**1.8 Comparison with the upper extremity**

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

#### **Figure 6.**

*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.*

#### **Figure 7.**

*"H-reflexes" of the A) peroneus longus and B) extensor hallucis longus muscles by stimulation of the common peroneal nerve and recorded with surface electrodes. In reality" H-reflexes" may be H-reflexes of the triceps surae muscle caused by spreading of stimuli to a branch of the posterior tibial nerve. Calibration 10 ms/div, 3 mV/div.*

**47**

**Figure 8.**

*brevis muscle. Calibration: 10 ms /div, 2 mV / div.*

*Recording of Proprioceptive Muscle Reflexes in the Lower Extremity*

may have served an important role in primate evolution.

the upper extremity than in the lower one as well. As in the lower extremities the proprioceptive reflexes are important in the process of walking and running, they might be related to grip and climbing functions in the upper extremities and thus

When the common peroneal nerve is stimulated, the stimulus spreads readily to the motor branches of the posterior tibial nerve. Thus, volume conduction is a source of error especially when the reflexes of the pretibial muscles are recorded with surface electrodes. The stimulation spreading to branches of the posterior tibial nerve may elicit H-reflex of the triceps surae muscle, recorded with electrodes on the surface of the anterior tibial muscle. This reflex response may imitate the myotatic reflex of the anterior tibial muscle (**Figure 6**). A similar problem may be encountered by recording of responses of the peroneus longus and extensor hallucis longus muscles (**Figure 7**), as well as the foot muscles (**Figure 8**). However a

*F-responses of the tibial nerve in the abductor hallucis brevis muscle, latency 50 ms. stimulation at the ankle, upper 10 responses with surface electrodes. The lower 10 sweeps are recorded from the extensor digitorum brevis muscle: A) with a concentric needle electrode, no responses, and B) with surface electrodes, active electrode on the muscle and reference placed in the distal end of 5th metatarsal bone. Observe the "medium latency reflexes" of the extensor digitorum brevis muscle, which are volume conducted F-responses of the abductor hallucis* 

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

**1.9 Problems with volume conduction**

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

the upper extremity than in the lower one as well. As in the lower extremities the proprioceptive reflexes are important in the process of walking and running, they might be related to grip and climbing functions in the upper extremities and thus may have served an important role in primate evolution.
