The rectus capitis lateralis and the condylar triangle: important landmarks in posterior and lateral approaches to the jugular foramen

Abstract

OBJECTIVE The rectus capitis lateralis (RCL) is a small posterior cervical muscle that originates from the transverse process of C-1 and inserts onto the jugular process of the occipital bone. The authors describe the RCL and its anatomical relationships, and discuss its utility as a surgical landmark for safe exposure of the jugular foramen in extended or combined skull base approaches. In addition, the condylar triangle is defined as a landmark for localizing the vertebral artery (VA) and occipital condyle. METHODS Four cadaveric heads (8 sides) were used to perform far-lateral, extended far-lateral, combined transmastoid infralabyrinthine transcervical, and combined far-lateral transmastoid infralabyrinthine transcervical approaches to the jugular foramen. On each side, the RCL was dissected, and its musculoskeletal, vascular, and neural relationships were examined. RESULTS The RCL lies directly posterior to the internal jugular vein-only separated by the carotid sheath and in some cases cranial nerve (CN) XI. The occipital artery travels between the RCL and the posterior belly of the digastric muscle, and the VA passes medially to the RCL as it exits the C-1 foramen transversarium and courses posteriorly toward its dural entrance. CNs IX-XI exit the jugular foramen directly anterior to the RCL. To provide a landmark for identification of the occipital condyle and the extradural VA without exposure of the suboccipital triangle, the authors propose and define a condylar triangle that is formed by the RCL anteriorly, the superior oblique posteriorly, and the occipital bone superiorly. CONCLUSIONS The RCL is an important surgical landmark that allows for early identification of the critical neurovascular structures when approaching the jugular foramen, especially in the presence of anatomically displacing tumors. The condylar triangle is a novel and useful landmark for identifying the terminal segment of the hypoglossal canal as well as the superior aspect of the VA at its exit from the C-1 foramen transversarium, without performing a far-lateral exposure.

The Tough Fibrous Tissue of The Supracondylar Groove As A Useful Landmark Via The Endoscopic Endonasal Approach To The Lower Clivus

“…Even if the SCG bone is drilled, it can still serve as a landmark to estimate the intraoperative location of the HGC EO under an endoscope. The additional use of the HGC compact bone as a landmark [13] would increase the accuracy of the endoscopic endonasal approach to access the LC.…”

Deconstruction of the Surgical Approach to the Jugular Foramen Region: Anatomical Study

“…14 The rectus capitis lateralis muscle and the condylar triangle it defines with the superior oblique muscle are useful intraoperative landmarks in understanding the overlap between the posterior and lateral approaches. 14,24 Exposure of the medial aspect of the jugular foramen can be achieved from a lateral approach. If the pathology is intrajugular (e.g., a glomus jugulare tumor), the jugular vein is opened and the medial wall kept intact to protect the lower cranial nerves coursing beneath it.…”

“…These included the suboccipital triangle (found between the superior and inferior oblique muscles), 23 and the condylar triangle (found between the superior oblique and rectus capitis lateralis muscles). 24 We also defined the jugular triangle between rectus capitis lateralis, TP-C1, and the base of the styloid process. This triangle represented the lateral limit of the jugular foramen (►Fig.…”

“…Triangles of the distal cervical region and posterolateral skull base have been previously described in separate reports. [21][22][23][24][25] We deconstructed the jugular foramen anatomy into contiguous triangles, similar to cavernous sinus and middle fossa triangles (►Table 2). These triangles, defined by specific landmarks (the mastoid tip, TP-C1, and styloid process), create a simplified surgical roadmap to the region (►Fig.…”

Immersive Surgical Anatomy of the Craniocervical Junction

“…This triangle encases the anterior third of the occipital condyle, the superior aspect of the genu of the V3 segment of the VA. Moreover, it provides a landmark for the terminal portion of the hypoglossal canal [10].…”