A. Square window test.
B. Triangle test.
C. Cone test.
Square window test- The position for assessing the square window is shown in the picture above.
- The 45degree angle seen between the palm and forearm is consistent with a gestational age of 30 to 32 weeks.
- The square window test of the wrist is performed by gently flexing the hand on the wrist and assessing the resultant angle.
- The wrists of babies younger than approximately 32 weeks can be flexed only to 45 to 90 degrees, whereas the wrists of term infants undergo full flexion.
- Sometime between birth and adulthood this flexion ability is lost.