Skeletal System and Joints

There are 6 types of Synovial joints;

  • Hinge, A hinge joint allows extension and flexion, e.g. the elbow,
  • Saddle, A saddle joint allows abduction, adduction flexion and extension, e.g. the thumb,
  • Ball and Socket, A ball and socket joint allows for most types of movement abduction adduction, rotation flexion and extension, E.g. hips and shoulders,
  • Condyloid, Condyloid joints are similar to a ball and socket joint. They allow the same type of movement to a lesser extent, e.g. The wrist,
  • Pivot, Pivot joints allow only rotation. E.g. neck and forearms have pivot joints. In the neck the occipital bone spins over the top of the axis. In the forearms the radius and ulna twist around each other.
  • Freely gliding, in a gliding or plane joint bones slide past each other. Carpals and tarsal’s joints are gliding joints.

Applications of Synovial Joints to Sports and Exercise Examples.

Hinge joints;

Elbow joint; these only flex and extend so only need two sets of muscles to move them (flexors and extensors). In the case of the arm the biceps brachii are the flexors and the triceps brachii are the extensors. The biceps brachii contract in weight lifting and flexes the elbow joint lifting the weight. To lower the weight the triceps brachii contract and the biceps brachii relax extending the elbow joint. In this one repetition the elbow joint has moved in all way it possibly can. The elbow joint components used consists of; bones; Ulna, Radius, Humorous; muscles; flexors; biceps brachii, brachialis; extensors; triceps brachii, anconeus.

Knee joint; also only possible to extend and flex this is very important when kicking a football. When you pull your foot back before a kick your hamstrings mostly so the biceps femoris flex your knee joint at the insertion (fibula). Then the powerful contraction of the anterior quadriceps extends the knee at the insertion (fibula) allowing you to kick the ball with your foot. The knee joint has now gone through both types of motion possible. The knee joint components used consists of; bones; tibia, fibular, patella, femur; muscles; hamstrings muscles group, quadriceps muscle group, patellar tendon.

Saddle joints; The best example of a saddle joint is the thumb. The thumb is very important in racket and ball sports and court sports and such other sports and exercise programmes that require the hand to grip. For example in badminton the racket needs to be held firm in the hand this would not be possible with out the thumb. Because the thumbs saddle joint can abduct, adduct, flex and extend the thumb can be moved almost anywhere for a firm and comfortable grip. When pressing your thumb against the racket the joint is being flexed and when releasing grip the thumb joint is being extended. Different athletes need different positions of the thumb on the racket for a comfortable grip, to move the thumb up the racket you would be abducting the thumb and to move the thumb down the racket you would be adducting the thumb.

When gripping a ball the thumb saddle joint is also important as the wide range of movement available allows you to engulf the ball in your hand so that our hand is all around the ball. Boxing and other fighting sports also benefit from the saddle joint of the thumbs as this type of joint allows the athlete to leave their thumb at the side of a closed hand when punching to avoid injuring this less stable joint than the other fingers which all have hinge joints. The thumb joint consists of; the first metacarpal, the carpals and the radius; muscles; hand flexors, extensors, adductors and abductors.

Ball and Socket joints; The shoulder joint is a good example of a Ball and Socket joint. The shoulder joint consists of; bones; the humorous, clavicle, scapular; muscles; supraspinatus, infraspinatus teres minor and subscapular of the musculotendinous cuff, the deltoids, pectoralis major, latissimus dorsi, triceps brachii, biceps brachii and the coracobrachialis. The wide range of movement is important in many sports and exercise programmes that require a lot of arm movement or strength. For example goal keeping in football requires a lot of arm movement as the goal keeper needs to lift their arms for save and sometimes to break their fall this involve abduction, adduction, rotation flexion and extension. When punching a ball away the shoulder needs to flex to raise the arm this flexion requires the most anterior part of the deltoid the pectoralis, and the biceps brachii. And when lowering their arm from the punch they usually extend the shoulder joint this requires the most posterior part of the deltoid the teres major and the latissimus dorsi. When saving a shot from open play with the intent of catching and holding the ball; the goalkeeper usually raises the arms via abduction when they raise the arms this requires the lateral part of the deltoid. The hip is also a ball and socket joint this is very good in rugby for a fly half as they need to be very agile the fact that the hips allows all kind of motion help them to change direction quickly. If the fly half was to be running forwards and suddenly needs to side step around an opposing player the abduction and adduction of the hips will allow them to. The adduction requires the; pectineus, adductor brevis, adductor longus, adductor magnus and the gracillis. The abduction requires; biceps femoris semitendinosis, tensor fasciae latae and the gluteus medius. Rotation of the hips can be useful in netball the player is only allowed to pivot on one foot the hip will need to rotate. This rotation will need the obturator externus.

Condyloid Joints; also allow involve abduction, adduction, rotation flexion and extension just like a ball and socket joint but to a lesser extent. About the best example of a Condyloid joint is the wrist. The wrist can be used ice hockey for a ‘wrist shot’ which involves a movement of the wrist for a slow but accurate shot. The exact movement needed is a flexion of the wrist held higher up in an anterior position the stick and an extension of the wrist held lower down the stick in a posterior position.  This movement requires the brachioradialis in the forearm. This type of joint is helpful in ice hockey as supple wrist are needed so that fine movements can be made with the ice hockey stick the wide range of movement allows more complex movements. Table tennis also need the wrist as the movements are fine and accurate to control the ball of the paddle some times a flick of the wrist is accurate and powerful enough to score a point.

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Pivot joints, these allow only rotation. A good example of this the neck, as a turn of the head can make a big difference in a football game. When a midfielder is considering his options they need to turn their head to look for the best player to pass to. This requires the sternocleidomastoid and the levator scapulae to turn the head. The forearms can also rotate. Turning the thumb outwards is called pronation, turning the thumb inwards is called supination.

Freely gliding; the metacarpal and carpals are a good example of this. Freely gliding joints only slide past each ...

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