unknown user

03-02-2004, 10:22 AM

Dear Biomch-L users,

I would really appreciate your comments and suggestions about the following

assumptions concerning elbow axes of rotation and their relation with

humerus and forearm long axes; my aim is to build a simple kinematic model

of the elbow in ADAMS(c) using rigid links and hinge joints.

Considering an arm in the frontal plane (forearm extended and supinated):

1)Humerus long axis (Yh): the line pointing upward from the midpoint between

medial and lateral epicondyle ( E = (EM+ EL)/2 ) to the glenohumeral

rotation centre (GH) [1];

2)Forearm long axis (Yf): the line pointing upward from the midpoint

between ulnar and radial styloid (US, RS) to E [1];

3)Carrying angle: angle formed by the forearm long axis and the humerus long

axis when the forearm is fully extended and supinated [3]; NB: in [3] I

didn't find the definition of the long axes with respect to the previously

defined anatomical landmarks, even if I supposed that the above given are

nevertheless applicable.

4)Prosupination axis: the line pointing upward from US to E [1];

5)Flexion-extension axis: assumed orthogonal to the prosupination axis [2]

passing through E; its direction should correspond to the Z axis of the

humerus bone embedded

system (see below different definitions suggested in [1]);

>From [1]:

1) Humerus (1st degree) Coordinate System - Xh1Yh1Zh1

Oh1: The origin coincident with GH.

Yh1: The line connecting GH and the midpoint of EL and EM, pointing to GH.

Xh1: The line perpendicular to the plane formed by EL, EM, and Yh1, pointing

forward.

Zh1: The common line perpendicular to Yh1- and Zh1-axis.

2) Humerus (2nd degree) Coordinate System - Xh2Yh2Zh2

Oh2: The origin coincident with GH.

Yh2: The line connecting GH and the midpoint of EL and EM, pointing to GH.

Zh2: The line perpendicular to the plane formed by Yh2 and Yf (see above),

pointing laterally. Zh2-axis is taken with 90 degrees flexed elbow.

Xh2: The common line perpendicular to Xh2- and Yh2-axis.

[1] Frans C.T. van der Helm , (2002) "ISB Recommendation on Definitions of

Joint Coordinate System of Various Joints for the Reporting of Human Joint

Motion - Part II: Shoulder, Elbow, Hand and Wrist, Shoulder", Submitted to

JBiomech 2002

[2] Veeger H.E.J, (1997) "Orientation of axes in the elbow and forearm for

biomechanical modeling" Proc. of the 1^ Conf. of the ISG

[3] Zatsiorsky V.M., (1998) "Kinematics of the Human Motion", Human

Kinematics

Many thanks

Best regards

Andrea G. Cutti

-----

Ing. Andrea Giovanni Cutti

PhD Student - Biomedical Engineering Group

University of Bologna

Viale Risorgimento 2

40136 - Bologna

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I would really appreciate your comments and suggestions about the following

assumptions concerning elbow axes of rotation and their relation with

humerus and forearm long axes; my aim is to build a simple kinematic model

of the elbow in ADAMS(c) using rigid links and hinge joints.

Considering an arm in the frontal plane (forearm extended and supinated):

1)Humerus long axis (Yh): the line pointing upward from the midpoint between

medial and lateral epicondyle ( E = (EM+ EL)/2 ) to the glenohumeral

rotation centre (GH) [1];

2)Forearm long axis (Yf): the line pointing upward from the midpoint

between ulnar and radial styloid (US, RS) to E [1];

3)Carrying angle: angle formed by the forearm long axis and the humerus long

axis when the forearm is fully extended and supinated [3]; NB: in [3] I

didn't find the definition of the long axes with respect to the previously

defined anatomical landmarks, even if I supposed that the above given are

nevertheless applicable.

4)Prosupination axis: the line pointing upward from US to E [1];

5)Flexion-extension axis: assumed orthogonal to the prosupination axis [2]

passing through E; its direction should correspond to the Z axis of the

humerus bone embedded

system (see below different definitions suggested in [1]);

>From [1]:

1) Humerus (1st degree) Coordinate System - Xh1Yh1Zh1

Oh1: The origin coincident with GH.

Yh1: The line connecting GH and the midpoint of EL and EM, pointing to GH.

Xh1: The line perpendicular to the plane formed by EL, EM, and Yh1, pointing

forward.

Zh1: The common line perpendicular to Yh1- and Zh1-axis.

2) Humerus (2nd degree) Coordinate System - Xh2Yh2Zh2

Oh2: The origin coincident with GH.

Yh2: The line connecting GH and the midpoint of EL and EM, pointing to GH.

Zh2: The line perpendicular to the plane formed by Yh2 and Yf (see above),

pointing laterally. Zh2-axis is taken with 90 degrees flexed elbow.

Xh2: The common line perpendicular to Xh2- and Yh2-axis.

[1] Frans C.T. van der Helm , (2002) "ISB Recommendation on Definitions of

Joint Coordinate System of Various Joints for the Reporting of Human Joint

Motion - Part II: Shoulder, Elbow, Hand and Wrist, Shoulder", Submitted to

JBiomech 2002

[2] Veeger H.E.J, (1997) "Orientation of axes in the elbow and forearm for

biomechanical modeling" Proc. of the 1^ Conf. of the ISG

[3] Zatsiorsky V.M., (1998) "Kinematics of the Human Motion", Human

Kinematics

Many thanks

Best regards

Andrea G. Cutti

-----

Ing. Andrea Giovanni Cutti

PhD Student - Biomedical Engineering Group

University of Bologna

Viale Risorgimento 2

40136 - Bologna

-----------------------------------------------------------------

To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl

For information and archives: http://isb.ri.ccf.org/biomch-l

Please consider posting your message to the Biomch-L Web-based

Discussion Forum: http://movement-analysis.com/biomch_l

-----------------------------------------------------------------