Answer: (1) Frontal Plane
(2) Sagittal axis
Explanation: A shoulder joint can do an abduction, which is taking a body part away from the center line or an adduction, which is moving it towards the center line.
In anatomy, a Plane describes the axis along which a movement is made. There are 3 reference planes but for abduction or adduction, it is the frontal plane.
Frontal Plane or coronal plane is perpendicular to the ground and divides the body into dorsal, also known as posterior and ventral or anterior.
In movement, an Axis is a straight line an object or body part rotates.
A shoulder joint rotates at a sagittal axis, i.e., passes horizontally from posterior to anterior.
