Wednesday, May 4, 2011

You need to step up on a step to reach an object on a high shelf over your head. Your starting point should be anatomical position and your finishing point should be the position you are in once your hand has reached the object overhead. Specify the movements, muscles, bones, and joints involved in reaching up above your head to the object on the shelf. Explain any and all movements individually across each joint involved specifying the actions involved (i.e. flexion, extension, etc.), the muscles causing such actions, the bones being pulled on by said muscles, the types of joints involved, and how these movements collectively relate to the overall scenario/movements in this application.

The upper arm is moved by the muscles of the shoulder girdle; the lower arm is moved by muscles of the upper arm; the fingers are moved by muscles of the lower arm. Raising the arm above your head is gliding movement at the synovial shoulder joint. This is extension and abduction movement. The bone of the upper arm – the humerus, articulates with the scapula at the shoulder joint. Muscles of the thorax and shoulder move the humerus: the deltoid contracts and pulls the deltoid tuberosity of the humerus, then the trapezius muscle further lifts the arm; teres major and latissimus dorsi contract pulling the intertubercular groove of the humerus. The shoulder ball-and-socket joint extends. Humerus articulates with radius and ulna at elbow joint. To extend the arm at the elbow joint, triceps brachii contracts, biceps brachii relaxes, to pull the tuberosity of the radius, and supinator muscle pulls the surface of the radius: This supinates the hinge synovial elbow joint. Finally, to reach the object on the shelf, pronator teres and quadratus contract, and the hand executes a pronation movement: the palm moves from anterior to posterior facing position. Extensor digitorum contracts to extend the phalanges of the fingers.


Coleman, D. (Director). (2005). Anatomy for beginners: The anatomy of movement. (Reality TV Show). United Kingdom.

Tortora, G.J., Derrickson B. (2010).  Introduction to the Human Body:  The Essentials of Anatomy and Physiology (8th Ed.).  Hoboken, NJ: John Wiley & Sons, Inc.

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