Changes in pennation angle in rotator cuff muscles with torn tendons.
Summary of "Changes in pennation angle in rotator cuff muscles with torn tendons."
BACKGROUND:
Although several authors have reported on the pennation angles of intact rotator cuff muscles, the relationship between their alteration and rotator cuff tears has not been fully clarified. The purpose of this study was to measure the pennation angles of human cadaveric rotator cuff muscles with torn tendons.
METHODS:
Twenty embalmed cadaveric shoulders were studied. Ten shoulders with various types of rotator cuff tears (tear group) were compared with ten shoulders that had intact rotator cuff tendons (control group). In seven shoulders with full-thickness tears, the area of the tear was determined by multiplying its length and width. After removing the muscles from the scapula, the superficial muscle fibers of each muscle were removed layer by layer until the entire intramuscular tendon was exposed. Photographs were taken and the pennation angles were then measured on digital images. The correlation between the size of the tear and the pennation angles of the supraspinatus and the infraspinatus muscles were determined statistically.
RESULTS:
The pennation angles of the supraspinatus and infraspinatus muscles in the tear group were significantly greater than those in the control group (P = 0.027 and 0.007, respectively). In seven shoulders with full-thickness rotator cuff tears, a positive correlation was found between the pennation angle of the supraspinatus muscle and the tear length (r = 0.854, P = 0.014). Moreover, a positive correlation was found between the pennation angle of the infraspinatus muscle and the tear area (r = 0.759, P = 0.048). On the other hand, the pennation angle was not affected by the presence of the partial-thickness tears in the remaining three shoulders. DISCUSSION AND
CONCLUSION:
In rotator cuff tears, the pennation angles of the involved rotator cuff muscles increased with increasing size of the tear.
Affiliation
Department of Orthopaedic Surgery, China-Japan Union Hospital of Jilin University, Changchun, China.
Journal Details
This article was published in the following journal.
Name: Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association
ISSN: 1436-2023
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22094606
- DOI: http://dx.doi.org/10.1007/s00776-011-0176-6
Medical and Biotech [MESH] Definitions
Shoulder Impingement Syndrome
Compression of the rotator cuff tendons and subacromial bursa between the humeral head and structures that make up the coracoacromial arch and the humeral tuberosities. This condition is associated with subacromial bursitis and rotator cuff (largely supraspinatus) and bicipital tendon inflammation, with or without degenerative changes in the tendon. Pain that is most severe when the arm is abducted in an arc between 40 and 120 degrees, sometimes associated with tears in the rotator cuff, is the chief symptom. (From Jablonski's Dictionary of Syndromes and Eponymic Diseases, 2d ed)
Rotator Cuff
The musculotendinous sheath formed by the supraspinatus, infraspinatus, subscapularis, and teres minor muscles. These help stabilize the head of the HUMERUS in the glenoid fossa and allow for rotation of the SHOULDER JOINT about its longitudinal axis.
Scattering, Small Angle
Scattering of a beam of electromagnetic or acoustic RADIATION, or particles, at small angles by particles or cavities whose dimensions are many times as large as the wavelength of the radiation or the de Broglie wavelength of the scattered particles. Also know as low angle scattering. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Small angle scattering (SAS) techniques, small angle neutron (SANS), X-ray (SAXS), and light (SALS, or just LS) scattering, are used to characterize objects on a nanoscale.
Hydrophthalmos
Congenital open-angle glaucoma that results from dysgenesis of the angle structures accompanied by increased intraocular pressure and enlargement of the eye. Treatment is both medical and surgical.
Glaucoma, Open-angle
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
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