ZOO 3733C Lecture Notes - Lecture 13: Epicranial Aponeurosis, Intramembranous Ossification, Orbicularis Oris Muscle
Document Summary
The skull consists of two parts: the cranium (8 bones) Bones of the skull develop via intramembranous ossification: consist of a peripheal compact part and a central part occupied by a spongy bone, these unosssifedd areas are called fontanelles. Mastoid and sphenoidal fontanelles: ossified within 6 months or more. Frontal belly raises the eyebrow and draws the scalp forward. Occipital belly draws back the galea aponeurotica and is also active during smiling and yawning. Produces wrinkles in forehead and gives facial expression of astonishment. Orbicularis oculi orbital part closes the eye tightly. Creates vertical folds & its contractions brings the skin and the eyebrow down medially, protecting the eye against light. Its contractions forms wrinkles on the skin of the bridge of the nose. Elevates the upper lip and the nasal wing that opens the nostrils, and can present an expression of displeasure. Zygomaticus minor aids in function of zygomaticus major. Zygomaticus major elevates the angle of the mouth while.
