Skull Bones PDF

Sutures: Only movable joint— temporomandibular joint Coronal suture: frontal and parietal bones Sagittal suture: parietal bones Lambdoidal suture: occipital and parietal bones Squamosal suture: temporal and parietal bones Temporozygomatic suture: zygomatic and temporal bones...

Sutures: Only movable joint— temporomandibular joint Coronal suture: frontal and parietal bones Sagittal suture: parietal bones Lambdoidal suture: occipital and parietal bones Squamosal suture: temporal and parietal bones Temporozygomatic suture: zygomatic and temporal bones Medial palatine suture: Palatine bones Transverse palatine suture: Maxillae and palatine bones Bones of the cranium Parietal bones ○ Form the roof and sides of the cranium ○ Articulate midline each other at the Sagittal suture Posteriorly- occipital bone at the lamboid suture Anteriorly- frontal bone at the coronal suture Inferiorly- temporal bone and the greater wing of the sphenoid bone Occipital bones ○ Forms the posterior floor of the cranial cavity ○ Inion ○ The large foramen magnum is found inferior to the occipital bone ○ Inner surface forms the posterior cranial fossa ○ Articulates with: Temporal bones Parietal bones Sphenoid bone Temporal bones ○ Two portions: Squamous portion Forms the side of the cranium Articulates with the parietal bone and the sphenoid bone Anterior projection: zygomatic process Petrous portion Houses the middle and inner ear structures Articulates with the occipital bone Inferiorly projects mastoid process and styloid process Sphenoid bone ○ Articulates with The occipital and temporal bones The maxillary and palatine bone The parietal bones The ethmoid and frontal bones ○ Form the lateral walls of the orbits  ○ Sella turcica— houses the pituitary gland ○ Two wings: lesser wing and greater wing (one body) ○ A gap between the lesser wing and the sphenoid body forms the optic foramen (canal) ○ Pterygoid process— medial and lateral pterygoid plates Foramina of the occipital bone Foramen magnum ○ Spinal cord ○ Vertebral arteries ○ CN XI (accessory nerve) Hypoglossal canal ○ CN XII (hypoglossal nerve) Jugular foramen (occipital and temporal bones) ○ Internal jugular vein ○ CN IX, X, XI (glossopharyngeal, vagal, accessory nerves) Foramen lacerum (sphenoid, occipital and temporal bones) ○ Covered by a cartilage plate Foramina of the temporal bone Carotid canal ○ Internal carotid artery External acoustic meatus ○ Opening to tympanic (auditory) cavity Internal acoustic meatus ○ VII and VIII CN (facial, vestibulocochlear nerves) Petrotympanic fissure ○ Chord tympanic nerve Stylomastoid foramen ○ CN VII Foramen lacerum (sphenoid, occipital and temporal bones) ○ Cartilage Processes of the temporal bone Mastoid process ○ Composed of mastoid air cells ○ Secretion can accumulate here (mastoiditis) Recurrent ear infections Styloid process ○ Serves as attachment for muscles and ligaments Zygomatic process ○ Portion of zygomatic arch  Postglenoid process ○ Posterior to temporomandibular joint Foramina of the sphenoid bone Foramen rotundum ○ Maxillary nerve passes Foramen ovale ○ Mandibular nerve passes Foramen spinosum ○ Middle meningeal artery passes Optic canal/foramen ○ Optic nerve (CN II) and ophthalmic artery Inferior orbital fissure ○ Infraorbital and zygomatic nerves, infraorbital artery and ophthalmic vein Bones of the face Ethmoid bone ○ Cribriform plate with foramina Passage of the olfactory nerves ○ Articulates with the Sphenoid and frontal bones The vomer The maxillary and lacrimal bones Frontal bone ○ Forms the forehead ○ Articulates with: nasal bones, maxillae, zygomatic ○ Zygomatic process or notch Nasal bones ○ Form the bridge of the nose ○ Articulate with each other, with the frontal and maxillary bones ○ Vomer forms the posterior part of the nasal septum ○ Inferior conchae ○ Separated bones located along the lateral walls of the nasal cavity Lacrimal bone ○ One in each orbit ○ Smallest bone of the face*** ○ Articulates with: the maxillary bone, ethmoid bone, frontal bone Palatine bones ○ Two L-shaped bones ○ Extend from the hard palate at the back of the mouth to the orbit ○ A small flattened area at the top of the vertical stem is located in the orbital floor  Zygomatic bones ○ Form the lateral part of the cheekbones ○ Articulate with the zygomatic process of the temporal bones to form the zygomatic arches ○ Articulate with the maxillary bones and w/ the greater wings (sphenoid bone) Mandible ○ Forms the movable lower jaw ○ Horseshoe-shaped bone ○ Mandible foramina Mandibular foramen inferior alveolar nerve and vessels Mental foramen mental nerve and vessels Maxillary bones ○ Form the upper jaw, the hard palate, the lateral walls of the nasal cavity and the floor of both orbits ○ Each one articulates with: frontal, nasal, lacrimal, ethmoid, sphenoid, palatine, and zygomatic bones Bones of the skull Frontal bone ○ Forms the anterior portion of the cranium, anterior floor of the cranial cavity and superior part of the face ○ Articulates: superiorly with parietal bone, sphenoid bone, ethmoid bone and lacrimal bones Inferiorly with the nasal, maxillary and zygomatic bones ○ Forms the anterior cranial fossa where the frontal lobes of the cerebral hemispheres lie Foramina of the palatine bone Greater palatine foramen ○ greater palatine nerve and vessels Lesser palatine foramen ○ lesser palatine nerve and vessels Foramina of the maxillary bone Incisive foramen ○ Nasopalatine nerve and branches of the sphenopalatine artery Infraorbital foramen and canal  ○ Infraorbital nerve and vessels Inferior orbital fissure ○ Infraorbital & zygomatic nerves ○ Infraorbital artery ○ Ophthalmic vein Alveolar process ○ Contains roots of maxillary teeth Frontal process ○ Forms medial infraorbital rim Palatine process ○ Forms anterior hard plate Zygomatic process ○ Forms lateral portion of infraorbital rim Cranium fossae 3 cranium fossae: anterior, middle, posterior Fossae of the skull 3 deeper depressions are present on the external surface of the skull 3 fossae Important landmarks of the skull for locating muscles, blood vessels and nerves Temporal fossa ○ Formed by portions of 5 bones: Zygomatic  Frontal Greater wing of the sphenoid Temporal Parietal ○ Contains the body of the temporalis muscle and blood vessels and nerves of the area Infratemporal fossa ○ Paired depression ○ Temporal fossa and infratemporal fossa are divided by the infratemporal crest of the greater wing of the sphenoid bone ○ Contains the Mandibular division of the CN V (trigeminal nerve)— enter the foramen ovale Pterygoid plexus / pterygoid muscles Maxillary artery (second portion) and branches Middle meningeal artery Inferior alveolar artery Posterior superior alveolar artery Pterygopalatine fossa ○ Cone-shaped paired depression ○ Located between the pterygoid process of the sphenoid bone and the maxillary tuberosity (close to the orbit apex) ○ Contains: Maxillary artery (third portion) and branches Infraorbital and sphenopalatine arteries Pterygopalatine ganglion and maxillary nerve Bones of the orbit 4 sided pyramid ○ The base is the anterior orbital margin ○ The apex at the posterior margin within the skull Orbital walls: roof, floor, medial, lateral ○ Roof Triangular Composed of the frontal bone and lesser wing of the sphenoid The optic canal lies between the sphenoid lesser wing and the body Optic foramen located at the apex of the orbit ○ Medial Rectangular From front to back is formed by the maxillary bone, lacrimal bone, ethmoid bone, and the body of the sphenoid ○ Floor (easiest to fracture because of sinus**) Triangular Composed of maxillary, zygomatic, palatine bone  Inferior orbital fissure separates the floor from the lateral wall ○ Lateral Triangular Composed of the zygomatic bone and the greater wing of the sphenoid bone ○ 7 Bones: Frontal, maxillary, zygomatic, sphenoid, ethmoid, palatine, lacrimal Orbital foramina and fissures Optic foramen or optic canal ○ Provides communication between the orbital cavity and the middle cranial fossa ○ Optic nerve exits ○ The ophthalmic artery enters Superior orbital fissure ○ Gap between the lesser wing and the greater wing of the sphenoid bone ○ Also a communication between the orbital cavity and the middle cranial fossa Superior orbital fissure ○ Annulus of Zinn or Common Tendinous Ring Above the circular tendon, pass: lacrimal nerve, frontal nerve, trochlear nerve, and superior ophthalmic nerve Through the superior orbital fissure: superior and inferior divisions of the oculomotor nerve, nasociliary nerve, abducens nerve  Through the optic canal and the tendinous ring, pass: optic nerve, ophthalmic artery ○ Inferior orbital fissure Allows passage of vessels and nerves between the orbit and the pterygopalatine and temporal fossae The inferior ophthalmic vein exits the orbit through the inferior orbital fissure below the ring tendon Paranasal sinuses: cavities lined w/ mucosa and air-filled Function: resonance of the voice, decrease the weight of the skull Communicate with the nasal cavity Orbit is surrounded on 3 sides by sinuses ○ Above- frontal sinus ○ Medial- ethmoid and sphenoid sinus ○ Below- maxillary sinus Bones of the neck Cervical vertebrae ○ Located between the skull and the thoracic vertebra ○ 7 cervical vertebrae, all w/ a central vertebral foramen for the spinal cord ○ Transverse foramen in the transverse process on each side of the vertebral foramen ○ The vertebral artery runs through these transverse foramina ○ Damage of the vertebrae can affect difficult in movement to paralysis Vertebral arteries  ○ First cervical vertebra ○ Atlas ○ Articulates w/ the occipital bone condyles ○ Irregular ring form Second cervical vertebra ○ Axis ○ Characterized by the odontoid process that articulates anteriorly w/ the anterior arch of the Atlas Hyoid bone ○ Suspended on the neck ○ Base of the tongue and larynx ○ Many muscles attach to the hyoid bone ○ Do not articulate w/ any of the bones ○ Mobility necessary for mastication, swallowing, and speech ○ Can be palpated (is not the “Adam’s apple” — thyroid cartilage)