Lecture Block: ENDC-413 Session: Skull & Pituitary Fossa Abdulrahman Alessa 2016-2017
Doctor’s Notes
My Additional Explanatory Notes
Human Skull a. protects brain and associated meninges b. form facial skeleton c. gives casing (bony covering) for eye, ear, nasal and oral cavities. Skull is divided embryonically into 1. Neurocranium ( Cranial Vault ), that includes 1. calvaria ( Roof = upper part) 2. Basicranium ( basal part toward the floor side) 2. Viscerocranium (bones that make Facial skeleton) There are total 22 bone in skull o 8 in neurocranium Paired parietal, paired temporal, frontal, occipital, sphenoid, ethamoid o 14 in facial skeleton Paired maxilla, paired zygomatic, paired lacrimal, paired nasal, paired palatine (Located within orbital cavity on the most medial wall then forms the hard palate), paired inferior concha (in nasal cavity, the inferior part of it) , a vomer and a mandible Definition of Sutures o These are fibrous joint (Synarthrosis) uniting all the skull bone
He mentioned all of structures in the diagram
For CSF Drainage
Doctor’s Notes
My Additional Explanatory Notes
Gross features of skull The external features of skull are studied by dividing it in to various regions : 1. Norma verticalis superior view of the skull 2. Norma frontalis anterior view of the skull 3. Norma occipitalis posterior view of the skull 4. Norma lateralis lateral view of the skull 5. Norma basalis inferior view of the skull Now we are going to study these views’ features, which is the bulk of this lecture Normal verticalis a. It is vault of the skull b. Covered by scalp (=Skin overlying skull) c. Three bones participate : i. Paired parietal, frontal, occipital bones Gross Features Sigittal suture unites 2 parietals Coronal suture unites frontal with parietal Lambdoid suture unites occipital with parietal Vertex ( Highest point of norma verticalis) Anterior/ Posterior fontanelles composed of membranes before sutures are well-developed Bregma meeting point of coronal and saggital sutures. It has clinical !mportance in newborns because it’s the site where anterior frontanelle will lie. It’s used to assess nutrition status of babies bulging anterior/posterior fontanelle is a sign of malnutrition or high intracranial pressure, while when depressed they indicate dehydration Lambda meeting point of sagittal and lambdoid sutures Parietal emissary foramen Superior and inferior temporal lines sometimes visible
Doctor’s Notes
My Additional Explanatory Notes
Normal frontalis a. Facial aspects of the skull ( anterior view) b. Participating Bones i. Frontal bone, Paired maxillae, Paired nasal, Paired zygomatic, the Mandible Gross Features The orbital opening External nasal aperture opening for nasal cavity. Pointing in apex (formed by two nasal bones) and broad in bases (formed by maxilla) Superciliary arches raised margins above orbits where eye brows are present more prominent more in males Glebella intersection of fronal and two nasal bones Nasion meeting of two nasal bones, just below glabella. Infra orbital foramen for passage of infraorbital nerve and vessels of maxillary branches Canine and incisive fossae for canine and incisive teeth in maxillary margin Zygomatic bone forms promeinice of cheek, articulates with maxillae and temporal bone to from zygomatic arch Zygomaticofacial and zygomaticotemporal foramina for corresponding branches of mandibular division
Doctor’s Notes
My Additional Explanatory Notes
Normal occipitalis a. The posterior aspects of the skull b. Bones participating : Occipital, Parietal bones, Mastoid part of temporal Gross Features Lambdoid suture Asterion 3 sutures of 3 bones meet : Occipital, Parietal bones, Mastoid part of temporal External occipital protuberance or crest Inion meeting point of occipital protuberance at superior nuchal line Highest nuchal line not usually visible Superior nuchal line Inferior nuchal line External occipital crest Mastoid emissary foramen sometimes visible
Doctor’s Notes
My Additional Explanatory Notes
Normal lateralis a. The lateral view of the skull b. Bone Participating: Frontal, Parietal, Temporal, Zygomatic, Sphenoid (by greater wing), Maxilla Gross features Temporal line Temporal fossa (above zygomatic arch) Pterion (meeting of four bones parietal, frontal, temporal, sphenoid) making H shaped suture posterior to it anterior branch of middle meningeal artery lies Zygomatic arch Mandibular fossa that lodges condyle of mandible forming TMJ Supramastoid crest upper laminae of zygomatic arch Suprameatal triangle ( Boundaries : superior margin of external acoustic meatus + supramastoid crest + a vertical line ) Mastoid process External acosutic meatus Styloid process Pterygomaxillary fissure (comuunicate infratemporal fossa with pterygopalatine fossa) Infratemporal fossa below zygomatic arch Lateral pterygoid plate Clinical Aspects Pteryion the surface landmark of middle meningeal artery, the source of epidural haemorrhage Suprameatal triangle forms the lateral boundary of mastoid air cells (entrum) and surgical intervention can be done for mastoidectomy
Doctor’s Notes
My Additional Explanatory Notes
Normal basalis a. The inferior or basal aspect of the cranium b. Divisible in three parts (Anterior, middle, and posterior), look at the picture below, and know where are the line well. Anterior part of Norma basalis c. Bones present are Maxilla, Palatine, Pterygoid process Gross features Formation of hard palate (maxillae in fron then palatine bone), know the sutures in this image Cruciform suture Incisive fossa Alveolar margin where there are sockets for teeth Posterior nasal spine posterior sharp part of palatine bone Greater and lessor palatine foramina for greater and lesser palatine nerves Pterygoid hamulus raised margin of medial pterygoid plate Parts of norma basalis will be discussed in details in two next pages
Doctor’s Notes
My Additional Explanatory Notes
Middle and lateral part a. Mid line features b. Bone participating Vomer has 2 alae, Sphenoid, Petrous part of temporal, Basilar part of occiput, Tympanic plate (part of temporal bone which forms boundaries of external acoustic meatus) o Gross features o Posterior nasal apertures leading to nasal cavity o Ala of vomer o Basilar part of sphenoid meets with basilae part of occipital to make central pillar o Body of sphenoid o Pharyngial tubercle maximal prominence of basilar part of occipital bone
Doctor’s Notes
My Additional Explanatory Notes
Lateral part Gross features Pterygoid process Medial and lateral pterygoid plates Pterygoid fossa between medial and lateral pterygoids see it in red star in image below Scaphoid fossa between 2 laminae of medial pterygoid see it in yellow star in image below Pterygoid hamulus Spine of sphenoid Foramen ovale and spinosum in greater wing of sphenoid Tubular sulcus where greater wing of sphenoid and petrous part of temporal meets, part of auditory tube lies here Mandibular fossa for TMJ Carotid canal lies in petrous part of temporal and opens to foramen lacerum Foramen lacerum lies between greater wing of sphenoid and petrous part of temporal Stylomastoid foramen Posterior part Gross features Foramen magnum gives way to medulla oblongata along with spinal cord, corresponding arteries and meninges External occipital crest Condyles of occipital bone articulate with 1st cervical vertebra (Atlas) Condylar canal just below condyles of occipital bone for hypoglossal nerve passage Squamous part of occipital bone Jugular foramen between pterous temporal and occipital bone where internal jugular vein, vagus and glossopharyngeal pass Stylomastoid foramen for facial nerve Groove for occipital artery between occipital bone and mastoid process Jugular fossa close to jugular foramen
Doctor’s Notes
Mandible A Midline central bone Has body, ramus, and processes (coronoid, condylar) Condylar process forms TMJ Ramus has external and internal surfaces There is alveolar margins gives sockets for teeth Mandibular foramen gives way to mandible and alveolar nerve
Interior of the skull
My Additional Explanatory Notes
Doctor’s Notes
Cranial Fossae posterior
My Additional Explanatory Notes
Anterior , middle and
Anterior cranial fossa Boundaries In front frontal bone Laterally frontal and part of parietal Floor frontal bone , cribriform plate of ethamoid Posteriorly Jugum sphenoidale( also forms part of the floor), Lessor wing of sphenoid Features Crista galli Cribriform plate with multiple openings for olfactory nerve Frontal crest Foramen cecum Jugum shenoidale Anterior clinoid process Middle Cranial fossa Boundaries Anterior wall lesser wing of sphenoid Posteriorly sloping part of petrous temporal Floor greater wing of sphenoid and squamous part of temporal + sella turcica and body of sphenoid Features Sulcus chiasmaticus between two crinoid processes, optic chiasm lies above this Optic canal communicate optic cavity with middle cranial fossa Sella tursica between tuberculum and dorsal sallae lodges pituitary gland Carotid sulcus bilaterally groove for internal carotid arteries Superior orbital fissure between greater and lesser wing of sphenoid Foramena lacerum,ovale, rotundum and spinosum Trigeminal impression ,tegmen tympani, arcuate eminence for middle air cavity on petrous temporal
Doctor’s Notes
My Additional Explanatory Notes
Posterior cranial fossa Boundaries Anterior midline clivus (basilar part of occipital bone) Anterior lateral petrous part of temporal Posterior squamous part of occipital Features Internal occipital protuberance and crest Foramen magnum Internal acoustic meatus where nerves and vessels go to internal ear Jugular foramen Condylar canal Groove for sigmoid sinus Groove for transvers sinus
Pituitary fossa Pituitary fossa lodges the pituitary gland Boundaries Anterior Tuberculum sellae,Sulcus chiasmaticus Posterior Dorsum selae Floor Sela tursica of body of sphenoid Roof diaphragma selae Lateral cavernous sinus groove Relations in lateral wall from medial to lateral: Cavernous sinus, internal carotid artery, 6th nerve, 3rd nerve and ophthalmic nerve Cavernous sinus thrombosis May occur due to infective emboli drained by inferior ophthalmic veins
Doctor’s Notes
My Additional Explanatory Notes
Pituitary gland (Embryology) 2 processes : one come from diencephalon (floor) and another from oral cavity (Rathke’s pouch). Neurohypophysis is got from diencephalon, whereas anterior pituitary from Rathke’s pouch.
Skull Foramina chart (You should know this table very well)
