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Peripheral Nerve Examination
Published in J. Terrence Jose Jerome, Clinical Examination of the Hand, 2022
Nikhil Agrawal, Chaitanya Mudgal
Any scars from trauma or previous surgery must be noted for anatomical significance. In long-standing ulnar nerve palsy, the motor end plates will undergo necrosis and the intrinsic muscles of the hand will atrophy in a clinically predictable fashion. Dorsally, this is perhaps most striking at the first dorsal interosseous muscle (Figure 8C.3). Atrophy can also be noted in the volar intrinsic muscles (Figure 8C.4).
Lower Limb Muscles
Published in Eve K. Boyle, Vondel S. E. Mahon, Rui Diogo, Handbook of Muscle Variations and Anomalies in Humans, 2022
Eve K. Boyle, Vondel S. E. Mahon, Rui Diogo, Malynda Williams
The dorsal interossei are comprised of four bipennate muscles that occupy the spaces in between the metatarsals (Standring 2016). Each muscle originates via two heads from adjacent metatarsals and inserts into the base of the proximal phalanx and dorsal digital expansion of its target digit (Standring 2016). The first dorsal interosseous muscle originates from the sides of the first and second metatarsals and inserts onto the medial aspect of digit two (Standring 2016). The second dorsal interosseous muscle originates from the sides of the second and third metatarsals and inserts into the lateral aspect of digit two (Standring 2016). The third dorsal interosseous muscle originates from the sides of the third and fourth metatarsals and inserts into the lateral aspect of digit three (Standring 2016). The fourth dorsal interosseous muscle originates from the sides of the fourth and fifth metatarsals and inserts into the lateral aspect of digit four (Standring 2016).
Exercise-Induced Improvement in Motor Learning
Published in Henning Budde, Mirko Wegner, The Exercise Effect on Mental Health, 2018
These single-pulse TMS results are complemented by paired pulse TMS studies that allow specific examination of local inhibitory or facilitative processes within the motor cortex (intra-cortical excitability). This technique pairs two TMS pulses with a particular inter-stimulus interval to target inhibitory (5 ms or less) or facilitatory (10–25 ms) intracortical circuits. A decrease in intracortical inhibition, which seems to be dependent on the level of the inhibiting neurotransmitter γ-aminobutyric acid (GABA), is generally assumed to reflect a favorable environment for the induction of neuroplasticity and therefore motor skill learning (Singh & Staines 2015). While the effect of long-term exercise on intracortical networks has, to the best of our knowledge, not been assessed to date in longitudinal studies with younger subjects, the effects of an acute bout of exercise has been examined with within-subjects designs. For example, Yamaguchi et al. reported a decrease in short-interval intracortical inhibition (SICI) of the leg area (tibialis anterior and soleus muscles) after just 7 min of low-intensity active cycling (Yamaguchi, Fujiwara, Liu, & Liu 2012). Similar effects were observed for the upper extremity (first dorsal interosseous muscle) after 30 min of low–moderate or moderate–high intensity cycling (Smith, Goldsworthy, Garside, Wood, & Ridding 2014). Likewise, 20 minutes of continuous biking with moderate intensity decreased SICI and increased intracortical facilitation (ICF) measured in the extensor carpi radialis muscle (Singh, Duncan, Neva, & Staines 2014).
Predictive value of motor-evoked potentials for motor recovery in patients with hemiparesis secondary to acute ischemic stroke
Published in Annals of Medicine, 2023
Cheng-Chang Yen, Hsin-Hung Chen, Chao-Hsien Lee, Ching-Huang Lin
TMS sessions were conducted by a trained medical examiner on the same day of the clinical assessment at ≤10 days after stroke onset. The paretic upper extremity was examined. The TMS session was conducted according to the practical guide published by the International Federation of Clinical Neurophysiology [20,21]. We employed monophasic electromagnetic stimulators (Magstim 200 Mono Pulse, MAGSTIM Co., UK). Patients were examined while lying on a bed with their heads slightly protruding beyond the edge of the bed in a quiet room. MEPs were recorded with surface electrodes from the first dorsal interosseous muscle of the upper extremity. In the TMS session of the upper extremity, we used a figure-of-eight coil. The juncture of the two wings of the coil was placed approximately 5 cm lateral to and 0–1 cm anterior to the vertex and contralateral to the paretic extremity, where the largest MEP in the paretic first dorsal interosseous muscle was elicited.
Transcranial magnetic stimulation to monitor disease progression in ALS: a review
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2023
Mamede De Carvalho, Michael Swash
We identified 4 publications that studied longitudinal changes in CMT in ALS patients. Zanette et al. (16) investigated a group of 9 patients with normal early inhibitory cortical circuits at baseline; recordings from the thenar eminence revealed no significant change after an average time of 7 months. Mills (17), studying responses in the first dorsal interosseous muscle (FDI), reported no change in CMT in a large group of patients, evaluated at intervals of about 3 months, with a mean of 3.1 follow-up studies. However, two other groups reported different results. Floyd et al. (18) investigated 30 patients with 2 or more follow-up studies over 18 months. Recording from the abductor digit minimi muscle (ADM), they observed an increment in CMT of 1.8%/month. In patients with progressive muscular atrophy there was no change in CMT. Using the same muscle, de Carvalho and Swash (19) studied 28 patients followed over 6 months; they reported a CMT increment of 1.5%/month.
The influence of model parameters on model validation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Benjamin W. Infantolino, Steph E. Forrester, Matthew T.G. Pain, John H. Challis
Given the value of musculoskeletal models but the corresponding lack of large databases of muscle model parameters it is of interest to examine how model performance depends on model parameters. Therefore, the purpose of this study was to examine the sensitivity of two different musculoskeletal models to the parameters describing the model. Specifically, the influence on model validity of using model parameters based on group mean data was investigated. These comparisons can be used to provide an estimate of the error associated with relying on mean data for model parameters as opposed to subject specific values in computer simulation modelling. Two models were examined; one was a phenomenological model of human jumping comprising a simple lumped-parameter model of jumping based on live subject data, and the other a model of the First Dorsal Interosseous causing abduction of the second metacarpalphalangeal joint with model parameters based on cadaveric measurements. These two models reflect different approaches to determining model parameters. In the model of jumping experimental data from experimental subjects is used to determine model parameters, such an approach has been used in many studies (e.g. Allen et al. 2010; Forrester et al. 2011). The second model was of the First Dorsal Interosseous muscle and reflects the approach that muscle morphological data is used specify the muscle model parameters (e.g. Delp et al. 1990; Jacobs et al. 1996). These two models analyses will be presented sequentially before a common Discussion section.