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Where does the cranial base flexion take place in humans?
Ricardo V Botelho1, Pedro B Botelho2, Juliete M Diniz1
1Programa de Pós-Graduação, Instituto de Assistência ao Servidor Público Estadual/ IAMSPE, São Paulo, SP, Brazil.
Anais Da Academia Brasileira De Ciencias
|May 14, 2020
Summary
Human cranial base flexion, crucial for larger brain capacity, originates within the sphenoid bone. This skull base angulation (CBA) is a distinct pre-chordal feature, not at the spheno-occipitalis synchondrosis (SOS).
Area of Science:
- Anthropology
- Human Anatomy
- Evolutionary Biology
Background:
- Modern humans exhibit the most flexed cranial base among all living species.
- Cranial base flexion is linked to increased cranial volume and brain size.
- The spheno-occipitalis synchondrosis (SOS) has been traditionally implicated in this flexion.
Purpose of the Study:
- To precisely determine the anatomical location of skull base flexure.
- To clarify the role of the spheno-occipitalis synchondrosis (SOS) in cranial base angulation (CBA).
Main Methods:
- Analysis of 50 magnetic resonance imaging (MRI) scans from normal adult subjects.
- Evaluation of normal cranial base angulation (CBA) in human subjects.
Main Results:
- The vertex of the cranial base angle consistently occurred within the sphenoid bone in all subjects.
- Cranial base flexure in humans originates from a specific pre-chordal location.
- Flexure does not arise from the transition between pre-chordal and chordal plates or the SOS.
Conclusions:
- Cranial base flexure in humans is an intrinsic feature of the sphenoid bone.
- The origin of human cranial base flexure is pre-chordal, within the sphenoid bone.
- The spheno-occipitalis synchondrosis (SOS) is not the primary site of cranial base flexion.
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