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Introduction
Published in J. Terrence Jose Jerome, Clinical Examination of the Hand, 2022
We know well that grip is the motor component of prehension. This can be divided into a power grip and a precision grip. They are self-explanatory (Figure 1.33).Power grip: Let us see the example of an orthopaedic surgeon holding the chisel and hammering it as an innate of his operative skills.Precision grip: Let us see the precision work again in the picture. This time the surgeon is focused extensively to achieve accuracy.
Peripheral nerve disorders
Published in Ashley W. Blom, David Warwick, Michael R. Whitehouse, Apley and Solomon’s System of Orthopaedics and Trauma, 2017
Michael Fox, David Warwick, H. Srinivasan
Complete paralysis of all thenar muscles (the ‘intrinsic-zero’ thumb) results in loss of effective power and precision grip. Correction requires stabilization of the carpometacarpal joint in the ‘opponens position’ (abduction, flexion and internal rotation) by opponensplasty using flexor superficialis of the middle or ring finger or extensor indicis proprius.
The Hand
Published in Louis Solomon, David Warwick, Selvadurai Nayagam, Apley and Solomon's Concise System of Orthopaedics and Trauma, 2014
Louis Solomon, David Warwick, Selvadurai Nayagam
Function can be measured subjectively using patient-completed scales, but objective tests are more reliable. There are several types of grip, which can be tested by giving the patient a variety of tasks to perform: picking up a pin (precision grip), holding a sheet of paper (pinch), holding a key (sideways pinch), holding a pen (chuck grip), holding a bag handle (hook grip), holding a glass (span) and gripping a hammer handle (power grip).
Typical Development of Finger Position Sense From Late Childhood to Adolescence
Published in Journal of Motor Behavior, 2023
Jinseok Oh, Arash Mahnan, Jiapeng Xu, Hannah J. Block, Jürgen Konczak
A different limitation of the current test is that it only examines finger position with respect to the abduction/adduction of the finger and not for finger flexion/extension – a degree of freedom with a larger range of motion. There is evidence that different degrees-of-freedom (DoF) of a joint exhibit difference in proprioceptive acuity or sensitivity. For example, wrist position sense acuity is anisotropic with the abduction/adduction DoF having a higher acuity than flexion/extension (Marini et al., 2016). Such higher acuity is associated with a higher mechanoreceptor density in abductor/adductor muscle and is thought to reflect differences in function and required feedback resolution (Hagert et al., 2005). It is known that finger flexion/extension is critical for grasping while abduction/adduction movements are crucial for fine motor skills such as the precision grip (e.g. pinching between the thumb and index finger). Thus, these differences in function may be also associated with differences in proprioceptive acuity.
The Role of Primary Motor Cortex: More Than Movement Execution
Published in Journal of Motor Behavior, 2021
Sagarika Bhattacharjee, Rajan Kashyap, Turki Abualait, Shen-Hsing Annabel Chen, Woo-Kyoung Yoo, Shahid Bashir
Theta-burst stimulation (TBS) is another TMS technique that has helped to evaluate the role of M1 in memory consolidation. TBS produces long-lasting excitatory or inhibitory effects on motor physiology and behavior (Huang et al., 2005). TBS studies are referred here because there is no direct evidence that indicates the involvement of M1 in consolidating (along with other downstream motor areas) the memory of an already performed task. To decipher this, Wilkinson et al. (2010) investigated the association of several cortical regions with implicit learning sequences. Five age- and IQ-matched groups of healthy participants were administered TBS with inhibitory effect over (1) M1, (2) SMA, (3) dorsolateral prefrontal cortex. They also received (4) intermittent TBS with excitatory effect over the areas and sham TBS. Interestingly, it was found that compared with sham TBS, sequence learning was abolished by TBS with an inhibitory effect over M1. However, sequence learning was not significantly affected by TBS with inhibitory effect over the other areas or by TBS with excitatory effect over M1. This establishes the crucial role of M1 in implicit sequence learning. Similar to this study, other studies observed the effect of intermittent TBS on M1 in subcortical stroke patients. It was found that intermittent TBS improves the training effects in a precision grip task (for details, refer to the reviews by Censor & Cohen, 2011; Reis et al., 2008; Tanaka et al., 2011).
Effect of object substitution, spontaneous compensation and repetitive training on reaching movements in a patient with optic ataxia
Published in Neuropsychological Rehabilitation, 2020
Josselin Baumard, Frédérique Etcharry-Bouyx, Valérie Chauviré, Delphine Boussard, Mathieu Lesourd, Chrystelle Remigereau, Yves Rossetti, François Osiurak, Didier Le Gall
Grasping corresponds to the shaping of the hand while taking an object (e.g., a paper clip calls for a precision grip whereas a pencil holder calls for a power grip; e.g., Bongers, Zaal, & Jeannerod, 2012; Castiello, 2005; Jeannerod, 1986). Graspable tools (in comparison with non-graspable tools) automatically attract visual attention (e.g., cup versus cactus; Garrido-Vásquez & Schubö, 2014) and elicit activity in the left premotor and parietal cortex (Grafton, Fadiga, Arbib, & Rizzolatti, 1997). That being said, the grasping component is in an intermediate position between reaching and using in that it can be viewed as a high-level perceptual-motor skill (Rosenbaum, Chapman, Weigelt, Weiss, & Van der Wel, 2012). Indeed, grasping may depend not only on structural information (i.e., the shape or size of the object; Ellis & Tucker, 2000) but also on functional information (i.e., knowledge about the function and the prototypical manipulation of an object; Buxbaum, Kyle, Tang, & Detre, 2006; Jax, Buxbaum, & Moll, 2006) and intentional/teleological information (i.e., the action to be done with the object; Osiurak et al., 2008; Rosenbaum et al., 2012). Function-based grasping may depend on the left inferior parietal lobe whereas structure-based grasping is associated with the left superior parietal lobe (Buxbaum, Sirigu, Schwartz, & Klatzky, 2003).