Fig 1.
Schematic sagittal section of shoulders showing different kinds of EIPMTs according to Le Double.
Modified from Lee 2014 [4]. CHL = coracohumeral ligament, CP = coracoid process, H = humerus, PMM = pectoralis minor muscle, SCM = subscapularis muscle, SSM = supraspinatus muscle.
Fig 2.
Exemplary photograph of a right shoulder seen from superior.
The ectopic pectoralis minor tendon (*) runs over the coracoid process and through the branches of the coracoacromial ligament (CAL). A = acromion, CAL = coracoacromial ligament, CP = coracoid process, H = humerus, PMM = pectoralis minor muscle.
Fig 3.
Right EIPMT (A and A’) and normal (B and B’) type shoulder from cranial (A and B) and lateral (A’ and B’).
Insertion areas are marked on the coracoid process. Red = PMM, black = CAL, blue = CHL, * medial CHL fibers, violet = CGL, green = coracobrachialis muscle/short head of biceps. Insertion areas of the PMM in EIPMT type shoulders are significantly bigger (red) and coracopectoral distances (yellow line) to the lateral border significantly smaller. In EIPMT type shoulders with tendons blending into the CHL the CGL insertion area must move more proximal and the CAL must be divided into two branches to give space to the CHL.
Table 1.
Dimensions of and relationships between shoulders with (EIPMT) and without (Normal) ectopic insertions.
CGL = coracoglenoid ligament CHL = coracohumeral ligament, PMM = pectoralis minor muscle.
Fig 4.
CHL retrieved from shoulders with EIPMT (A) showed a higher number of specimens with large amounts of elastic fibers (arrowhead) compared to normal shoulders (B). (resorcin-fuchsin stain, original magnification x20).
Fig 5.
CHL retrieved from shoulders with EIPMT (A) showed a higher number of specimens with predominant type I collagen fibers (orange) compared to normal shoulders (B, predominant collagen type III, yellow-green). (picrosirius-red, original magnification x10, polarized).
Table 2.
Prevalence and Le Double classification relative to previous studies.
N = number of included shoulders.