Children aged between 7 and 18 months are very active and have varied skills. Remember that gross motor skills like any other skills progress from simple to more complex movements. Do not assess a child's ability to stand if they cannot sit.

Introduce yourself to Mary and her mother and gain their consent. Have in mind a variety of test that will help you reach your goal. If the she does not want to do a certain test, move on. 

Comment on things that  Mary does  spontaneously which aid your assessment. Take advantage of these and start your assessment with that aspect of gross motor development.  

Gross motor development from 7months- 18 months
Observe the child in the supine position, pull-to-sit and sitting position, standing, ventral suspension and in the prone position. At every level comment on  gross movements, active and passive posture.

 

Gross Motor skills from 7 -18 months

 Video provided courtesy of http://www.medivisionfilms.com/,