Biceps Brachii Anatomy: Origin, Insertion & Action

[@ruigoncalves2]

I don’t understand how can the bicep supinate the forarm if it’s only connected to the Radius bone. Is it a combination movement with another forearm muscle?

[@BodyworksPrime]

That is correct, supination is only a secondary role of the biceps brachii. Its primary role is elbow flexion. However, when the forearm is pronated, the biceps brachii can still pull on the radius to aid the forearm back to a supinated position. If you look at the image at 2:07 (which is in a supinated position) and imagine the forearm pronating, the radius will twist therefore putting the insertion in a more advantageous place to supinate from. Also, its other insertion point on the bicipital aponeurosis can provide a little extra leverage if you look at the image at 2:21 (the image is again in a supinated position). Check out a muscle called 'the supinator muscle' which is located in the forearm, this is a primary supinator of the forearm. Also, when the forearm is in a pronated position, the brachioradialis muscle assists in supination too. I'll be posting a video about the brachioradialis muscle on Monday next week. I'll also add the 'supinator muscle' to my to do list and do a video on that sometime soon too. Hope that helps!

[@SaraMohmed-nw4ku]

how can I get more of these video of action of muscles

[@anwrmax492]

Bro tou didnt mention the brachialis head as i know the biceps have 3 heads just like the triceps

[@BodyworksPrime]

The brachialis is not a head of the biceps. It is a separate muscle. Bi means two in Latin, tri means three. This is why biceps starts with bi because it has two heads and the triceps starts with tri because it has three heads. My brachialis video is here if you are interested: kzbin.info/www/bejne/a3PQgGd7i7uSprs