title: 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.
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York.|Department of Neurological Surgery, Rutgers New Jersey Medical School, Newark, New Jersey.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Cohen
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York.
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Evins
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York.|Department of Neurology and Psychiatry, Neurosurgery, "Sapienza" University of Rome, Italy; and.
authors.forename: Gennaro
authors.initials: G
authors.lastname: Lapadula
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York.|Department of Neurological Surgery, Temple University Medical School, Philadelphia, Pennsylvania.
authors.forename: Leopold
authors.initials: L
authors.lastname: Arko
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York.
authors.forename: Philip E
authors.initials: PE
authors.lastname: Stieg
authors.affiliation: Department of Neurological Surgery, Weill Cornell Medical College, New York, New York.
authors.forename: Antonio
authors.initials: A
authors.lastname: Bernardo
mesh_terms: D002574:Cervical Vertebrae / Q000033:anatomy & histology* / Q000601:surgery; D006801:Humans; D009334:Neck Muscles / Q000033:anatomy & histology* / Q000601:surgery; D009777:Occipital Bone / Q000033:anatomy & histology* / Q000601:surgery; D019291:Skull Base / Q000033:anatomy & histology* / Q000601:surgery; D014711:Vertebral Artery / Q000033:anatomy & histology* / Q000601:surgery
keywords: C1TP = C-1 transverse process; CN = cranial nerve; ICA = internal carotid artery; IJV = internal jugular vein; RCL = rectus capitis lateralis; VA = vertebral artery; anatomy; far lateral; jugular foramen; muscle; rectus capitis lateralis; suboccipital triangle