**1.4 Tendon reflexes and H-reflexes of the proximal muscles**

The L3-4 posterior roots can be studied with the patellar reflex (**Figure 4a** and **b**), and the adductor reflex [6]. The adductor tendon reflex can be evoked by ipsilateral tap to the medial epicondyle of the femur. Surprisingly, this reflex may also be elicited easily by tap to several sites of the lower extremity: for instance contralateral patellar tap, as well as ipsi- and contralateral anterior superior iliac spine tap. On the contrary, patellar tendon reflex was obtained only by ipsilateral tap to the patellar tendon. H-reflex of the adductor muscle (latency 16.4 ms, SD 1.6) is obtained by percutaneous

**41**

**Figure 3.**

*Calibration as above.*

*Recording of Proprioceptive Muscle Reflexes in the Lower Extremity*

stimulation of the obturator nerve at the level of pubic tubercle. Even a mediumlatency reflex, "late polysynaptic reflex response" of more than 50 ms was described in the adductor muscle [6]. However, these methods are rarely used in routine ENMG studies. The H-reflex of the quadriceps femoris muscle is readily recorded by stimulation of the femoral nerve [4], but we have not gained any experience with this method. The Achilles tendon reflex may also be recorded with surface electrodes on the triceps surae muscle. This recording was not used in routine ENMG studies. We should also

*A. M-response of the right peroneus longus muscle in a patient aged 80 with a right L5 root syndrome: Right L5 compression in MRI, positive needle EMG finding in the right L5 paraspinal muscle, F-response latency asymmetrically prolonged in the right extensor digitorum brevis muscle but bilaterally normal in the abductor hallucis muscles. Stimulation of the common peroneal nerve at the fibular head. Latency of the M-response 3.9 ms. The H-reflex cannot be elicited in spite of changes of the stimulation intensity 3.0-11.7 mA (submaximal and supramaximal). Calibration: 8 ms/div and 5 mV/div. No medium latency reflexes (see Figure 9). The tibialis posterior nerve was evidently not coactivated with the stimulation of the common peroneal nerve, there was only plantar dorsiflexion. B. M-response and H-reflex (arrow) of the left peroneus longus muscle of the patient. Latency of the M-response 4.0 ms and H-reflex 31.2 ms. stimulation intensity 3.1-14.4 mA.* 

remember that the tendon reflex and H-reflex have distinct differences [7].

*DOI: http://dx.doi.org/10.5772/intechopen.95575*

*Recording of Proprioceptive Muscle Reflexes in the Lower Extremity DOI: http://dx.doi.org/10.5772/intechopen.95575*

#### **Figure 3.**

*Proprioception*

**Figure 2.**

*observed (not shown).*

**40**

of the given muscle [4], but we have found it too difficult for routine use. No H-reflex for the L5-level was described for clinical use in root syndromes. We have tried to measure H-reflexes of the peroneus longus and extensor hallucis longus muscles, but these measurements were hampered by volume conduction of reflexes of the triceps surae muscle. However, H-reflex of the peroneus longus muscle can be confirmed by recording it with EMG needle electrode (**Figure 2**). The peroneus longus H-reflex may disappear in the symptomatic side of a patient with unilateral L5 root syndrome (**Figure 3**). Problems with volume conduction are

*H-reflex of peroneus longus, 32 years old male. Stimulation with 2 cm bipolar surface electrode to common peroneal nerve at the fibular head causing clear ankle dorsiflexion; ten concurrent stimulations with increasing stimulation current. Simultaneous recording of peroneus longus with both surface electrodes (interelectrode distance ca 3 cm), a 30 G concentric needle electrode, and soleus with surface electrodes (interelectrode distance ca 3 cm). Note the typical appearance of H-wave, latency 32 ms (vertical line), reaching its maximal amplitude before M-wave (contrary to the performance of F-responses) and appearance of H-wave solely on peroneus longus and not on soleus. 2 mV/div, 8 ms/div. A similar recording with surface electrodes on the lateral gastrocnemius muscle was also performed and no reflex response of this muscle was* 

The L3-4 posterior roots can be studied with the patellar reflex (**Figure 4a** and **b**), and the adductor reflex [6]. The adductor tendon reflex can be evoked by ipsilateral tap to the medial epicondyle of the femur. Surprisingly, this reflex may also be elicited easily by tap to several sites of the lower extremity: for instance contralateral patellar tap, as well as ipsi- and contralateral anterior superior iliac spine tap. On the contrary, patellar tendon reflex was obtained only by ipsilateral tap to the patellar tendon. H-reflex of the adductor muscle (latency 16.4 ms, SD 1.6) is obtained by percutaneous

**1.4 Tendon reflexes and H-reflexes of the proximal muscles**

discussed at the end of this chapter.

*A. M-response of the right peroneus longus muscle in a patient aged 80 with a right L5 root syndrome: Right L5 compression in MRI, positive needle EMG finding in the right L5 paraspinal muscle, F-response latency asymmetrically prolonged in the right extensor digitorum brevis muscle but bilaterally normal in the abductor hallucis muscles. Stimulation of the common peroneal nerve at the fibular head. Latency of the M-response 3.9 ms. The H-reflex cannot be elicited in spite of changes of the stimulation intensity 3.0-11.7 mA (submaximal and supramaximal). Calibration: 8 ms/div and 5 mV/div. No medium latency reflexes (see Figure 9). The tibialis posterior nerve was evidently not coactivated with the stimulation of the common peroneal nerve, there was only plantar dorsiflexion. B. M-response and H-reflex (arrow) of the left peroneus longus muscle of the patient. Latency of the M-response 4.0 ms and H-reflex 31.2 ms. stimulation intensity 3.1-14.4 mA. Calibration as above.*

stimulation of the obturator nerve at the level of pubic tubercle. Even a mediumlatency reflex, "late polysynaptic reflex response" of more than 50 ms was described in the adductor muscle [6]. However, these methods are rarely used in routine ENMG studies. The H-reflex of the quadriceps femoris muscle is readily recorded by stimulation of the femoral nerve [4], but we have not gained any experience with this method. The Achilles tendon reflex may also be recorded with surface electrodes on the triceps surae muscle. This recording was not used in routine ENMG studies. We should also remember that the tendon reflex and H-reflex have distinct differences [7].

#### **Figure 4.**

*a. Electrical recording of the patellar reflex, 33 years old male. Stimulation with tendon hammer electrically connected to EMG-machine. Recording is triggered by a strike to prepatellar tendon. Recording in the rectus femoris muscle with both concentric needle electrode (30 G) and surface electrodes and an accelerometer connected to tibia. Three separate recordings of same stimulation protocol. 7-10 superimposed responses. Patellar reflex at ca 20 ms. 20 ms/div. b. Electrical recording of the patellar reflex, responses shown in a.*

**43**

*Recording of Proprioceptive Muscle Reflexes in the Lower Extremity*

A medium latency reflex response (60-80 ms) of the soleus muscle can be recorded by supramaximal stimulus of the common peroneal nerve, which causes powerful twitch contraction of the peroneal muscles [8] (**Figure 5a**). Originally this reflex response was considered to use low-threshold muscle afferents and a transcranial loop, possibly involving the primary motor cortex and the supplementary motor area [9]. Later on it was demonstrated that the medium-latency reflex response of the soleus muscle to stretch does not involve a long reflex loop [10]. Soleus stretch resulting from unexpected perturbation during human walking elicits both short and medium latency reflex responses. It was concluded by cooling, ischaemia and tizanidine studies that the afferent receptors of the short latency component are Ia afferents and those of the medium latency component are

By stimulation of the common peroneal nerve at the fibular neck, only the medium latency reflex response can be recorded in electroneurography of the human soleus muscle [8] (**Figure 5a**). It was observed that stimulation of the common peroneal nerve results in long lasting (up to 200 ms) soleus H-reflex depression [12]. On the contrary, by stimulation of the posterior tibial nerve at the popliteal space, no medium latency reflex response can be recorded from the

**1.6 Calculations of conduction velocities and the role of β-efferents in the** 

the upper extremity [13] and 48 m/s in the lower extremity [7].

The distances between the stimulation and recording sites were measured when the responses depicted in **Figure 5a** were recorded. The afferent pathway for H-reflex latency 27.0 ms was 640 mm between the stimulation site at the popliteal space, and L1 spinal level. Respectively, the distance of the efferent pathway between L1 spinal level and the estimated motor point of the soleus muscle was 750 mm. Considering that the synaptic delay in the spinal cord is about 1 ms [7] we can conjecture that the afferent conduction time from the stimulation site to the spinal cord is 11 ms and the efferent conduction time is 15 ms. The respective conduction velocities are for Ia afferents 58 m/s and for α motor efferents 50 m/s. These values match well with the recordings of Ia afferent conduction velocity 64 m/s and α motor conduction velocity 56 m/s of the median nerve [13], assuming that the respective values are slightly slower in the lower than in the upper extremity. The more distally recorded Ia afferent conduction velocity between the popliteal fossa and ankle is 56 m/s [7]. Cutaneous afferents are slower than Ia afferents, 61 m/s in

A similar calculation may be performed for the medium latency reflex latency 62 ms. The distance from the proximal part of the soleus muscle (site of the most proximal muscle spindles) to the L1 spinal level was 670 mm, and the distance from L1 to the motor point of the soleus muscle was 750 mm. The estimated afferent conduction time is 30 ms and the efferent conduction time 31 ms, the spinal synaptic delay time was again estimated to be 1 ms. By these values we may calculate, that the afferent conduction velocity for II-afferent pathway is 22 m/s, and for the efferent conduction velocity is 24 m/s. This afferent conduction velocity matches well with the II-afferent conduction velocity 21 m/s observed in the lower extremity [14]. But the efferent conduction velocity 24 m/s is far too slow for the α motor efferent pathway, which was calculated to be 50 m/s in the H-reflex arch (see above).

*DOI: http://dx.doi.org/10.5772/intechopen.95575*

**1.5 Medium latency reflex responses**

II-afferents, respectively [11].

anterior tibial muscle [8].

**medium latency reflexes**

## **1.5 Medium latency reflex responses**

*Proprioception*

**42**

**Figure 4.**

*a. Electrical recording of the patellar reflex, 33 years old male. Stimulation with tendon hammer electrically connected to EMG-machine. Recording is triggered by a strike to prepatellar tendon. Recording in the rectus femoris muscle with both concentric needle electrode (30 G) and surface electrodes and an accelerometer connected to tibia. Three separate recordings of same stimulation protocol. 7-10 superimposed responses. Patellar reflex at ca 20 ms. 20 ms/div. b. Electrical recording of the patellar reflex, responses shown in a.*

A medium latency reflex response (60-80 ms) of the soleus muscle can be recorded by supramaximal stimulus of the common peroneal nerve, which causes powerful twitch contraction of the peroneal muscles [8] (**Figure 5a**). Originally this reflex response was considered to use low-threshold muscle afferents and a transcranial loop, possibly involving the primary motor cortex and the supplementary motor area [9]. Later on it was demonstrated that the medium-latency reflex response of the soleus muscle to stretch does not involve a long reflex loop [10]. Soleus stretch resulting from unexpected perturbation during human walking elicits both short and medium latency reflex responses. It was concluded by cooling, ischaemia and tizanidine studies that the afferent receptors of the short latency component are Ia afferents and those of the medium latency component are II-afferents, respectively [11].

By stimulation of the common peroneal nerve at the fibular neck, only the medium latency reflex response can be recorded in electroneurography of the human soleus muscle [8] (**Figure 5a**). It was observed that stimulation of the common peroneal nerve results in long lasting (up to 200 ms) soleus H-reflex depression [12]. On the contrary, by stimulation of the posterior tibial nerve at the popliteal space, no medium latency reflex response can be recorded from the anterior tibial muscle [8].

## **1.6 Calculations of conduction velocities and the role of β-efferents in the medium latency reflexes**

The distances between the stimulation and recording sites were measured when the responses depicted in **Figure 5a** were recorded. The afferent pathway for H-reflex latency 27.0 ms was 640 mm between the stimulation site at the popliteal space, and L1 spinal level. Respectively, the distance of the efferent pathway between L1 spinal level and the estimated motor point of the soleus muscle was 750 mm. Considering that the synaptic delay in the spinal cord is about 1 ms [7] we can conjecture that the afferent conduction time from the stimulation site to the spinal cord is 11 ms and the efferent conduction time is 15 ms. The respective conduction velocities are for Ia afferents 58 m/s and for α motor efferents 50 m/s. These values match well with the recordings of Ia afferent conduction velocity 64 m/s and α motor conduction velocity 56 m/s of the median nerve [13], assuming that the respective values are slightly slower in the lower than in the upper extremity. The more distally recorded Ia afferent conduction velocity between the popliteal fossa and ankle is 56 m/s [7]. Cutaneous afferents are slower than Ia afferents, 61 m/s in the upper extremity [13] and 48 m/s in the lower extremity [7].

A similar calculation may be performed for the medium latency reflex latency 62 ms. The distance from the proximal part of the soleus muscle (site of the most proximal muscle spindles) to the L1 spinal level was 670 mm, and the distance from L1 to the motor point of the soleus muscle was 750 mm. The estimated afferent conduction time is 30 ms and the efferent conduction time 31 ms, the spinal synaptic delay time was again estimated to be 1 ms. By these values we may calculate, that the afferent conduction velocity for II-afferent pathway is 22 m/s, and for the efferent conduction velocity is 24 m/s. This afferent conduction velocity matches well with the II-afferent conduction velocity 21 m/s observed in the lower extremity [14]. But the efferent conduction velocity 24 m/s is far too slow for the α motor efferent pathway, which was calculated to be 50 m/s in the H-reflex arch (see above).

#### **Figure 5.**

*a. the tibial H-reflex of the soleus muscle elicited with submaximal stimuli, minimum latency 27.0 ms. The stimulation was changed to the common peroneal nerve at the knee joint and supramaximal stimuli elicited the medium latency reflexes of soleus, minimum latency 62.0 ms (vertical line). The" M-response" was reflected from the pretibial muscles. For calculations of the afferent and efferent conduction velocities of the reflex responses* see text*. Calibration: 10 ms/div, 2 mV/div. A voluntary healthy subject, male, age 31 y, height 166 cm. b. H-reflex of the median nerve (2 uppermost sweeps), latency 15,5 ms (arrow), stimulation: Median nerve at the elbow, recording with surface electrodes on the forearm flexors. The stimulation was changed to the radial nerve at the spiral groove (2 middle responses). When the stimulus was turned to supramaximal value, medium latency reflex responses, latency 30.5 ms, were elicited (vertical line, 5 lowermost sweeps) from the forearm flexors. Calibration: 8 ms/div, 2 mV/div. A voluntary healthy subject, male, age 31 y, height 166 cm.*

**45**

**Figure 6.**

*Recording of Proprioceptive Muscle Reflexes in the Lower Extremity*

This fact justifies the hypothesis that the efferent pathway of the medium latency reflexes consists of skeletofusimotor β motor fibres, which are thinner and slower

Ib afferent nerve fibres from Golgi tendon organs are slightly smaller than those of Ia afferents [11]. The electrically evoked excitatory postsynaptic potential may be curtailed by the inhibitory postsynaptic potential of only slightly longer latency than the excitatory postsynaptic potential [7]. There is a Ib inhibitory volley from the Golgi tendon organs, which originate from the proximal tendon insertion of the anterior tibial muscle, elicited by the strong contraction of the muscle by stimulation of the posterior tibial nerve at the popliteal space. This inhibitory volley may reach the spinal cord and prevent the occurrence of the medium latency reflex response. The lack of medium latency reflex was pointed out in this muscle [8]. Unexpected perturbation during walking elicits short- and medium-latency soleus reflex responses [11]. However, soleus stretch, caused by electric stimulation of the common peroneal nerve and powerful contraction of the pretibial muscles, elicits only a medium-latency reflex response of the soleus muscle. It may be considered that the Ia reciprocal inhibitory influence [7] plays a role in inhibition of the soleus

The forearm flexor muscles (for example m. flexor carpi radialis and m. flexor digitorum superficialis) show H-reflexes, when the median nerve is stimulated at the elbow [4]. When the stimulation is changed to the radial nerve at the spiral groove, a medium reflex response may be recorded at the same site than the median H-reflex (**Figure 5B**). Thus, the respective reflex responses seem to be elicited in

*The" reflex" response of the anterior tibial muscle (latency 27.4 ms), recorded by the stimulation of the posterior tibial nerve at the popliteal fossa. Superficially it may be reminiscent to a myotatic reflex of the anterior tibial muscle, but in reality it is the H-reflex of the triceps surae muscle, volume conducted to the recording site (compare with the H-reflex recording in Figure 4). The" M-response" points out the direct* 

*activation of the triceps surae muscle. Calibration: 8 ms/div, 2 mV/div.*

than α motor fibres. β motor efferents have been observed in man [15].

**1.7 The possible influence of inhibitory pathways on the reflex responses**

*DOI: http://dx.doi.org/10.5772/intechopen.95575*

short-latency reflex response in this situation.

**1.8 Comparison with the upper extremity**

*Proprioception*

**44**

**Figure 5.**

*a. the tibial H-reflex of the soleus muscle elicited with submaximal stimuli, minimum latency 27.0 ms. The stimulation was changed to the common peroneal nerve at the knee joint and supramaximal stimuli elicited the medium latency reflexes of soleus, minimum latency 62.0 ms (vertical line). The" M-response" was reflected from the pretibial muscles. For calculations of the afferent and efferent conduction velocities of the reflex responses* see text*. Calibration: 10 ms/div, 2 mV/div. A voluntary healthy subject, male, age 31 y, height 166 cm. b. H-reflex of the median nerve (2 uppermost sweeps), latency 15,5 ms (arrow), stimulation: Median nerve at the elbow, recording with surface electrodes on the forearm flexors. The stimulation was changed to the radial nerve at the spiral groove (2 middle responses). When the stimulus was turned to supramaximal value, medium latency reflex responses, latency 30.5 ms, were elicited (vertical line, 5 lowermost sweeps) from the forearm flexors. Calibration: 8 ms/div, 2 mV/div. A voluntary healthy subject, male, age 31 y, height 166 cm.*

This fact justifies the hypothesis that the efferent pathway of the medium latency reflexes consists of skeletofusimotor β motor fibres, which are thinner and slower than α motor fibres. β motor efferents have been observed in man [15].
