Peroneal Components Research Articles

Effects of Topical Cyclosporin A Application on Preventing Epineural Scar Formation in Rats: Experimental Study

The aim of this study is to evaluate macroscopic, histopathologic and immunohistochemical effects of topical cyclosporin administration on prevention of epineural scar formation in rats.This experimental study was performed in two groups, each consisting of ten rats. Sciatic nerve was opened bilaterally. Tibial and peroneal components were set apart with blunt dissection. Abrasion injury was achieved by repetitive rubbing over biceps femoris muscle. In the control group saline sucked cotton peds were administered over opened sciatic nerve region bilaterally, whereas cyclosporin sucked peds were administered in the second group for five minutes duration. Eight weeks after surgery both groups were sacrificed and nerve complexes were evaluated microscopically, histopathologically and immunohistochemically. No side effects were observed after 5 minutes single dose topical cyclosporine administration in our study. Cutaneous, muscular and deep fascial repairment were almost completed according to Petersen’s numerical grading system (p<0.05). Nerve adherence was significantly decreased (p<0.001) in the ones treated with cyclosporin than the control group. FGF expression was demonstrated and individual evaluations of the control and the study groups immunhistochemically. The ratio of fibroblast/fibrosit number showed that both groups results were parallel. Single dose topical cyclosporin administration is shown to be successfull in preventing epineural scar formation after peripheric nerve neurolysis.

Medial Sural Perforator “Nerve through Flap”: Anatomical Study and Clinical Application

Background: Nerve recovery after a complex trauma is affected by many factors and a poorly vascularized bed is often the cause of failure and perineural scar. Many techniques have been devised to avoid this problem and the possibility to transfer a nerve with a surrounding viable sliding tissue could help in this purpose; Methods: We performed an anatomic study on 8 injected specimens to investigate the possibility to raise a medial sural artery perforator (MSAP) flap including the sural nerve within its vascularized sheath; Results: In anatomic specimens, a visible direct nerve vascularization was present in 57% of legs (8 out of 14). In 43% a vascular network was visible in the fascia layer. There were no vascular anomalies. In one patient the MSAP flap was raised including the sural nerve with its proximal tibial and peroneal components within the deep sheath. The tibial and peroneal component of the sural nerve were anastomized independently with the common digital nerve of 4th and 5th fingers and with the collateral nerve for the ulnar aspect of the 5th. After 9 months, the patient showed an improving nerve function both clinically and electromyographically without any problem due to nerve adherence; Conclusions: Given the still debated advantage of a vascularized nerve graft versus a non-vascularized one, this flap could be useful in those cases of composite wounds with nerve lesions acting as a “nerve through flap”, in order to reduce nerve adherence with a viable surrounding gliding tissue.

Neuromuscular variations in the gluteal region - Embryological basis and clinical significance.

Piriformis, is a key muscle in the gluteal region. Under its lower border sciatic nerve and inferior gluteal nerves exit. During routine educational dissection of the lower limb, bilateral gluteal regions in fifteen cadavers (30 gluteal regions) focusing on the variations of inferior gluteal nerve and sciatic nerve with respect to piriformis muscle were observed in the department of anatomy, All India Institute of Medical Sciences, New Delhi, India. In one of the left sided specimens, inferior gluteal nerve had an abnormal course, piercing superior belly of piriformis muscle instead of emerging through the lower border of it along with variation of the sciatic nerve. The common peroneal component of the sciatic nerve was coming out between the two anomalous tendinous slips of the piriformis muscle, whereas the tibial component, emerged along lower border of the piriformis muscle bilaterally in the same cadaver. In the remaining cadavers, there were no variations of the inferior gluteal nerve with respect to the piriformis muscle. But in another cadaver, there was a similar variation of the sciatic nerve bilaterally. Inferior gluteal and sciatic nerves, when compressed by muscle belly or tendinous slips of the piriformis muscle, may cause lurching gait and sciatica respectively. Knowledge of the different variations of these peripheral nerves with respect to the piriformis muscle is important to clinicians and surgeons for the accurate diagnosis and intervention.

Ischiadic Nerve Lesion Due to Metastasis of a Non-Differentiated Urethra Carcinoma: Case Report and Review of the Literature

In clinical practice, we encounter mechanical lesions of the ischiadic nerve most frequently with a trauma of the pelvis circle or because of surgical injury in the alloplastic treatment of the hip joint. Other causes for nerve lesions are sporadic or even rare. To such ones also belongs compression of the nerve by metastasis of a urethra carcinoma to the gluteus maximus muscle. A typical manifestation of this nerve injury is a tibioperoneal paresis with a preponderance in its peroneal component. The diagnostic process can be additionally complicated by a contemporal vertebrogenic syndrome with radiculopathy, the more so, when an intervertebral disc protrusion on imaging would be discovered. We present a case of a woman with a two-year history of an undifferentiated urethra carcinoma which has metastasized into the gluteus muscle and has produced a compression of the ischiadic nerve.

Transfer of the peroneal component of the sciatic nerve in total brachial plexus lesion: An anatomical feasibility study

Closed brachial plexus lesions (BPLs) are generally associated with a traumatic mechanism of forced traction between the neck and the shoulder-arm complex. For brachial plexus reconstruction different techniques have been proposed with donor motor nerves like intercostal nerves, or the ipsilateral cervical plexus, the phrenic nerve, the contralateral C7 root, and many others.Despite all these surgical possibilities, the overall recovery is generally poor and not satisfactory. The principal drawback is linked to the loss of upper limb proprioception, in a way that dramatically influences even a good motor recovery, so in complete BPLs the sensory loss still represents a debilitating problem. In this anatomical feasibility study, the possibility to transfer the peroneal component of the sciatic nerve as a donor for complete BPLs has been evaluated. This technique would conceptually bring an important motor and sensory contribution to the upper limb using pure motor and sensory branches of the sciatic nerve. Performing immediate tendon transfer for foot drop palsy could significantly decrease the morbidity of the surgical procedure.

Anatomical Variation in the Division of Sciatic Nerve in Sudanese Subjects – Cadaveric Study form may 2016 to june 2017

Background: The Sciatic nerve is the widest nerve of the body. It consists of two components, namely: the tibia and the common peroneal components derived from the ventral rami of L4 to S3 spinal nerves of the lumbosacral plexus. It exits the pelvis through the greater sciatic foramen below the Piriformis muscle and descends between the greater trochanter of the femur and ischial tuberosity of the pelvis to the knee. Higher division of the sciatic nerve is the most common variation where the TN and CPN may leave the pelvis through different routes which may lead to various clinical manifestations Likewise, their adequate knowledge will help in increasing surgical precision and decreasing morbidity. Material and methods: The study is a descriptive cross-sectional study conducted at the department of anatomy of several medical faculties in Sudan from May 2016 to June 2017. In which 50 male cadaver (100 lower extremities) age ranges from 50 to 70 years were dissected to level the bifurcation. Result: In the 100 explored sciatic nerves we get fife types of bifurcation; Inside the pelvis, High up in the gluteal region & upper third of the back of the thigh , The middle of the back of the thigh, The lower of the back of the thigh & At Popleteal fossa with the last one been the most frequently reported variant. One variant is the nerve exit the pelvis as two roots united at the gluteal region to divide again at the poplteal fossa. Discussion: According to the literature, the anatomical variant described in 50 cadavers is considered relatively not rare. Conclusion: The most frequent reported nerve is that nerve exiting the pelvis as sciatic nerve 79 %(78 – 80 %), passing anterior to piriformis 92% (90 – 94%),posterior to; superior gemelli 92%, obturator internus, inferior gemilli, quadrates femoris 100%.In the 20% of nerves (10 cadaver) with pelvic division the tibial component is keeping the anterior relation to piriformis in all cases & in both side, while the c

Variations in sural nerve formation pattern and distribution on the dorsum of the foot.

The sural nerve, a cutaneous nerve, is clinically important because it is frequently for nerve conduction testing, biopsy, and harvesting for nerve grafts. This nerve exhibits a wide variety of variation in formation, distribution on the dorsum of the foot, and so on, depending on the population observed. In this study, we examined the variation in the sural nerve in 110 Korean cadavers. Of these cadavers, 86.1% of the sural nerves corresponded to type A, where tibial and peroneal components were united to form the sural nerve. These two components most frequently united (65.9%) in the third quarter of the calf, and when the union position was expressed as a ratio to calf length, it corresponded to 0.408 in men and 0.346 in women, with a statistically significant difference. Due to this sexual dimorphism in addition to shorter calf length in females, the length of the sural nerve was shorter in females (male average length: 14.5 ± 4.8 cm; female average length: 11.4 ± 2.9 cm). In terms of distribution of the lateral dorsal cutaneous nerve, the distal continuation of the sural nerve on the dorsum of the foot, it showed variation in association with the superficial peroneal nerve. The innervation of the sural nerve extended most frequently up to the lateral two and a half toes, solely or in conjunction with the superficial peroneal nerve. Obtaining further information regarding sural nerve variation will be useful for various clinical procedures and interpretation of sural nerve conduction results. Clin. Anat. 30:525-532, 2017. © 2017 Wiley Periodicals, Inc.

Anatomical variation in bifurcation and trifurcations of sciatic nerve and its clinical implications: in selected university in Ethiopia.

BackgroundThe Sciatic nerve is the widest nerve of the body. It consists of two components, namely: the tibia and the common peroneal components derived from the ventral rami of L4 to S3 spinal nerves of the lumbosacral plexus. It exits the pelvis through the greater sciatic foramen below the Piriformis muscle and descends between the greater trochanter of the femur and ischial tuberosity of the pelvis to the knee. The purpose of this study is to identify the course and variations in branching pattern of the sciatic nerve which may lead to various clinical manifestations.MethodsTwenty-eight formalin fixed cadavers comprising of 56 lower limbs are used for this study, of which six specimens were female cadavers. Dissection of gluteal region and posterior compartment of the thigh was done to expose the sciatic nerve. Variations in the sciatic nerve anatomy; their relationship to Piriformis muscle and a point of bifurcation and trifurcation were noted and recorded.ResultsForty-two lower limbs (75 %) showed normal anatomy of sciatic nerve. Fourteen regions (25 %) showed variations in the sciatic nerve, of which six regions (11 %) showed a variation of the sciatic nerve in relation to Piriformis muscle, three regions (5 %) showed trifurcation of the sciatic nerve and five regions (9 %) showed variation in the origin of the sural nerve.ConclusionThe knowledge regarding the level of division and distribution of the sciatic nerve and its location is of great importance. The sciatic nerve is frequently involved in daily medical practice of neurology, orthopedics, rehabilitation and anesthesia. Its long course makes it vulnerable to nerve injury. Even in this era the cadaver is the best means to study anatomy. It emphasizes proper clinical implications, for the surgeons to practice efficient surgical recombination and avoid errors.

Bilateral variant of sciatic nerve exhibiting intra-pelvic division

Context (background): In case of high division of the sciatic nerve in the pelvis its, common peroneal component may pierce the Piriformis muscle. This anatomical variant can explain many clinical findings. Aims: Its objective is to report a case of high division of the sciatic nerve in order to contribute towards better anatomical understanding of the gluteal region. Methods and Material: Routine undergraduate dissection of a male cadaver revealed bilateral variation in sciatic nerve. Results: Sciatic nerve is dividing into tibial and common peroneal components in the pelvis. Common peroneal component is piercing through the piriformis muscle. Tibial component is emerging between piriformis and superior gemelli muscle. Conclusions: Sciatic nerve variation can lead to a Piriformis muscle syndrome, inadvertent injury during operations in the gluteal region, failure of sciatic nerve block and/or sciatic neuropathy. The differences in routes of these two nerve components can explain them.

Where should the tip of the needle be located in ultrasound-guided peripheral nerve blocks?

Data now exist describing the appropriate positioning of the needle tip and pattern of local anaesthetic spread after injection. The recent literature has been analysed in search of studies on the optimal procedure for common approaches centred on block efficacy, performance time, and safety. Large peripheral nerves are surrounded by a gliding layer, the adventitia or paraneurium. Ultrasonically, a circumneural spread corresponds to adventitial extraneural injection. Nerve expansion with fascicular separation matches intraneural injection. Deliberate intraneural injection remains controversial, and is not advisable at the present time. For popliteal sciatic nerve blocks, positioning the needle in the common nerve sheath between the tibial and peroneal components and obtaining a circumneural spread surrounding both divisions predict rapid surgical anaesthesia. Using axillary and infraclavicular approaches, ultrasound-guided perivascular injection aiming at circumferential spread around the artery appears a valuable alternative to individual targeted nerve injections. For single injection interscalene block, an injection into the fascial sheath but far from the plexus proved to be as effective as an injection adjacent to the nerve structures. Fascial plane approaches are appealing alternatives for thin nerves that run between muscles and cannot be regularly visualized with the current resolution of ultrasound systems. The ultrasound appearance of nerves and target injections are better understood. The specific distributions of local anaesthetic spread that predict success are significantly different from one anatomical site to another. It seems advisable to avoid intraneural injection.

Clinical importance of anatomical variants of sciatic nerve in relation to the piriformis muscle

Abstract Background and aims : The sciatic nerve usually emerges below the Piriformis muscle. Each anatomical variant of sciatic nerve is associated with a specific clinical presentation. The aim of the study was to identify the variants of sciatic nerve and to discuss their clinical importance. Materials and methods : Twenty one embalmed cadavers of known age and sex were used for this study. Gluteal regions of both sides were dissected to expose sciatic nerve. Variation of sciatic nerve in relation to piriformis was observed. Results and Conclusion: Out of the 42 dissected specimens - Five showed variations in sciatic nerve. Three specimens (two on right and one on left side) displayed common peroneal branch passing through piriformis. Three specimens (two on right and one on left side) showed tibial nerve emerging below piriformis.ln one specimen on left side common peroneal nerve emerged as two parts in relation to piriformis - one passing through piriformis and another below piriformis. A very unusual variant in which the tibial and common peroneal components of sciatic nerve were sandwiched between the three heads of piriformis muscle is also reported here in one case of right side. These variants are usually misdiagnosed in most of the cases due to similarity of clinical symptoms with low back ache and sciatica. Therefore the possibility of each such variant should be kept in mind by the clinicians.

Practice of yoga may cause damage of both sciatic nerves: a case report

Sciatic nerve traumatic damage very rarely occurs bilaterally. We describe the case of a 67-year-old woman who reported a bilateral traumatic lesion of the sciatic nerve during practice of yoga. Nerve conduction studies showed a bilateral sciatic nerve neuropathy, mostly affecting the peroneal component. Lumbar plexus MRI documented regular anatomical features of the main principal nerve roots with bilateral T2 signal alteration of roots L4, L5 and S1 that extended into the sciatic nerves showing both increase in size, probably related to chronic injury of nerves, and an alteration in diffusion signal that suggested a recent acute overlapped process.

Clinical importance of anatomical variants of sciatic nerve in relation to the piriformis muscle

Background and aims : The sciatic nerve usually emerges below the Piriformis muscle. Each anatomical variant of sciatic nerve is associated with a specific clinical presentation. The aim of the study was to identify the variants of sciatic nerve and to discuss their clinical importance. Materials and methods : Twenty one embalmed cadavers of known age and sex were used for this study. Gluteal regions of both sides were dissected to expose sciatic nerve. Variation of sciatic nerve in relation to piriformis was observed. Results and Conclusion: Out of the 42 dissected specimens - Five showed variations in sciatic nerve. Three specimens (two on right and one on left side) displayed common peroneal branch passing through piriformis. Three specimens (two on right and one on left side) showed tibial nerve emerging below piriformis.In one specimen on left side common peroneal nerve emerged as two parts in relation to piriformis - one passing through piriformis and another below piriformis. A very unusual variant in which the tibial and common peroneal components of sciatic nerve were sandwiched between the three heads of piriformis muscle is also reported here in one case of right side. These variants are usually misdiagnosed in most of the cases due to similarity of clinical symptoms with low back ache and sciatica. Therefore the possibility of each such variant should be kept in mind by the clinicians.

Neuraxial Blockade in Patients with Preexisting Spinal Stenosis, Lumbar Disk Disease, or Prior Spine Surgery

Patients with spinal canal pathology, including spinal stenosis and lumbar disk disease, are often not considered candidates for neuraxial blockade because of the risk of exacerbating preexisting neurologic deficits or developing new neurologic dysfunction. In contrast, a history of spine surgery is thought to increase the likelihood of difficult or unsuccessful block. In this retrospective study we investigated the risk of neurologic complications and block efficacy in patients with preexisting spinal canal pathology, with or without a history of spine surgery, after neuraxial anesthesia. During the 15-year study period, all patients with a history of spinal stenosis or lumbar radiculopathy undergoing a neuraxial technique were studied. Patient demographics, preoperative neurologic diagnoses and neurologic findings at the time of surgery/neuraxial block, details of the neuraxial block including technique (spinal vs. epidural, single injection vs. continuous), injectate, technical complications (paresthesia elicitation, bloody needle/catheter placement, inability to advance catheter, accidental dural puncture), and block success were noted. New or progressive neurologic deficits were identified. All patients were followed until resolution or last date of evaluation. There were 937 patients included, 207 (22%) of whom had undergone spinal surgery. A history of spinal stenosis was present in 187 (20%), lumbar radiculopathy in 570 (61%), and peripheral neuropathy in 210 (22%) patients; 180 patients (19%) had multiple neurologic diagnoses. A majority of patients had active but stable neurologic symptoms at the time of surgery. Overall block success was 97.2%. A history of spine surgery did not affect the success rate or frequency of technical complications. Ten (1.1%; 95% confidence interval [CI] 0.5%-2.0%) patients experienced new deficits or worsening of existing symptoms. Three (1.4%) complications occurred in patients with a history of spinal surgery, and the remaining 7 (1.0%) in patients without prior surgical decompression or stabilization (P = NS). Although an orthopedic procedure was not a risk factor, in 5 of the 6 patients in which the surgery was a unilateral lower extremity procedure, the postoperative deficit involved the operative side. Likewise, in both patients undergoing bilateral orthopedic procedures who developed bilateral deficits, the outcome was worse on the previously affected side. A surgical cause was presumed to be the primary etiology in 4 (40%) of 10 patients. The primary etiology of the remaining 6 (60%) complications was judged to be nonsurgical (including anesthetic-related factors). The presence of a preoperative diagnosis of compressive radiculopathy (P = 0.0495) or multiple neurologic diagnoses (P = 0.005) increased the risk of neurologic complications postoperatively. We conclude that patients with preexisting spinal canal pathology have a higher incidence of neurologic complications after neuraxial blockade (1.1%; 95% CI 0.5%-2.0%) than that previously reported for patients without such underlying pathology. However, in the absence of a control group of surgical patients with similar anatomic pathology undergoing general anesthesia, we cannot determine whether the higher incidence of neurologic injury is secondary to the surgical procedure, the anesthetic technique, the natural history of spinal pathology, or a combination of factors and the relative contributions of each.

Pudendal Nerve Injury After a Sciatic Nerve Block by the Posterior Approach

We report a pudendal nerve injury that developed after a posterior approach to the sciatic nerve. A classical Labat's posterior sciatic nerve block on the right side was performed using an insulated needle and a nerve stimulator set at an initial current of 2 mA, 2 Hz frequency, and 0.1 ms duration. Painful paresthesia radiating to the right side of the patient's penis and right leg was experienced shortly after needle insertion. The needle was immediately withdrawn and redirected laterally. Motor responses for the common peroneal and tibial components of the sciatic nerve were elicited at 0.48 mA in both cases and a 10-mL bolus of mepivacaine 1.5% was injected onto each component. The sciatic nerve block was combined with a femoral nerve block to facilitate a knee arthroscopy. The trauma resulted in erectile dysfunction and partial loss of penile sensation as well as evidence of injury to the sciatic nerve itself. Symptoms and clinical signs of pudendal nerve injury lasted 7 months. This is the first time that sexual dysfunction as a result of a unilateral pudendal nerve injury that occurred after a posterior sciatic nerve block has been reported.

The Propensity of Common Peroneal Nerve in Thigh-Level Injuries

Sciatic nerve lesions comprise the largest subset of lower extremity nerve injuries. Military gunshot injury reports in civilians are not as predominant as wartime experience. Most sciatic nerve injuries result in deficits to the peroneal component. This study aims to report experience with civilian sciatic nerve injuries and to suggest the mechanism behind the peculiarity of the common peroneal component in thigh-level injuries. A retrospective study was conducted on 1,463 civilian patients with military gunshot sciatic nerve injury diagnosed and evaluated by neurophysiologic studies during a period of 3 years. Most of the patients (95.4%) presented with thigh-level injury in which 95% suffered complete but isolated common peroneal territory palsy. The rest of the patients had either solitary complete tibial division palsy or complete tibial and common peroneal deficits. The propensity of the common peroneal nerve in thigh-level injuries inflicted by military-type weapons in civilians is consistent with wartime injury reports. Because of its special anatomic situation, entrapment of the common peroneal nerve whether distally or proximally may render its axons more prone to mechanical damage. Moreover, the smaller contribution of the common peroneal component to the main nerve may result in its damage more readily than the tibial component whose larger contribution may spare some of its fibers. Finally, the components of the sciatic nerve diverge at a variable distance from the knee. Thus, distal thigh injuries may involve the diverging common peroneal nerve where it has a superficial position and is more prone to injury.

Poster 118: Sciatic Neuropathy Following Hip Arthroplasty: A Case Report

Setting: Freestanding inpatient rehabilitation hospital. Patient: A 72-year-old man with diabetes mellitus. Case Description: The subject sustained a fall, resulting in right femoral neck fracture, and underwent right total hip arthroplasty (THA). Postoperatively, he developed ipsilateral foot drop. Assessment/Results: Following prolonged inpatient stay for multiple medical issues, the subject was transferred to our inpatient rehabilitation hospital. Electrodiagnostic studies done 6 weeks following surgery noted severe sciatic neuropathy on the right side involving both the tibial and peroneal components, with underlying sensorimotor neuropathy likely secondary to diabetes.

ULTRASONOGRAPHIC ASSESSMENT OF THE CANINE SCIATIC NERVE

To describe the ultrasonographic technique for investigation of the canine sciatic nerve, four canine cadaver pelvic limbs, two live healthy dogs, and five canine patients with suspected peripheral sciatic nerve lesions were examined with a high-resolution linear ultrasound transducer. The caudal part of the lumbosacral trunk and the origin of the sciatic nerve were visualized through the greater ischiatic foramen. The two components of the sciatic nerve, common peroneal and tibial nerves, were distinguished along the entire length of the nerve, until they branched at the level of the distal femur. In healthy live dogs they appeared as two adjacent hypoechoic tubular structures with internal echotexture of discontinuous hyperechoic bands, surrounded by a thin rim of highly echogenic tissue. The common peroneal component had a smaller diameter and was on the cranial aspect of the tibial component. An ultrasonographic lesion compatible with a peripheral nerve sheath tumor was found in one dog. Improved understanding of the ultrasonographic anatomy of the sciatic nerve supports clinical use of this modality.

Plantar fasciitis and fascial rupture: MR imaging findings in 26 patients supplemented with anatomic data in cadavers.

Understanding of the normal anatomy of the plantar aponeurosis (PA) and familiarity with pathologic conditions are required for an accurate evaluation of the patient with subcalcaneal heel pain. In this study, we evaluated the diagnostic capabilities of magnetic resonance (MR) imaging in the assessment of the PA with close anatomic correlation. Herein, we describe the MR imaging features of plantar fasciitis and fascial rupture in 26 patients. High-spatial-resolution MR imaging was performed in four cadaveric feet, and a prescribed imaging plane was used for depiction of the peroneal component of the PA. MR imaging delineated the anatomy of the PA and perifascial soft tissues. The peroneal component was best visualized in prescribed sagittal oblique images. Perifascial edema was the most common finding of plantar fasciitis, and it was remarkable in those cases with acute fascial rupture. MR imaging reliably delineated the anatomy of the PA and may allow precise localization and definition of the extent of involvement in disease processes.

Effect of Intertrial Delay on Whole Nerve Cuff Recordings of Muscle Afferents in Rabbits

Objective. The effect of the stationary period on the muscle afferent responsiveness to passive stretch was studied to determine if muscle afferent activity might be suitable as feedback in motor-neural prostheses control. Methods. Muscle afferent activity was recorded using nerve cuff electrodes applied individually to the tibial and peroneal components of the sciatic nerve in five rabbit preparations. The ankle joint was rotated using a servomotor. The delay between trapezoidal movements was varied (excursion = 30°, velocity = 20°/s) and the duration was increased stepwise in successive trials(2 s, 5 s, 10 s, 20 s, 30 s, and 180 s). Results. An increase in amplitude of the afferent activity with increasing intertrial delay was observed. The afferent responses following a 2-s delay were subtracted from the responses following each of the remaining intervals (5 s-2 s, 10 s-2 s, 20 s-2 s, 30 s-2 s and 180 s-2 s) and were then compared. During the ramp phase a statistically significant difference was found in 85% and 76% of the cases for the tibial and peroneal nerve responses. Significant differences were below 21% for both nerves during four other phases examined. Conclusions. It is suggested that the enhancement in afferent responses caused by the increased intertrial delay may be explained by the change in the mechanical properties of the intrafusal and extrafusal muscle fibers. The consequences of this, when applying muscle afferent activity in motor-neuro prostheses, are discussed.