Biomechanics Blog I: Activity Analysis

Since I have been staying at home more, I have been wearing my glasses rather than my contacts.
When I wake up and go get my glasses they are typically on my bathroom counter. My starting position consists of standing upright with my arms extended down beside me, palms facing towards my body. As I go to reach for my glasses on the counter, both of my arms become slightly flexed at the elbows as I bring them up from the starting position. Next, both of my elbows extend out in order to reach my glasses laying on the counter. This step can also include shoulder flexion, depending on how high the counter/shelf your glasses are on. My MCP, DIP, and PIP joints all gently flex to grasp the sides of my glasses.
My wrists then consists of ulnar deviation as I begin to grab my glasses off of the counter. As my end position, my elbows go into flexion as I bring my glasses to my face and my wrists participate in radial deviation when sliding them on.

Throughout this activity, the osteokinematics movement was based in the sagittal plane and frontal axis. I feel that this motion is also an open kinematic chain, since the distal portion of my arm is moving more than my proximal. The arthrokinematics of the elbow (hinge joint) features the ulna which rolls and glides in the same direction on the humerus by the MCL, this creates a concave-convex motion. The primary mover for elbow flexion, which is bringing my glasses to my face, is the brachialis muscle that is activated in a concentric way.