Related Experiment Videos
Morphology of the torn rotator cuff
E Itoi1, H C Hsu, S W Carmichael
1Orthopedic Biomechanics Laboratory, Mayo Clinic/Mayo Foundation, Rochester, MN 55905, USA.
Journal of Anatomy
|April 1, 1995
Summary
Rotator cuff tears significantly alter shoulder anatomy, increasing functional tendon length and decreasing muscle fiber length. These morphological changes in the supraspinatus, infraspinatus, and subscapularis muscles indicate physiological abnormality, potentially improved by surgical repair.
Area of Science:
- Orthopedic Surgery
- Anatomy
- Biomechanical Engineering
Background:
- Rotator cuff tears are common shoulder injuries.
- Understanding the morphological changes associated with rotator cuff tears is crucial for effective treatment.
Purpose of the Study:
- To determine the morphological characteristics of shoulders with torn rotator cuffs.
- To investigate the relationship between tear size and specific anatomical parameters.
Main Methods:
- Analysis of 41 embalmed shoulder specimens.
- Measurement of extramuscular and intramuscular tendon dimensions, tear size, muscle fiber length, and muscle volume.
- Calculation of tendon and muscle cross-sectional area (CSA).
Main Results:
- 44% incidence of full-thickness tears and 29% incidence of partial-thickness tears observed.
- Increased tear size correlated with significantly increased functional tendon length (supraspinatus, infraspinatus, subscapularis).
- Muscle fiber length decreased in the supraspinatus and infraspinatus with increasing tear size.
Conclusions:
- Rotator cuff tears lead to significant morphological changes, including increased functional tendon length and decreased muscle fiber length.
- These alterations create a physiologically abnormal rotator cuff unit.
- Surgical repair may restore normal anatomy and glenohumeral joint kinetics.