External rotation (or lateral rotation) is rotation away from the center of the body.
The muscles of external rotation include:
- of arm/humerus at shoulder
- Deltoid muscle
- Infraspinatus
- Teres minor
- of thigh/femur at hip
- Gluteus maximus
- Lateral rotator group
- piriformis
- gemellus superior
- obturator internus
- gemellus inferior
- obturator externus
- quadratus femoris
- Sartorius
- of leg at knee
- Biceps femoris
- of eyeball (motion is also called "extorsion" or excyclotorsion)
- Inferior rectus muscle
- Inferior oblique muscle
Famous quotes containing the words external and/or rotation:
“For those parents from lower-class and minority communities ... [who] have had minimal experience in negotiating dominant, external institutions or have had negative and hostile contact with social service agencies, their initial approaches to the school are often overwhelming and difficult. Not only does the school feel like an alien environment with incomprehensible norms and structures, but the families often do not feel entitled to make demands or force disagreements.”
—Sara Lawrence Lightfoot (20th century)
“The lazy manage to keep up with the earth’s rotation just as well as the industrious.”
—Mason Cooley (b. 1927)