Final answer:
Pronator teres syndrome is characterized by forearm pain, tingling, and numbness, especially in the thumb to middle fingers, along with weakness in the forearm and hand. It is caused by compression or entrapment of the median nerve by the pronator teres muscle. It should not be mixed up with pronator drift, which is related to corticospinal lesions.
Step-by-step explanation:
The pronator teres syndrome is a condition that affects the forearm and can cause symptoms such as pain, tingling, and numbness on the palm side of the forearm, especially affecting the thumb, index, and middle fingers. Patients may also experience weakness in the forearm and hand. It is related to the pronator teres muscle, which originates on the humerus and inserts on the radius, responsible for pronating the forearm (turning it so the palm faces downwards). A key diagnostic feature of this syndrome is difficulty or pain while attempting to turn the forearm into pronation or when resisting this motion.
Conversely, this condition should not be confused with a pronator drift, which is a sign of a contralateral corticospinal lesion characterized by one arm drifting into a pronated position when held straight out with the palms facing upward. Pronation is a movement of the forearm where the palm moves from the palm forward (anterior) to the palm backward (posterior) position. The pronator quadratus is another muscle involved in the pronation of the forearm, working alongside the pronator teres.
In contrast, forearm extensors include the triceps brachii and anconeus, and the supinator is the muscle that performs the opposite function of the pronators, turning the forearm anteriorly, which is referred to as supination. Understanding these muscle groups and their functions can help in distinguishing the various conditions affecting the forearm and its movements.