Osteology, Scalp and Face MCQs

Explanation: The greater wing of the sphenoid bone extends from the sphenoid body in a lateral, superior, and posterior direction. It contributes to the floor of the middle cranial fossa , lateral wall of the skull , and posterolateral wall of the orbit . Three key foramina pierce the greater wing of the sphenoid: Foramen rotundum → transmits the maxillary nerve Foramen ovale → transmits the mandibular nerve Foramen spinosum → transmits the middle meningeal vessels These foramina are critical anatomical landmarks and are involved in neurovascular transmission. Explanation of Other Options Option A & B: Incomplete - omit one or more foramina that pierce the sphenoid. Option D - Includes foramen lacerum: Incorrect - the foramen lacerum is located between the sphenoid, temporal, and occipital bones and is not a true opening through the sphenoid bone.

Internally, the pterion is related to various anatomical structures. Namely, the anterior division of the middle meningeal vessels, middle cerebral vessels, Sylvain fissure, circle of Willis, insula and Broca's motor speech area (on the left) and optic nerve. Reference: Textbook of Gray's Anatomy, Volume 2, 3rd Edition, Page number - 858

Explanation: The lateral pterygoid does not elevate the mandible. Its primary function is depression (opening the mouth) and protrusion of the mandible. It actively pulls the condyle and articular disc forward during mouth opening. Movements of the TM Joint and Muscle Actions: Elevation (closing the mouth): Masseter (Option C) Temporalis (especially anterior and middle fibers) (Option D) Medial pterygoid (Option A) Depression (opening the mouth): Lateral pterygoid Assisted by digastric, mylohyoid, and geniohyoid Protrusion: Lateral pterygoid (primary) Medial pterygoid (assists) Retraction: Posterior fibers of temporalis Deep fibers of masseter Side-to-side movements: Alternating contraction of medial and lateral pterygoids