biology 223 human anatomy and physiology week 10; lecture 2; wednesday dr. stuart s. sumida soft...
TRANSCRIPT
![Page 1: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/1.jpg)
Biology 223Human Anatomy and PhysiologyWeek 10; Lecture 2; WednesdayDr. Stuart S. Sumida
Soft Tissues of the Head – Part II
Detail on Mastication
![Page 2: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/2.jpg)
“True” Muscles of mastication
All V3 innervation
1. Temporalis m.
2. Masseter m.
3. Medial pterygoid
4. Lateral pterygoid upper head: to articular
disclower head: to neck of
mandibular condyle
“Accessory” Muscles of mastication
Vital for normal chewing, but not mandibular adductors/protractors
• Buccinator VII
•Digastric V3 & VII
•Tongue XII
ADDUCTORS – jaw closing/raising
![Page 3: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/3.jpg)
Floor:
Temporal fossa/floor
parietal frontal
sq. temporalSP
![Page 4: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/4.jpg)
Temporalis m.
Temporal fossa/structures related to roof
![Page 5: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/5.jpg)
KNM ER 460 Australopithecus boiseii
![Page 6: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/6.jpg)
Temporal fossa roof/ temporal fascia
![Page 7: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/7.jpg)
masseter
Three layers:
Superficial, middle and deep with slightly different fiber orientations; important in recruitment for chewing
zygomatic
![Page 8: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/8.jpg)
temporalis
buccinatorPosterior belly of digastric
Stylomandibular ligament
![Page 9: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/9.jpg)
Lateral pterygoid: upper head
lower head
Line of action of lateral pterygoids is from anterior to posterior in horizontal plane. They PROTRACT or pull the mandible forward.
INFRATEMPOR-AL FOSSA
borders:
Lateral: ramus of mandible
Medial: lateral pterygoid plate
Roof: greater wing of sphenoid, adj. maxilla & palatine bones
Inferior: continuous with deep cervical fascia
![Page 10: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/10.jpg)
Mental foramen for V3 sensory branch
Coronoid process of mandible
Mandibular notch
neck
condyle
Mandibular fossa
Articular emminence
![Page 11: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/11.jpg)
lingula
Mandibular foramen for inferior alveolar branch of V3, vv.
Injections to numb the lower teeth also numb chin and lower lip but not uppers
Mylohyoid line for m. attachment
Mylohyoid groove for V3 branch to mylohyoid
![Page 12: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/12.jpg)
Tensor veli palatini
Medial pterygoid
Lateral pterygoid upper head – to articular disc
Lateral pterygoid lower head to neck of mandibular condyle
Sphenoid/Muscular origins
“Pterygoid” means “talon-like”
![Page 13: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/13.jpg)
MRI series 1 of 6 – coronal section, anterior to posterior
Temporalis m.
Masseter m.
![Page 14: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/14.jpg)
MRI series 2 of 6
Lateral pterygoid
Upper head: to articular disc
Lower head: to neck of mandibular condyle
![Page 15: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/15.jpg)
MRI series 3 of 6
Medial pterygoid
![Page 16: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/16.jpg)
MRI series 4 of 6
![Page 17: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/17.jpg)
MRI series 5 of 6
![Page 18: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/18.jpg)
MRI series 6 of 6
![Page 19: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/19.jpg)
Mastication = process in which food is bitten, held and chewed withing the oral cavity
•Incisors = nipping and cutting (shear)•Molars = crushing, with shear generated as cusps occlude
Occlusion = close-packing of teeth in functioanlly approprite position
Mal-occlusion can lead to abnormal stresses on TMJ, and therefore arthritis
![Page 20: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/20.jpg)
Chewing movements and mechanics
Generally acts as 2nd order lever system = compression at TMJ
Turning moment generated along mandibular corpus and ramus = sheer at TMJ
NOTE different vectors of temporalis m.
![Page 21: Biology 223 Human Anatomy and Physiology Week 10; Lecture 2; Wednesday Dr. Stuart S. Sumida Soft Tissues of the Head – Part II Detail on Mastication](https://reader035.vdocuments.mx/reader035/viewer/2022081603/56649f1e5503460f94c3675b/html5/thumbnails/21.jpg)
Chewing in mammals (and therefore humans) is asymmetric and unilateral:
WORKING SIDE:
•GREATEST ADDUCTOR FORCE,
• but articular emminence is less substantially loaded
BALANCING SIDE:
•LESS ADDUCTOR FORCE
•articular emminence is substantially loaded
•INITIAL ACTION CONTRACTION OF INFERIOR HEAD OF LATERAL PTERYGOID MUSCLE TO INITIATE MANDIBULAR DEVIATION TO WORKING SIDE