Lab 4 - Module 1 - Extensor Compartments of the Arm and Forearm: Page 3 of 9
Radial Nerve of the Arm
| Rotate the bones of the Upper extremity to and anterior view. |
| Add the Radial nerve which is a direct continuation of the posterior cord of the brachial plexus. |
| Add the Brachial artery The radial nerve enters the arm posterior to the brachial artery, medial to the humerus, and anterior to the long head of the triceps |
| The Radial nerve continues between the Brachialis. |
| And Radial nerve continues between the Brachioradialis muscle to the lateral epicondyle of the humerus, where it divides into deep and superficial branches. |
What physical findings would allow you to differentiate between an injury proximal to the humeral insertion of the triceps and a mid-humeral injury? |
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Injury to the radial nerve proximal to the origin of the triceps results in paralysis of the triceps, brachioradialis, supinator, and extensors of the wrist, thumb, and fingers, as well as loss of sensation to the skin supplied. Fracture of the mid-shaft of the humerus will result in the inability to extend the wrist and thumb resulting in the characteristic clinical sign of wrist drop. Sensation may be lost on the dorsum of the lateral hand and lateral 2 ½ proximal phalanges. |
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