Supination
Supinatio
Definition
Supination and pronation of the hand are rotational movements which occur at the superior radioulnar joint.
These rotational movements are facilitated due to the presence of an annular ligament which holds the upper end of the radius in close apposition with the ulna. Since the upper radial end is freely mobile within the annular ligament, it allows the radius to rotate medially and laterally around the long axis of the ulna, bringing about pronation and supination movements.
For instance, if we place the forearm on a flat surface and flip the hand such that the palm faces downwards, this is pronation. Here, the distal end of radial bone has rotated medially over the ulna. However, if we bring the hand back to its original position with palm facing upwards, this is supination movement. In this case, the distal radius has rotated laterally over the ulna.
Two major supinators of the forearm are supinator muscle and the long head of biceps muscle.
References
Text by Antoine Micheau, MD - Copyright IMAIOS and reviewed by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.
Jones, O. (2020). Anatomical terms of movement in ‘TeachMeAnatomy’. Available at URL: https://teachmeanatomy.info/the-basics/anatomical-terminology/terms-of-movement/ [accessed on Feb 11th, 2023]
Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 7: Upper Limb’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp. 735.
