Which axis runs from left to right and is associated with flexion and extension movements in the sagittal plane?

Which axis runs from left to right and is associated with flexion and extension movements in the sagittal plane?

• A. Frontal axis
• B. Sagittal axis
• C. Longitudinal axis
• D. Transverse axis

Answer: (A)

Flexion and extension happen in the sagittal plane, which runs from left to right through the body. The axis that allows these movements must be perpendicular to that plane, so it is the frontal axis that runs side to side. This left-to-right axis provides the pivot for bending and straightening joints, like at the elbow or knee, when you perform flexion or extension. For contrast, rotations in the transverse plane use a vertical (longitudinal) axis, while abduction and adduction in the frontal plane occur around the sagittal (front-to-back) axis.

Flexion and extension happen in the sagittal plane, which runs from left to right through the body. The axis that allows these movements must be perpendicular to that plane, so it is the frontal axis that runs side to side. This left-to-right axis provides the pivot for bending and straightening joints, like at the elbow or knee, when you perform flexion or extension. For contrast, rotations in the transverse plane use a vertical (longitudinal) axis, while abduction and adduction in the frontal plane occur around the sagittal (front-to-back) axis.