Research
Stretching positions for the coracohumeral ligament: Strain measurement during passive motion using fresh/frozen cadaver shoulders
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* Corresponding author: Tomoki Izumi t.izumi@sapmed.ac.jp
- † Equal contributors
1 Doctoral Course of Physical Therapy, Graduate School of Health Sciences, Sapporo Medical University, Sapporo, Japan
2 Department of Orthopaedic Surgery, Sapporo Daiichi Hospital, Sapporo, Japan
3 Department of Orthopaedic Surgery, Japan Self Defence Force Sapporo General Hospital, Sapporo, Japan
4 Department of Physical Therapy, Sapporo Medical University, Sapporo, Japan
5 2nd Department of Anatomy, Sapporo Medical University, Sapporo, Japan
6 Department of Physical Therapy, Hokkaido Bunkyo University, Eniwa, Japan
Sports Medicine, Arthroscopy, Rehabilitation, Therapy & Technology 2011, 3:2 doi:10.1186/1758-2555-3-2
Published: 19 January 2011Abstract
Background
Contracture of the coracohumeral ligament is reported to restrict external rotation of the shoulder with arm at the side and restrict posterior-inferior shift of the humeral head. The contracture is supposed to restrict range of motion of the glenohumeral joint.
Methods
To obtain stretching position of the coracohumeral ligament, strain on the ligament was measured at the superficial fibers of the ligament using 9 fresh/frozen cadaver shoulders. By sequential measurement using a strain gauge, the ligament strain was measured from reference length (L0). Shoulder positions were determined using a 3 Space Tracker System. Through a combination of previously reported coracohumeral stretching positions and those observed in preliminary measurement, ligament strain were measured by passive external rotation from 10° internal rotation, by adding each 10° external rotation, to maximal external rotation.
Results
Stretching positions in which significantly larger strain were obtained compared to the L0 values were 0° elevation in scapula plane with 40°, 50° and maximum external rotation (5.68%, 7.2%, 7.87%), 30° extension with 50°, maximum external rotation (4.20%, 4.79%), and 30° extension + adduction with 30°, 40°, 50° and maximum external rotation (4.09%, 4.67%, 4.78%, 5.05%)(P < 0.05). No positive strain on the coracohumeral ligament was observed for the previously reported stretching positions; ie, 90° abduction with external rotation or flexion with external rotation.
Conclusions
Significant strain of the coracohumeral ligament will be achieved by passive external rotation at lower shoulder elevations, extension, and extension with adduction.