A Comprehensive View of Your Upper Extremity Joints and Movements
Our bodies joints, muscles, and tissues move in numerous ways working together, and when we gain an understanding of how it all works, we realize just how complicated of a system the body can be. Let’s briefly explain each joint in the upper extremities and the movements they provide.
The Shoulder
Our shoulder moves through several different planes- flexion, extension, abduction, internal rotation, and external rotation. These movements are possible because the shoulder is a ball-and-socket joint that allows for maximum range of motion. What do these movements look like?
- Flexion: Flexion describes the movement of the shoulder when it lifts our arm straight up in front of us, such as when we reach our arm out for a handshake.
- Extension: Extension occurs when our arm is reaching behind us, such as the beginning phase of throwing a bowling ball.
- Abduction: Abduction is another way to raise the arm, however in this motion, the arm moves out to the side and overhead, as if we are trying to make a snow angel.
- Internal rotation: Internal rotation involves the shoulder joint spinning inwards towards the body. Picture someone wearing an arm sling, when their arm is turned closer to their body, their shoulder is in internal rotation.
- External rotation: External rotation is just the opposite of internal; that is, the shoulder joint is spinning outward, away from the center of your body.
Another part of the shoulder involves the scapula, commonly known as the shoulder blade. The scapula is responsible for stabilizing the shoulder and allowing your arm to connect to your collar bone. You’ve probably heard about the rotator cuff, which is a group of stabilizing muscles that all originate from the scapula. Not only do these muscles stabilize, but they also assist in various shoulder movements.
The Elbow
Our elbow is not quite as dynamic as our shoulder, and that is by design. While the shoulder allows for increased range of motion, the elbow aims for stability. The elbow is known as a synovial hinge joint, and only moves through two planes- flexion and extension.
- Flexion occurs when we bend our elbow, such as when we do a bicep curl in the gym.
- Extension is when we straighten our elbow.
The elbow is vital in connecting our hand to various parts of our body when eating, drinking, bathing, and other self-care tasks. Because the elbow is designed to be stable, the ligaments, which are tissues connecting bone to bone, are designed to take on more force and keep the elbow from moving in ways it shouldn’t.
The Wrist
The wrist is composed of the distal radius and ulna, which are the two bones that make up your forearm, as well as the eight carpal bones in your hand. The wrist is capable of four movements; flexion, extension, radial deviation, and ulnar deviation.
- Flexion: Wrist flexion is the movement when we bend our wrist towards the inside of our forearm.
- Extension: Wrist extension involves lifting our hand up, such as when we put our hand in front of someone as if telling them to stop.
- Radial deviation: This movement occurs when our writ bends sideways, as if we were trying to touch our thumb to our forearm.
- Ulnar deviation: Ulnar deviation is just the opposite of radial deviation. Both of these movements alternate with each other when we wave our hand at someone as if saying hello.
Other unique movements in this area of the body, while not technically wrist movements, are pronation and supination. Pronation involves rotating our palm downward, such as when a person is playing a piano. Supination involves rotating our hand upward like we are going to hold a plate.
The Hand
The hand is quite a complicated body part. Would you believe us if we said there are 27 bones in the human hand? Well, there are! This includes the eight previously mentioned carpal bones, five metacarpal bones, and 14 phalanges. The carpal bones serve as the connection from the hand to the forearm, as well as a stable base of support for our fingers when gripping. Each finger has one metacarpal bone connecting to the carpal bones. Phalanges are the bones that make up what we know as fingers, and each finger has three phalanges, except for the thumb, which has two. With all of these bones comes a lot of joints, and these joints allow for a unique ability for humans to grasp and hold a variety of objects.
With all of these joints and ways your upper body can move, it’s easy to understand why injuries can be common occurrences, whether they are big or small. If you are experiencing any kind of pain or dysfunction in an upper extremity, contact us at ProTailored Physical Therapy, where are occupational therapists specialize in the ability to treat upper body injuries!