For an L4, possible muscle function includes: medial knee flexors (3/5) and ankle dorsiflexors (3/5) as well as all levels from L3 (knee extensors 3/5) and L2 (hip adductors 3/5, hip flexors 3/5), L1 (lower trunk, hip flexors 2/5), and above. For an L5 lesion, possible muscle function includes: hip abductors (2/5), lateral knee flexors (3/5), ankle invertors (3/5), toe extensors (palpable at ankle). L5 clues in this patient are the hip abductors, foot inversion, and toe extension. We would expect stronger muscle groups if the child was S1-3 as well as hip extension and ankle plantarflexion present to some extent.
Here is a resource I find helpful: https://depts.washington.edu/dbpeds/HOW%20SB%20LESIONS%20IMPACT%20DAILY%20FUNCTION.pdf