Related Experiment Video
Updated: Jul 11, 2026

In Vivo Quantification of Hip Arthrokinematics during Dynamic Weight-bearing Activities using Dual Fluoroscopy
Published on: July 2, 2021
A method for in-vivo kinematic analysis of the forearm
Shian Chao Tay1, Roger van Riet, Tomita Kazunari
1Orthopaedics Biomechanics Laboratory, Division of Orthopaedic Research, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
Purpose:
To develop a method for in-vivo kinematic study of normal forearm rotation using computed tomographic (CT) images and a custom apparatus which allows for control of amount of forearm rotation.
Methods:
The forearm of one asymptomatic volunteer was CT-scanned in five positions: neutral, 60 degrees pronation, maximal pronation, 60 degrees supination, and maximal supination. Surface registration of the pronated/supinated image datasets with the neutral position was performed. The resulting transformation matrices were decomposed into finite helical axis (FHA) parameters. Kinematics were expressed as motion of the radius relative to the ulna.
Results:
The axes of the forearm passed through the volar region of the radial head at the proximal radioulnar joint (PRUJ), extending towards the dorsal region of the ulnar head at the distal radioulnar joint (DRUJ). Distinct FHAs were calculated for each forearm position analyzed relative to neutral rotation. Forearm pronation FHAs were different from forearm supination FHAs.
Conclusions:
Our experimental methodology is capable of describing the in-vivo kinematics of the forearm with good accuracy and reliability. Future in-vivo studies would need to be performed using a larger sample size to further validate our preliminary results. An ideal clinical application of this methodology would be in the comparative study of patients with forearm dysfunction.
Related Concept Videos
Muscles that Move the Forearm
Forearm Flexors
The biceps brachii, brachialis, and brachioradialis are forearm flexors. The biceps brachii is made up of two heads. Its long head originates at the supraglenoid tubercle of the scapula, whereas that of the short head is...
Muscles of the Forearm that Move the Hand and Fingers
Anterior Compartment
The anterior compartment muscles originate from the humerus. They primarily function as flexors and are also known as flexor muscles. They typically insert on the carpals, metacarpals, and phalanges. The superficial layer includes the flexor carpi radialis,...
Bones of the Upper Limb: Radius
The radius has a nail-shaped head, and a short...
Bones of the Upper Limb: Humerus
Bones of the Upper Limb: Ulna
Kinematic Equations for Rotation
For instance, imagine a point A on a rigid body engaged in circular motion. The translational velocity of this particular point can be calculated by taking the time derivatives of the displacement equation, which essentially measures the...
