title: The Infundibular Recess Passes through the Entire Pituitary Stalk.
abstract: OBJECTIVE
  The infundibular recess (IR), commonly illustrated as a V-shaped hollow in the sagittal view, is recognized as a small extension of the third ventricle into the pituitary stalk. The precise morphology of the human IR is unknown. The present study sought to delineate the morphology of the IR using magnetic resonance imaging.
  
  
  METHODS
  Subjects included 100 patients without acute cerebral infarcts, intracranial hemorrhage, intrasellar or suprasellar cysts, hydrocephalus, inflammatory disease, or brain tumors. Patients with symptoms of increased intracranial pressure, intracranial hypotension, or pituitary dysfunction were excluded. Thin-sliced, seamless T2-weighted sequences involving the optic chiasm, entire pituitary stalk, and pituitary gland were performed in axial and sagittal planes for each patient. The numbers of slices delineating the pituitary stalk and IR were recorded from the axial images and quantified as ratios.
  
  
  RESULTS
  The pituitary stalk consistently appeared as a styloid- or cone-shaped structure with variable inclinations toward the third ventricle floor. The IR was delineated as a smoothly tapering, tubular extension of the third ventricle located in the central portion of the pituitary stalk. In 81 % of patients, the IR passed through the entire length of the pituitary stalk and reached the upper surface of the pituitary gland, which was identified in 40 % of the midsagittal images.
  
  
  CONCLUSIONS
  The IR is a cerebrospinal fluid-filled canal passing through the center of the pituitary stalk and connects the third ventricle to the pituitary gland. It may function in conjunction with the pituitary gland.
authors.affiliation: Department of Neurological Surgery, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, 279-0021, Urayasu, Chiba, Japan. shotaro@juntendo-urayasu.jp.
authors.forename: S
authors.initials: S
authors.lastname: Tsutsumi
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hori
authors.affiliation: Division of Radiological Technology, Medical Satellite Yaesu Clinic, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ono
authors.affiliation: Division of Radiological Technology, Medical Satellite Yaesu Clinic, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tabuchi
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Aoki
authors.affiliation: Department of Neurological Surgery, Juntendo University Urayasu Hospital, 2-1-1 Tomioka, 279-0021, Urayasu, Chiba, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yasumoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D008959:Models, Neurological; D010902:Pituitary Gland / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D010904:Pituitary Gland, Posterior / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Infundibular recess; MRI; Pituitary stalk