University:
Kentucky State University
Course:
BIO 301 | Human Anatomy
Academic year:

2020
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224

Pages:

76
Author:

crawniadxfo

Skull-2 Norma Basalis Interna Norma Basalis Externa Norma basalis interna Base of the skull- superior view The interior of the base of the skull is divided into three cranial fossae Anterior cranial fossa Middle cranial fossa Posterior cranial fossa Frontal lobe Parietal lobe Temporal lobe Occipital lobe Cerebellum Anterior cranial fossa Contains frontal lobes Middle cranial fossa Contains temporal lobes Posterior cranial fossa Contains the brain stem (midbrain, pons and medulla oblongata) and cerebellum The numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back Inferior surface of brain Foramina of skull and cranial nerves passing through Anterior cranial fossa Formed by: 1- Frontal bone 2- Ethmoid bone in the midline 3-Two parts of the sphenoid bone, the body (midline) and the lesser wings (laterally) Orbital plates of the frontal bone are thin plates of frontal bone, form the roof of the orbit Frontal crest is a small crest projects from frontal bone Crista galli is a sharp upward projection of the ethmoid bone in the midline Cribriform plate of the ethmoid is a sieve-like structure lateral to crista galli Note the anterior cranial fossa is above the nasal cavity and the orbits Orbital plates of frontal bone Frontal crest Crista galli of ethmoid Latin: Crest of the rooster Cribriform plate of ethmoid The small perforations in the cribriform plate are for the olfactory nerves. Foramen caecum Lesser wing of sphenoid Anterior clinoid process The medial end of the lesser wing of the sphenoid forms the anterior clinoid process Note: Medial to Anterior clinoid process: Optic canal Lateral to Anterior clinoid process: Superior orbital fissure Middle cranial fossa Formed by: - Body of sphenoid - Greater wing of the sphenoid - Squamous and petrous parts of the temporal bone Greater wing of the sphenoid Body of sphenoid Squamous and petrous parts of the temporal bone Squamous part Petrous part Resembles a bat having a centrally placed body with greater and lesser wings that are outstretched on each side The superior orbital fissure is a slitlike opening between the lesser and greater wings of the sphenoid The body of the sphenoid: contains the sphenoid air sinuses Sphenoid bone Sphenoid bone Anterior view Body of Sphenoid bone Greater wing of Sphenoid bone Lesser wing of Sphenoid bone Pterygoid plates Foramen rotundum: situated behind the medial end of the superior orbital fissure. Transmits the maxillary nerve Foramen ovale: lies posterolateral to the foramen rotundum transmits the mandibular nerve Foramen spinosum (small) lies posterolateral to the foramen ovale. Transmits the middle meningeal artery Carotid canal: Transmits the internal carotid artery Foramen lacerum lies between the apex of the petrous part of the temporal bone and the sphenoid bone. In life is filled by cartilage and fibrous tissue, and only small blood vessels pass through this tissue Meckl’s cave: impression on the apex of the petrous part of the temporal bone for the trigeminal ganglion Foramen rotundum Foramen ovale Foramen spinosum Ophthalmic nerve Maxillary nerve Mandibular nerve Trigeminal ganglion Foramen lacerum Meckl’s cave (Trigeminal impression) Carotid canal The median part of the middle cranial fossa is formed by the body of the sphenoid Sulcus chiasmaticus (chiasmatic groove) is related to the optic chiasma and leads laterally to the Optic canal On the superior aspect of the body is a depression called the Sella turcica which contains the pituitary gland (hypophyseal fossa) Posterior to the hypophyseal fossa is the Dorsum sellae The superior angles of the dorsum sellae have two tubercles called the Posterior clinoid processes In front of the hypophyseal fossa is the Tuberculum sellae PITUITARY GLAND Turkish saddle Tuberculum sellae Dorsum sellae The sella turcica (hypophyseal fossa) which CONTAINS THE PITUITARY GLAND Optic canals Sulcus chiasmaticus (chiasmatic groove) Is the groove between the optic canals Optic canal transmits the optic nerve and the ophthalmic artery Ophthalmic artery is a branch from internal carotid artery Posterior cranial fossa Formed mostly by parts of temporal and occipital bones The foramen magnum transmits 1- Medulla oblongata and its surrounding meninges 2- Spinal roots of the accessory nerves 3- Two vertebral arteries. . The hypoglossal canal is situated above the anterolateral boundary of the foramen magnum and transmits the hypoglossal nerve The jugular foramen lies between the petrous part of the temporal bone and the occipital bone. It transmits the following structures Anterior part: the inferior petrosal sinus Middle part: the 9th, 10th, and 11th cranial nerves Posterior part: the large sigmoid sinus. The sigmoid sinus turns down through the foramen to become the internal jugular vein. The internal acoustic meatus (on the posterior surface of the petrous part of the temporal bone): transmits the vestibulocochlear nerve and the facial nerve. The internal occipital crest runs upward in the midline posteriorly from the foramen magnum to the internal occipital protuberance Occipital bone Clivus is the sloping midline surface of the occipital bone anterior to the foramen magnum Internal acoustic meatus Transmits the vestibulocochlear nerve and the facial nerve. Cerebellar fossa Ethmoid bone Delicate bone located between the two orbits Ethmoid bone Cribriform plate Orbital plate Perpendicular plate Crista galli Norma Basalis Externa Maxilla Palatine process of maxilla Palatine bone (horizontal plate) Incisive foramen Greater palatine foramen Lesser palatine foramen The vomer Sphenoid bone (greater wing and pterygoid plates) Lateral pterygoid plates of sphenoid Medial pterygoid plates of sphenoid Humulus of Medial pterygoid plate of sphenoid Inferior orbital fissure It is formed between the greater wing of sphenoid bone and maxilla Zygomatic arch Temporal bone Foramen lacerum Opening of the carotid canal Jugular foramen Is located behind the carotid canal Foramen ovale Foramen spinosum Choanae (posterior nasal aperture) The mandibular fossa of the temporal bone and the articular tubercle form the upper articular surfaces for the temporomandibular joint. External auditory meatus Anterior nasal aperture Articular tubercle Mandibular fossa Occipital bone Foramen magnum Chondyles of occipital bone (articulate with C1 vertebra) Atlas (1st cervical vertebra) Foramen magnum Parts of occipital bone: 1: Basilar part (in front the foramen magnum) 2: Occipital chondyles (sides of foramen magnum) 3: Squamous part (behind the foramen magnum) 1 2 2 3 External occipital crest External occipital protuberance Jugular foramen Styloid process of the temporal bone Mastoid process Mastoid notch The stylomastoid foramen In the interval between the styloid and mastoid processes Transmits the facial nerve Infra temporal fossa Anterior wall: back of the maxilla Medial wall: lateral pterygoid plate Roof: infratemporal surface of the greater wing of sphenoid bone Lateral wall: ramus of mandible Communications Temporal fossa: through the gap deep to the zygomatic arch Orbit: through the inferior orbital fissure Pterygo-palatine fossa: through the pterygo-maxillary fissure Infra-temporal fossa Pterygopalatine fossa is a small space below the apex of orbit Pterygomaxillary fissure is a vertical fissure between the pterygoid plate and back of the maxilla. It leads medially into the pterygopalatine fossa The Superior orbital fissure is a fissure between the greater and lesser wings of the sphenoid bone and the maxilla. It leads forward into the orbit The Inferior orbital fissure is a fissure between the greater wing of the sphenoid bone and the maxilla. It leads forward into the orbit Norma basalis externa Base of the skull- inferior view The hard palate which is made of: A-The palatal processes of the maxillae B-The horizontal plates of the palatine bones The choanae (posterior nasal apertures) The vomer Medial and lateral pterygoid plates of the sphenoid bone Occipital chondyles External occipital crest External occipital protuberance Superior nuchal line Incisive foramen Greater palatine foramen Lesser palatine foramen Foramen ovale Foramen spinosum Opening for carotid canal Stylomastoid foramen Hypoglossal canal Jugular foramen Foramen lacerum

Skull-2

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