What's the difference between thereunder and whereinto?

Thereunder

Definition:

• (adv.) Under that or this.

Example Sentences:

• (1) Case 1: mild weakness in right upper and lower limbs and left small hand muscles, mild superficial and deep sensory disturbance on bilateral palms and soles and decrease of vibration on bilateral lumbar regions and thereunder.

Whereinto

Definition:

• (adv.) Into which; -- used relatively.
• (adv.) Into what; -- used interrogatively.

Example Sentences: