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Although the direction indicated by "proximal" and "distal" is always respectively towards or away from the point of attachment, a given structure can be either proximal or distal in relation to another point of reference. Thus the elbow is distal to a wound on the upper arm, but proximal to a wound on the lower arm. [30]
"Dorsal" means "in the direction away from the ridge of the human back or its equivalent in other animals. In human neuroanatomy the word is somewhat distorted, becoming synonymous with "superior" in the forebrain, i.e. in the direction of the roof of the cranial cavity"cranial cavity and thence to the body. "Ventral" in the central nervous ...
At the primary motor cortex, motor representation is orderly arranged (in an inverted fashion) from the toe (at the top of the cerebral hemisphere) to mouth (at the bottom) along a fold in the cortex called the central sulcus. However, some body parts may be controlled by partially overlapping regions of cortex.
The motor neuron sends an electrical impulse to a muscle. When the neuron in the cortex becomes active, it causes a muscle contraction. The greater the activity in the motor cortex, the stronger the muscle force. Each point in the motor cortex controls a muscle or a small group of related muscles. This description is only partly correct.
In the thenar eminence, the recurrent branch of the median nerve provides motor innervation to: [4] opponens pollicis muscle; abductor pollicis brevis muscle; superficial part of flexor pollicis brevis muscle; A separate, more proximal branch of the median nerve additionally provides motor innervation to the 1st and 2nd lumbricals of the hand.
An appropriate classification of motor nuclei and tracts would be by their functions. When broken down by function there are two major pathways: medial and lateral. The medial pathway helps control gross movements of the proximal limbs and trunk. The lateral pathway helps control precise movement of the distal portion of limbs. [1]
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Proximal and distal, which describe a position that is closer to (proximal) or farther from (distal) the trunk of the body. [1] For example, the shoulder is proximal to the arm, and the foot is distal to the knee. Superficial and deep, which describe structures that are closer to (superficial) or farther from (deep) the surface of the body.