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Lateral release is often an integral step in surgical correction of hallux valgus and can be performed using open or minimally invasive techniques. We investigated whether these techniques cause iatrogenic damage to arteries, nerves, tendons, or joint capsules. In this cadaver study, lateral release was performed on 9 pairs of specimens by a specialized foot surgeon. The specimens were randomly assigned to each group. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis. Iatrogenic damage to arteries, nerves, tendons, or joint capsules was rare, regardless of the surgical technique used. However, with the minimally invasive technique, the tendon of the extensor hallucis longus muscle and the sensitive terminal branches of the fibular nerve were at risk due to their anatomical proximity to the access portal. The deep transverse metatarsal ligament was potentially at risk if the adductor hallucis muscle was completely detached from the lateral sesamoid. When the deep transverse metatarsal ligament was transected there was risk of damaging the underlying plantar neurovascular structures. Both surgical techniques are safe in terms of the risk of injury to neighboring neurovascular and soft tissue structures.

The "toe phenomenon" refers to the extension (dorsiflexion) of the great toe, which occurs instead of the normal flexion following stimulation of the foot sole. Its clinical significance was not fully appreciated until Joseph Jules François Félix Babiński (1857-1932) described it in 1896. In 1881, Ernst Strümpell (1853-1925) had described a continuous (tonic) extension of the big toe, a finding that years later the French neurologist Jean-Athanase Sicard (1872-1929) recognized as an equivalent of the "toe phenomenon", also indicating pyramidal tract dysfunction. Previously, this phenomenon had been mentioned in patients only passingly and without providing a picture of it. In 1887, the German neurologist Adolph Seeligmüller (1837-1912) mentioned the tonic extension of the big toe among the characteristic clinical features of spastic infantile hemiplegia-a condition first described by the Austrian physician Moritz Benedikt (1835-1920) in 1868. Seeligmüller incorrectly attributed the tonic extension of the big toe to spastic contracture of the extensor hallucis longus muscle. However, he put great emphasis on this sign and considered it worth being illustrated. Adolph Seeligmüller therefore provided the very first graphic illustration of the (tonic) "toe phenomenon" in the medical literature. Of note, the first photographic illustration of this sign made by Babiński appeared only in 1900, when it had already been adopted by neurologists all over the world.

The main tendon of the extensor hallucis longus (EHL) muscle attaches to the dorsal aspect of the distal phalanx of the great toe. One or multiple accessory tendons of the EHL have been reported in several ethnic/regional groups, except Taiwan. This study aimed to investigate the incidence, length, and insertion of the accessory tendon of the EHL in Taiwanese people. Anatomical dissection was performed on 48 feet of 24 formalin-embalmed cadavers. The occurrence and morphological characteristics of the accessory tendon of the EHL were recorded and analyzed. The accessory tendon of the EHL was found in 97.92% (47/48) of the legs that were dissected. In one male cadaver, an independent muscle belly was identified in each leg, whereas all the other accessory tendons originated from the main tendon of the EHL. In this study, the insertion of the accessory tendon were classified into four patterns. The most common insertion sites were the first metatarsophalangeal (MTP) joint capsule and proximal phalanx of the great toe. The length of the accessory tendons did not correlate with age or with sex when the two tendons with independent muscle belly were excluded. The accessory tendon of the EHL appears to be a regular feature in Taiwanese people. Most accessory tendons of the EHL (85.7%) attached on the first MTP joint capsule may play a role in the prevention of capsular impingement during great toe extension.

A positive Phoenix sign occurs when a patient, with a suspected focal nerve entrapment of the Common Fibular (Peroneal) Nerve (CFN) at the level of the fibular neck, demonstrates an improvement in dorsifexion after an ultrasound guided infiltration of a sub-anesthetic dose of lidocaine. Less than 5 cc’s of 1% or 2% lidocaine is utilized and the effect is seen within minutes after the infiltration, but usually lasts only 10 minutes. This effect may be due to the vasodilatory action of lidocaine on the microcirculation in the area of infiltration. This nerve block has significant diagnostic utility as it is highly specific in the confirmation of true focal entrapment of the CFN, has high predictive value for a patient who may undergo surgical nerve decompression if they have demonstrated a positive Phoenix Sign, and may help in the surgical decision-making process in patients who have had a drop foot for many years but still may regain some motor function after decompression. In this retrospective review, 26 patients were tested, and 25 of this cohort demonstrated a Positive Phoenix Sign (an increase in dorsiflexion strength of the Extensor Hallucis Longus muscle (EHL)). One patient had no response to the peripheral nerve block. Of the 25 patients who demonstrated a positive “Phoenix Sign” and underwent nerve decompression of the CFN, and 25 (100%) showed an increase in dorsiflexion strength of the EHL after nerve decompression surgery of the CFN. The one patient in this cohort who did not demonstrate any improvement in dorsiflexion of the EHL after the nerve block did not have any improvement after surgery.

The extensor hallucis longus muscle originates from the anterior surface of the fibula and on the interosseous membrane medial to the origin of the extensor digitorum longus. Its distal attachment is typically located on the dorsal aspect of the distal phalanx of the hallux. However, EHL tendon variations have been reported in anatomical studies based on adults and fetuses. The most common variation is an additional tendinous slip in the region of the distal attachment. Additional tendinous slips can have specific names depending on where they insert. This wide range of morphological variations among the additional tendons has necessitated appropriate classification system to rank all types that could be used by clinicians. The main goal of this review is to summarize information from the available literature about the extensor hallucis longus muscle and to compare classification systems and the results of previous studies. Another aim is to create a new classification system.

From the evolutionary myology, the additional tendon of the extensor hallucis longus (EHL) muscle represents the sample of a new acquisition. We aimed to determine whether the insertion pattern of the EHL muscle differs in Koreans according to demographic populations, especially between Jeju islanders and the Korean Peninsula inhabitants. We used 69 Korean cadavers and classified the tendinous insertion of the EHL muscle as Pattern I, Pattern II, and Pattern III. The ratio of each Pattern in adult cadaveric samples was compared between demographic populations. The proportion of Pattern I, Pattern II, and Pattern III of the EHL muscle was 30.43, 63.77, and 5.80%, respectively, further divided into 18.00 vs. 36.04%, 72.00 vs. 60.47%, 10.00 vs. 3.49% in Jeju islanders vs. peninsular Koreans. There was a considerable difference in the insertion patterns of the EHL muscle in each regional group (p = 0.032), but not in each gender, age, and body sides of lower limbs. The findings of this study indicate that there was a higher incidence of the accessory tendon(s) of the EHL muscle in Koreans and the distributed insertion patterns of the EHL muscle was significantly different between Jeju islanders and peninsular Koreans.

Extensor hallucis capsularis (EHC) is an accessory tendon located medially to extensor halluces longus (EHL) tendon. Most EHC is known to originate as a tendinous slip of the EHL tendon, although it may be splitted from the tibialis anterior (TA) tendon or the extensor halluces brevis (EHB) tendon. During routine dissection of a 49-year-old male cadaver, independent muscle bellies of EHC were discovered bilaterally. The EHL muscle arose from the middle anteromedial aspect of fibula, lateral to the origin of TA muscle and medial to extensor digitorum longus (EDL) muscle. An additional muscle bellies were separated from EHL muscle at the point of 6 cm away from EHL origin in the right leg, and 3 cm away in the left. They coursed downward as EHC to reach the first metatarsophalangeal joint capsule. This muscle, unlike the variations identified to date, is considered to extend to EHC, and the name “extensor hallucis capsularis muscle” is offered. This kind of variation may be important for investigating the development of deformity at the first metatarsophalangeal joint, such as hallux valgus.

Few studies have reported about isolated contracture in the extensor hallucis longus (EHL) muscle, but none of the EHL muscle contracture after distal tibial physeal injury. Two such cases in 16- and 14-year-old boys who underwent surgeries for distal physeal injury of the tibia at a previous hospital are presented. Extension contracture of the hallux appeared 1-2 months post-surgery. Physical examinations revealed that the extension contracture of the first metatarsophalangeal joint was aggravated in plantar flexion of the ankle due to a tenodesis effect, and magnetic resonance imaging showed atrophy and signal changes in the anterior compartment muscles. This was diagnosed as EHL muscle contracture due to anterior compartment syndrome (ACS) after distal tibial physeal injury. The EHL tendon transfers were performed in both cases, with favorable short-term results. Therefore, the EHL tendon transfer might be preferable in case of the EHL muscle contracture due to partial ACS.

Introduction The extensor hallucis longus originates from about the middle three fifths of the anterior surface of the fibula, medial to the origin of the extensor digitorum longus, and inserts into the distal phalanx of the great toe. The goal of this study was to examine the insertion of the extensor hallucis longus tendon and thus prepare its first classification in human fetuses. Material and Methods Fifty spontaneously-aborted human fetuses (26 male, 24 female, 100 lower limbs), aged 18–38 weeks of gestation, were examined. Results The classification comprised three types of extensor hallucis longus insertion. The most common was type I (68%), which was characterized by a single tendon that ends as an extensor hood inserting into the dorsal aspect of the base of the distal phalanx of the great toe. The second most frequent was type II (27%), which was characterized by two distal tendons: the dominant one ends as an extensor hood inserting into the distal phalanx of the great toe, and the auxiliary inserts separately into the dorsal aspect of the proximal phalanx of the great toe, medial to the insertion of the extensor hallucis brevis tendon. Finally, type III (5%), the least frequent type, was characterized by two distal tendons: the dominant one ends as an extensor hood inserting into the distal phalanx of the great toe, and the auxiliary connects to the tendon of the extensor hallucis brevis. Conclusion The extensor hallucis longus demonstrates great variability in the approach of its tendon to the foot, at least in fetuses, as indicated by this initial classification.

Backgroud The accessory tendon of the extensor hallucis longus (ATEHL) muscle is a common abnormal structure, and its clinical significance remains debatable. In this study, we provide the incidence of the ATEHL and characterize its morphological types in Asian cadavers and investigate its clinical applications. Methods The tendons from 50 adult cadaveric feet, fixed in 10% formalin, were analyzed. We measured the length and width of both the ATEHL and the extensor hallucis brevis (EHB). Results All dissected specimens had an ATEHL. The first metatarsophalangeal joint was surrounded by an accessory tendon that inserted onto the joint capsule and the dorsal base of the proximal phalanx. We classified the ATEHL into 3 types based on their directions. Differences in ATEHL type based on sex were not statistically significant. Conclusions We found an ATEHL in all cadaveric specimens in this study. We surmise that the ATEHL acts as an antagonist with the EHB when the toe is extending, which might help prevent the occurrence of hallux valgus deformity.

Closed rupture of the extensor hallucis longus (EHL) tendon is rare, with most cases caused by either direct penetrating trauma or predisposing factors such as corticosteroid injection and iatrogenic trauma incidences. Almost all of the previous case reports have reported on rupture of the EHL tendon rather than the EHL muscle. In this report, we highlight an unusual clinical presentation of a rupture of the EHL muscle and discuss its predisposing factors. This patient was a taekwondo athlete with EHL muscle rupture secondary to repetitive overuse without any underlying systemic or local predisposing factors or direct trauma. Fifteen months after successful surgical treatment, he became fully functional again as an elite taekwondo athlete.

OBJECTIVEIntraneural ganglion cysts are rare and benign mucinous lesions that affect peripheral nerves, most frequently the common peroneal nerve (CPN). The precise pathophysiological mechanisms of intraneural ganglion cyst development remain unclear. A well-established theory suggests the spread of mucinous fluid along the articular branch of the peroneal nerve as the underlying mechanism. Clinical outcome following decompression of intraneural ganglion cysts has been demonstrated to be excellent. The aim of this study was to evaluate the correlation between clinical outcome and ultrasound-detected morphological nerve features following decompression of intraneural ganglion cysts of the CPN.METHODSData were retrospectively analyzed from 20 patients who underwent common peroneal nerve ganglion cyst decompression surgery at the Universität Ulm/Günzburg Neurosurgery Department between October 2003 and October 2017. Postoperative clinical outcome was evaluated by assessment of the muscular strength of the anterior tibial muscle, the extensor hallucis longus muscle, and the peroneus muscle according to the Medical Research Council grading system. Hypesthesia was measured by sensation testing. In all patients, postoperative morphological assessment of the peroneal nerve was conducted between October 2016 and October 2017 using the iU22 Philips Medical ultrasound system at the last routine follow-up appointment. Finally, the correlations between morphological changes in nerve ultrasound and postoperative clinical outcomes were evaluated.RESULTSDuring the postoperative ultrasound scan an intraneural hypoechogenic ring structure located at the medial side of the peroneal nerve was detected in 15 (75%) of 20 patients, 14 of whom demonstrated an improvement in motor function. A regular intraneural fasicular structure was identified in 3 patients (15%), who also reported recovery. In 1 patient, a recurrent cyst was detected, and 1 patient showed intraneural fibrosis for which recovery did not occur in the year following the procedure. Two patients (10%) developed neuropathic pain that could not be explained by nerve ultrasound findings.CONCLUSIONSThe results of this study demonstrate significant recovery from preoperative weakness after decompression of intraneural ganglion cysts of the CPN. A favorable clinical outcome was highly correlated with an intraneural hypoechogenic ring-shaped structure on the medial side of the CPN identified during a follow-up postoperative ultrasound scan. These study results indicate the potential benefit of ultrasound scanning as a prognostic tool following decompression procedures for intraneural ganglion cysts of the CPN.

Most of the anatomic variations of the extensor hallucis longus (EHL) muscle are related to the tendon of insertion. We show a double origin of the EHL from the medial aspect of the fibula and the lateral aspect of the tibia. A 27-year-old male with a double closed fracture of tibia and fibula showed an involuntary extension of the big toe during foot plantar flexion after surgery. A tendon fibrosis by the fixation plates could be the cause of the foot functional alteration. Interestingly, the anatomic variation described could be related to the postsurgical foot dysfunction, since when the fibrotic tissue was removed the normal extension of big toe recovered. As illustrated in this case report, knowledge of anatomic variations is very useful, particularly in the context of foot surgery.

OBJECTIVEThe objective of this study was clinical assessment of the reduction of pathological motor phenomena with the recovery of long toe extensors, and evaluation of functional outcome with simultaneous nerve and tendon transfer in cases of common peroneal nerve (CPN) injuries.METHODSSeven male patients (mean age 26.4 years) received a partial tibial nerve transfer to the extensor hallucis longus muscle (MEHL) and extensor digitorum longus muscle (MEDL) motor branches, after a mean of 2.7 months following a traction-type injury to the CPN. Tibialis posterior muscle (MTP) tendon transfer through the interosseous route was performed on the same day. The follow-up period included a clinical neurological examination, a modified Stanmore System questionnaire (MSSQ), electromyographic examination of the interference pattern, and a video-based analysis of the gait biomechanics in the 3rd and 12th months. Video analysis of the gait investigated the presence or reduction of “stair-climbing maneuver” (SCM), foot slap (FS), and foot stability during the gait cycle.RESULTSThe average range of active dorsiflexion in the 3rd month was 0.85°. SCM accompanied walking in 6 patients (86%). FS accompanied walking in 3 patients (43%) and 3 patients (43%) avoided FS by planting the entire foot on the ground. All patients required orthopedic support (shoe inserts) to compensate for mediolateral foot instability. The average MSSQ score was 80.4 points. The average duration for the effective recovery of function (≥ 4 points on the Medical Research Council grading system) of long toe extensors was 11.2 months. The average range of active dorsiflexion in the 12th month increased to 4.4°. A reduction of FS was observed in 5 patients (71%). Excessive foot eversion was reduced in 4 patients (57%). Another 3 patients (43%) required no specific orthopedic shoe inserts. Reduction of pathological motor phenomena with recovery of the long toe extensors resulted in an increase of functional outcome. The average MSSQ score after 12 months was 92.4 points.CONCLUSIONSPartial tibial nerve transfer to the motor branches of the extensor hallucis longus and the long toe extensors along with the simultaneous tibialis posterior tendon transfer produce the reduction of FS and bring mediolateral stability to the foot, i.e., improved gait biomechanics. The reduction of pathological motor phenomena at the time of recovery of the long toe extensors is reflected in an increase in patients’ functional perception of the injured lower extremity during daily walking.

Introduction The extensor hallucis longus (EHL) muscle is important for diagnosis of neurologic lesions. It is also a target muscle for treatment. We investigated EHL with ultrasonography to determine optimal needle placement for safety and accuracy. Methods A total of 96 legs of 48 healthy volunteers were examined through ultrasonography. Four published electromyographic methods for finding the EHL were assessed. We identified the midpoint of EHL (MD) using landmarks to determine optimal needle placement. Results Mean values of bimalleolar line-MD on skin (MD-S) and tibial crest-MD-S were 10.5 ± 1.2 cm and 3.6 ± 0.4 cm, respectively. The depth of MD was 1.6 ± 0.2 cm. According to 4 EMG methods, the probability of needle penetrating EHL was 13% to 79% and that of needle penetrating the neurovascular bundle was 50% to 89%. Conclusions Using ultrasonography, we could determine optimal needle placement in the EHL. Muscle Nerve 59:331-336, 2019.

The original version of this article unfortunately contained mistakes. The names of all authors are inadvertently inverted and are now corrected in the authorgroup of this article.

The present paper is for the interest for the disciples of surgery, orthopedics and sports medicine. The aim is to study the variations in insertion of extensor hallucis longus muscle encountered d...

The extensor hallucis longus (EHL) muscle inserts into the dorsum of the base of the distal phalanx of the big toe, yet variants may possess one or more accessory tendinous slips that insert into o...

Extensor hallucis longus tendon injury and surgical treatment recommendations are infrequently reported. In contrast to long extensor tendon injuries to the foot, flexor and extensor tendon injuries of the hand have been extensively studied and surgical treatment protocols have been delineated. In biomechanical studies, the Massachusetts General Hospital technique has been shown to have superior strength to other tenorrhaphies and to allow for early active mobilization. The purpose of this study was to examine the use of this technique for repair of extensor hallucis longus tendon injuries to allow for early active motion with minimal risk of rupture. We performed a retrospective review of 6 extensor hallucis longus tendon repairs at the toe level. These patients all regained active motion of the great toe. None had loss of extension. There were no tendon ruptures with this technique of tendon repair. The Massachusetts General Hospital technique can be used to repair the extensor hallucis longus tendon with good functional outcome and minimal risk of tendon rupture.

The accessory extensor tendon of the first metatarsophalangeal joint (1st MTPJ) was evaluated in 32 cadaver feet. Eighty-one percent of feet possessed an accessory tendon to the 1st MTPJ. Of those feet possessing an accessory tendon to the 1st MTPJ, approximately 92% originated from the extensor hallucis longus muscle-tendon unit, while approximately 8% originated from the tibialis anterior muscle-tendon unit. All accessory tendons inserted onto the dorsal/dorsomedial capsule of the 1st MTPJ. Accessory tendons were found to be bilateral in the majority (87.5%) of specimens. Differences in sex distribution of the accessory tendon of the 1st MTPJ were not statistically significant. The difference in distribution of an accessory tendon to the 1st MTPJ in those feet that demonstrated clinical hallux valgus versus those that did not demonstrate hallux valgus was not statistically significant ( p = 1.0000, respectively, Fisher's exact test). This tendon is unique to the human foot (lacking in primates) and is a fairly constant structure (80%). The data presented do not lend support for the accessory tendon of the 1st MTPJ to play a role in the development of hallux valgus. At the present time, the role of this accessory tendon on the biomechanics of the 1st MTPJ remains unknown.

Muscles within the anterior crural compartment (extensor digitorum longus, EDL; tibialis anterior, TA; and extensor hallucis longus, EHL) and within the peroneal compartment were excited simultaneously and maximally. All muscles were kept at constant length with the exception of EDL, for which muscle length was changed by moving its proximal tendon. Active and passive force was measured at proximal as well as distal EDL tendons and at the combined distal tendons of TA and EHL (TA+EHL). In the initial experimental condition, a difference (Fproximal > Fdistal) in EDL force, amounting to 0-14% of proximal force, was confirmed for most EDL lengths. This is interpreted as a clear proof of extramuscular myofascial force transmission, as no significant EDL length effects could be shown on TA+EHL force. Repeated measurements were confirmed to cause marked changes of both proximal and distal length-force characteristics, such as a shift of the whole ascending limb of the active curve, including optimum length, to higher lengths without decreasing optimum force, and decreasing active force at low lengths (by ~57%). Repeated measurements also lowered proximal and distal EDL passive force (by up to 35%). The proximo-distal difference in passive as well as active EDL force was decreased, but persisted. At most lengths, this difference for active force amounted to a constant fraction (14%) of proximal force. TA+EHL force was not affected significantly. Subsequently, acute effects of experimental surgical alterations were studied: The first manipulation was full lateral fasciotomy of the anterior crural compartment that caused a further decrease in active force at the proximal EDL but not at the distal EDL tendon. Passive forces showed no further significant changes. The proximo-distal EDL active force difference decreased to 0-5% of proximal force. After fasciotomy, TA+EHL force increased by 30%. This was interpreted as evidence of increased intramuscular and decreased extramuscular myofascial force transmission. The second manipulation was full isolation of EDL from TA+EHL, but not from extramuscular connective tissues, which caused a further decrease of the EDL proximo-distal force differences, indicating a stiffening effect of the presence of TA+EHL on the extramuscular matrix. For EDL active force the difference was no longer significantly different from zero. In contrast, for EDL passive force the proximo-distal force difference persisted. It is concluded that extramuscular myofascial force transmission is an important feature of the anterior crural compartment. The magnitude of this force transmission requires that it be considered in analysis of muscular function. J. Morphol. 256:306-321 2003

Force transmission from muscle fibers via the connective tissue network (i.e., myofascial force transmission) is an important determinant of muscle function. This study investigates the role of myofascial pathways for force transmission from multitendoned extensor digitorum longus (EDL) muscle within an intact anterior crural compartment. Effects of length changes exclusively of head III of rat EDL muscle (EDL III) on myofascial force transmission were assessed. EDL III was lengthened at the distal tendon. For different lengths of EDL III, isometric forces were measured at the distal tendon of EDL III, as well as at the proximal tendon of whole EDL and at the distal tendons of tibialis anterior and extensor hallucis longus (TA+EHL) muscles. Lengthening of EDL III caused high changes in force exerted at the distal tendon of EDL III (from 0 to 1.03 ± 0.07 N). In contrast, only minor changes were found in force exerted at the proximal EDL tendon (from 2.37 ± 0.09 to 2.53 ± 0.10 N). Increasing the length of EDL III decreased TA+EHL force significantly (by 7%, i.e., from 5.62 ± 0.27 to 5.22 ± 0.32 N). These results show that force is transmitted between EDL III and adjacent tissues via myofascial pathways. Optimal force exerted at the distal tendon of EDL III (1.03 ± 0.07 N) was more than twice the force expected on the basis of the physiological cross-sectional area of EDL III muscle fibers (0.42 N). Therefore, a substantial fraction of this force must originate from sources other than EDL III. It is concluded that myofascial pathways play an important role in force transmission from multitendoned muscles.

Dysfunction of the lower limb's muscles can cause severe impairment and immobilisation of the patient. As one of the leg's major motor and sensory nerves, the deep peroneal nerve (synonym: deep fibular nerve) plays a very important role in muscle innervation in the lower extremities. We report the case of a 19-year-old female patient, who suffered from a brace-like exostosis 6-cm underneath her left fibular head causing a partially irreversible paresis of her deep peroneal nerve. This nerve damage resulted in complete atrophy of her extensor digitorum longus and extensor hallucis longus muscle, and in painful sensory disturbance at her left shin and first web space. The tibialis anterior muscle stayed intact because its motor branch left the deep peroneal nerve proximal to the nerve lesion. Diagnosis was first verified 6 years after the onset of symptoms by a magnetic resonance imaging (MRI) scan of her complete left lower leg. Subsequently, the patient was operated on in our clinic, where a neurolysis was performed and the 4-cm-long osteocartilaginous exostosis was removed. Paralysis was already irreversible but sensibility returned completely after neurolysis. The presented case shows that an osteocartilaginous exostosis can be the cause for partial deep peroneal nerve paresis. If this disorder is diagnosed at an early stage, nerve damage is reversible. Typical for an exostosis is its first appearance during the juvenile growth phase.

During routine dissection of an adult human cadaver, a suite of tendinous anomalies was discovered in the left hallucal region. Whereas the main tendon of the extensor hallucis longus muscle inserted normally, two accessory tendons were found coursing medial and lateral to the main tendon. The most lateral tendon originated from a supernumerary muscle belly and merged with the tendon of extensor hallucis brevis to form a composite tendon. The most medial tendon crossed the metatarsophalangeal joint and joined the composite tendon deep to the tendon of extensor hallucis longus. A terminal tendon, consisting of these three contributions, inserted upon the proximal hallucal phalanx. This variant likely arose due to atypical differentiation of the common extensor muscle mass during development, and is of particular significance to clinicians performing arthroscopy, tendon transfers, and other surgical procedures.

A prospective study of consecutive patients undergoing surgery for central lumbar spinal stenosis.To evaluate symptoms and signs in patients undergoing surgery for central spinal stenosis and to correlate the findings to age, preoperative duration of symptoms, and radiographically detected constriction.The degree of constriction of the spinal canal considered to be symptomatic of lumbar canal stenosis is not clear, nor is the relation between the clinical appearance of the disease and the degree of radiographically verified constriction.One hundred five consecutive patients scheduled for decompression surgery were included in a prospective study. The day before surgery, all patients were interviewed and examined, using a defined protocol that included data on age, gender, preoperative duration of symptoms, walking ability, and occurrence of pain at rest and at night. Included were data recording straight leg raising test results, reflex disturbance, and extensor hallucis longus muscle weakness. All radiographs were examined by a neuroradiologist. The anteroposterior diameters at each site from L1-L2 to L5-S1 were recorded. For the computer analysis, the site of and width at the narrowest site was registered, as well as the number of sites with an anteroposterior diameter of less than 10 mm. A statistical analysis was performed using chi-square analysis, nonparametric tests, analysis of variance, and logistic regression.Pain at rest and at night was reported by 68 and 60 patients, respectively, and was more common in younger patients (P = 0.065 and 0.015, respectively). A severe reduction of walking ability (0.5 km) was reported by 70 patients. The straight leg raising test results were negative in 70 patients, positive60 degrees in 16, positive 30-60 degrees in 14, and positive30 degrees in 5. Younger patients had a positive straight leg raising result (P = 0.028, analysis of variance) more often. Reflex disturbances correlated to patient age: Older patients had reflex disturbances more often. There was no correlation between preoperative duration and pain or neurologic disturbances: Patients with longer preoperative duration of symptoms did not demonstrate more severe symptoms. There was a total myelographic block of the spinal canal in 13 patients. The mean value of the antero-posterior diameter in the other patients was 6.8 mm (range, 4-11 mm). In patients younger than 70 years L4-L5 was the site for the most pronounced constriction, whereas L3-L4 was the narrowest site in the older patients. Degenerative spondylolisthesis was found in 32 patients, and they had a more pronounced constriction of the spinal canal (5.6 mm compared with 6.7 mm in those without displacement, P = 0.02). There was a (nonsignificant) tendency toward more walking disturbances in patients with a more pronounced constriction of the spine. There was no correlation between reflex disturbances or extensor hallucis longus weakness and radiographically detected constriction.Pain was more intense and positive straight leg raising test results were more common in younger patients, whereas reflex disturbances were more common in the elderly. The vertebral site for the lowest anteroposterior value was higher with higher age. Preoperative duration did not affect the severity of symptoms or signs. Patients with more pronounced stenosis tended to have a more severe reduction of walking ability. There was no correlation between symptoms and signs and radiographically detected constriction.

The plantar response is a reflex that involves not only the toes, but all muscles that shorten the leg. In the newborn the synergy is brisk, involving all flexor muscles of the leg; these include the toe ‘extensors’, which also shorten the leg on contraction and therefore are flexors in a physiological sense. As the nervous system matures and the pyramidal tract gains more control over spinal motoneurones the flexion synergy becomes less brisk, and the toe ‘extensors’ are no longer part of it. The toes then often go down instead of up, as a result of a segmental reflex involving the small foot muscles and the overlying skin, comparable to the abdominal reflexes. With lesions of the pyramidal system, structural or functional, this segmental, downward response of the toes disappears, the flexion synergy may become disinhibited and the extensor hallucis longus muscle is again recruited into the flexion reflex of the leg: the sign of Babinski. A true Babinski sign denotes dysfunction of the pyramidal tract, and should be clearly distinguished from upgoing toes that do not belong to the flexion synergy of the leg. Correct interpretation of the plantar response depends only to a minor degree on the method or site of stimulation of the foot. It is therefore most important to assess the response in the entire leg.

The peroneal nerves and their blood supply are at risk during high tibial osteotomies. Fixation of nerves by fibrous tissues, compression by tendinous arcades of the peroneus longus tendon, and narrow passages for nerves crossing dense fibrous septa are all factors which favor the development of peroneal nerve lesions. Intraoperative soft tissue retraction and pull by retractors may damage nerves and vessels. The muscle branch for the extensor hallucis longus muscle is particularly at risk during the fibular osteotomy since it runs directly on the bone.

Surgical Principles In varus osteoarthritis of the knee the force of weight bearing, which normally passes through the centre of the weight bearing surfaces, is medially displaced [4, 8]. In order to redistribute the load evenly over a larger articular surface a modified Maquet upper tibial osteotomy via midline vertical incision is performed. By valgus overcorrection of 5°, the tibial plateau is tilted and this changes the mechanical axis in such a way, that the resultant forces pass through the centre of the knee joint and at a right angle to the plane tangential to the articular surfaces [7, 9]. The degree of correction (varus deformity + 5°) is determined preoperatively on the basis of a full length, single stance weight bearing film (120 cm × 30 cm, distance at least 3 m) [8]. The fibula is divided to allow adequate correction of the tibia; this is done by excising a segment of the fibula. Because of variations in the innervation of the extensor hallucis longus muscle this should be performed in a relatively safe area, about 160 mm distal to the fibular head [5] through a postero-lateral approach [4]. The size of the excised segment depends on the degree of correction required. A dome osteotomy (barrel vault osteotomy) above the level of the tibial tubercle allows a correction of up to 25°. The osteotomy is compressed with at least four staples in two different planes. Contrary to the technique described by Maquet [8] the distal tibial fragment is not advanced anteriorly.

The purpose of this study was to look closely at the anatomy of the extensor hallucis longus, ligament or tendon capsularis Accessory Extensor hallucis longus muscle; defi ne its occurrence frequency, it is a muscle that is not present in all feet and raises controversy in the reviewed literature. The ligament is a ligament capsularis dorsalis pedis group that accompanies the extensor hallucis longus muscle medial to it forever. We intend to demonstrate by our dissections, a ligament more common than it seems and where is its origin and insertion as well as their function, presentation and location by using photographs of cadaver feet and its width measures and characteristics. To achieve our object of study in this article, fi rst 50 dissected human cadaver fi ngers, making the relevant measurements.

A 23-year-old healthy laborer involved in a work-related injury, sustained excessive left ankle plantarflexion, which resulted in closed rupture of the extensor hallucis longus muscle without any predisposing factors. He had an associated fracture of the second metatarsal shaft. The muscle proximal to the musculotendinous junction was excised, and the tendon was looped through a longitudinal slit in the main extensor digitorum communis tendon and sutured to it. The second metatarsal fracture was fixed with Kirschner wires. The patient regained full function and was symptom free 6 months after surgery.

Iatrogenic, isolated weakness or paralysis of the extensor hallucis longus muscle is a common complication in patients who have had a proximal tibial and fibular osteotomy. To investigate why this complication occurs, we dissected the deep peroneal nerve and neighboring structures, such as the tibia and fibula and the muscles of the leg, in twenty-nine specimens from cadavera, paying special attention to the motor branches supplying the extensor hallucis longus. Of forty-six motor nerves that were identified, eight entered the muscle from the lateral side in an area seventy to 150 millimeters distal to the fibular head; all of them ran close to the fibular periosteum. We suggest that, in some patients, the nerve supply to the extensor hallucis longus is at high risk for injury during a tibial osteotomy because of the proximity of the bone to the motor branches.

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 goal of the present study was to test the hypothesis that epimuscular myofascial force transmission occurs between deep flexor muscles of the rat and their antagonists: previously unstudied mechanical effects of length changes of deep flexors on the anterior crural muscles (i.e., extensor digitorum longus (EDL), as well as tibialis anterior and extensor hallucis longus muscle complex (TA + EHL) and peroneal (PER) muscles were assessed experimentally. These muscles or muscle groups were kept at constant length, whereas, distal length changes were imposed on deep flexor (DF) muscles before performing isometric contractions. Distal forces of all muscle-tendon complexes were measured simultaneously, in addition to EDL proximal force. Distal lengthening of DF caused substantial significant effects on its antagonistic muscles: (1) increase in proximal EDL total force (maximally 19.2%), (2) decrease in distal EDL total (maximally 8.4%) and passive (maximally 49%) forces, (3) variable proximo-distal total force differences indicating net proximally directed epimuscular myofascial loads acting on EDL at lower DF lengths and net distally directed loads at higher DF lengths, (4) decrease in TA + EHL total (maximally 50%) and passive (maximally 66.5%) forces and (5) decrease in PER total force (maximally 51.3%). It is concluded that substantial inter-antagonistic epimuscular myofascial force transmission occurs between deep flexor, anterior crural and peroneal muscles. In the light of our present results and recently reported evidence on inter-antagonistic interaction between anterior crural, peroneal and triceps surae muscles, we concluded that epimuscular myofascial force transmission is capable of causing major effects within the entire lower leg of the rat. Implications of such large scale myofascial force transmission are discussed and expected to be crucial to muscle function in healthy, as well as pathological conditions. © 2008 Elsevier Ltd. All rights reserved.

A 35-year-old woman presented with bilateral leg pain on walking that had been present since childhood. Clinical examination showed bilateral absence of the tibialis anterior tendons and the left extensor hallucis longus tendon. Magnetic resonance imaging revealed that signal intensities in the location of the tibialis anterior muscles bilaterally and the left extensor hallucis longus muscle were uniformly high on T1-weighted images, consistent with fat tissue and aplastic muscles: findings not previously reported.

Muscles within the anterior crural compartment (extensor digitorum longus, EDL; tibialis anterior, TA; and extensor hallucis longus, EHL) and within the peroneal compartment were excited simultaneously and maximally. All muscles were kept at constant length with the exception of EDL, for which muscle length was changed by moving its proximal tendon. Active and passive force was measured at proximal as well as distal EDL tendons and at the combined distal tendons of TA and EHL (TA+EHL). In the initial experimental condition, a difference (Fproximal > Fdistal) in EDL force, amounting to 0-14% of proximal force, was confirmed for most EDL lengths. This is interpreted as a clear proof of extramuscular myofascial force transmission, as no significant EDL length effects could be shown on TA+EHL force. Repeated measurements were confirmed to cause marked changes of both proximal and distal length-force characteristics, such as a shift of the whole ascending limb of the active curve, including optimum length, to higher lengths without decreasing optimum force, and decreasing active force at low lengths (by ~57%). Repeated measurements also lowered proximal and distal EDL passive force (by up to 35%). The proximo-distal difference in passive as well as active EDL force was decreased, but persisted. At most lengths, this difference for active force amounted to a constant fraction (14%) of proximal force. TA+EHL force was not affected significantly. Subsequently, acute effects of experimental surgical alterations were studied: The first manipulation was full lateral fasciotomy of the anterior crural compartment that caused a further decrease in active force at the proximal EDL but not at the distal EDL tendon. Passive forces showed no further significant changes. The proximo-distal EDL active force difference decreased to 0-5% of proximal force. After fasciotomy, TA+EHL force increased by 30%. This was interpreted as evidence of increased intramuscular and decreased extramuscular myofascial force transmission. The second manipulation was full isolation of EDL from TA+EHL, but not from extramuscular connective tissues, which caused a further decrease of the EDL proximo-distal force differences, indicating a stiffening effect of the presence of TA+EHL on the extramuscular matrix. For EDL active force the difference was no longer significantly different from zero. In contrast, for EDL passive force the proximo-distal force difference persisted. It is concluded that extramuscular myofascial force transmission is an important feature of the anterior crural compartment. The magnitude of this force transmission requires that it be considered in analysis of muscular function. J. Morphol. 256:306-321 2003

Muscles within the anterior crural compartment (extensor digitorum longus, EDL; tibialis anterior, TA; and extensor hallucis longus, EHL) and within the peroneal compartment were excited simultaneously and maximally. All muscles were kept at constant length with the exception of EDL, for which muscle length was changed by moving its proximal tendon. Active and passive force was measured at proximal as well as distal EDL tendons and at the combined distal tendons of TA and EHL (TA+EHL). In the initial experimental condition, a difference (Fproximal > Fdistal) in EDL force, amounting to 0-14% of proximal force, was confirmed for most EDL lengths. This is interpreted as a clear proof of extramuscular myofascial force transmission, as no significant EDL length effects could be shown on TA+EHL force. Repeated measurements were confirmed to cause marked changes of both proximal and distal length-force characteristics, such as a shift of the whole ascending limb of the active curve, including optimum length, to higher lengths without decreasing optimum force, and decreasing active force at low lengths (by ~57%). Repeated measurements also lowered proximal and distal EDL passive force (by up to 35%). The proximo-distal difference in passive as well as active EDL force was decreased, but persisted. At most lengths, this difference for active force amounted to a constant fraction (14%) of proximal force. TA+EHL force was not affected significantly. Subsequently, acute effects of experimental surgical alterations were studied: The first manipulation was full lateral fasciotomy of the anterior crural compartment that caused a further decrease in active force at the proximal EDL but not at the distal EDL tendon. Passive forces showed no further significant changes. The proximo-distal EDL active force difference decreased to 0-5% of proximal force. After fasciotomy, TA+EHL force increased by 30%. This was interpreted as evidence of increased intramuscular and decreased extramuscular myofascial force transmission. The second manipulation was full isolation of EDL from TA+EHL, but not from extramuscular connective tissues, which caused a further decrease of the EDL proximo-distal force differences, indicating a stiffening effect of the presence of TA+EHL on the extramuscular matrix. For EDL active force the difference was no longer significantly different from zero. In contrast, for EDL passive force the proximo-distal force difference persisted. It is concluded that extramuscular myofascial force transmission is an important feature of the anterior crural compartment. The magnitude of this force transmission requires that it be considered in analysis of muscular function. J. Morphol. 256:306-321 2003