Scaption is an abduction (or adduction) movement in the scapular plane. It is a save movement direction to choose after trauma and operation of the shoulder joint in many cases.  When about 80 % of the scaption glenohumeral movement is free other movement directions can be treated to regain the normal physiological range of movement.

image 1

here we see that the arm is abducted in the scapular plane. the schoulderblade (scapula) is not lying in an frontal plane but makes a more or less dependent on individual posture and anatomy a 30 degrees angle with the frontal plane. see angle between red and blue line in image 2.

image 2

this is a sight from above through the head down . the blue line represents the frontal plane the red line represents the scapular plane the yellow line represents the plane of the glenoid fossa. the black arrow represents the plane the arm movement should be done in.

Scaption movement