Biomechanics of Drinking a Glass of Water

Every morning, the first thing I do is drink a glass of water. From the point that I grasp the glass of water to actually bringing the glass of water to my mouth in order to take a drink, there is a lot going on behind the scenes. The action starts with my elbow in a slightly flexed position, my wrist in a slightly extended position, and my fingers flexed around the glass of water. As I bring the glass to my mouth, my elbow ends in full or near full flexed position, my shoulder in a slightly flexed position, my wrist is still in an extended position, and my fingers will flexed around the glass of water. Let's look at one specific joint in the action of drinking a glass of water. The osteokinematics of the elbow joint for this activity is flexion going from mid-range flexion (about 90°) to full or near full flexion (about 145°) in an open kinematic chain. The prime mover of elbow flexion is the biceps brachii, which performs a concentric contraction in the sagittal plane about a coronal axis. The arthrokinematics of elbow flexion include the concave trochlear notch of the ulna rolling and gliding anteriorly on the the convex trochlea of the humerus and the concave radial head rolling and gliding anteriorly on the convex capitulum of the humerus.