CAS BI 106 Lecture Notes - Lecture 11: Orbicularis Oculi Muscle, Latissimus Dorsi Muscle, Orbicularis Oris Muscle
Document Summary
How to focus this material: muscles of facial expression, frontalis- on forehead above eyes, raise eyebrows and frontalis will contract, orbicularis oculi- around the eye, squint eyes to contract, zygomaticus major- under zygomatic bone, smile to contract. To smile we use both zygomaticus major and orbicularis oculi: masseter- cheek towards jaw. Helps chew: orbicularis oris- around mouth, depressor anguli oris- under mouth muscle, near ends of lips, contracted when frown, platysma- neck muscle, muscles that keep our head up, muscles of breath, external intercostals. Internal intercostals: central tendon of diaphragm, muscles that keep us upright as bipedal organisms. 3 sets of intercostals (bring ribs up and out) Innermost intercostal runs straight up and down: superior to lateral. Internal intercostal inferior/lateral to superior/ medial (45 degree angle: external intercostal, superior lateral to inferior medial (45 degree angle) Internal oblique- muscle inside after you cut external oblique: transverse abdominal- deepest oblique. under of internal oblique.
