Flexor carpi radialis
The radial artery runs on the radial side of the wrist, lateral to the tendon of flexor carpi radialis. So, the radial pulse will be felt immediately lateral to this tendon. Remember--the radial artery enters the wrist on the anterior side. This means that the extensor tendons, which are on the posterior side of the wrist, will not be involved with the radial artery! The tendons for flexor digitorum profundus and superficialis are found more towards the center of the wrist, not on the wrist's lateral side. These tendons cross under the flexor retinaculum to reach the hand.