Pterygopalatine Fossa Approach

The pterygopalatine fossa (PPF) is a narrow space located between the posterior wall of the antrum and the pterygoid plates.

The microsurgical transmaxillary transantral approach is usually chosen to remove lesions in this region.

1. Maxillary nerve (CN V2)

A branch of the trigeminal nerve (CN V)

Enters the fossa via the foramen rotundum

Gives off multiple branches in the fossa, including:

Zygomatic nerve

Infraorbital nerve

Posterior superior alveolar nerve

Pterygopalatine nerves (to the pterygopalatine ganglion)

2. Pterygopalatine ganglion (parasympathetic ganglion)

Suspended from CN V2 by the pterygopalatine nerves

Function: relay station for parasympathetic fibers from the greater petrosal nerve

Has sensory, sympathetic, and parasympathetic roots:

Parasympathetic root: via greater petrosal nerve (branch of CN VII → joins deep petrosal to form nerve of the pterygoid canal)

Sympathetic root: via deep petrosal nerve (from internal carotid plexus)

Sensory root: from the maxillary nerve (CN V2)

3. Nerve of the pterygoid canal (Vidian nerve)

Formed by the union of:

Greater petrosal nerve (parasympathetic, from CN VII)

Deep petrosal nerve (sympathetic)

Enters the fossa through the pterygoid canal

Carries autonomic fibers to the pterygopalatine ganglion

4. Branches from the pterygopalatine ganglion These distribute the autonomic fibers (mainly postganglionic parasympathetic and sympathetic) along with sensory fibers from CN V2:

Greater palatine nerve

Lesser palatine nerves

Nasopalatine nerve

Posterior superior lateral nasal nerves

Pharyngeal branch

A total of 12 pterygopalatine fossae from six formalin-fixed cadaveric heads (five female, one male) were dissected using both endoscopic approach and anatomical microscopic dissection to measure the lengths, diameters, and anatomical relationships of the nerves and arteries.

The maxillary nerve measured 15.93 ± 6.19 mm in length and 3.96 ± 0.69 mm in diameter, while the infraorbital nerve measured 24.4 ± 4.38 mm in length and 3.00 ± 0.71 mm in diameter. The greater palatine nerve measured 13.15 ± 4.25 mm in length and 2.70 ± 0.39 mm in diameter. The Vidian nerve measured 16.78 ± 1.18 mm in length and 2.15 ± 0.51 mm in diameter. The pterygopalatine ganglion had a width of 4.59 ± 1.16 mm and a height of 5.18 ± 1.63 mm. The infraorbital nerves were primarily located lateral to the infraorbital artery, while the greater palatine nerves were typically found medial to the descending palatine arteries.

The findings indicate that the maxillary, infraorbital, and greater palatine nerves, together with the pterygopalatine ganglion, are key landmarks for defining the surgical boundaries of the pterygopalatine fossa. These insights are expected to enhance the safety and precision of surgical interventions in this complex anatomical region, ultimately improving patient outcomes ¹⁾

The study provides a detailed anatomical analysis of the pterygopalatine fossa (PPF) using both endoscopic and traditional microscopic dissection techniques on formalin-fixed cadaveric heads. This dual-approach design is commendable, as it enhances the validity of anatomical observations and allows correlation with practical surgical perspectives. Given the increasing reliance on endoscopic endonasal approaches in skull base and maxillofacial surgery, the research fills a critical gap in detailed morphometric data on neural and vascular structures in the PPF.

2. Sample Size and Demographics

The authors dissected 12 PPFs from six cadaveric heads (five female, one male). While the sample size is within an acceptable range for cadaveric studies, the gender imbalance and small total number of specimens could limit generalizability. Anatomical variability by sex, age, and side (left/right) should be addressed more explicitly, as such factors can influence surgical planning in clinical scenarios.

3. Methodological Strengths

The use of both endoscopic and microscopic dissection is a notable strength, providing complementary views of a deeply located anatomical region.

The quantitative measurements (lengths and diameters of nerves, ganglion dimensions, spatial relationships) are presented with standard deviations, suggesting methodological rigor and repeatability.

The inclusion of vascular-neural relationships, particularly between the infraorbital and descending palatine arteries and their adjacent nerves, enhances the surgical utility of the findings.

4. Limitations

The study relies solely on formalin-fixed specimens, which may affect tissue elasticity and size, potentially altering measured dimensions compared to fresh or in vivo conditions.

No comparative or clinical correlation (e.g., imaging validation or intraoperative navigation data) is provided. This weakens the immediate translational impact for surgical practice.

While measurements are given, there is no statistical analysis comparing sides, sexes, or anatomical variations. Inclusion of such data could elevate the anatomical insights beyond simple description.

The anatomical terminology is occasionally redundant (e.g., “infraorbital nerve was lateral to the infraorbital artery” stated without exploring the implications for surgery or variants).

5. Interpretation and Clinical Relevance

The identification of the maxillary, infraorbital, and greater palatine nerves and the pterygopalatine ganglion as consistent landmarks for defining the PPF’s surgical boundaries is a key takeaway. This can aid in:

Minimizing iatrogenic injury during endonasal approaches

Navigating dense neurovascular networks during tumor resections or nerve decompressions

However, without correlating these findings with surgical outcomes or complications, the claim that this will “enhance the safety and precision” of interventions, while plausible, remains somewhat speculative.

6. Conclusion and Future Directions

The study provides a solid anatomical foundation for further research and surgical refinement. For future work, the authors—or others—should consider:

Correlating findings with intraoperative or radiological data

Expanding the sample size with attention to demographic variability

Exploring variants and rare configurations that could impact atypical presentations or complications

Final Evaluation This is a well-conceived cadaveric study that offers practical insights for endonasal surgeons. Its principal value lies in its detailed mapping of neurovascular elements of the PPF using modern techniques. However, to fully translate into improved patient outcomes, further clinical validation and broader anatomical exploration are necessary.

Fortes et al dissected six PPF in three cadaveric specimens prepared with intravascular injection of colored material using two different injection techniques. An endoscopic endonasal approach, including a wide nasoantral window and posterior antrum wall removal, provided PPF access.

They produced the best anatomical model by injecting colored silicone via the common carotid artery. They found that, using an endoscopic approach, a retrograde dissection of the sphenopalatine artery helped to identify the internal maxillary artery (IMA) and its branches. Neural structures were identified deeper to the vascular elements. Notable anatomical landmarks for the endoscopic surgeon are the vidian nerve and its canal that leads to the petrous portion of the internal carotid artery (ICA), and the foramen rotundum, and V2 that leads to Meckel's cave in the middle cranial fossa. These two nerves, vidian and V2, are separated by a pyramidal shaped bone and its apex marks the ICA.

This anatomical model provides the means to learn the endoscopic anatomy of the PPF and may be used for the simulation of surgical techniques. An endoscopic endonasal approach provides adequate exposure to all anatomical structures within the PPF.

These structures may be landmarks to identify and control deeper neurovascular structures. The significance is that an anatomical model facilitates learning the surgical anatomy and the acquisition of surgical skills. A dissection superficial to the vascular structures preserves the neural elements. These nerves and their bony foramina, such as the vidian nerve and V2, are critical anatomical landmarks to identify and control the ICA at the skull base ²⁾.

The following conditions may require an endoscopic endonasal approach to the PPF, particularly for extended skull base access or management of neurovascular structures.

• Maxillary nerve (V2) schwannoma
• Adenoid cystic carcinoma (originating from minor salivary glands)
• Squamous cell carcinoma of the maxillary sinus or nasopharynx extending into the PPF
• Minor salivary gland adenocarcinoma with lateral extension

• Juvenile nasopharyngeal angiofibroma (classic indication for transpterygoid access)
• Arteriovenous malformations or aneurysms involving distal branches of the internal maxillary artery
• Severe posterior epistaxis requiring endoscopic ligation of the sphenopalatine artery or maxillary artery

• Mucoceles of the sphenoid sinus with lateral extension
• Fibro-osseous lesions (e.g., osteomas, fibrous dysplasia) of the pterygoid process or maxilla

• Invasive pituitary macroadenomas (Knosp grade III–IV) extending toward the cavernous sinus and lateral PPF

1. > Transpterygoid corridor may improve access to the lateral sella and parasellar region

• Vidian neuralgia (rare cases treated with vidian nerve section)
• Sluder’s neuralgia (pterygopalatine ganglion neuralgia)

• Abscesses of the PPF or infratemporal fossa

1. > Rare, but potentially accessible via endoscopic routes