x Disorders of the Biceps and the Triceps JB (1).docx
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Disorders of the Biceps and the Triceps
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Figure 1: Anterior view with the biceps, with long head in red, short head in green (from https://en.wikipedia.org/wiki/Biceps)
The biceps flexes the elbow, but perhaps contrary to popular belief, it is not the most powerful flexor of the forearm– a role which actually belongs to the deeper brachialis muscle. Indeed, when the forearm is in pronation (the palm faces the ground), there is only a minimal contribution from the biceps brachii to elbow flexion (Figure 2). In this position, the main flexor of the elbow is the brachialis, with contributions from the brachioradialis, and supinator as well.
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(Modified from https://en.wikipedia.org/wiki/Biceps)
The triceps has three proximal divisions known as “heads”: two which originate from the posterior humerus, the lateral head and medial head; and one, the long head, which originates from the infraglenoid tubercle of scapula (Figure 3). These then blend together and insert on the olecranon process of ulna. The triceps is an extensor muscle of the elbow joint and is an antagonist of the biceps and brachialis muscles. It can also fixate the elbow joint – that is, hold it in a fixed position – when the forearm and hand are used for fine movements. The triceps is supplied by the deep brachial artery and posterior circumflex humeral artery and is innervated by the radial nerve.
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Figure 3: View from behind of the triceps, with long head in red, lateral head in yellow and medial head (deep and obscured mostly) in green. (from https://en.wikipedia.org/wiki/Triceps)
Patient Presentation
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Figure 4: The hook test. When the biceps tendon is intact, the examiner’s finger can grasp (or “hook”) the lateral edge of the biceps tendon. An absence of any “hookable” tendon suggests a rupture. (courtesy https://openorthopaedicsjournal.com/VOLUME/11/PAGE/1364/FULLTEXT/)
Patients with a distal triceps rupture likewise present after a painful pop, usually after a fall. (When a patient lands on the outstretched hand, there may be a force tending to collapse, or flex, the elbow. The triceps can be injured as it resists this force.)
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Figure 5: The biceps tendon prepared for surgical reattachment into a socket on the radius is shown (photo A[MF1] ). A small metallic button is placed on the end of the tendon, to lock on the opposite surface of the radius (See diagram B)
(Courtesy https://openorthopaedicsjournal.com/VOLUME/11/PAGE/1364/FULLTEXT/)
(The nerves at risk are the lateral antebrachial cutaneous and the radial nerve; injury to the former is more common, to the latter more severe.)
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Figure 6: The real Popeye did not have a “Popeye” sign.
As many bodybuilders know, the triceps accounts for approximately 60 percent of the upper arm's muscle mass; thus exercising this muscle, and not the biceps, is apt to produce larger arms.
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Physical examination to diagnose disorders of the biceps and triceps.
[MF1]May have to use top and bottom/ or left and right
