Gross Anatomy SESSION 15 Dr. Firas M. Ghazi Skull: Neurocranium
Gross Anatomy SESSION 15 Dr. Firas M. Ghazi
Skull: neurocranium Curricular Objectives By the end of this session students are expected to: Practical 1. Identify the cranial bones and the sutures in between 2. Review the landmarks seen in frontal, lateral, superior and posterior views of skull 3. Recognize the main features of the inferior view of skull 4. Label the major foramina of the inferior view of skull and List one content 5. Follow the groove for superior Sagittal sinus to its termination 6. Distinguish the three cranial fossae, and their boundaries, & acknowledge their content 7. Recognize the major landmarks within each cranial fossae 8. Label the main foramina within each cranial fossae and List one content 9. Trace the groove for middle Meningeal artery and recall its relation to pterion 10. Locate the anterior & posterior fontanels of neonatal skull & recall their closure time 11. Identify structures seen in anterior and lateral views of skull X-ray 12. Palpate the glabella and external occipital protuberance Theory 1. Define the facial and cranial skeleton 2. List the paired and unpaired cranial bones 3. Summarize the main features of frontal, lateral, superior and posterior views of skull 4. Outline the major foramina of the inferior view of skull and recall their content 5. Review the structures and spaces related to the inferior view of skull 6. Define the cranial cavity and review its parts and content 7. Outline main features of anterior, middle and posterior cranial fossae 8. State the content of each of the major foramina within the three cranial fossae 9. Describe the lining of the cranial cavity by the dura 10. Underline the course of middle Meningeal artery and extradural hematoma 11. Uncover the possible manifestations of fractured base of skull 12. Review the clinical importance of the skull fontanels
Selected references and suggested resources Clinical Anatomy by Regions, Richard S. Snell, 9th edition Grant's Atlas of Anatomy, 13th Edition McMinn's Clinical Atlas of Human Anatomy, 7th Edition Anatomy for Babylon medical students (facebook page) Human Anatomy Education (facebook page) Human anatomy education (you tube channel)
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Session check list
Clinical importance Skull fractures, Extradural hematoma, Bulged and depressed fontanels are some of the common clinical problems encountered in clinical practice
Key landmarks Mastoid process/ hard palate/ medial and lateral pterygoid plates/ petrous bone
Skull facts: It is made up of 22 bones, 8 forming the neurocranium, and 14 forming the face. It lodges special senses (eye, ear, olfaction, taste) Its cranial cavity contains brain, meninges, parts of cranial nerves, vessels, & venous sinuses 12 pairs of cranial nerves leave brain & cranial cavity, pass through skull foramina & fissures It has a lot of foramina transmitting many structures between spaces. Skull bones are made up of a layer of spongy bone called the diploe coated by external and internal tables of compact bone. Extradural space a space in between internal table of cranial cavity and dura mater lining it
Cranial Bones Task 1: use a model to identify the following bones 1. Frontal 2. Parietal 3. Temporal 4. Ethmoid 5. Sphenoid (Body/Greater wing/Lesser wing) 6. Occipital bone Task 2: using a model, identify and trace the following sutures then answer related questions 1. Coronal 2. Sagittal 3. Lambdoid 4. Metopic
Sutures How important is the metopic suture to clinical practice? can be defined as…………………………… Skull exterior Task 3: use a model to identify the following structures and respond to related questions I. Superior view: 1. Sutures 2. Parietal emissary foramen 3. Anterior and Posterior fontanel in neonatal skull What structure pass through the emissary foramen, state its clinical significance List three clinical situations in which the fontanels can be of help II. Posterior view: 1. External occipital protuberance 2. Superior nuchal lines 3. Wormian (sutural) bones Distinguish between scalp and neck using surface landmarks Why it is important to know about the small wormian bones? III. Lateral view of skull 1. Superior and inferior temporal lines, Pterion 2. Mastoid process, External acoustic meatus 3. Styloid process List the bones that can be seen in lateral view
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IV. Inferior view of skull 1. Occipital condyles / Foramen magnum 2. Pharyngeal tubercle 3. Mastoid process/ Styloid process/ Spine of sphenoid 4. Hard palate 5. Mandibular fossa / Squamotympanic fissure 6. Carotid canal (lower opening) What structure articulate with occipital condyles? name the joint & its movement The area anterior to pharyngeal tubercle represents the upper end of which structure? The hard palate separates between two cavities, name and locate them Name the cavities connected by Squamotympanic fissure & the nerve passing through List the structures that pass through the foramen magnum
Skull interior (cranial cavity) Task 4: use a model to identify the following structures and respond to related questions I. Anterior cranial fossa 1. Crista galli / Cribriform plate of ethmoid 2. Orbital plates of frontal bone 3. Anterior clinoid process What is the structure transmitted by cribriform plate of ethmoid, where to? Orbital plates of frontal bone separates the anterior cranial fossa from which cavity? II. Middle cranial fossa 1. Sella turcica (pituitary gland) 2. Cavernous sinus / Groove for internal carotid artery 3. Optic canal / Superior orbital fissure 4. Foramen rotundum/ Foramen lacerum/ Foramen ovale 5. Foramen spinosum / Groove for middle meningeal artery List four cranial nerves pass from middle cranial fossa to orbit and their foramen Name the structures passing through the above foramina Identify the above foramina on the inferior view of skull III. Posterior cranial fossa 1. Internal occipital protuberance 2. Groove for the transverse sinus and sigmoid sinus 3. Hypoglossal canal 4. Jugular foramen 5. Internal acoustic meatus Name the structures passing through the above foramina What are the cranial nerves passing through the Internal acoustic meatus
Important to know: Task 5: use a model to trace the following structures and respond to related questions 1. Follow the groove for middle Meningeal artery from its entry foramen to the side of skull Name the division of the artery and locate them/ Which of them is related to pterion Relate the artery to dura mater What do you expect if the artery is injured 2. Insert a flexible probe through the lower end of the carotid canal Identify the point of exit of the probe Which structure pass through this canal?
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Review question: Each statement on the right describes a structure. Indicate the foramen through which it passes Letter Statement Foramen 1. Motor nerve of the tongue A. Foramen magnum 2. Nerve supplying the superior oblique B. Foramen rotundum 3. It supplies blood to meninges C. Internal acoustic meatus 4. It provides sensory supply of maxilla D. Jugular foramen 5. artery alongside the body of sphenoid E. Optic canal 6. a large vein draining the head F. Superior orbital fissure 7. it’s a largeerve concerned with vision G. Hypoglossal canal It’s H. Foramen ovale It’s a n I. Foramen lacerum J. Foramen spinosum K. Carotid canal
Home work: 1. A ball hit the left temporal region of a 16-year-old young girl while watching a baseball game. She lost consciousness for a short time then regain it. Few hours later, she developed an increasing headache, and had a seizure. The patient was diagnosed as having Extradural hematoma resulting in elevated intracranial pressure
A. What is the thinnest area on the lateral side of skull? B. Name the artery passing deep to this area C. What type of intracranial hemorrhage is expected from injury of this artery?
2. A patient was admitted to ER after receiving a blow on his head complaining of headache. CT scan of skull was done to exclude skull fracture. On inspecting the radiographic film you noticed a small piece of bone near the vertex. A. What possibilities you put in mind? B. How to decide which possibility is more accurate.
3. As a 4th year medical student you where requested to assess the status of hydration of an infant by examining his skull. A. Name the structures that can help you in your task B. How they are formed? C. Where can you find them? D. When they are usually closed? E. List 2 more clinical uses of these structures.
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