Which bones primarily participate in SBS flexion?

Which bones primarily participate in SBS flexion?

• A. The greater wings of the sphenoid and lateral angles of the occiput
• B. The petrous parts of the temporal bones
• C. The nasal bones
• D. The zygomatic arches

Answer: (A)

SBS flexion is driven mainly by the sphenoid and occiput at the cranial base. In this motion, the sphenoid tends to move forward, with its greater wings acting as the key anteriorly directed leverage, while the occiput rotates and moves in the opposite direction, with its lateral angles serving as the primary posteriorly directed points. These two regions are the major articulating surfaces at the SBS, so they are the ones that predominantly participate in the flexion posture. The other parts mentioned—nasal bones, zygomatic arches, and the petrous portions of the temporal bones—don’t form the main SBS articulation and thus don’t drive this motion.

SBS flexion is driven mainly by the sphenoid and occiput at the cranial base. In this motion, the sphenoid tends to move forward, with its greater wings acting as the key anteriorly directed leverage, while the occiput rotates and moves in the opposite direction, with its lateral angles serving as the primary posteriorly directed points. These two regions are the major articulating surfaces at the SBS, so they are the ones that predominantly participate in the flexion posture. The other parts mentioned—nasal bones, zygomatic arches, and the petrous portions of the temporal bones—don’t form the main SBS articulation and thus don’t drive this motion.