ABSTRACT
This article describes nerve conduction studies of the deep temporal nerve (DTN) and the mylohyoid nerve (MHN) motor branches of the trigeminal nerve. These nerves were stimulated intraorally with a pediatric surface stimulator. Compound muscle action potentials were recorded over the temporalis and mylohyoid muscles with surface electrodes. Forty-two subjects were studied. In all subjects the MHN response was elicited bilaterally, giving an upper latency limit of 2.3 ms. The mean MHN amplitude was 4.9 mV (SD = 1.8 mV, minimum = 1.3 mV). The maximal side-to-side amplitude difference was 0.4 ms. and the maximal side-to-side amplitude difference was 2.2 mV. The DTN response was only elicited bilaterally in 25 (60%) subjects. The average DTN latency was 2.1 ms (SD = 0.3, maximum = 2.7 ms). The average DTN amplitude was 4.3 mV (SD = 2.0, minimum = 0.3 mV). The MHN responses were the least technically demanding, and were more consistently elicited than the DTN responses. These nerve conduction techniques should prove useful in patients with trigeminal nerve disorders.
Subject(s)
Motor Neurons/physiology , Neural Conduction/physiology , Trigeminal Nerve/physiology , Adult , Electromyography , Facial Muscles/innervation , Female , Humans , Male , Middle Aged , Trigeminal Nerve/cytology , Trigeminal Nerve/ultrastructureABSTRACT
We set out to study the relationship between a motor unit's size and firing rates and its recruitment threshold and recruitment order. The data were collected from the first dorsal interosseous muscle of 11 normal subjects and analyzed using the precision decomposition and macro electromyography techniques. Our study showed that the recruitment order of a motor unit varies directly with its recruitment threshold (P<0.00005) and that there is a progressive increase in the macro potential size of successively recruited motor units (P=0.002). The firing rates of motor units vary inversely with their recruitment order (P=0.006), the smaller, earlier recruited units consistently reaching higher firing rates than the larger, later recruited units. This study conforms the existence of a size principle of motor unit recruitment in humans and reveals the interactions between a motor unit's size and its firing rate properties.
Subject(s)
Electromyography/methods , Adult , Electrodes , Female , Humans , Male , Motor Neurons/physiology , Muscle Contraction/physiology , Muscle Fibers, Skeletal/physiology , Needles , Recruitment, Neurophysiological , Sensory Thresholds/physiologyABSTRACT
Painful legs, moving toes is a rare syndrome characterized by leg pain and uncontrolled toe movements. We present a 35-year-old man with a 1-year history of unilateral knee, calf, and medial ankle pain with spontaneous movements of second through fifth toes. Electrodiagnostic studies showed an absent lateral plantar nerve response consistent with a tarsal tunnel entrapment neuropathy. Cine magnetic resonance imaging revealed a large accessory soleus muscle compressing the flexor hallucis longus in the tarsal tunnel of the affected extremity. Lidocaine block of the tibial nerve at the popliteal fossa did not stop these movements, but blockade of the medial and lateral plantar nerves distal to the medial malleolus stopped them temporarily. Treatment with foot orthotics and cessation of running activity decreased the symptoms. We conclude that painful leg and moving toes in this patient resulted from a compression neuropathy at the tarsal tunnel possibly caused by a large adjacent accessory soleus muscle.
Subject(s)
Muscle, Skeletal/abnormalities , Neuralgia/etiology , Restless Legs Syndrome/physiopathology , Tarsal Tunnel Syndrome/physiopathology , Toes/physiopathology , Adult , Diagnosis, Differential , Electromyography , Humans , Magnetic Resonance Imaging , Male , Muscle, Skeletal/innervation , Muscle, Skeletal/physiopathology , Nerve Compression Syndromes/diagnosis , Nerve Compression Syndromes/physiopathology , Neuralgia/diagnosis , Neuralgia/physiopathology , Peripheral Nerves/physiopathology , Restless Legs Syndrome/diagnosis , Signal Processing, Computer-Assisted , Toes/innervationABSTRACT
This study describes the casualties referred during the Persian Gulf War and underscores the valuable role of Army physical medicine and rehabilitation (PMR) services in evaluation and early rehabilitation of wartime casualties. Data regarding demographics, injury types, medical complications, complications of immobility and functional limitations were collected by military physiatrists at five Army Medical Centers with PMR services. Active duty soldiers injured in the Persian Gulf War who were referred totalled 222. Musculoskeletal injuries occurred in 57%, peripheral nerve injuries in 44%, penetrating wounds in 32%, fractures in 28%, brain injuries in 8%, amputations in 7%, burns in 6% and spinal cord injuries in 3%. The primary referral service was orthopedics (64%). Electrodiagnosis evaluations were performed for 41% of all referrals. Lower limb and upper limb contractures occurred in 10% and 9% of patients, respectively. Ambulatory impairments were seen in 48%. Nerve injuries were associated with penetrating wounds in 68%, with amputations in 67% and with fractures in 58%.
