Exam 4 Session 1 Lectures 37-39 PDF

Exam 4 Session 1 Lectures 37-39 Eric Iribar [email protected] 954–881-1083 Erica Sickel [email protected] 724-859-3263 Lecture 37: Intro to skull Dr.Harper Lecture Objectives “I can mentally reconstruct all the...

Exam 4 Session 1 Lectures 37-39 Eric Iribar [email protected] 954–881-1083 Erica Sickel [email protected] 724-859-3263 Lecture 37: Intro to skull Dr.Harper Lecture Objectives “I can mentally reconstruct all the bones of the skull. Including being able to recall which bones surround any particular bone and what kind of joint they might make” “I can describe the boundaries of the cranial fossae and recall the neurovascular structures entering and leaving them” “I am able to visualize the positions and contents of the cavernous sinus” “I can diagnose the superficial indicators and major types(Le Fort) of skull fractures”  BUY A SKULL https://a.co/d/99ByFV7 https://a.co/d/6UpMRVj  Bones of skull Skull (Cranium)- Consists of 28 bones Connected by fibrous interlocking joints called Sutures Cranium can be divided into two sections based on function: ○ Neurocranium- portion that encases the brain The Neurocranium is further divided into 2 portions: Calvaria- Intramembranous ossification Cranial Base- endochondral ossification ○ Viscerocranium- facial bones  Overview of the Skull Unpaired Bones Frontal Frontal Sphenoid Sphenoid l ita cip Oc Ethmoid Ethmoid Vomer le ndib Ma Mandible Gray’s 857 Gray’s 855  Overview of the Skull Paired Bones Parietal Parietal Nasal Temporal Temporal Nasal Lacrimal Zygomatic Maxilla Inferior Nasal Zygomatic Concha Gray’s 857 Gray’s 855  Overview of the Skull Paired Bones Maxilla Palatine Zygomatic Malleus Incus Stapes Parietal Temporal Gray’s 862 Inferior View  Sutures of the Skull Coronal Suture Bregma Parietal Frontal Lambda Sagittal Suture Occipital Lambdoid Parietal Suture Lambda Gray’s 859 Gray’s 860  Sutures of the Skull Bregma HY Pterion - area where brain case Coronal Suture is very thin and Squamous Suture branch of middle meningeal artery Frontal Parietal lies underneath Lambda Pterion Lambdoid This part of the skull is very thin and prone to Suture fracture and the Temporal l ita fractured bones can ip injure the MMA c Oc (epidural hematoma) Sphenoid Gray’s 857 Pterion & Epidural Hematoma Pterion is an area of weakness in the skull. The anterior branch of the middle meningeal artery lies deep to pterion. Therefore, fracture to pterion can rupture the middle meningeal artery (via foramen spinosum)→ epidural hematoma. Blood accumulates between the skull and the dura mater  Basicranial Features & Foramina Zygomatic arch Hard palate Mandibular fossa Inferior orbital fissure Petrotympanic fissure Foramen ovale Chorda tympani n. (CN VII br) Foramen spinosum Styloid process Stylomastoid foramen Jugular foramen CN VII (Facial n.) Mastoid process Occipital condyle Carotid canal Foramen magnum Foramen lacerum 12  Basicranial Features & Foramina Incisive foramen Greater palatine Lesser palatine foramen foramen Greater palatine n., a. Lesser palatine n., a. Choana (internal nares) Lateral & medial plates of the pterygoid process, Sphenoid 13 Superior nuchal line External occipital protuberance  Complex Bones - Temporal and Sphenoid Sphenoid Bone - “Bat bone” Temporal bone - mixture/fusion of different bones via synostosis (bone touching bone). Squamous part is the flat bone, Sphenoid sinus - airspace inside the body of the bat. Has 2 mastoid part makes up mastoid process, and tympanic part exits on the anterior side. makes up EAM (external auditory meatus) and styloid process. Looking from inside out, have thick petrosal part Spine of Sphenoid ≠ styloid process. It is near the foramen spinosum  Cartilaginous Neurocranium Neurocranium forms initial cartilaginous basket AKA framework around developing brain. Endochondral ossification proceeds from initial “ossification centers” Skull bones can be a mix of intramembranous and endochondral ossification Bones slowly envelope entire cranium over time, except patches where they do not connect which are fontanelles AKA soft spots in neonates Sphenoid Mastoid fontanelle fontanelle (becomes asterion) (becomes pterion) Premature Suture Closure: Craniosynostosis Premature closure of the cranial sutures → cranial malformations Rarely affect brain development but complications may depend on the affected suture & timing of the synostosis (before/after birth) Scaphocephaly - Premature closure of sagittal suture, reduced anterior fontanelle Plagiocephaly - Premature closure of lambdoid suture on one side only, diagonally twisted appearance Oxycephaly (cone head) - Premature closure of coronal suture ***do not have to know name, have to be able to know description/what suture is closed** Premature Suture Closure: Craniosynostosis  External Features of the Skull Mandible Mandibular Notch Mandibular Foramen Coronoid Lingula Process Condylar Process Ramus Mental Protuberance Angle Alveolar Body Mental Part Foramen Netter  Mandibular foramen- where TMJ and Mandible inferior alveolar n., a., and v. travels Mandibular notch TMJ- where mandible articulates with the temporal Condylar bone process Mandibular fossa, Temporal bone Articular disk Articular tubercle Head of mandible  Sinuses Around the nasal cavity there are paranasal sinuses: Frontal sinus- inside the frontal bone Ethmoid sinus- inferior to the frontal sinus and superior to the nasal cavity Sphenoid sinus- posterior to Ethmoid sinus Maxillary sinus- inferior to the obits and inside the maxillary bone Common site for sinusitis  Calvaria = top part of the skull Frontal sinus Coronal suture Middle meningeal groove Groove for Arachnoid Fovea superior sagittal Arachnoid granulations (what reabsorb sinus our CSF from our ventricular system) Sagittal suture Fovea are impressions of arachnoid granulations - structures filled with CSF that extend into the venous sinuses through openings in the dura mater and allow the drainage of CSF from subarachnoid space into venous system (more on this later) Anterior cranial fossa Crista galli Falx Foramen cecum cerebri Cribriform plate CN I (Olfactory bulbs & nn.) Sphenoid bone (lesser wing) Sphenoid bone Anterior clinoid processes (body) Middle Cranial Fossa Greater petrosal nerve comes out of foramen lacerum In lesser wings b/w lesser and greater wings Lesser petrosal nerve comes out of foramen ovale dasf What passes through here? Other side forms roof of MMA! middle ear Cavernous Sinus A Dural Venous Sinus with the internal carotid artery and cranial nerves running through it Much more on this later, just a little sneak peak  Optic canal Superior orbital fissure CN III (oculomotor n.) CN IV (trochlear n.) CN V1 (Trigeminal n.) CN II (Optic n.) & CN VI (abducens n.) Ophthalmic a. Inferior orbital fissure J. Millard 27 Foramen Lacerum and Pterygoid Canal Big picture - we are here Foramen Lacerum and Pterygoid Canal Foramen Lacerum has a floor of cartilage inferiorly. Internal carotid artery runs superiorly above this floor, while the Pterygoid Canal is found in the anterior wall of the foramen lacerum and opens into the PT fossa What goes through canal? Nerve of pterygoid canal which a mixture of greater petrosal nerve, and sympathetics fibers from carotid artery which is called deep petrosal nerve. Posterior Cranial Fossa fgh CN 2-5 Foramen Rotundum Superior Orbital Fissure CN V2 CN III Foramen Ovale CN IV CN V3 CN V1 CN VI CNII and ophthalmic artery come out of the optic canal  CN 7 – 12 Internal Acoustic Meatus Hypoglossal Canal CN VII CN XII CN VIII Jugular Foramen Foramen Magnum Internal jugular vein CN XI CN IX Brainstem/spinal cord Vertebral arteries CN X CN Xi TQs from last year Diagnose the major types of craniosynostoses and their clinical presentations. Describe the boundaries of the cranial fossae Recall which bones and neurovascular structures surround any particular bone.