Skull Bones PDF

The Skull Intramembranous ossification Joined by sutures (fibrous joints) which fuse together in adulthood Composed of neurocranium (which houses brain hence neuro) and viscerocranium (the face)  The Skull Appreciate! Don’t worry we’ll break it down These images are from: https://www.in...

The Skull Intramembranous ossification Joined by sutures (fibrous joints) which fuse together in adulthood Composed of neurocranium (which houses brain hence neuro) and viscerocranium (the face)  The Skull Appreciate! Don’t worry we’ll break it down These images are from: https://www.instantanat omy.net/index.html Neurocranium Composed of 8 bones: 4 midline (frontal, ethmoidal, sphenoidal, occipital) and 2 bilateral pairs (temporal, parietal) Roof/calvarium (frontal, occipital, parietal), floor/basicranium (frontal, sphenoid, ethmoid, occipital, parietal, temporal) Frontal Bone Glabella tap: Parkinson’s Tap on glabella (of frontal bone) - normal reflex is to blink but eventually you stop In Parkinson’s patients continue to blink Parietal Bone Occipital Bone Ethmoid Bone closer to nose lacrimal bone : (in eye)  at cribiform plate) (unite - Labrynths cavities 2 orbital Ethmoid Bone Between - for faux cerebri) part Crista galli (pointy - Where: roof of nasal cavity, between 2 orbital cavities (eye). Part of anterior cranial fossa Anatomy Forms ethmoidal labyrinths which are composed of: ○ Lateral sheet (orbital plate) ○ Medial sheet (superior and middle conchae - more in nose) Labyrinths unite at cribriform plate which has ○ Holes for olfactory nerve (CNI) fibres ○ Crista galli - for attachment of falx cerebri (dura mater) Foramen caecum - emissary veins Perpendicular plate forms part of nasal septum Provides link between: Cranial and nasal (cribriform plate/foramen caecum) → CSF leak causes nasal drip Nasal and orbit → air causing orbital emphysema Sphenoid Bone  - butterfly bone turcica for pituitary gland Sphenoid Bone dorsum sellde sellae and - sella bound by : tuberculum Sella turcica Chiasma-optic canal - for optic - chiasmatic sulcus/groove Located in middle cranial fossa around back of nasal cavity/orbit/temple opthalmic division < Composed of body, greater/lesser wings, maxillary neuve pterygoid process mandibular nerve Body: middle meningeal < artery Sella turcica (depression) contains hypophyseal fossa where pituitary Superior view Yoramen lacerum gland sits -meningeal arteries connects , the cranial a cavit veins to superficial veins) ○ Bound by tuberculum sellae deep petrosal nerve (anterior) and dorsum sellae - ↳ connects with the greater petrosal (posterior) nerve which supplies the lacrimal gland and other the Anterior/posterior clinoid processes x2 glands in nasal cavity Chiasmatic groove/sulcus is formed "Horners Syndrome' ↳ damage causes by optic chiasm Lesser wing Forms division between anterior/middle cranial fossa Borders optic canal with body Posterior view  - PerygoihamuTERVEALATular raphe Sphenoid Bone - pterygoid muscles Greater wing Foramen rotundum - V2 Foramen ovale - V3 Foramen spinosum - middle meningeal vessels Spine provides attachment for sphenomandibular l. And tensor veli palatini Superior view Pterygoid processes Medial pterygoid plate - contains pterygoid hamulus which acts as a pulley for tensor veli palatini and attachment for pterygoidmandibular raphe anatomical Landmark for inferior alveolar > nerve block - Lateral pterygoid plate - attachment of medial/lateral pterygoid muscles Pterygoid canal (runs horizontally through root of pterygoid process) opens into pterygopalatine fossa Posterior view Temporal Bone  Temporal Bone ↳ temporalis muscle Squamous nerve branch of facial Temporalis muscle ↑ to front 23 of tongue taste sensation - the Petrotympanic fissure - chorda tympani runs- through middle ear and joins lingual nerve Zygomatic Process articulates with zygomatic bone & masseter Lateral surface - masseter m. muscle P TMJ. EAM Tympanic External auditory meatus (i.e. your ear) Articulates with head of mandible to form temporomandibular joint (TMJ) Styloid Process Stylomandibular l. Of TMJ Styloglossus m. Petromastoid Mastoid process - sternocleidomastoid, posterior belly of digastric, splenius capitis Mastoid Air cells Petrous part - inner ear and boundary between middle/posterior cranial fossa  Temporal Bone quamous Squamous Temporalis muscle romastoid Petrotympanic fissure - chorda tympani Zygomatic Process articulates with zygomatic bone Lateral surface - masseter m. Tympanic External auditory meatus (i.e. your ear) man process Articulates with head of mandible to form temporomandibular joint (TMJ) Styloid Process Stylomandibular l. Of TMJ Styloglossus m. Petromastoid Mastoid process - sternocleidomastoid, posterior belly of digastric, splenius capitis Mastoid Air cells Petrous part - inner ear and boundary between middle/posterior cranial fossa Neurocranium Roof Mainly made up of frontal, 2x parietal, and occipital bones Sutures: coronal, sagittal, lambdoid Bregma (front), lambda (back) Pterion is point between sphenoid (greater wing), temporal, frontal, parietal bones. Anterior division of middle meningeal a. Runs under here so trauma can cause extradural haematoma Neurocranium - Floor/basicranium Made up of frontal, ethmoidal, sphenoid, -Attachment of faux cerebri (dura matter) temporal, parietal, occipital bones Divided into anterior, middle, posterior cranial fossa at: lesser wing of sphenoid petrous part of temporal bone Contains the cranial foramena  Cranial Foramena Bare minimum: (try learn them all) Formen CN Other Olfactory Nerve Cribriform Plate 1 Optic Nerve Optic canal 2 Opthalmic Artery Ophthalmic a. Opthalmic Opulomotor , Superior orbital fissure 3, 4, 5(1), 6 Sup ophthalmic v. Trochlear (Abducens Maxillary Foramen rotundum 5(2) Nerve Mandibular Foramen ovale 5(3) Nerve Middle Meningeal Foramen spinosum Middle meningeal a./v. Artery Internal Carotid Artery Carotid canal Internal carotid a. Facial N. Internal acoustic meatus 7, 8 Vestibulocochlear N. Jugular foramen 9, 10, 11 Inferior petrosal and sigmoid sinus → acossopharyngeal Vagus IJV Accessory Hypoglossal canal 12 Hypoglossal neuve Foramen magnum Medulla oblongata, meninges, vertebral a. Viscerocranium Nasal Bone Vomer Lacrimal Bone Zygomatic Bone Contains maxillary, frontal, and temporal processes where it articulates Zygomaticofacial foramen - zygomaticofacial n. and vessels Maxilla  vessels and nasopalatine vessels Incisive fossa incisive canals for greater palatine : Maxilla of soft palate - nasal spine : attachment nerve Posterior palatine PALATE : Greater - HARD - Greater Palatine foramen : lesser palatine nerve PALATE : foramen : Soft - Lesser palatine Forms roof of palate At the front: Incisive canals are on either side of the incisive fossa ○ Greater palatine vessels and nasopalatine nerves travel between the oral/nasal cavities At the back: Posterior nasal spine and posterior margin of horizontal palates ○ Attachment of soft palate Palatine canal (from pterygopalatine fossa) forms: ○ Greater palatine foramen - greater palatine n. and vessels to supply the hard palate ○ Lesser palatine foramen - lesser palatine n. and vessels to supply the soft palate Mandible  Articulates with TMJ Condylar Process : - muscle attached Temporalis which supplies teeth and Mandible Coronoid Process : alveolar nerve > mental foramen > Inf - canal - - mandibular - > Mandibular foramen skin of chin - - Lingual nerve Mylohyoid groove > - Mylohyoid line > Mylohyoid - nerve - Important parts Made up of body and ramus Condylar process forms temporomandibular joint (TMJ) with temporal bone Coronoid process - attachment of temporalis m. Mandibular foramen forms mandibular canal which finishes as mental foramen ○ Inferior alveolar n. (from V3) supplies teeth as travels through this and turns into the mental n. as it exits to supply skin of chin ○ Inferior alveolar vessels also ttravels through Mylohyoid line forms mylohyoid groove ○ Lingual n. ○ N. to mylohyoid  > - Mandibular Foramen > - Mylohyoid line Mandibular Canal Mylohyoid groove Mandible > Submandibular - Sublingual fossa Fossa Other bits: Alveolar border = where teeth are Mandibular symphysis = midline, and encloses mental protuberance Superior/inferior mental spines on inside of chin Sublingual and submandibular fossa Retromolar triangle - behind wisdom tooth Neck of condylar process - lateral pterygoid Lingula - sphenomandibular l. E E · G r n  - Synovial Joint Mandible Head of condylar Temporomandibular Joint (TMJ) : - tubercle Temporal Tympanic : Lateral , , a stylomandibular sphenom Ligaments : - - Fibrocartilage Synovial joint Formed by: head of condylar process (mandible) and lateral ~ tubercle of tympanic part of (temporal bone) Ligaments: Lateral, sphenomandibular, stylomandibular Articular surfaces are covered with fibrocartilage and ↑ medial divided into 2 by articular disc Muscles of mastication: Masseter, temporalis, medial/lateral pterygoid Develop from 1st pharyngeal arch ALL INNERVATED BY mandibular nerve (V3) All muscles elevate ○ Except lateral pterygoid (oriented horizontally onto pterygoid process) which instead moves side to side + protracts > - From 1st pharyngeal arch nerve ○ Temporalis m. (deep temporal n.) also retracts > From mandibular lateral pterygoid - jaw by attaching to condylar process > All - elevate except : ↳ side to side temporalis ) ↳ retraction  Temporal, Infratemporal, Pterygopalatine Fossa Temporal Fossa: Fossa: Temporal Temporalis m. > - Temporalis muscle Deep temporal n. and artery -> Deep temporal nerves arteries Middle temporal a. (from maxillary a.) > -Middle temporal artery temporal branch Zygomaticotemporal branch of V2 > Zygomatico - 4 sensation in the midface Feeds into Infratemporal Fossa: between ramus of mandible and wall of pharynx Feeds into Pterygopalatine Fossa: under zygomatic arch Communicates with nose, eye, middle cranial fossa Maxillary n. (V2) and artery Pterygopalatine ganglion