OVERVIEW AND BASIC CONCEPTS PART-6
ANATOMICOMEDICAL TERMINOLOGY
Terms of Movement Part-1
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Various terms describe movements of the limbs and other parts of the body. Most movements are defined in relationship to the anatomical position, with movements occurring within, and around axes aligned with, specific anatomical planes.
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While most movements occur at joints where two or more bones or cartilages articulate with one another, several nonarticulated structures exhibit movement (e.g., tongue, lips, eyelids, and hyoid bone in the neck). It is often advantageous to consider movements in antagonistic (opposing) pairs:
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Flexion and extension movements generally occur in sagittal planes around a transverse axis. Flexion indicates bending or decreasing the angle between the bones or parts of the body.
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For joints above the knee, flexion involves movement in an anterior direction. Extension indicates straightening or increasing the angle between the bones or parts of the body.Extension usually occurs in a posterior direction.
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The knee joint, rotated 180° to more superior joints is exceptional in that flexion of the knee involves posterior movement and extension involves anterior movement.Dorsiflexion describes flexion at the ankle joint, as occurs when walking uphill or lifting the front of the foot and toes off the ground.
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Plantarflexion bends the foot and toes toward the ground, as when standing on your toes. Extensions of a limb or part beyond the normal limit—hyperextension (overextension)—can cause injury, such as “whiplash” (i.e., hyperextension of the neck during a rear-end automobile collision).
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Abduction and adduction movements generally occur in a frontal plane around an anteroposterior axis. Except for the digits, abduction means moving away from the median plane (e.g., when moving an upper limb laterally away from the side of the body) and adduction means moving toward it.
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In abduction of the digits (fingers or toes), the term means spreading them apart—moving the other fingers away from the neutrally positioned 3rd (middle) finger or moving the other toes away from the neutrally positioned 2nd toe. The 3rd finger and 2nd toe medially or laterally abduct away from the neutral position.
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Adduction of the digits is the opposite—bringing the spread fingers or toes together, toward the neutrally positioned 3rd finger or 2nd toe. Right and left lateral flexion (lateral bending) are special forms of abduction for only the neck and trunk.
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The face and upper trunk are directed anteriorly as the head and/or shoulders tilt to the right or left side, causing the midline of the body itself to become bent sideways. This is a compound movement occurring between many adjacent vertebrae.
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As you can see by noticing the way the thumbnail faces (laterally instead of posteriorly in the anatomical position), the thumb is rotated 90° relative to the other digits. Therefore, the thumb flexes and extends in the frontal plane and abducts and adducts in the sagittal plane.
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Circumduction is a circular movement that involves sequential flexion, abduction, extension, and adduction (or in the opposite order) in such a way that the distal end of the part moves in a circle. Circumduction can occur at any joint at which all the above-mentioned movements are possible (e.g., the shoulder and hip joints).