The Proprioceptive Capability of the Glenohumeral Joint with Special Reference to Shoulder Instability

Jerosch, J, Thorwesten L, Steinbeck J

Abstract in digital collection (conference)

Abstract

Histologie investigation Material and Methods: The glenohumeral joint capsules of 12 human shoulder specimens have been histologically investigated by light microscopy. Serial sections of 15 micrometers were performed. For specific identification of neural elements we made use of a special silver impregnation technique. Results: Axons of different diameters ranging from 0,2 um to 70 um were discovered within the ligaments. Close to the humeral site we found small nerves forming neurovascular bundles. Within their connective tissue sheaths, the axons exhibited a serpentine configuration, which may give extra length and may allow stretching of the nerve during motion. In addition to these axonal structures, we detected nerve endings which can be classified as type II mechanoreceptors. They were located directly beneath the synovial membrane and close to the humeral insertionsite of the ligaments. Clinical Investigation Material and methods: In 27 healthy volunteers we evaluated the proprioceptive function of the glenohumeral joint by an angle reproduction test. The volunteers were asked to place the arm in different positions with and without visual control. The test was performed for the dominant as weil as for the non dominant extremity for the following positions: 50°, 100°, 150° abduction, 50°, 100°, 150° flexion, +45°, 0°, -45° rotation in 90° of abduction. The documentation of the joint position was perfonned with a motion analysing system. Results: The results showed significant differences between the measurements with and without visual control. Proprioception seems to be worse below the shoulder level (50° abduction, flexion). Better results in comparison with the entire group had two volunteers with general good coordinative capabilities. We could not demonstrate differences between the dominant and non dominant extremity nor between male and female. Neurophysiologic lnvestigation Material and Methods: In 8 patients, which were operated on due to subacromial pathology, we performed intraoperative stimulation of the anterior g]enohumeral joint capsule. The stimulation was performed with a bipolar electrode in a nonconductive medium. Parallel we registered the EMG signal (needle-electrodes) of the deltoid muscle, the trapezius muscle, the pectoralis muscle, as weil as the rotator cuff musculature. Results: Due to technical problems the measurements could not be completed in l patient. In all other patients we got positive EMG readings in at least three muscles. Conclusion: Mechanoreceptors located in the g]enohumeral ligaments may be responsible for controlling the stabilising shoulder musculature. On this premise, a posttraumatic Bankart-laesion will lead to a loss of a feedback mechanism.

Details zur Publikation

Release year: 1995
Language in which the publication is written: English