What are the boundaries of the masseteric space?

Boundaries of the Masseteric Space

The masseteric space is located between the masseteric fascia and the pterygoid muscle fascia, enclosing the masseter muscle, ramus of the mandible, and related structures.

Anatomical Boundaries

The masseteric space is a distinct compartment within the masticator space with the following specific boundaries:

External/Lateral Boundary:

• Masseteric fascia (a layer of the superficial layer of deep cervical fascia)
• Superficial muscular aponeurotic system (SMAS) in the facial region 1

Internal/Medial Boundary:

• Pterygoid muscle fascia
• Ramus of the mandible 2

Superior Boundary:

• Extends to the zygomatic arch
• Continues into the temporal fossa in its upper portion 3

Inferior Boundary:

• Lower border of the mandible

Anterior Boundary:

• Anterior margin of the masseter muscle
• Blends with the buccal space anteriorly

Posterior Boundary:

• Posterior margin of the ramus of the mandible
• Communicates with the parotid space posteriorly

Clinical Significance

Understanding the boundaries of the masseteric space is crucial for several reasons:

• Infection Pathway: Infections from mandibular teeth can spread to the masseteric space through the pterygomandibular and infratemporal spaces 3

• Diagnostic Imaging: CT and MRI are essential for visualizing pathology within this space, as clinical examination alone may be insufficient 4, 5

• Surgical Approach: Proper identification of the boundaries guides surgical drainage procedures for abscesses 5

• Fascial Relationships: The masseteric fascia follows both masticatory movements of the mandible and masseter, as well as movements of the zygomaticus muscles 1

Common Pathologies

The masseteric space can be affected by:

1. Infections: Often odontogenic in origin, particularly from mandibular molars

   • Presents with trismus and swelling of the masseteric region 4
   • May spread superiorly to the temporal fossa 3

2. Tumors: Both benign and malignant neoplasms can involve this space 2

Diagnostic Considerations

When evaluating pathology in the masseteric space:

• CT imaging shows characteristic changes in affected muscles (decreased CT values) 4
• MRI provides better soft tissue contrast for evaluating extent of infection or tumor
• Clinical presentation typically includes trismus and facial swelling 5

Understanding these boundaries is essential for proper diagnosis and management of masseteric space pathologies, particularly in cases of odontogenic infections that may spread to this compartment.