An unique variation of the peroneus tertius muscle

Peroneus tertius (fibularis tertius) is a muscle unique to humans. It often appears to be a part of extensor digitorum longus, and might be described as its "fifth tendon". Although its insertion variation has been reported by many authors, variations of its origin points are not common. A variation of the peroneus tertius muscle was found during routine dissection of a 75-year-old male cadaver. The muscle originated from the extensor hallucis longus. The muscle belly of the extensor hallucis longus arose from the middle two-fourths of the medial surface of the fibula, medial to the extensor digitorum longus, and anterior surface of the interosseous membrane. It lay under the extensor digitorum longus, and lateral to the tibialis anterior muscle. The muscle belly of the extensor hallucis longus divided into medial and lateral parts 17 cm below its origin point. The lateral part, named as peroneus tertius, continued downward to reach the medial part of the dorsal surface of the base of the fifth metatarsal bone. The medial part ran also downward and divided into two tendons reaching the dorsal surface of the base of the distal phalanx of the great toe. This kind of variation may be important during foot or leg surgery.     

Fibularis tertius: revisiting the anatomy

Fibularis tertius (FT) may be used during reconstructive surgery and muscle transposition with retention of function. The muscle was examined in both lower limbs of 41 cadavers. Measurements were made of muscle belly length and width, tendon length and width, and the size of the origin on the fibula. Tendon insertion, nerve and blood supplies were also examined. FT was absent in five (6.1%) lower limbs of three (7.3%) subjects. The size of its origin demonstrated inter- and intra-individual variation. FT arose from the distal fibula and on average occupied (28.4 +/- 9.1)% (mean +/- S. D.) of the total shaft length. In all cases the tendon inserted into the dorsal surface of the shafts of both the fourth and fifth metatarsals. A small nerve branch consistently arose from the deep fibular nerve near the origin of extensor digitorum longus. The nerve ran parallel to the length of this muscle, between it and extensor hallucis longus, before piercing FT. Anatomy textbooks describe FT as inserting into the fifth metatarsal only. This study, supported by data from previous reports, suggests that the "textbook" accounts of FT should be updated to record that most commonly its tendon reaches both the fourth and fifth metatarsals.     

Fibularis Tertius: Anatomical Study and Review of the Literature

Although there is much morphological variation in the anterior compartment of the leg, there is little information about the morphological variability of the fibularis tertius muscle (FTM). The main aim of the present study was to characterize the morphology (origin and insertion) and frequency of occurrence of the FTM and to use these findings as the basis for a new classification of the fibularis tertius tendon. Classical anatomical dissection was performed on 106 lower limbs fixed in 10% formalin. The presence of the FTM and the morphology of both its origin and its insertion were described. The FTM was present in 91 limbs (85.8%). Three types of origin were observed: Type 1, the most common type, with its origin on the distal half fibula (67%); Type 2, with the origin on the distal third fibula (22%); and Type 3, with an origin from the tendon of the extensor digitorum longus (11%). In addition, six types of insertion were distinguished. The most common was Type I (45%), a single distal attachment where the tendon inserts into the shaft of the fifth metatarsal bone. The rarest was Type VI, characterized by fusion with an additional band of the fibularis brevis tendon, which gives rise to the fourth interosseus dorsalis muscle. Two morphological variants of insertion could be distinguished, fan‐shaped and band‐shaped. Both the origin and insertion of the FTM are very morphologically variable, with three types of origin (Types 1–3) and six types of insertion point (Types I–VI) observed. Knowledge of such variations is essential for both clinicians and anatomists. Clin. Anat. 32:1082–1093, 2019. © 2019 Wiley Periodicals, Inc.     

Morphology of peroneus tertius muscle

Peroneus tertius (PT) muscle is peculiar to man, and man is the only member among the primates in whom this muscle occurs. The muscle is variable in its development and attachment. Because of functional demands of bipedal gait and plantigrade foot, part of extensor digitorum brevis (EDB) has migrated upwards into the leg from the dorsum of foot. PT is a muscle that evolution is rendering more important. In a total of 110 cadavers, extensor compartment of leg and dorsum of foot were dissected in both the lower limbs and extensor digitorum longus (EDL), and PT muscles were dissected and displayed. PT was found to be absent in 10.5% limbs, the incidence being greater on the right side. The remaining limbs in which the PT muscle was present had a very extensive origin from lower 3/4th of extensor surface of fibula (20% on right and in 17% on left), and the EDL was very much reduced in size. In approximately 12%, the tendon of PT was thick or even thicker than the tendon of EDL. In 4%, the tendon extended beyond fifth metatarsal up to metatarsophalangeal joint of fifth toe, and in 1.5%, it extended up to the proximal phalanx of little toe. In two cases (both on the right side), where PT was absent, it was replaced by a slip from lateral margin of EDL. We conclude that PT, which is preeminently human, is extending its purchase both proximally and distally.     

踝关节外侧韧带和距下关节韧带修复重建的应用解剖

目的 :为踝关节外侧韧带和距下关节韧带损伤修复重建提供解剖学基础。方法 :在 3 2侧经防腐固定、8侧冷藏新鲜标本上解剖观测踝关节外侧韧带和距下关节韧带及小趾趾长伸肌腱、第 3腓骨肌腱、腓骨短肌腱、伸肌下支持带 ,在新鲜标本上摹拟修复术。结果 :小趾趾长伸肌腱、第 3腓骨肌腱、腓骨短肌腱、伸肌下支持带解剖位置恒定 ,与踝关节外侧韧带和距下关节韧带相毗邻 ,具有一定的长、宽、厚度 ,可形成移植供体。结论 :①陈旧性踝关节外侧韧带和距下关节韧带的损伤 ,原位修复较难 ,用肌腱转位修复是一种可行的方法 ;②可用腓骨短肌腱修复距腓前和跟腓韧带损伤 ,小趾趾长伸肌腱和第 3腓骨肌腱转位修复距下关节韧带 ,伸肌下支持带可用作加强缝合 ,术式经标本摹拟具有可行性。     

An additional radial wrist extensor and its clinical significance

The knowledge of anatomical variations in the antebrachial and dorsal regions of the arm and hand are useful in hand surgery. The extensor carpi radialis intermedius and extensor carpi radialis accessorius are two classic variants described for the radial wrist extensors, in the antebrachial region. We report an additional extensor carpi radialis muscle taking origin from the common extensor origin, between the extensor carpi radialis longus and extensor digitorum communis. The tendon of the variant muscle divides below the abductor pollicis longus and becomes attached to the base of the second and third metacarpal bone. Due to its considerable size and independent origin from the lateral epicondyle, we suggest the present variation should be named extensor carpi radialis tertius. The clinical significance of the present variation is discussed.     

The consistent presence of the human accessory deep peroneal nerve

Twenty-four human legs were dissected macroscopically to study the morphological details of the accessory deep peroneal nerve. This nerve arose from the superficial peroneal nerve and descended in the lateral compartment of the leg, deep to peroneus longus along the posterior border of peroneus brevis. Approaching the ankle joint, this nerve passed through the peroneal tunnels to wind around the lateral malleolus; it then crossed beneath the peroneus brevis tendon anteriorly to reach the dorsum of the foot. The accessory deep peroneal nerve was found in every case examined and constantly gave off muscular branches to peroneus brevis and sensory branches to the ankle region. In addition, this nerve occasionally had muscular branches to peroneus longus and extensor digitorum brevis, and sensory branches to the fibula and the foot. The anomalous muscles around the lateral malleolus were also innervated by this nerve. Neither cutaneous branches nor communicating branches with other nerves were found. The present study reveals that the accessory deep peroneal nerve is consistently present and possesses a proper motor and sensory distribution in the lateral region of the leg and ankle. It is not an anomalous nerve as has previously been suggested.     

The peroneocuboid joint: morphogenesis and anatomical study

The peroneocuboid joint, between the peroneus longus tendon and the cuboid bone, has not been anatomically well-defined and no embryological study has been published. Furthermore, the ossification of the os peroneum (a sesamoid inside the peroneus longus tendon) and its associated pathology has been considered to be generated by orthostatic and/or mechanical loads. A light microscopy analysis of serially sectioned human embryonic and fetal feet, the analysis of human adult feet by means of standard macroscopic dissection, X-ray and histological techniques have been carried out. The peroneus longus tendon was fully visible until its insertion in the 1st metatarsal bone already at embryonic stage 23 (56–57 days). The peroneocuboid joint cavity appeared at the transition of the embryonic to the fetal period (8–9th week of gestation) and was independent of the proximal synovial sheath. The joint cavity extended from the level of the calcaneocuboid joint all the way to the insertion of the peroneus longus tendon in the 1st metatarsal bone. The frenular ligaments, fixing the peroneus longus tendon to the 5th metatarsal bone or the long calcaneocuboid ligament, developed in the embryonic period. The peroneus longus tendon presented a thickening in the area surrounding the cuboid bone as early as the fetal period. This thickening may be considered the precursor of the os peroneum and was similar in shape and in size relation to the tendon, to the os peroneum observed in adults. To the best of our knowledge, this is the first study to show that the os peroneum, articular facets of the peroneus longus tendon and cuboid bone, the peroneocuboid joint and the frenular ligaments appear during the embryonic/fetal development period and therefore they can not be generated exclusively by orthostatic and mechanical forces or pathological processes.     

Bilateral tibial hemimelia I

Congenital absence of tibia is a rare anomaly. We report a case of bilateral tibial hemimelia born to phenotypically normal parents. The two amputated legs with tibial dysplasia obtained from a 3-year-old boy were studied by radiography and anatomical dissection. The radiological evaluation revealed a normal hip joint. The lower end of femur was normal without any bifurcation, shortening or bowing. Fibula was present on both legs and there was no sign of bowing or doubling. Both right and left tibiae were absent. In addition, on the right side, five tarsal bones, two metatarsals and the corresponding digital rays were absent. On the left side, three tarsal bones were absent. Dissection of the amputated segments showed the presence of extensor digitorum longus, peroneus tertius, peroneus longus and brevis, gastrocnemius, and soleus. Following bilateral knee disarticulation the patient was fitted with prosthesis and is doing well.     

Anatomical study on the extensor digitorum profundus muscle in the Japanese

An anatomical study on the extensor digitorum profundus muscle was made using 832 upper limbs from 416 Japanese adults. The separate muscles derived from the extensor digitorum profundus consist of 10 kinds: namely, the extensor pollicis longus, extensor pollicis et indicis accessorius, extensor indicis radialis, extensor indicis proprius, extensor indicis ulnaris, extensor indicis et medii accessorius, extensor medii proprius, extensor annularis proprius, extensor carpi profundus and extensor digiti brevis. The configuration of the muscles (except for the extensor digiti brevis) in the upper limb was classified into 13 types according to their arrangement and insertion. The most frequent type involved coexistence of the extensor pollicis longus and the extensor indicis proprius: it was observed in 664 limbs (79.8%). The next type involved coexistence of the extensor pollicis longus, extensor indicis proprius and the extensor medii proprius: it was observed in 67 limbs (8.1%). It appears that the extensor digiti brevis of man is derived from the most ulnar part of the extensor digitorum profundus which does not migrate proximally.     

Longitudinal Split of the Peroneus Brevis Tendon and Lateral Ankle Instability: Treatment of Concomitant Lesions

OBJECTIVE: To describe the clinical picture, pathophysiology, and treatment of concomitant lesions of the peroneus brevis tendon and lateral ligament injuries to the ankle. BACKGROUND: In some cases, chronic lateral ankle instability is associated with a longitudinal partial tear in the peroneus brevis tendon. Patients who suffer from this lesion usually have atypical posterolateral ankle pain combined with signs of recurrent ligament instability ("giving way"). The tendon injury is often overlooked because it is combined with the ligament injury, and the injury mechanisms are similar. DESCRIPTION: Tears or laxity in the superior peroneal retinaculum allow the anterior part of the injured peroneus brevis tendon to ride over the sharp posterior edge of the fibula, leading to a longitudinal tear in the tendon. This combined injury should be suspected in patients with recurrent giving way of the ankle joint and retromalleolar pain. The diagnosis can be established using either ultrasonography or magnetic resonance imaging. DIFFERENTIAL DIAGNOSIS: Ligament injury, tenosynovitis, peroneus longus tendon lesion, os peroneum fracture, distal peroneus brevis tendon tear, or anomalous peroneus tertius tendon. TREATMENT: The tendon injury and the ligament insufficiency should be repaired at the same time. CONCLUSIONS: We recommend reconstruction of the superior peroneal retinaculum, combined with repair of the tendon, using side-to-side sutures and anatomical reconstruction of the lateral ankle ligaments.     

Anatomic bases of ankle arthroscopy: study of superficial and deep peroneal nerves around anterolateral and anterocentral approach

We studied the anatomy of the anterolateral and anterocentral portal sites for ankle arthroscopy with reference to the superficial peroneal nerve (SPN) in 29 cadavers (51 ankles) and the deep peroneal nerve (DPN) in 11 cadavers (21 ankles). In relation to the level of division into the medial and intermediate cutaneous nerves and their terminal branches, we classified the structure of the SPN surrounding the ankle into five types. We also identified the point where the SPN and the DPN cross the level of the talocrural joint. 32% of specimens had different SPN division types on the two sides and there was an average of 2 nerves at the level of the talocrural joint. Branches of the SPN were found lateral to the edge of the peroneus tertius tendon in 11.8% of specimens, and at its lateral edge in 27.5%. The DPN and some branches of the SPN were positioned around the lateral edge of the extensor hallucis longus tendon. We consider that the anterolateral portal should be made at least 2 mm lateral to the peroneus tertius tendon to avoid injury to the SPN, since the diameter of the scope is 2.7 mm. The anterocentral portal is unsuitable for arthroscopy due to a high risk of injury to the DPN and branches of the SPN.     

Morphological description of combined variation of distal attachments of fibulares in a foot

An interesting case of peculiarity of the distal attachment of the three fibular muscles is reported in the left foot of a male adult cadaver of Indian origin. The fibularis brevis, just inferior to the fibular malleolus, gave off an additional slender tendon anteromedial to its main tendon. This was attached to the dorsal digital expansion of the little toe while its main tendon was inserted to the customary bone. The tendon of fibularis longus on the plantar aspect just medial to the cuboid tunnel received a prominent slip of attachment of the tendon of tibialis posterior. The fibularis tertius had two parallel-running tendons attached to the bases of the fourth metatarsal and the fourth and fifth metatarsals respectively. The combined variation of the three fibulares in a single foot has not been reported previously. The more distal attachment of the fibularis brevis in this case is a regression in evolution. Weakness of both the fibularis brevis and fibularis longus is found in pes cavovarus. The former can be used as a rotational graft in soft tissue loss of the leg.     

Analysis of the gross anatomical variations found in four cases of trisomy 13.

The variations and defects observed during detailed gross anatomical dissections of four cases of trisomy 13 are described. Emphasis is on the muscular system where previously undocumented variations, absences, and supernumerary elements were observed. A muscle phenotype which includes absence of palmaris longus, palmaris brevis, plantaris, and peroneus tertius, the presence of pectorodorsalis muscles and muscles from the central tendon of the diaphragm to the pericardium near the pulmonary veins, and variations in the extensor indicis, extensor carpi radialis longus and brevis, biceps, and suprahyoid muscles is discussed. The brain defects which include absent olfactory bulbs and tracts and hypoplastic commissures are compared to those defects seen in cases of alobar holoprosencephaly wherein severe defects of the ethmoid bone are concomitants. Previously well-documented defects of the viscera are included.     

Analysis of the gross anatomical variations found in four cases of trisomy 13

The variations and defects observed during detailed gross anatomical dissections of four cases of trisomy 13 are described. Emphasis is on the muscular system where previously undocumented variations, absences, and supernumerary elements were observed. A muscle phenotype which includes absence of palmaris longus, palmaris brevis, plantaris, and peroneus tertius, the presence of pectorodorsalis muscles and muscles from the central tendon of the diaphragm to the pericardium near the pulmonary veins, and variations in the extensor indicis, extensor carpi radialis longus and brevis, biceps, and suprahyoid muscles is discussed. The brain defects which include absent olfactory bulbs and tracts and hypoplastic commissures are compared to those defects seen in cases of alobar holoprosencephaly wherein severe defects of the ethmoid bone are concomitants. Previously well-documented defects of the viscera are included.     

Effect of diffusion distance on measurement of rat skeletal muscle glucose transport in vitro.

The relationships between muscle size, diffusion distance, and glucose uptake were studied using the Type IIb epitrochlearis (13 +/- 1 mg intact), Type I soleus (25 +/- 1 mg), and mixed Type IIa/IIb extensor digitorum longus (25 +/- 1 mg) from 60-70 g rats. Using intact muscles, the relative rates of 3-O-methyl-glucose uptake in response to 2 mUml-1 insulin were soleus = epitrochlearis greater than extensor digitorum longus, a finding inconsistent with the fibre-type compositions and the relative GLUT-4 protein levels (soleus greater than extensor digitorum longus greater than epitrochlearis). To test whether these results were influenced by substrate diffusion limitations in the tubular muscles, soleus and extensor digitorum longus were split longitudinally from tendon to tendon into strips of comparable size (13 +/- 1 mg) to the epitrochlearis. Insulin-stimulated rates of 3-O-methyl-glucose uptake were significantly enhanced in the split soleus (+120%) and split extensor digitorum longus (+200%), but not in the epitrochlearis, with the relative rates being soleus greater than extensor digitorum longus greater than epitrochlearis. Diffusion distances of the split soleus and extensor digitorum longus, as reflected by [14C]mannitol space equilibration time, were markedly enhanced (by at least 50%) relative to the intact muscles, and were comparable to that of the epitrochlearis. These results indicate that when muscles of different size and/or shape are used for in vitro measurement of glucose transport, the muscle preparations used must have similar diffusion distances for physiologically meaningful comparisons to be made.     

Accessory peroneal nerves in the human

The Nervus peroneus profundus accessorius was described by Ruge (1878) in the lower mammals and for the first time identified by Bryce (1897) in man. It is an accessory terminal branch of the superficial peroneal (musculocutaneous) nerve which winds round the lateral malleolus beneath the tendons of the peronei muscles and reaches the dorsum of the foot; there it often supplies the lateral portion of the extensor digitorum brevis muscle. In further investigations this nerve has been traced in 21.2% of subjects resp. in 13.5% of legs. This nerve, however, is not the only accessory branch of the common peroneal nerve: In 14 out of 140 subjects (10%) resp. in 22 out of 280 legs (7.9%) a Nervus peroneus superficialis accessorius has been found. This nerve pierces the anterior crural intermuscular septum either in common with deep peroneal (anterior tibial) nerve or at a lower point. Then it descends in front of the septum rarely giving off muscular branches to the extensor digitorum longus and peroneus tertius muscles; in the lower half of the leg it pierces the crural fascia, passes in front of the ankle joint and becomes the medial cutaneous nerve of the dorsum of the foot. This accessory superficial peroneal nerve may be of importance in surgery of the leg and foot.     

家兔趾长伸肌肌内神经、运动终板和肌梭的分布

目的：探究家兔趾长伸肌肌内神经、运动终板与肌梭的分布。方法：改良Sihler’s染色法、乙酰胆碱酯酶染色法及HE染色法。结果：趾长伸肌是短肌束构成的长肌,肌束起点高的,止点相应亦较高。连于第2趾的肌纤维占据了肌腹上1／3,止于其余3趾的肌纤维位于下2／3。趾长伸肌的神经来自2条肌外神经干,上支及其分支支配第2趾的肌纤维,下支司其余3趾。运动终板分布除冠状切面上为弥漫的黑色颗粒外,其余各切面均为一条连续的运动终板带。各部的肌梭密度分别是：起端33.95个／g、肌腹中部44.76个／g、止端为零。结论：家兔趾长伸肌内,肌梭分布不均匀。肌内神经分支密集的部位,运动终板集聚、肌梭密度亦高。家兔趾长伸肌具有划分亚部的特征。     

Investigation of the nerve distribution pattern of leg muscles in rat

Information about the distribution of intramuscular nerve fibres within the skeletal muscles will enhance the understanding of their morphological structure and functions. This study was designed to examine the entire intramuscular nerve distribution pattern in rat leg muscles. The tibialis cranialis, tibialis caudalis, extensor digitorum longus, flexor digitorum longus, gastrocnemius, peroneus longus and brevis muscles were dissected from origo and insertion points under a surgical microscope in seven rats. These skeletal muscles from right hindlimbs were stained with Sihler’s stain. The diameter of extramuscular and major nerve branches, number of major and minor nerve branches and anastomoses were measured and photographed under a stereomicroscope. In addition, serial sections were obtained from the left hindlimb muscles with S100 immunohistochemical staining and transferred to the computer to reconstruct images. A significant difference was found between the gastrocnemius and tibialis caudalis (p < 0.001), flexor digitorum longus and tibialis caudalis (p < 0.003), and peroneus longus and tibialis caudalis (p < 0.049) with regard to the diameter of major branches. The gastrocnemius was significantly different from the flexor digitorum longus, peroneus longus, extensor digitorum longus, tibialis caudalis and tibialis cranialis with regard to the number of minor nerve branches (p < 0.001). Knowledge of the branching pattern and some key landmarks, such as the number and diameter of major and minor nerve branches and the number of anastomoses between the nerve branches of skeletal muscles, is helpful in surgical or therapeutic interventions and botulinum toxin injections in areas of high extramuscular and intramuscular nerve density.     

带血管蒂趾长伸肌瓣及肌骨瓣的临床应用

目的:探讨带血管蒂肌(骨)瓣的临床应用;方法:应用带血管蒂趾长伸肌(骨)瓣逆行转位修复22例小腿中下1/3胫腓骨开放性骨折并软组织缺损;结果:均获得成活;结论:实践证明该术式是修复小腿骨皮缺损的比较理想的手术方法。