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Shouldering the burdens of locomotion & posture: glenohumeral joint structure in strepsirrhines.
Author(s) -
Burrows Anne M,
WrightFitzgerald Adrian S
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.171.3
Subject(s) - anatomy , rotator cuff , quadrupedalism , arboreal locomotion , medius , scapula , labrum , medicine , biology , surgery , ecology , habitat , arthroscopy
The present study compares soft‐tissue morphology of the shoulder joint (acromioclavicular, coracoclavicular, and glenohumeral joints) among broad phylogenetic, locomotor, and postural behavior ranges in prosimian primates. Adult specimens of Galago moholi (a vertical clinger and leaper), Cheirogaleus medius (an arboreal quadruped), Eulemur macaco (an arboreal quadruped that also frequently engages in suspensory behavior), and Tarsius syrichta (a vertical clinger and leaper) were dissected. The rotator cuff muscles were also dissected and weighed among the species. Results showed that muscle mass of individual components of the rotator cuff musculature do appear to be adaptive. Two soft‐tissue components of the glenohumeral joint, but not the acromioclavicular and coracoclavicular joints, also were adaptive. The quadrupedal species, C. medius and E. macaco , both had glenohumeral ligaments and E. macaco , which also uses suspensory postures, had a relatively deeper articular surface for the humerus due to the shape of a deep, “cup‐like” glenoid labrum. Additionally, the present study noted a lack of a teres minor muscle in G. moholi , C. medius , and E. macaco despite previous studies describing them. A relatively robust teres minor muscle was found in T. syrichta . Overall, these results show that soft‐tissue joint morphology itself may be as adaptive as osseous morphology.