Skull and Face

1. Skull and Face Boonsirm Withyachumnarnkul, M.D., Ph.D. Department of Anatomy, Faculty of Science Mahidol University

2. Bony Landmarks of Skull and Face • Vertex • Superciliary arch • Zygoma • Mental symphysis • Entrance to orbit • Anterior nasal aperture

3. Three foramina vertically alligned • Supraorbital foramen … for supraorbital nerve • Infraorbital foramen … for infraorbital nerve • Mental foramen ... for mental nerve

4. Muscles of Facial Expression • Develop from the 2nd branchial arch, thus all are supplied by CN VII. • Most are thin, originate from facial bones to insert on facial skin, except platysma, and are intermingled at their insertions.

5. Muscles of Facial Expression • Muscle of the forehead … frontalis, as part of the occipitofrontalis • Muscles of the mouth • Muscle of the eyelids • Muscle of the nose • Platysma

6. Muscles of the Mouth • Orbicularis oris • Zygomaticus major • Zygomaticus minor • Levator labii superioris • Levator labii superioris alaque nasi • Buccinator • Depressor anguli oris • Depressor labii inferioris • Mentalis • Risorius • Platysma

7. Muscles of the Mouth

8. Muscle of the Eyelids • Orbicularis oculi • Orbital part • Palpebral part

9. Buccal Pad Fat • Between masseter and buccinator muscles • Brown fat … for heat generation, especially for children

10. Parotid Duct • One finger-breadth below zygomatic arch • Open into the mouth cavity (vestibule) at the level of the 2nd molar tooth (crown)

11. Facial Nerve • Comes out from stylomastoid foramen • Five branches • Temporal • Zygomatic • Buccal • Mandibular • Cervical

12. Facial Palcy • No wrinkle of forehead • Angle of mouth drops • Sagging lower eyelid • Other signs relating to malfunctions of structures innervated by facial nerve

13. Trigeminal Nerve • Sensory • Ophthalmic division • Maxillary division • Mandibular division • Motor .. To 1st branchial arch • Muscles of mastication • Messeter • Temporalis • Medial pterygoid • Lateral pterygoid

14. Arteries of the Face(rich, tortuous and highly anastomosed) • From external carotid artery • Facial artery • Superficial temporal artery • Transverse facial artery • From internal carotid artery • supraorbital artery • supratrochlear artery

15. Veins of the Face • Two important veins • Facial vein • Retromandibular vein • Facial veins have no valves • Connection of facial veins, pterygoid plexus and cavernous sinus

16. Lymph Drainage of the Face • Submental lymph nodes • Submandibular lymph nodes • Parotid lymph nodes

17. Scalp, Cranial Cavity and Venous Sinuses Boonsirm Withyachumnarnkul, M.D., Ph.D. Department of Anatomy, Faculty of Science Mahidol University Head2.ppt in C (Mahidol)

18. Scalp • Five layers of scalp • skin • dense subcutaneous tissue • epicranial aponeurosis • loose areolar connective tissue • periosteum

19. Scalp • Clinical relevance • infection spreading from loose areolar connective tissue, via emissary veins, to meninges-meningitis • hematoma

20. Skull Cap or Calvaria • Suture • coronal (frontoparietal) • anterior fontanelle • sagittal (interparietal) • lambdoid (occipitoparietal) • posterior fontanelle

21. Skull Cap or Calvaria • Three layers of skull cap • outer table • diploe • inner table

22. Cranial Fossae • Anterior cranial fossa • Middle cranial fossa • Posterior cranial fossa • Boundaries • lesser wing of sphenoid • superior border of petrous bone

23. Anterior Cranial Fossa • important landmarks • crista galli & cribriform plate of ethmoid • sella turcica • tuberculum sellae • hypophyseal fossa • dorsum sellae

24. Middle Cranial Fossa • important landmarks • foramina • superior orbital fissure • foramen rotundum • foramen ovale • foramne spinosum • groove for middle meningeal artery

25. Posterior Cranial Fossa • important landmarks • grooves for transverse & sigmoid sinuses • foramen magnum

26. Dura Mater • Outer and inner layers • position of the middle meningeal artery

27. Dura Mater • Falx cerebri • Falx cerebelli • Tentorial cerebelli and notch • Diaphragmatic sellae

28. Intradural Venous Sinuses • Superior and inferior sagittal sinuses • Straight sinus • Transverse and sigmoid sinuses

29. Intradural Venous Sinuses • Cavernous sinus • relationship among internal carotid artery, CN III, CN IV, CN V1 and CN VI • venous connections • clinical relevance • thrombophlebitis

30. Orbit and Eye Boonsirm Withyachumnarnkul, M.D., Ph.D. Department of Anatomy, Faculty of Science Mahidol University

31. Eye From the Outside • eyelids • palpebral fissure • plica semilunaris • caruncle • lacrimal puncta • cornea • sclera • conjunctiva • bulbar • palpebral • Sty • pterygium

32. Bony Parts of the Orbit • Entrance of the Orbit • frontal bone • zygomatic bone • maxillary bone • More Bones Inside • ethmoid bone • greater and lesser wing of sphenoid • lacrimal bone

33. Foramina of the Orbit • optic foramen (canal) • optic n. • ophthalmic a. • superior orbital fissure • all other nerves • superior ophthalmic vein • inferior orbital fissure • infraorbital n. & a. • inferior ophthalmic v. • infraorbital groove & foramen • zygomatic & infraorbital n. • supraorbital notch & foramen • supraorbital n.

34. Eyeball

35. Eyeball • Muscles • Extrinsic (Extra-ocular) • Intrinsic

36. Levator Palpebrae Superioris • Supplied by CN III • insert on the upper lid • if paralyzed ptosis

37. Superior Rectus Inferior Rectus Lateral Rectus Medial Rectus Superior Oblique Inferior Oblique Extra-Ocular Muscles

38. Actions of the Extra-Ocular Muscles • Around vertical axis • medial or adduction • lateral or abduction • Around horizontal axis • upward or elevation • downward or depression • Around antero-posterior axis • medial rotation • lateral rotation

39. Superior Rectus Make a 10-15 o with an AP axis adduct medial rotate elevate

40. Inferior Rectus depress adduct lateral rotate

41. Medial and Lateral Recti • Medial Rectus • adduction • Lateral Rectus • abduction

42. Superior Oblique • depress • abduction • medial rotate

43. Inferior Oblique • elevate • abduction • lateral rotate

44. Periorbita and Orbital Fat

45. Insertions of the Extra-Ocular Muscles

46. Nerves of the Extra-Ocular Muscles • Oculomotor Nerve (CN III) • supplies all except lateral rectus and superior oblique • Trochlear Nerve (CN IV) • superior oblique • Abducens Nerve (CN VI) • lateral rectus

47. Oculomotor nerve (CN III) Superior Division • levator palpebrae superioris* • superior rectus Inferior Division • inferior rectus • inferior oblique • medial rectus *not an extra-ocular muscle

48. Functional Tests of the Extra-Ocular Muscle • Principle • align the muscle axis with the eyeball AP axis • contract the muscle • e.g., for Superior Rectus • abduct, first • then, elevate • Therefore, test for the superior rectus function is to abduct and elevate

49. Parts of the Eyeball • Three layers • sclera • choroid • retina • anterior chamber • posterior chamber • cornea • iris • ciliary muscle • suspensory ligament • lens • hyaloid canal • vitreous body • aqueous humor

50. Clinical Relevance • lenticular cataract • glaucoma • Schlemn’s canal • Myopia (near sightedness) • hyperopia (far sightedness) • presbiopia (old-aged sightedness)