World Confederation of Physical Therapy Congress 2011
Institute of Physical Therapy,
Prevention and Rehabilitation
June 23 th. 2011, Amsterdam, NL
Display No: RR-PO-203-27 - Thu
Mainz, Germany
Analysis of the Humeroscapular Angular Motion Ratio using a New
Combined Palpatory and Photogrammetric Measuring Procedure
Ulrich Betz, Andreas Thoesen, Nadja Leyendecker, Friedrich Bodem, Philipp Drees
Introduction
Results
Purpose: The scapula has an elemental, but as yet not fully investigated role in
shoulder biomechanics. Various patterns of the relative motions between
humerus, scapula and thorax are described. The scapular motion itself does not
receive much attention in clinical examinations, however.
Relevance: Nevertheless, some specialists suggest that a biomechanical
dysfunction of the scapula may be involved in disorders of the glenohumeral
joint. To contribute to the further investigation of this issue, we have developed a
practicable method for a reliable determination of the humeroscapular ratio.
Results: In a more summarizing description
the scapulo-humeral motion patterns
observed in all 101 subjects could be
divided in two phases. In the initial setting
phase there is an average motion ratio
6.42 : 1 of the humerus to the scapula, while
in the main phase of the abduction
movement it is 1.2 : 1.
Scapular-Rotation SR
60°
40°
20°
0°
0°
20° 40° 60° 80° 100° 120° 140°
Arm-Abduktion AA
Considered in more detail, however, the scapular motion patterns as a
function of the scaption angle were very individual in the different subjects.
Methods
Some Examples:
(Arm-Abduktion AA = Scapular-Rotation SR + Gleno-Humeral-Abduktion GHA)
Participants: In an initial study we
examined 101 healthy subjects (54
female; 47 male; mean age: 28). None of
them had suffered from shoulder
disorders at any time or from back pain
within the last 6 months.
Scapular-Rotation SR
AA
SR
Gleno-Humeral-Abduktion GHA
Scapular-Rotation SR
GHA
AA
SR
Gleno-Humeral-Abduktion GHA
Scapular-Rotation SR
AA
GHA
SR
Gleno-Humeral-Abduktion GHA
GHA
AA=
SR+GHA
AA=
SR+GHA
AA=
SR+GHA
GHA
GHA
GHA
SR
SR
Methods: The measurements were taken
with the subject seated upon a chair with
a special headrest avoiding excessive
movement of the spine during positioning
of the arm. The arm was positioned
against a wall oriented in parallel to the
scapular plane. The scapular position
was then determined by photogrammetry
at 14 different scaption (arm abduction in
the scapular plane) angles.
SR
Arm-Abduktion AA
Scapular-Rotation SR
AA
SR
Arm-Abduktion AA
Gleno-Humeral-Abduktion GHA
Scapular-Rotation SR
AA
GHA
SR
Gleno-Humeral-Abduktion GHA
Arm-Abduktion AA
Scapular-Rotation
GHA
AA
AA=
SR+GHA
SR
SR
Gleno-Humeral-Abduktion GHA
GHA
AA=
SR+GHA
AA=
SR+GHA
GHA
GHA
SR
GHA
SR
SR
As opposed to previous investigations
with optoelectronical methods, all
scapular landmarks were palpated and
marked on the skin at each scaption
angle. We thus reduced measurement
distortion caused by a movement
between the skin and the shoulder blade
during arm abduction. A distortion of this
kind is likely to occur when markers
invariably fixed on the skin are used.
Arm-Abduktion AA
Arm-Abduktion AA
Arm-Abduktion AA
The angular movement of the shoulder blade started in some individuals at a
scaption angle of 0 degrees already, but in one individual at 99 degrees only.
Scapular-Rotation SR
AA
SR
Gleno-Humeral-Abduktion GHA
Scapular-Rotation SR
AA
GHA
SR
Gleno-Humeral-Abduktion GHA
GHA
AA=
SR+GHA
AA=
SR+GHA
GHA
GHA
At each scaption angle we took a
standardized digital photograph. The land
marks visible in the photo were digitised
and analysed by dedicated computer
programs.
vertical
SR
SR
Arm-Abduktion AA
GHA
Analysis: The data obtained were
handled statistically applying regression
analysis, Student - t , and Wilcoxon
testing.
Arm-Abduktion AA
Comparing the left and right side within particular individuals, we found
distinctive differences, too.
SA
Considering all subjects, we could not verify statistically significant differences
between the right and left side, between men and women and between right
and left-handers, however.
Conclusions
Implications
• The beginning of scaption is dominated by the gleno - humeral portion of the
motion.
The high individuality of scapular motion patterns found in our study shows that it
is very difficult to define an individual humeroscapular ratio observed in a patient
to be outside the normal physiological range. The “restore physiological
movment”-approach in physiotherapy should be reconsidered from this
perspective.
• In the main scaption phase gleno – humeral and scapular motions are
involved in nearly equal proportions.
• The scaption patterns are very individual and vary in a wide range
• It obviously does not make sense to define a narrow range of
humeroscapular ratios as physiological.
Contact
ulrich.betz@unimedizin-mainz.de