Fine motor skill
Fine motor skill is the coordination of small muscle movements which occur in body parts such as the fingers, usually in coordination with the eyes. In relation to motor skills of hands and fingers, the term dexterity is commonly used. When applied to the theory of human aptitude, this is called "manual dexterity". The high level of manual dexterity that humans exhibit can be attributed to the manner in which manual tasks are controlled by the nervous system.
Hand movements are initiated by commands originating from a region of the primary motor cortex that contain a high number of specialized corticospinal (CST) neurons, termed corticomotoneuronal (CM) cells. CM cells descend into the spinal cord to form monosynaptic connections with motor neurons in the anterior horn. Research has shown that these monosynaptic connections may account for the high amount of manual dexterity observed in primates, including humans.
Two types of motor skills 
Motor skills are movements and actions of the muscles. They are categorized in two groups: gross motor skills and fine motor skills. Gross motor skills involve movement of the arms, legs, feet, or entire body. This includes actions such as running, crawling, walking, swimming, and other activities that involve larger muscles. Fine motor skills are the small movements that occur in the hands, wrists, fingers, feet, toes, lips and tongue. They are the smaller actions that occur such as picking up objects between the thumb and finger, using a pencil to write carefully, holding a fork and using it to eat, and other small muscle tasks that occur on a daily basis.
These two motor skills develop together and strongly involve coordination. Through each developmental stage of a child’s life, toddlerhood, preschool, and school age, motor skills will gradually develop and between age 6 and 12 children typically will have mastered basic fine motor skills. They will keep developing with age and with practice and the increased use of muscles while playing sports, playing an instrument, using the computer, and writing.
Common problems 
Fine motor skills can become impaired. Some reasons for impairment could be injury, illness, stroke, congenital deformities, cerebral palsy, and developmental disabilities. Problems with the brain, spinal cord, peripheral nerves, muscles, or joints can also have an effect on fine motor skills, and decrease control. If an infant or child up to age five is not developing their fine motor skills, they will show signs of difficulty controlling coordinated body movements with the hands, fingers, and face. In young children, the delay in the ability to sit up or learn to walk can be an early sign that there will be issues with fine motor skills. Children may also show signs of difficulty with tasks such as cutting with scissors, drawing lines, folding clothes, holding a pencil and writing, and zipping a zipper. These are tasks that involve fine motor skills, and if a child has difficulty with these they might have poor hand eye coordination and could need therapy to improve their skills.
Many tests have been developed in order to assess fine motor skills. Among them include force matching tasks. Humans exhibit a high degree of accuracy in force matching tasks where an individual is instructed to match a reference force applied to a finger with the same or different finger. Humans also exhibit a high degree of accuracy during grip force matching tasks. These aspects of manual dexterity are apparent in the ability for humans to effectively use tools.
- Jean-Alban Rathelot; Peter L. Strick (1). "Subdivisions of primary motor cortex based on cortico-motoneuronal cells". PNAS. National Academy of Sciences. Retrieved 21 May 2012.
- Woo-Hyung Park; Charles T. Leonard and Sheng Li (17). "Finger force perception during ipsilateral and contralateral force matching tasks". NIHPA Manuscripts. National Center for Biotechnology Information, U.S. National Library of Medicine. Retrieved 21 May 2012.
- Harrison, Linda M.; Margaret J. Mayston and Roland S. Johansson (21). "Reactive control of precision grip does not depend on fast transcortical reflex pathways in X-linked Kallmann subjects". Journal of Physiology (527.3): 641–652.
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