Presentation on theme: "Bony Anatomy of the Skull"— Presentation transcript:
1Bony Anatomy of the Skull MyologyBony Anatomy of the Skull
2Bone Surface Markings Depressions and openings: Fissure: narrow opening between adjacent parts of bones for nerves and vesselsForamen: hole, openingFossa: shallow depressionSulcus: grooveMeatus: tubelike passagewayProcesses that form jointsCondyle: large rounded prominenceFacet: smooth flat surfaceHead: rounded articular projectionProcesses for tendon and ligament attachment:Crest: prominent border or ridgeEpicondyle: prominence above a condyleLinea: line, less prominent than a crestTrochanter: large projection of bone found only on the femurTubercle: small rounded processTuberosity: large, rounded, usually roughened process
3Osteology of the Skull: Cranium Gross AnatomyOsteology of the Skull: Cranium
7Frontal BoneThe large bone that makes up the forehead and supplies the upper edge and roof of the orbit (eye socket).The frontal bone articulates (comes together) with a number of other bones including the parietal, nasal, ethmoid, maxillary, and zygomatic bones.Landmarks:Squama: flat portion that forms the foreheadSupraorbital margin: ridge under the eyebrow, forming the upper part of the orbit (eye socket)Supraorbital foramen: small hole within supraorbital margin for blood vessels and nervesFrontal sinuses: hollow spaces behind the squama, act as sound chambers to give the voice resonance.
11Temporal BonesA large irregular bone situated at the base and side of the skull. The temporal bone is connected with the mandible (the jaw bone) via the temporomandibular (TM) joint.The temporal bone is formed of three parts (squamous, tympanic and petrous) that are distinct at birth but then fuse. The petrous portion of the temporal bone contains the structures of the inner ear.Landmarks:Squama: flat portion of the temporal bone forming the anterior and superior part of the templeZygomatic process: process forming part of the cheekPetrous portion: internal, forming part of the floor of the cranium. Contains the ear canal and internal ear structures.Mandibular fossa: socket between squama and petrous portion, articulates with the condyle of the mandible (TMJ)External auditory meatus: opening to the ear canalMastoid process: bony prominence behind the external auditory meatusStyloid process: looks like an elephant’s tusk located between the mastoid process and the jaw. Acts as a point of attachment for muscles and ligaments.
12Temporal Bone (Lateral View) (Purple Colored Bone)
13Parietal Bones The main bone on the side of the skull. The word "parietal" comes from the Latin "parietalis" meaning "belonging to the wall."It articulates (joins) with the other parietal bone in the midline (top of the head), with the frontal bone in front of it, with the occipital bone behind it, and with the sphenoid and temporal bones lower down on the side of the skull.
16OcciputFrom the Latin, meaning the part of the head opposite the front.The bone that forms the rear and the rear bottom of the skull.The occipital bone articulates (joins) with the parietal and temporal bones of the skull, the sphenoid bone in front of it, and the first cervical vertebra (the atlas) beneath itLandmarks:Foramen magnum: large hole, allowing passage of the spinal cordExternal occipital protuberance (EOP): prominent projection on back of occiputNuchal lines: a superior and inferior line running laterally from the midline, serve as a point of muscle attachment
17Occipital Bone (Posterior View) (Orange Colored Bone)
20Sphenoid BoneA prominent, irregular, wedge-shaped bone at the base of the skull. The sphenoid bone has been called the "keystone" of the cranial floor since it is in contact with all of the other cranial bones.The Greek physician Galan wrote that the sphenoid bone was "like a wedge thrust between the skull and the superior maxilla."LandmarksGreater wings: large lateral projections of bone that help to form the lateral border of the skullLesser wings: smaller lateral projections of bone above the greater wingsPterygoid processes: two long downward projections from the greater wings that act as a point of muscle attachment.Sella turcica: known as the Turkish Saddle which cradles the pituitary gland.
21Sphenoid Bone (Lateral View) (Green Colored Bone)
22Sphenoid Bone (Floor of Cranium) (Green Colored Bone)
23Ethmoid BoneAn irregularly shaped, spongy bone that provides the floor of the front part of the skull and the roof of the nasal cavity.The ethmoid consists of two masses of thin plates enclosing air cells and looks like a sieve.Landmarks:Lateral masses: form most of the wall between the nasal cavity and the orbitsPerpendicular plate: forms the superior portion of the nasal septumCribiform plate: forms the roof of the nasal cavityOlfactory foramina: small holes within the cribiform plate for passage of the first cranial nerve (for smell)Crista galli: upward extension of bone above the cribiform plate, acts as an anchoring point for one of the coverings of the brain.Nasal concha (turbinates): two scroll-shaped projections with a mucus membrane on either side of the nasal septum. Function to cause air turbulence and trap inhaled particles.
27MaxillaThe largest bones of the face, except for the mandible and form, by their union, the whole of the upper jaw.They hold the upper teeth, and connect on the left and right to the zygomatic bones (cheek bones).Each assists in forming the boundaries of three cavities, namely, the roof of the mouth, the floor and lateral wall of the nose, and the floor of the orbit.Landmarks:Infra Orbital foramen: hole below the orbit, for blood vessels and nervesAlveolar process: arch of the maxilla containing the upper teethPalatine process: horizontal projection of the maxilla forming the anterior ¾ of the hard palate.
29Zygomatic Bones Commonly referred to as the cheekbone. It is situated at the upperand lateral part of theface: it forms theprominence of the cheekand part of the lateral walland floor of the orbit.It articulates with thezygomatic arch of thetemporal bone.
38Vomer One of the unpaired facial bones of the skull. Located in the midsagittal line,and touches thesphenoid, theethmoid, the left andright palatine bones,and the left and rightmaxillary bones.
39Vomer (Anterior View) (Center wall in nasal cavity)
40Mandible Largest and strongest bone of the face. Forms the lower jaw andholds the lower teeth inplace.The mandible consists ofa curved, horizontalportion, the body, and twoperpendicular portions,the rami, which unite withthe ends of the body nearlyat right angles.
41Mandible Largest and strongest bone of the face. Forms the lower jaw and holds the lower teeth in place.Landmarks:Body: curved horizontal portion of the mandibleRami: two upward projections of bone that are perpendicular to the body of the mandible.Angle of the mandible: angle formed where the body meets the ramusCondylar process: a condyle on the posterior portion of the ramus that articulates with the mandibular fossa of the temporal bone.Coronoid process: a sharp projection of bone on the anterior portion of the ramus that acts as a point of muscle attachment.Alveolar process: arch of bone containing the lower teethMental foramen: small hole on the side of the body for blood vessels and nerves.
44Palpation of the Cranium Occiput: Prone; place hands on the back of the head between partner’s ears. Slide your fingers superiorly to the External Occipital Protuberance (EOP) two to three inches. Then slide fingers laterally to the mastoid process behind the ears.Superior Nuchal Lines: Prone or supine; locate the EOP and then slide your fingers laterally moving your fingerpads up and down feeling for the edge of the superior nuchal line.Parietal Bone: Prone or supine; place both hands on the top of the cranium. Palpate the sagittal suture between the parietals. From the suture, palpate the parietal bones down towards the earsTemporal Bone: Supine; locate the mastoid process by placing your fingers behind the ear lobe. The zygomatic arch can be palpated by placing your fingers anterior to the external auditory meatus. Palpate anteriorly along the arch with your finger and thumb. The flat squamous portion can be palpated superior to the mastoids and external auditory meatus. The styloid process can be palpated between the mandible and the mastoid process (palpate very gently)
45Frontal bone: Supine; palpate the region of the forehead from the eyebrows up toward the coronal suturesMandible: Supine: place your fingers inferior to the bottom teeth and palpate the body of the mandible. Move inferiorly and palpate the base of the mandible from the chin to the angle of the mandible. Then curl your fingertips underneath the edge to palpate the submandibular fossa. To palpate the angle of the mandible slide posterior alone the base of the mandible. The angle is located between the body and the ramus. To palpate the mandibular condyle place your finger anterior to the ear canal and below the zygomatic arch. Ask your partner to open his/her mouth fully, the condyle will protrude laterally and become more palpable.Nasal bones: Supine; locate the bridge of the noseZygomatic bone: Supine, return to the zygomatic arch of the temporal bone and continue to move anteriorly until you reach the zygomatic (cheek) bone.Maxilla: Supine; palpate inferior to the zygomatic bone down to the mouth. The maxilla forms the center of the face. The alveolar processes can also be palpated where the teeth insert into the maxilla.