The 3rd Bhava house in an Indian horoscope signifies courage, hence hands, shoulders, chest are also signified by this Bhava.
The Ear, Nose and throat problems are also signified by this Bhava house. Younger siblings of a person come under his house.
This house is also connected with printing and publishing, short journeys. So bus transport falls in this house.

Mars is Karaka for strength in Vedic astrology, and so much of the 3rd house activities depend on the placement and strength of Mars.
As this house is 7th to the 9th house the 3rd lord is also Maraka lord for father.
If 3rd is afflicted in a horoscope either there will be no younger siblings or there may not be good relations with younger ones.

The effect of different planets in 3rd house of a horoscope is:

Sun- Courageous and authoritative

Moon- younger siblings will be happy and prosperous

Mars – Good nature. Very courageous, rather rash if   Mars be exalted or in Aries, bad for younger brothers, if afflicted by Saturn the person may suffer with ear trouble and undergo an operation also.

Mercury : depending on the sign concerned the native can be a cheat also but will be affectionate to younger siblings.

Jupiter – Always victorious and endowed with high mental strength

Venus – Is not good as happiness will be short lived. Could get annoyed very easily.

Saturn – Good for longevity

Raahu- Long lived . steady mind.

Kaytu- courageous, religious, wealthy and strict observer of religious norms

As per the norms of Vedic astrology, the results of 3rd house will be experienced in the dasa and antar Dasas of 3rd lord.

Accurate horoscope predictions based on Indian Astrology by ‘The Himalayan Ashram of Vedic Astrologers’ are available in the United States of America (US), Canada (CA), Australia (AU), New Zealand (NZ), South Africa (ZA), Japan (JP), Singapore (SG), Hong Kong (HK), Malaysia (MY), United Kingdom (England, UK), France (FR), Switzerland (CH) , Netherlands (NL), Norway (NO), Sweden (SE) and India (IN).