Masticatory space constitutes the following spaces except:
**Core Concept**
The masticatory space, also known as the masticator space, is a fascial space in the head and neck region that contains the muscles of mastication (chewing). This space is bounded by the parotid gland superiorly, the masseter muscle anteriorly, the medial pterygoid muscle posteriorly, and the inferior border of the mandible inferiorly.
**Why the Correct Answer is Right**
The masticatory space is a critical area for surgical and medical procedures, as it contains vital structures such as the facial nerve, the external carotid artery, and the jugular vein. The space is also a common site for infections and abscesses, which can spread to other areas of the head and neck. The muscles of mastication, including the masseter, temporalis, and medial and lateral pterygoid muscles, are responsible for the movement of the mandible during chewing.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it is not a part of the masticatory space. The infratemporal fossa is a separate fascial space located below the zygomatic arch and is not directly related to the masticatory space.
* **Option B:** This option is incorrect because it is not a part of the masticatory space. The pterygopalatine fossa is a separate fascial space located between the pterygoid plates and the palatine bone, and is not directly related to the masticatory space.
* **Option C:** This option is incorrect because it is a part of the masticatory space. The pterygomandibular space is a smaller fascial space within the masticatory space, located between the medial pterygoid muscle and the lateral pterygoid muscle.
**Clinical Pearl / High-Yield Fact**
The masticatory space is a common site for infections and abscesses, particularly after dental procedures or trauma to the head and neck region. Recognizing the boundaries and contents of this space is crucial for accurate diagnosis and treatment of infections and other conditions.
**Correct Answer: D. Infratemporal fossa.**