In MPDS most commonly involved muscle is:
**Core Concept**
Myofascial pain dysfunction syndrome (MPDS) is a condition characterized by pain and limited mobility in the masticatory muscles, leading to temporomandibular joint (TMJ) disorders. The condition is often associated with abnormal muscle function and trigger points in the muscles of mastication.
**Why the Correct Answer is Right**
The masseter muscle is the most commonly involved muscle in MPDS due to its thick and bulky structure, which makes it prone to strain and overuse. The masseter muscle plays a crucial role in mastication and is often used excessively in activities such as clenching, grinding, or chewing. The pain and dysfunction associated with MPDS can be attributed to the formation of trigger points in the masseter muscle, which can lead to referred pain in the TMJ and surrounding tissues.
**Why Each Wrong Option is Incorrect**
**Option A:** The medial pterygoid muscle is also involved in mastication, but it is not the most commonly affected muscle in MPDS.
**Option B:** The lateral pterygoid muscle is a key muscle in TMJ function, but it is not typically involved in the same way as the masseter muscle in MPDS.
**Option C:** The temporalis muscle is another muscle of mastication, but it is not as commonly associated with MPDS as the masseter muscle.
**Clinical Pearl / High-Yield Fact**
The masseter muscle is often the first muscle to be affected in MPDS, and its involvement can lead to a cascade of symptoms and dysfunction in the TMJ and surrounding tissues.
**Correct Answer: C. Temporalis muscle.