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At the conclusion of this chapter, the student should be able
to:
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- 1. Name, locate, and describe the structure and ligamentous
reinforcements of the articulations of the elbow, forearm, wrist,
and hand.
- 2. Name and demonstrate the movements possible in the joints
of the elbow, forearm, wrist, and hand regardless of the starting
position.
- 3. Name and locate the muscles and muscle groups of the elbow,
forearm, wrist, and hand, and name their primary actions as agonists,
stabilizers, neutralizers, or antagonists.
- 4. Analyze the fundamental movements of the forearm, hand,
and fingers with respect to joint and muscle actions.
- 5. Describe the common athletic injuries of the forearm, elbow,
wrist, and fingers.
- 6. Perform an anatomical analysis of the elbow, forearm, wrist,
and hand in a motor skill.
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In much the same way that the shoulder girdle’s cooperation
with the shoulder joint contributes to the wide range of motion
available to the hand, the cooperative movements of the elbow, radioulnar,
and wrist joints contribute to the versatility and precision of
its movements. Although the hand is intrinsically skillful, its
usefulness is greatly impaired when anything interferes with the motions
of the forearm or wrist. Injury to any one of the joints involved
makes this painfully obvious to the sufferer.
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The elbow is far more complex than the simple hinge joint that
it appears to be. The two bones of the forearm attach to the humerus
in totally different ways. The humeroulnar joint is indeed a true hinge
joint, but the humeroradial joint is far from it. It has been classified
as an arthrodial or gliding type of joint, but it is more accurately
described as a restricted ball-and-socket joint. Inspection of the
articulating surfaces as depicted in Figure 6.1 or of the skeleton
itself will help make this clear. The distal end of the humerus
presents a spool-like process (trochlea) on the medial side and
a spherical knob (capitulum) on the lateral side. The ulna articulates
with the humerus by means of a semicircular structure that is cupped
around the back and underside of the trochlea. The inner surface
of this is known as the semilunar notch. It terminates below and
in front in the small coronoid process, and above and in back in
the broad olecranon process.
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The radius articulates with the humerus by means of a slightly
concave, saucerlike disc, which is directly beneath the capitulum
when the arm is hanging straight down. In spite of the joint’s
ball-and-socket structure, the radius is unable to abduct or adduct
because of the annular ligament that encircles the radial head and
binds it to the radial notch of the ulna. Furthermore, because of
this and other ligamentous connections with the ulna, the ...