Comparative Primate Anatomy

1222 Words5 Pages
NOTES FOR FEBRUARY 27 LECTURE February 28, 2012 Having defined the major locomotor categories and the biological classification of the living primates, we move now to establishing Morphological and Behavioral Correlates which will help in interpreting the fossil record. We will begin by noting the difference among Quadrupeds, Brachiators and Bipeds. A. Basic movements of the forelimb 1. Quadrupeds move their forelimbs forward (protract) and backward (retract) in the sagittal plane. much the same way as dogs. 2. Brachiators raise their arms above their heads, in other words they abduct and adduct their arms in the coronal plane. They propel and suspend their bodies with their arms. 3. Bipeds do not support or propel their body with their arms. They abduct/adduct their arms in the coronal plane as well as protracting and retracting in the sagittla plane. B. Orientation of the Scapula 1. Quadrupeds have a deep thoracic cage, i.e. the distance between the vertebral column and the sternum is greater than the breadth of the thoracic cage. 2. The scapula tends to be more to the sides of the thoracic cage. 3. The glenoid fossa is directed downward. 4. Quadrupeds support their body weight not their forelimbs. 5. Brachiators: the scapula is on the back of the thoracic cage. 6. Glenoid fossa is direct laterally. 7. Bipeds: the scapula is on the back of the thoracic cage. 8. Glenoid fossa is direct laterally. A. Size comparisons of supraspinatus and infraspinatus fossae 1. Large supraspinatus fossa is found in primates that hold their arms above the shoulder: Ateles Alouatta Hylobates Pan and Gorilla 1. Large infraspinatus fossa is seen in animals that lift their
Open Document