Today we will discuss movements of the upper limb. Our objectives here are simply to describe the movement of the major joints. Again, we emphasize the importance of movements of the upper limb in terms of positioning the hand. We begin with the shoulder, which is a ball and socket joint that permits multiaxial movements. Flexion and extension carry the arm, if you will, forward and backward, anteriorly and posteriorly, inflection and extension. The shoulder joint also permits abduction and adduction. Abduction carries the limb away from the midline. Adduction carries it towards the midline. The shoulder also allows medial and lateral rotation. Twisting the arm medially sometimes called internal rotation, or twisting it laterally sometimes called external rotation. The elbow is a complicated joint. It actually involves the humerus, the radius, and the ulna. The humeroulnar joint is a hinge joint. The olecranon on sit-in a groove on the humerus called the trochlea. Trochlea means pulley. It did movement forwards and backwards. Flexion and extension are permitted at the humeroulnar joint. The radius and humerus have almost the characteristics of a ball and socket joint. The radius can both flex and extend along the humerus as it's connected to the ulna. It's carried forward and backwards, anteriorly and posteriorly, by the ulna as it flexes and extends. But also because of the anatomy of the joint between the humerus and the radius, there can be rotation at that joint, and that rotation is called pronation and supination. Putting one's palm on a table, for example, is pronation. Lifting the palm up, as my colleague would say to hold a cup of soup, is supination. At the wrist, the joint between the radius and carpal bones allows both flexion and extension and a small amount of abduction and adduction, moving the hand from side to side in abduction or adduction. There's very little movement between the carpal bones, although there is some. The next major set of movements we see are between the metacarpals and the phalanges. These joints permit both flexion and extension as well as abduction and adduction. Abduction and adduction by definition referred to either spreading the digits apart thusly as abduction or pulling them together as adduction. You can see that these are important movements in spreading one's fingers to grasp something. The interphalangeal joints, the joints between the proximal and middle phalanx and between the middle and distal phalanx, these interphalangeal joints are responsible for flexion and extension. The thumb is special. We're all aware. We speak about the opposable thumb as being a critical feature in evolution in the unique human ability to grasp things. In part, that's because the thumb is not in the same plane as the palm. We can see this lateral view, showing the index, center, ring finger, and little finger all lined up in the same plane, and the thumb is set at an angle and away from the rest of the palm. We have a special set of terms to describe movement of the thumb. Abduction carries the thumb away from the plane of the palm and adduction carries it towards the palm. Flexion carries the thumb across the palm and extension carries it backward. Then there's a special movement, combination of several joints, called opposition. That carries the tip of the thumb against the tip of the fingers and allows us to do this movement. Allows us to get what's called the pulpy part of our thumb against our fingers to grasp something. Requires a small amount of rotation. Together flexion, abduction and opposition create the opposable thumb, which is characteristic of the human hand. Let's now review what we know about the movements of the upper extremity. Again, this is just as simple, quick quiz, no pressure. It just make us think about how we can apply what we've just learned. For example here, patting your stomach involves primarily, which of the following movements? Abduction of the shoulder, adduction of the shoulder, medial rotation or lateral rotation? Think about that for a moment. If you said medial rotation, that's good. That place is the palm of your hand against your stomach. The opposite movement, moving it away from your stomach would be lateral rotation. Placing the palm of your hand on the table involves principally what movement? Medial rotation of the shoulder, flexion of the elbow, pronation of the forearm or extension of the wrist? If you said pronation of the forearm, that's good. It's a movement that places your palm facing downward. The opposite movement, lifting your palm upwards to hold, as my colleague says, a cup of soup, that movement, the opposite of pronation is supination. Making a fist requires extension of the digits, flexion of the digits, flexion of the wrist or extension of the wrist? You think about that for a moment, it seems pretty clear that it requires flexion of the digits which closes the joints and pulls the tips of the fingers against the palm. Which movements are involved in making the AOK sign as I've done here? Flexion of the index finger, abduction of the thumb, flexion of the thumb, opposition of the thumb? You remember how important the movements of the thumb are and how they're a little more complicated than movements of the rest of the upper limb because of the mobility afforded the thumb. If you said all of those, that's correct. We need to abduct the thumb, to pull away from the palm, we need to flex the thumb to get it into position. To touch the index finger, we need to twist it a bit and then we need to bring the index finger in contact with it. This is very important movement. An example of the importance of grasp and the ability of our thumb to do with these many marvelous things. Spreading of the fingers is defined as abduction, adduction, flexion or extension? If you said abduction, that's good. By convention the middle finger of the hand is the central point. Things that move the fingers away from the middle fingers are abduction. Things which pull it toward are adduction. Thank you. We'll move on to the next lecture soon.
