The human hand is a miracle of evolution. The ability to perform such fine finger movements depends on the motor and sensory cortices. The evolution of the cortical mechanisms in human beings enables the hand to reach its high levels of skill. Hand function is the result of neurologic development, physiologic maturation, and functional development of learned patterns of movement and motor control. Hand function does not develop in isolation.The small muscles in the hand allow fine control of the thumb and fingers.Asymmetry of the heads of the second and fifth palm bones allows rotation of the articulated fingers during opposition with the thumb.Special configurations of joints at the bases of the fifth, fourth, and second fingers facilitate tip-to-tip precision grips with the thumb.A special saddle joint and associated ligaments at the base of the thumb facilitate refined rotation.The proportional lengths of the thumb and other fingers give us an opposable thumb with precise, firm contact between its tip and the ends of each of the other fingers.The fingertips are broad and equipped with highly sensitive pads of skin.The most complex adaptations of the human hand involve the thumb, wherein a unique, fully independent muscle (the flexor pollicis longus) gives this digit remarkable strength in pinch and power grips. The features of human hands are easily distinguishable from those of the great apes, and they underpin the refined function and manipulatory abilities of our hands. The greater the difficulties with hand function, the greater the impairment in skills that allow for independence and participation in academic and social activities Īnatomy and Evolution Hand function has great significance for occupational performance. The feedback used in both grasping and lifting of an object is dependent on the brain interpreting correctly, what is seen on the hand responding appropriately.
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