2The Cranial Cavity Vault Sutures: (Coronal, Sagittal & Lambdoid) -Impressions:arachnoid granulations, middle meningeal aa., and superior sagittal sinus.
3The Cranial Cavity The Base of skull 1- Anterior Cranial fossa 2- Middle Cranial fossa3- Posterior Cranial fossaWe should know for each fossa:Formed by? bonesBoundaries? wallsContents?Main Features? foramina
4Anterior Cranial Fossa Formed by: orbital plates of the frontal bone, cribriform plate of the ethmoid, lesser wing of sphenoid & anterior part of body of sphenoid.Boundaries: inner surface of the frontal bone, lesser wings of the sphenoid on the sides and groove for the optic chiasma.Contains: the frontal lobes of the brainMain features:Foramen cecum (emissary vein)Crista Galli (attachment of the falx cerebri)Cribriform plate (olfactory bulbs and the olfactory nerves)Anterior clinoid processes (attachment of tentorium cerebelli)
5Middle Cranial Fossa Formed by: median part- body of sphenoid bone Lateral concavities - greater wing of sphenoid, squamous and petrous parts of temporal bone.Boundaries: Ant. lesser wing of sphenoidPost. upper border of petrous part of temporal boneLat. greater wing of sphenoid, parietal bone and squamous part of temporal bone.Contains: the temporal lobes of the brain.
6Middle Cranial FossaFeatures: (7 foramina, median part, petrous part of temporal bone)1- Optic Canal: (ophthalmic a. & optic nerve) ―→ to the orbit.2- Superior orbital fissure: (superior ophthalmic vein, lacrimal, frontal, nasocilliary, Abducent, Oclomotor & Trochlear nerves) ―→ to the orbital cavity.3- Foramen rotundum: (maxillary branch of Trigeminal (V) nerve) ―→ to the pterygo-palatine fossa.4- Foramen ovale: (mandibular branch (sensory & motor) of trigeminal (V) nerve & the lesser petrosal nerve) ―→ to the infratemporal fossa.
8Middle Cranial FossaFeatures: (7 foramina, median part, petrous part of temporal bone)The petrous part of temporal bone:Medial groove for greater petrosal nervesLateral groove for Lesser petrosal nerveArcuate eminence: (semicircular canal in inner ear)Tegmen tympani: (roof mastoid antrum, tympanic cavity and auditory tube)
9Middle Cranial FossaFeatures: (7 foramina, median part, petrous part of temporal bone)The Median part of Middle Cranial Fossa: (body of the sphenoid)Sulcus Chiasmatis: a groove for optic chiasma.Tuberculum sellae: (with middle clinoid processes)Sella Turcica (Turkish saddle): a depression for the pituitary gland.Dorsum Sellae: (with posterior clinoid process)
10Posterior Cranial Fossa Formed by: Occipital bone, Mastoid part & post. half of petrous temporal bone.Boundaries: superior border of petrous part of temporal bone & internal surface of occipital bone.Contains: cerebellum, midbrain, pons and medulla oblongata.Main features: (Roof, 4 Foramina, 4 sinus grooves)Roof: by a fold of dura called tentorium cerebelli that is attached to the upper border to the petrous part of temporal bone.
12Posterior Cranial Fossa Sinus grooves: these are deep impressions for the venous sinuses which are:1- Superior Petrosal sinus on upper border of petrous part of temporal bone.2- Inferior Petrosal sinus on lower border of petrous part of temporal bone.3- Sigmoid sinus which is S shaped on mastoid and petrous parts of temporal bone.4- Transverse sinus on each side of internal occipital protuberance.
131- Cervical Vertebrae (Spines) Bones of the Neck1- Cervical Vertebrae (Spines)2- Hyoid bone:
14Cervical Spines They are 7 cervical vertebrae Unique transverse foramen in the transverse processes (vertebral vein and vertebral artery) There are:3 Atypical (C1,C2 & C7)4 typical (C3-C6)All have transverse processes
15Typical Cervical Spine Features: 1- The vertebral body is small and longer from side to side than anteroposteriorly; the superior surface is concave, and the inferior surface is convex. 2- The vertebral foramen is triangular. 3- The superior facets of the articular processes are directed superoposteriorly, and the inferior facets are directed inferoposteriorly. 4- The spinous processes are short and bifid. 5- The transverse process has anterior and posterior tubercles and in between a groove for spinal nerve.
16Atypical Cervical Spine – C1 C1 vertebra (Atlas):Ring-like shapeEncloses the odontoid process of C2 & Spinal cord with meningesNo Spinous process No BodyHas two lateral masses connected by anterior and posterior arches.It has concave superior articular facets (Kidney shaped) to receive the occipital condyles.
17Atypical Cervical Spine – C2 C2 vertebra (Axis):The strongest cervical vertebra.Has two large, flat surfaces, the superior articular facetsHas tooth-like dens (odontoid process).Both dens and the spinal cord are encircled by the atlas. The dens lies anterior to the spinal cord and separated by the transverse ligament of the atlas.It has a large bifid spinous process that can be felt deep in the nuchal groove.
18Atypical Cervical Spine – C7 C7 vertebra:It has long spinous process, which is not bifid.Its transverse processes are large and directed downward which allow differentiation from T1 Spine that has upward directed transverse process.
19Hyoid BoneIt is a U-shaped bone that lies in the anterior part of the neck level of the C3)It is suspended by muscles that connect it to:Mandible by mylohyoid, genohyoid &digastric musclesStyloid processes by stylohyoid muscle and ligamentThyroid cartilage by thyrohyoid muscleManubrium by sternohyoid muscleScapulae by omohyoid muscleThe hyoid does not articulate with any other bone.The hyoid consists of a body, greater and lesser horns.Functionally, the hyoid serves as an attachment for anterior neck muscles and a prop to keep the airway open.