Examination of the accessory tendons of extensor hallucis longus muscle in fetuses

There are various data about the incidence of accessory tendons (AT) of extensor hallucis longus (EHL) muscle; however, their function is unknown. This study aimed to determine the incidence and morphometric features of the AT of EHL muscle in fetuses in order to provide more information to discuss its possible function. Forty-five fetuses (26 female and 19 male) were used in this study. Fetuses were grouped as Group A (16-21 weeks), Group B (22-27 weeks), and Group C (28-34 weeks) according to their age. In 23 (51%) out of 45 fetuses, there were AT. These were bilateral in 15 fetuses (65%) and unilateral in eight fetuses (35%). Fifty-two percent of the fetuses in group A, 43% in group B, and 67% in group C had AT. AT were observed in 14 female (54%) and 9 male (47%) fetuses. In all cases, the AT were always diverging to the medial side of the main EHL tendons and attached to the metatarsophalangeal joint capsule distal to the joint space. Significant correlations were observed in this study between EHL and AT widths as well as between EHL width and EHL-AT distance on both sides. The present study is the first to provide morphometric data about the AT of EHL muscle in fetuses which will be of use in understanding their function, particularly in biomechanics of the great toe.     

The organogenetic development of the human extensor hallucis longus muscle

The organogenetic investigations on the human crural and foot musculature give only a general idea for the development of the m. extensor hallucis longus (Schomburg 1900; Bardeen 1907), but it is not possible to understand the sequence of the changes of the primordium of this muscle during its morphogenesis. To the best of our knowledge, so far no interpretation of these changes is known, although it is of great significance to the evolutionary myology. Therefore, it seemed reasonable to us to carry out an investigation on the organogenesis of the m. extensor hallucis longus from the evolutionary myology point of view, using the results of previous detailed comparative-anatomical study of the same muscle. The basis of such an investigation was well-grounded a few years ago (Kaneff 1977).     

A variation of the extensor hallucis longus muscle (accessory extensor digiti secundus muscle)

An accessory muscle adjacent to the extensor hallucis longus muscle (EHL) was observed between the EHL and the extensor digitorum longus muscle (EDL) in the anterior side of both legs of the cadaver of a 72-year-old male, during educational dissection, and it was observed that the tendon of this muscle extended to the second toe. The tendon of this muscle united with the second toe tendon of the EDL. These common tendons appeared before reaching the toe media phalanxes and extended to the related media phalanxes of toe. However, an additional tendon separating from this accessory muscle tendon united with the EHL tendon at the left foot. This accessory muscle, unlike the variations identified to date, is considered to extend to the second toe, and the name ??accessory extensor digiti secundus muscle?? is offered.     

An unusual flexor hallucis longus muscle

During the dissection of the posterior compartment of the left leg, an unusual flexor hallucis longus muscle of a fifty two years-old male cadaver was observed. On the medial side of the flexor hallucis longus, on its lower distal half, a prominent aponeurotic structure was observed. A small unusual muscle mass was attached to this aponeurotic structure. The muscular fibres of the unusual mass were arranged in form of bipennate muscle. It originated via a broad tendon from the muscular fibres of the tibialis posterior and the deep transverse fascia covering the same muscle. It inserted on the aponeurosis of the lower medial half of the flexor hallucis longus muscle. Having in mind the very different pathology in the region of the ankle and the foot, the significance of such a muscle mass could be of practical importance.     

Metabolic recovery of mouse extensor digitorum longus and soleus muscle

Heat produced by a 1-s isometric tetanus of mouse extensor digitorum longus muscle (EDL; n=6) and a 1.5-s isometric tetanus of soleus muscle (n=7) was measured with thermopiles at 20 °C, and separated into initial heat (I) and recovery heat (R). In EDL the initial heat was 190±40 (SD) mJ g^–1 and in soleus 52±9 (SD) mJ g^–1. The recovery heat production rate immediately following the tetanus was almost zero in both muscles. It rose in 12±6 s (EDL) and in 30±3 s (soleus) to a maximum, to decrease thereafter monoexponentially with a time constant of 30.7±5.7 s (EDL) and 41.7±7.2 s (soleus). The measured recovery ratio (R/I) differed between EDL (0.95±0.14) and soleus (1.54±0.22). The value for soleus muscles was significantly different from the theoretical value of 1.13. EDL muscles were freeze-clamped at rest (n=10) and during the recovery phase, 1 min after the onset of the tetanus (n=10), to determine lactate and creatine phosphate. It was found that no significant amount of net lactate was produced. The amount of creatine phosphate reformed corresponded to the recovery heat produced. The results suggest that metabolic recovery after short tetani of EDL and soleus muscles occurs predominantly through oxidative phosphorylation, but knowledge of respiratory control in the living cell is insufficient to explain its slow onset immediately following contraction and the finding that EDL recovers faster than soleus.     

Revascularization of the freely grafted extensor digitorum longus muscle in the rat

The process of revascularization of free grafts of the extensor digitorum longus muscle in rats has been studied by gross, histological and electron microscopic methods. During the first day after transplantation the muscle is entirely avascular, and it consists of a thin peripheral zone of surviving muscle fibers and a large central area of ischemic muscle. The original blood vessels of the graft undergo a sequence of intrinsic and cell-mediated destruction. Scattered sinusoidal vessels begin to grow into the graft starting on the second day, and ingrowing blood vessels progressively invade the deeper tissues of the graft. Most new vessels form in the connective tissues, but some vessels, especially larger ones, grow into persisting basal laminae from preexisting vessels and, occasionally, even into basal laminae from degenerated muscle fibers and nerves. The differentiation of new arterioles and venules in free muscle grafts is described. By the end of the first week, the entire graft is revascularized, and ultimately a fairly normal relationship between new capillaries and regenerating muscle fibers is established. In mature grafts, however, irregularities are sometimes found in the organization of smooth muscle cells associated with larger vessels.     

(足母)长伸肌腱移位治疗(足母)外翻的应用解剖学

目的:探讨(足母)长伸肌腱移位治疗(足母)外翻的解剖学入路及手术的要点.方法:(1)100例正常足及100例(足母)外翻足,测量(足母)长伸屈肌腱的位置;(2)对20具尸体40足解剖,观察(足母)长伸肌腱、(足母)长屈肌腱、(足母)短伸肌腱、腓浅神经、腓深神经、隐神经及周围血管走行特点,并测量上述结构与解剖标志的相对位置.结果:正常(足母)长伸肌腱的位置在踝横纹处位于胫骨前肌外侧(9.44±4.26)mm,在跖附关节中点外侧(2.00±2.22)mm,跖趾关节中点外侧(1.32±1.46)mm,止点位于末节趾骨基底中点(2.22±2.42)mm范围内,(足母)长屈肌腱在跖趾关节中点外侧(0.44±2.42)mm.在(足母)外翻的患(足母)者中,(足母)长伸肌腱在踝横纹处位于胫骨前肌外侧(9.32±3.46)mm,在跗跖关节中点外侧(3.00±2.22)mm,跖趾关节中点外侧(4.22±2.26)mm,止点位于末节趾骨基底中点(2.02±2.32)mm范围内,(足母)长屈肌腱在跖趾关节中点外侧(3.24±2.32)mm.(足母)趾背侧皮肤由隐神经、腓浅及腓深神经支配.结论:(1)正常与(足母)外翻足的比较中,伸肌腱的位置在足横纹及止点处无明显的差异,在跖附关节及跖趾关节处,外翻足的伸肌腱明显外移(P＜0.05).(足母)长屈肌腱也明显外移(P＜0.05).(2)手术中隐神经终末支易受损伤.(3)伸肌腱内移并止点重建可矫正(足母)外翻.     

长伸肌腱移位治疗外翻的应用解剖学

目的:探讨长伸肌腱移位治疗外翻的解剖学入路及手术的要点。方法:(1)100例正常足及100例外翻足,测量长伸屈肌腱的位置;(2)对20具尸体40足解剖,观察长伸肌腱、长屈肌腱、短伸肌腱、腓浅神经、腓深神经、隐神经及周围血管走行特点,并测量上述结构与解剖标志的相对位置。结果:正常长伸肌腱的位置在踝横纹处位于胫骨前肌外侧(9.44±4.26)m m,在跖附关节中点外侧(2.00±2.22)m m,跖趾关节中点外侧(1.32±1.46)m m,止点位于末节趾骨基底中点(2.22±2.42)m m范围内,长屈肌腱在跖趾关节中点外侧(0.44±2.42)m m。在外翻的患者中,长伸肌腱在踝横纹处位于胫骨前肌外侧(9.32±3.46)m m,在跗跖关节中点外侧(3.00±2.22)m m,跖趾关节中点外侧(4.22±2.26)m m,止点位于末节趾骨基底中点(2.02±2.32)m m范围内,长屈肌腱在跖趾关节中点外侧(3.24±2.32)m m。趾背侧皮肤由隐神经、腓浅及腓深神经支配。结论:(1)正常与外翻足的比较中,伸肌腱的位置在足横纹及止点处无明显的差异,在跖附关节及跖趾关节处,外翻足的伸肌腱明显外移(P<0.05)。长屈肌腱也明显外移(P<0.05)。(2)手术中隐神经终末支易受损伤。(3)伸肌腱内移并止点重建可矫正外翻。     

桡侧腕短伸肌双副腱1例

作者在解剖1例成年男性标本时,发现其右桡侧腕短伸肌双副腱变异（图1）.现报道如下：     

、趾短伸肌应用解剖及去神经游离移植的临床应用

目的：旨在为、趾短伸肌去神经游离移植修复腭裂、腭咽闭合不全、面瘫等提供形态学基础。方法：①对２２只足标本的、趾短伸肌的形态变异及神经支配进行解剖观察；②在１０９例手术中以神经刺激仪确认、趾短伸肌的神经，并测肌的长度，体积及重量。结果：①、趾短伸肌与长腱合并机会分别为５５．７％、６２．８％；趾短伸肌发出腱至第５趾的占７６．９％；②肌的神经支配三种类型比率分别是２４．４％、３２．８％、４２．７％；③肌的长度在８．３～１３．１ｃｍ，体积１．８～３．１ｃｍ３，重量１．９～３．２ｇ。结论：、趾短伸肌肌腱有与长腱合并的变异，趾短伸肌腱常有发出第五趾者；神经支配有三型；肌的长度、重量、体积适合肌肉游离移植的成活，是腭裂、腭咽闭合不全、尿道上裂及面瘫等外科治疗可靠的组织移植材料。     

Adaptation of rat extensor digitorum longus muscle to gamma irradiation and overload

The right extensor digitorum longus (EDL) muscle of growing male rats was overloaded by ablation of its synergist tibialis anterior (TA) muscle. Four weeks later, the overloaded muscle was heavier and contained larger type IIA, IIX and IIB fibres than either untreated contralateral muscle or control muscle from an untreated animal. The myonuclear-to-myoplasmic volume ratio was maintained in the overloaded muscle. Overloaded EDL muscle, previously subjected to a dose of irradiation sufficient to sterilise satellite cells, and EDL muscle which had been only irradiated, were significantly lighter and contained significantly smaller fibres than controls, though a significant amount of normal EDL muscle growth did occur following either treatment. The myonuclear-to-myoplasmic volume ratio of the irradiated muscles was smaller than in controls. Overloaded muscle, with or without prior irradiation, possessed a smaller proportion of fibres containing IIB myosin heavy chain (MHC) and a larger proportion of fibres containing IIA and IIX MHC; a significant percentage of these fibres coexpressed either type IIA and IIX MHC or type IIX and IIB MHC. Thus in the absence of satellite cell mitosis, muscles of young rats possess a limited capacity for normal growth but not for compensatory hypertrophy. Adaptations in MHC gene expression to chronic overload are completely independent of satellite cell activity.     

Transposition of the soleus into the bed of the extensor digitorum longus muscle in the rat

In 38 rats the slow soleus muscle was transposed, with its neurovascular bundle intact, into the bed of the fast extensor digitorum longus muscle. Transposed muscles underwent degeneration and regeneration like free muscle grafts. Both contractile and histochemical properties remained those of the soleus muscle, supporting the conclusion that the nerve to a slow muscle is pre-eminent in determining the functional and histochemical characteristics of the muscle.     

Anatomical variations of the flexor hallucis longus muscle and the consequences for tendon transfer. A cadaver study

The aim of this study was to evaluate the occurrence of anatomical variations of the musculotendinous junction of the flexor hallucis longus muscle. Eighty cadaver specimens preserved according to Thiels method were assessed. Following careful dissection, the distance between the musculotendinous junction and the bone–cartilage border of the distal tibia was determined. Three typical anatomical variations were found: (1) a long lateral and shorter medial muscle belly; (2) equal-length medial and lateral muscle bellies; (3) a long medial and shorter lateral muscle belly. As a special variation in two cases only one lateral muscle belly was found. When planning a flexor hallucis longus transfer, preoperative magnetic resonance tomography (MRT) should be carried out in order to guarantee sufficient coverage of an existing soft tissue defect. These anatomical characteristics have also to be considered when interpreting ultrasonic or MRT findings in this region.     

Effect of growth on efficiency and fatigue in extensor digitorum longus muscle of the rat

The effect of growth on work output, energy consumption and efficiency during repetitive dynamic contractions was determined using extensor digitorum longus muscles of 40-, 60-, 120- and 700-day-old male Wistar rats. When work output of each contraction was normalized to the work output of the first contraction it was found that work output initially increased over the first 10–20 contractions by approximately 8% in each age group. Thereafter a faster decrease in work output was found in the youngest group (approximately 2% each contraction) compared to the older groups (approximately 0.7% each contraction). After 40 contractions the reduction in work output was significantly different only between the youngest group and the two oldest groups (–30% vs –5%). These differences in fatigue were not associated with differences in adenosine 5-triphosphate and phosphocreatine concentrations or in lactate production. Total work output and high-energy phosphate consumption increased by approximately 555% and 380% from age 40 to 120 days, respectively. Consequently, efficiency was significantly higher (approximately 32%) in the older groups compared to 40-day-old animals. Normalized for muscle mass, mean rate of high-energy phosphate consumption was similar in all groups whereas mean power output was significantly lower in the youngest group (approximately 46%). Thus, the difference in efficiency between the young and the other groups may be attributed to a lower external power production in the youngest group rather than changes in energy turnover.     

A rare anomaly of the extensor digitorum longus

We encountered the absence of the tendon to the fourth toe of the extensor digitorum longus muscle of the right leg in the body of a 73-year-old Japanese woman during the course of educational dissection at Nagoya City University Medical School. The tendon to the fourth toe of the extensor digitorum longus muscle was solely absent. To our knowledge, this anatomical variation has never been cited in the medical literature. We document the precise gross anatomical findings with some morphometric measurements. Moreover, we discuss the morphology of this anomaly in relation to previously described variations and anomalies of the extensor digitorum longus muscle.     

Anatomical and mechanical relationship between the proximal attachment of adductor longus and the distal rectus sheath

The objectives of this study were to investigate the anatomical relationship between the proximal adductor longus (AL) and rectus abdominis muscles and to determine whether unilateral loading of AL results in strain transmission across the anterior pubic symphysis to the contralateral distal rectus sheath. Bilateral dissections were conducted on 10 embalmed cadavers. Strain transfer across the pubic symphysis was examined on seven of these cadavers. An AL contraction was simulated by applying a controlled load in the direction of its proximal tendinous fibers, and the resultant strain in the contralateral distal rectus sheath was measured using a foil‐type surface mounted microstrain gage. Adductor longus attached to the antero‐inferior aspect of the pubis. In 18 of the 20 limbs, the proximal attachment of AL was tendinous on its superficial surface and muscular on its deep surface. The proximal AL tendon was found in most instances to have secondary communications with structures such as the contralateral distal rectus sheath, pubic symphysis anterior capsule, ilio‐inguinal ligament, and contralateral proximal AL tendon. Despite these consistent anatomical observations, strain measured in the contralateral distal rectus sheath upon unilateral loading of the proximal AL varied considerably between cadavers. Measured strain had an average ± 1SD of 0.23 ± 0.43%. The proximal attachment of AL contributes to an anatomical pathway across the anterior pubic symphysis that is likely required to withstand the transmission of large forces during multidirectional athletic activities. This anatomical relationship may be a relevant factor in explaining the apparent vulnerability of the AL and rectus abdominis attachments to injury. Clin. Anat. 2013. © 2012 Wiley Periodicals, Inc.     

Variant course of extensor pollicis longus tendon in the second wrist extensor compartment

Among the muscles involved in thumb movement, the extensor pollicis longus (EPL) tendon of the hand is considered the most consistent structure with the least variation among individuals. There have been a few reports regarding different types of supernumerary tendons; however, an abnormal course of the EPL tendon is extremely rare. We describe a case of a variant course of a single EPL tendon appearing in the second extensor compartment of the wrist. This case was observed incidentally during wrist surgery, and demonstrates a unique variation of tendon course, which has not been reported previously. The knowledge of this anatomic variation is helpful in surgical planning and for making accurate diagnoses.