM), at Lo - 10%, Lo, and Lo + 10%, respectively. Caffeine diminished the length dependence of activation and suppressed the length dependence of staircase potentiation, giving increases in DT of 65±13, 53 ± 11, and 45 ± 12% for Lo - 10%, Lo, and Lo + 10%, respectively. Dantrolene administered after caffeine did not reverse this effect. Dantrolene alone depressed the potentiation response, but did not affect the length dependence of staircase potentiation, with increases in DT of 58 ± 17, 26 ± 8, and 18 ± 7%, respectively. This study confirms that there is a length dependence of staircase potentiation in mammalian skeletal muscle which is suppressed by caffeine. Since dantrolene did not alter this suppression of the length dependence of potentiation by caffeine, it is apparently not directly modulated by Ca2+ availability in the myoplasm.

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