Arterial Supply to the Free Edge of the Tentorium

Abstract

Normally, the arterial branches supplying the free edge of the cerebellar tentorium are rarely visualized on cerebral angiography. However, they may serve as important feeding arteries in hypervascular tumors or dural arteriovenous fistulas. Therefore, a precise understanding of the anatomy of these vessels is essential when planning treatment strategies. In this review, we summarize the anatomical characteristics of the arteries supplying the free edge of the tentorium, review their historical descriptions, and discuss their clinical implications.

Introduction

Understanding the arterial supply to the free edge of the cerebellar tentorium is indispensable for the endovascular treatment of adjacent lesions. In particular, the tentorial branches frequently contribute to the vascular supply of dural arteriovenous fistulas (DAVFs), and hypervascular tumors also involve them as major feeders.^1,2) This region contains several small but critical arterial branches, including the artery of Davidoff and Schechter (ADS), the artery of Wollschlaeger and Wollschlaeger (W&W), and the meningohypophyseal trunk (MHT).^1,3–5) These vessels arise from both the posterior circulation and the cavernous segment of the internal carotid artery (ICA), forming a complex anastomotic network along the tentorial edge.

In this review, we summarize the anatomical characteristics of the arteries supplying the free edge of the tentorium, review their historical descriptions, and discuss their clinical implications.

Free Edge Arterial Supply

The arterial supply to the free edge of the tentorium cerebelli arises mainly from the following 3 arteries: the medial tentorial artery (MTA; artery of Bernasconi–Cassinari), which arises from the MHT or the inferolateral trunk (ILT); the dural branches of the posterior cerebral artery (PCA); and the superior cerebellar artery (SCA)^4,6) (Fig. 1).

Fig. 1. Illustration of the arterial anatomy supplying the free edge of the tentorium (lateral-oblique view). The ILT runs superior to the abducens nerve and gives off superior ①, anterior and posterior branches. The latter 2 further divide into medial (anteromedial ②, posteromedial) and lateral (anterolateral ③, posterolateral ④) branches. The superior branch supplies the lateral portion of the free edge of the tentorium and is referred to as the marginal tentorial artery. The meningohypophyseal trunk ⑤ arises from the posterior aspect of the cavernous segment of the internal carotid artery and gives rise to the MTA ⑥. The MTA crosses over the abducens nerve, courses along the free edge of the tentorium overlying the trochlear nerve, and supplies its medial portion. From the posterior cerebral artery arises the ADS ⑦, which originates from the superior aspect of the P1–P2 junction or the proximal P2 segment, courses posterolaterally through the ambient cistern, and supplies the free edge of the tentorium. The artery of W&W ⑧ arises from the SCA, courses through the ambient cistern beneath the tentorium, and enters the tentorial dura via the posterior portion of the tentorial notch.

ADS, artery of Davidoff and Schechter; ILT, inferolateral trunk; MTA, medial tentorial artery; SCA, superior cerebellar artery; W&W, Wollschlaeger and Wollschlaeger

Arteries originating from the ICA

MHT

The MHT arises near the roof of the cavernous sinus and typically gives rise to 3 branches: 1) the inferior hypophyseal artery, which courses medially to supply the posterior pituitary capsule; 2) the dorsal meningeal artery, which enters the posterior wall of the cavernous sinus to supply the clival dura mater and abducens nerve; and 3) the MTA, also known as the artery of Bernasconi and Cassinari, which courses toward the free edge of the tentorium⁴⁾ (Fig. 1). Inoue et al. classified the MHT as complete or incomplete. In the complete type, all 3 branches arise from the MHT; in the incomplete type, 1 or more branches originate directly from the cavernous segment of the ICA, most often the dorsal meningeal artery.⁷⁾

In a cadaveric study of 10 skull base specimens, Peltier et al. reported that the MTA originated from the MHT in 95% of cases bilaterally. In contrast, in the remaining 5% of the specimens, it arose from the ILT. A single-branch configuration was observed in 64% of cases, whereas multiple branches were present in 36%. The mean length of the MTA was 21.7 mm (range, 20.0–23.4 mm), and the mean diameter was 0.53 mm (range, 0.49–0.60 mm). The MTA courses superiorly along the roof of the cavernous sinus and exits just beneath the entry zone of the trochlear nerve. It then crosses the abducens nerve and courses within the free edge of the tentorium, running in close proximity to and overlying the trochlear nerve. Continuing along the dorsal base of the falx cerebri, it gives off small branches along its course, ultimately reaching the falcotentorial junction.⁸⁾ The MHT frequently gives rise to branches supplying the oculomotor, trochlear, and abducens nerves.⁹⁾ Figure 2 shows the MTA coursing toward the free edge of the cerebellar tentorium, which arises from the MHT.

Fig. 2. Angiography of an internal carotid artery aneurysm. (A) Lateral view of the left internal carotid artery angiogram. 3D reconstruction, superior (B)/left oblique view (C) of the left internal carotid artery. The white arrows indicate the medial tentorial artery arising from the meningohypophyseal trunk.

ILT

The ILT originates from the lateral aspect of the horizontal segment of the cavernous ICA. In anatomical studies, the ILT was identified in all examined specimens. In 15 of the 18 sides, it originated as a single trunk and gave rise to 3 to 4 branches supplying the adjacent cranial nerves and the tentorium. On the remaining 3 sides, the ILT originated as 2 distinct trunks.^3,7,10) The ILT gives rise to superior, anterior, and posterior branches. After crossing superior to the abducens nerve, the ILT gives off a tentorial branch, named the superior branch, and then divides into 2 branches, which are the anterior and posterior branches. The superior branch is not always present and has been observed in 6%–40% of cadaveric specimens.^3,7) It primarily supplies the roof of the cavernous sinus and extends posteriorly to perfuse the free edge of the tentorium. In the absence of the MTA arising from the MHT, a tentorial branch may originate from the ILT, referred to as the marginal tentorial artery or the lateral artery of the cavernous sinus.¹¹⁾ The MTA of the MHT and the marginal tentorial artery of the ILT are essentially the same vessel, distinguished chiefly by their origin and nomenclature. Figure 3 shows an angiography of a patient with a posterior lateral tentorial DAVF, in which the marginal tentorial artery originates from the ILT.

Fig. 3. Angiograms of a posterolateral tentorial dural arteriovenous fistula. (A) Lateral view of the right internal carotid artery angiogram. (B) 3D reconstruction, superior view of the right internal carotid artery. The yellow arrows indicate the marginal tentorial artery arising from the inferolateral trunk. The artery courses along the free margin of the tentorium cerebelli.

The anterior branch divides into medial and lateral components: the anteromedial branch courses through the superior orbital fissure to communicate with the intraorbital compartment, whereas the anterolateral branch passes through the foramen rotundum to establish connections with the extracranial circulation. The posterior branches course posterolaterally, where it anastomoses with the branches of the accessory meningeal artery and communicate with the middle meningeal artery (MMA).³⁾

The ILT supplies branches to the tentorium cerebelli and the orbit via the superior orbital fissure, where it may anastomose with the ophthalmic artery and provide branches to the oculomotor and trochlear nerves. It also provides branches to the maxillary nerve (V2) in the foramen rotundum, the trigeminal ganglion, the mandibular nerve (V3) in the foramen ovale, and the foramen lacerum, where it anastomoses with a branch of the ascending pharyngeal artery.^12,13)

Artery originating from the PCA

ADS

The ADS arises from the superior aspect of the P1–P2 junction or the proximal P2 segment of the PCA. It courses posterolaterally through the ambient cistern, giving rise to a dural branch that approaches the free edge of the tentorium.⁵⁾ This artery supplies a region of approximately 3–4 cm along the posteromedial edge of the tentorium, reinforcing the blood flow provided by the MHT (artery of Bernasconi and Cassinari).^10,14) After joining the contralateral ADS at the falcotentorial junction, it penetrates the dura mater, ascends within the falx cerebri, and proceeds toward the attachment of the superior sagittal sinus.¹⁵⁾

According to Griessenauer et al., PCA-derived dural branches were identified in 5 of 11 cases (45.5%) in cadavers in their series. In their study, they were consistently observed to originate from the P2 segment of the PCA and to enter the deep portion of the tentorium near the center of the tentorial notch. The artery then courses posteriorly toward the midline, ascends, and supplies the falcotentorial junction. The mean diameter was reported as 0.8 mm, with an average length of 1.2 cm, and it was more frequently observed in males and on the left side.⁵⁾ Although ADS typically arises from the P2 segment, variants originating from the P1 segment have also been described.¹⁶⁾

Artery originating from the SCA

Artery of W&W

The artery of W&W from the SCA courses through the ambient cistern beneath the tentorium and enters the tentorial dura via the posterior portion of the tentorial notch.¹⁾ It originates near the free edge of the tentorium and courses rostrally to end in the inferior surface of the tentorium. Ono et al. reported that a dural branch arising from the SCA was identified in 7 of 25 cadaveric specimens (28%).¹⁷⁾ Byrne and Garcia reported that in a series of midline tentorial DAVFs, SCA-derived dural branches were identified in 5 of 11 cases (45.5%) on angiography.¹⁾ Furthermore, Umeoka et al. reported that during microvascular decompression for trigeminal neuralgia, SCA-derived dural branches were identified in 15 of 58 cases (25.9%). In 4 of these cases, the branches were transected without any resulting clinical complications.¹⁸⁾ Figure 4 shows angiography of a patient with a posteromedial tentorial DAVF, demonstrating the ADS arising from the left PCA and the artery of W&W arising from the right SCA.

Fig. 4. Angiograms in a patient with a posteromedial tentorial dural arteriovenous fistula. (A) Anteroposterior view of the vertebral artery angiogram. (B) 3D reconstruction of the anteroposterior view of the vertebral artery angiogram. (C) Lateral view of the vertebral artery angiogram. (D) 3D reconstruction of the lateral view of the vertebral artery angiogram. The red-colored vessel indicates the artery of Wollschlaeger and Wollschlaeger, arising from the superior cerebellar artery, while the green-colored vessel represents the artery of Davidoff and Schechter, arising from the posterior cerebral artery. The orange-colored vessel indicates the dural branch of the occipitoparietal artery.

Historical Descriptions

The arteries supplying the free edge of the cerebellar tentorium were successively described in the 1950s and 1960s. This section provides an overview of the historical descriptions involving these vessels.

Artery of Bernasconi–Cassinari

The artery of Bernasconi and Cassinari, also known as the MTA, arises from the MHT and supplies the free edge of the tentorium. In 1956, Bernasconi and Cassinari performed carotid artery direct-puncture angiography in 5 of 7 patients with meningiomas, identified this artery, and designated it as the “artery of Bernasconi and Cassinari.”¹⁹⁾

ADS

The ADS was first described in 1965 by Wollschlaeger and Wollschlaeger, who performed barium angiography in autopsy cases. In 9 of 10 cases, they identified the dural branch of the PCA as the ADS and reported that its arterial supply territory involves the inferomedial surface of the cerebellar tentorium.¹⁴⁾ The vessel was named in honor of 2 pioneers of neuroradiology at the Albert Einstein College of Medicine. Leo Davidoff, a neurosurgeon trained under Harvey Cushing, was a pioneer who recognized the importance of independent training programs in neuroradiology. Manny M. Schechter, then chair of neuroradiology at the same institution, founded the second neuroradiology training program in the United States in 1960.²⁰⁾

Artery of W&W

In their 1965 study of the ADS, the Wollschlaegers also reported a dural branch arising from the SCA in 1 of 10 cadaveric specimens. In that single case, the SCA dural branch was described as a small arterial anastomosis from the SCA to the ADS.¹⁴⁾ The Wollschlaegers reported that this small connecting artery between the SCA and ADS is encountered only infrequently and typically courses toward the quadrigeminal plate.²¹⁾ In 2017, Tayebi Meybodi et al. conducted an anatomical study and demonstrated that this artery originates from the lateral mesencephalic segment of the SCA, and then courses beneath the tentorium, which is distinct from the ADS. They proposed the term “artery of Wollschlaeger and Wollschlaeger” for this artery.⁶⁾ However, considerable controversy remains in the literature regarding whether the artery of W&W should be regarded as a subtype of the ADS or as an independent artery.^1,18,22,23)

Paul B. Wollschlaeger was born in Berlin and received his medical degree from the University of Munich in 1955. His wife, Gertraud Wollschlaeger, also received her medical degree before moving to the United States in 1957, where she trained in radiology at St. Luke’s Hospital in Cleveland. In 1961, the couple moved to New York and undertook a neuroradiology fellowship under Manny M. Schechter at the Albert Einstein College of Medicine. Paul Wollschlaeger later served as a professor of radiology at the University of Missouri from 1964 to 1971 and at Wayne State University in Detroit, where he and Gertraud continued to work together throughout their careers.²⁴⁾ Since then, this vessel has been considered as a characteristic finding of tentorial meningiomas.

Clinical Implications

The cranial nerves potentially supplied by dural arteries that perfuse the cerebellar tentorium can be organized as follows.²⁵⁾ The oculomotor nerve receives its vascular supply from the MHT and the ILT within the cavernous sinus, and more anteriorly, from branches of the ophthalmic artery. The trochlear nerve is supplied by the MHT and predominantly by the ascending branch of the ILT, with additional contributions from the ophthalmic artery branches. Although the trigeminal nerve has an extensive extracranial vascular network, its cavernous segment and the trigeminal ganglion are supplied by branches of the ascending pharyngeal artery, the MMA, the accessory meningeal artery, and the ILT. The abducens nerve is primarily supplied from the medial aspect by branches of the intracavernous ICA. When these arteries potentially contribute to the vascular supply of cranial nerves, embolization through such routes should be undertaken only after careful consideration of the risk of cranial neuropathy and strict evaluation of procedural indications.²⁶⁾

Bhatia et al. evaluated the embolization of DAVFs involving the ADS using liquid embolic agents and emphasized that recognition of the ADS is critical to avoid complications.²⁷⁾ Although the ADS is generally regarded as a dural feeder without parenchymal contribution, Ono et al., in a cadaveric study, observed that as the ADS courses around the brainstem and enters the tentorium near the tentorial apex, it may give off branches to the inferior colliculus and the mid-cerebellar region; however, the precise site of origin and frequency of such branches were not determined.¹⁷⁾ A variant in which the ADS arises from the collicular artery has also been reported. While the classic ADS originates from the P2 segment of the PCA, origins from the P1 segment have also been described; in such cases, careful evaluation is required to exclude a collicular artery-derived vessel.²⁸⁾ Figure 5 shows a case of a posteromedial tentorial DAVF embolized with n-butyl-2-cyanoacrylate (NBCA). Reflux of the NBCA cast into the proximal segment of the collicular artery led to brainstem infarction.

Fig. 5. Angiograms of a posterior medial tentorial dural arteriovenous fistula treated with NBCA embolization. Anteroposterior (A) and lateral (B) right external carotid angiograms demonstrate a dural arteriovenous fistula mainly supplied by the mastoid branch of the occipital artery. The catheter was navigated distally into the right middle meningeal artery, and embolization was performed using NBCA. (C) Postoperative CBCT. The white arrowhead indicates the NBCA cast located in the collicular artery within the ambient cistern. (D) Postoperative T2-weighted coronal MRI. The yellow arrowhead indicates a brainstem infarction. Anteroposterior (E) and lateral (G) views of the preoperative vertebral artery angiogram, and anteroposterior (F) and lateral (H) 3D fusion images of the right vertebral artery angiogram and the NBCA cast. The thick white arrows indicate reflux of the NBCA cast into the collicular artery. The thin white arrows demonstrate a dural branch arising from the collicular artery and directed toward the shunt. Although this vessel was too small to be clearly identified on preoperative angiography, it was retrospectively confirmed by comparison with the postoperative NBCA cast.

CBCT, cone beam CT; NBCA, n-butyl-2-cyanoacrylate

Dural branches arising from the PCA and SCA are well recognized as feeders in shunt lesions and hypervascular tumors located in the vicinity of the tentorium. Dural branches of the PCA and SCA have been reported to enter the free edge of the tentorium, course anteriorly, and penetrate the clivus to serve as feeders of cavernous sinus DAVFs.²⁶⁾ In principle, the dural branches of the PCA and SCA are directed toward the free edge of the tentorium; however, when a shunting lesion is located near the cavernous sinus, they may, albeit rarely, contribute as feeders. Figure 6 shows a case of a cavernous sinus DAVF. The dural branch of the SCA extends into the free edge of the tentorium and demonstrates a branch that penetrates the clivus to supply the shunt. This possibility must always be considered when planning the treatment of cavernous sinus DAVFs.

Fig. 6. Angiograms of a right cavernous sinus dural arteriovenous fistula. (A) Anteroposterior view of the right external carotid artery angiogram. (B) Anteroposterior view of the left external carotid artery angiogram. (C) Anteroposterior view of the left vertebral artery angiogram. (D) Lateral view of the vertebral artery angiogram, demonstrating a dural branch arising from the right SCA coursing anteriorly. (E–G) Axial fusion images of the vertebral artery angiogram and T2-weighted MRI. The yellow arrowhead indicates the entry point of the SCA dural branch into the free edge of the tentorium. The white arrowheads demonstrate the branch penetrating the clivus and supplying the shunt.

SCA, superior cerebellar artery

Conclusion

The free edge of the cerebellar tentorium is supplied by an arterial network, including the ADS, the artery of W&W, and the MTA arising from either the MHT or the ILT. Although small in caliber, these vessels can serve as critical feeders in arteriovenous shunts and hypervascular tumors, and they may occasionally establish connections with the brain parenchyma, thereby carrying a risk of procedural complications. Therefore, recognition of their anatomy is essential for safe embolization, accurate angiographic interpretation, and effective treatment planning in endovascular treatment.

Disclosure Statement

The authors declare no conflict of interest.