title: Morphological analysis and morphometry of the foramen magnum: an anatomical investigation.
abstract: OBJECTIVE
  The objectives were to study the morphology of the foramen magnum in dry     skulls and to evaluate its antero-posterior diameter, transverse diameter and     the foramen magnum index.
  
  
  METHODS
  The foramen magna of 53 dry     human cadaver skulls that were obtained from the neuroanatomy laboratory were     examined. Different shapes of the foramen magnum were macroscopically noted and     classified. The antero-posterior and transverse diameters were measured and the     average foraminal index was calculated.
  
  
  RESULTS
  The foramen magnum shapes were     determined as a round shape in 22.6% of cases, egg shape in 18.9%, tetragonal in     18.9%, oval in 15.1%, irregular in 15.1%, hexagonal in 5.6% and pentagonal in     3.8% of the cases. In 20.7% of skulls, the occipital condyle was observed to     protrude into the foramen. The mean antero-posterior and transverse diameter of     the foramen magnum was determined as 31 ± 2.4 mm and 25.2 ± 2.4 mm respectively.     The average foramen magnum index was 1.2 ± 0.1.
  
  
  CONCLUSIONS
  The present study     has determined the various shapes of foramen magnum and its morphometry. The     data obtained may be of useful to the neurosurgeon in analyzing the     morphological anatomy of craniovertebral junction. The findings are also     enlightening for the anthropologists, morphologists and clinical anatomists.
authors: Manipal University, Centre for Basic Sciences, Kasturba Medical College, Department of Anatomy, Mangalore, India.
authors: P
authors: P
authors: Chethan
authors: K G
authors: KG
authors: Prakash
authors: B V
authors: BV
authors: Murlimanju
authors: K U
authors: KU
authors: Prashanth
authors: Latha V
authors: LV
authors: Prabhu
authors: Vasudha V
authors: VV
authors: Saralaya
authors: Ashwin
authors: A
authors: Krishnamurthy
authors: M S
authors: MS
authors: Somesh
authors: C Ganesh
authors: CG
authors: Kumar
mesh_terms: D000328:Adult; D002102:Cadaver; D005539:Foramen Magnum / Q000033:anatomy & histology*; D006801:Humans; D009777:Occipital Bone / Q000033:anatomy & histology; D012016:Reference Values; D012886:Skull / Q000033:anatomy & histology