Head and Neck Osteology and Arthrology PDF

Head and Neck Osteology and Arthrology Head Osteology ➔ Definitions ◆ Cranium: the skeleton of the head ◆ Neurocranium: the bony case of the brain, including cranial meninges Singular bones → frontal, ethmoid, sphenoidal, and occipital...

Head and Neck Osteology and Arthrology Head Osteology ➔ Definitions ◆ Cranium: the skeleton of the head ◆ Neurocranium: the bony case of the brain, including cranial meninges Singular bones → frontal, ethmoid, sphenoidal, and occipital Paired bones → temporal and parietal Calvaria → dome-like roof of the neurocranium (skullcap) Cranial base → floor of the neurocranium ◆ Viscerocranium: anterior part of the cranium Singular bones → mandible, ethmoud, and vomer Paired bones → maxillae, inferior nasal conchae, zygomatic, palatine, nasal, and lacrimal ◆ Fontanel: unossified area in the infant cranium ◆ Suture: fibrous joint between cranial bones tallow brainto grow ◆ Air sinuses Pneumatized bones: contain air spaces that increase with age zygoma d g Pof ant I  ➔ Frontal view of cranium looking straighton someones face ◆ Frontal bone: the skeleton of forehead and superior margin of the roof of the orbit forehead Glabella → smooth, slightly depressed area between the superciliary arches between eyebrows n Superciliary arches → Ridge extending on each side of the glabella; typically greater in males where eyebrows sit Supraorbital margin → angular boundary between squamous (flat) and orbital parts frontal Supraorbital foramen → located in the supraorbital margin IV A ◆ Zygomatic bones: form prominence of N comes here cheeks, lie inferolateral to orbits, and rest on maxillae cheekbones Zygomaticofacial foramen → on facial zygomatic side O Zygomaticotemporal foramen → on temporal side ◆ Orbit: quadrangular pyramid, with base inward anteriorly, apex posteriorly, and 4 walls Lacrimal bone → contributes to the pyramid medial wall; contains fossa for lacrimal sac Orbital plate of ethmoid bone (lamina papyracea) → posterior to the lacrimal bone, very thin bone; contributes to the medial wall Frontal bone → contributes to the superior wall (roof) Sphenoid bone → greater wing contributes to the lateral wall, while the lesser wing contributes to the superior wall near the apex ○ Optic canal: through the lesser wing Orbital process of butterfly shaped palatine bone → contribute slightly to the apex Zygomatic bone → É contributes significantly to the lateral wall Maxilla → contribute significantly to the inferior wall I Superior orbital fissure → located  between the greater and lesser wings of the sphenoid Inferior orbital fissure → between maxilla, zygomatic, and greater wing of the sphenoid Infraorbital groove → depression on the orbital surface of the maxilla ◆ Nasal cavity Nasal bones → lies over the ridge of the nose and make up the base of the nose Piriform aperture → pear-shaped anterior opening of the nose in the cranium Nasal septum: ○ Perpendicular plate of ethmoid ○ Vomer Nasal conchae → curvy bony plates on the lateral wall of each nasal cavity Parts ○ Inferior: an individual bone ○ Middle and superior: part of the ethmoid bone ◆ Maxillae: form the upper jaw and is the supporting bone for maxillary teeth Alveolar processes → tooth sockets (alveoli) Infraorbital foramen → inferior to each orbit Zygomatic process → articulates with the zygomatic bone Maxillary tuberosity → posterior on the maxilla, behind the last tooth ○ Most prominent after growth of wisdom tooth where theydrop 0 lower Jaw ◆ Mandible: U-shaped that supports the mandibular teeth Body → horizontal part Ramus → vertical part not present in babies at birth ○ Angle → union of body & ramus Mental protuberance → forms the prominence of the chin Mental foramen → on the outside of the body mental nerve Coronoid process → anterior to condylar process Mandibular notch → between coronoid & condylar processes here Condylar process → inserts into the mandibular fossa of the temporal bone to form the TMJ Alveolar processes of mandible → house the lower teeth sockets Interalveolar septa → bony partitions separating tooth sockets Mental spine → site of attachment for muscles Mandibular foramen → next to and guarded by the lingula Lingula → spinous process protecting the mandibular foramen and the nerve  ➔ Lateral view of the cranium ◆ Bones LATERAL VIEW Parietal: superior & lateral part of the neurocranium Temporal: lies inferior to parietal bones on both sides ○ Squamous part → anterior and upper part, contributes to the allows sound to travel temporal fossa ○ Zygomatic process → forms part of the zygomatic arch ○ External auditory meatus → external ear opening in infants ○ Mastoid process → posteroinferior to external acoustic meatus L opening underdeveloped at ○ Styloid process → anteromedial to the mastoid process ○ Articular tubercle → front boundary of mandibular fossa birth Zygomatic arch: formed by the zygomatic process (temporal bone) and temporal process (zygomatic bone) Greater wing of sphenoid bone: anterior to the temporal bone and inferior to frontal Pterion: weak area of bone junctions Temporal fossa: muscle-filled space prone to injury middle meningitis  q styloid process ◆ Infratemporal fossa Medial to the ramus of the mandible and the zygomatic arch Sphenoid bone ○ Infratemporal crest ○ Lateral pterygoid plate Pterygomaxillary fissure: connects infratemporal fossa and pterygopalatine fossa Pterygopalatine fossa: pyramidal space, medial to pterygomaxillary fissure Sphenopalatine foramen: opening on medial wall of O pterygopalatine fossa, leading to nasal cavity Inferior orbital fissure: communicates the infratemporal fossa with the orbit  ➔ Superior view of the cranium SUPERIOR VIEW ◆ Bones and joints (sutures) Coronal suture: separates frontal and parietal bones crown Sagittal suture: sprataes parietal bones RUS L Lambdoid suture: separates parietal and temporal bones from occipital bone backside Al think lambda sign ➔ Occipital view of rhe cranium ◆ Bones Occipital bone ○ External occipital protuberance → muscle and ligament attachment ○ External occipital crest → extends medially from external occipital 49the's protuberance to foramen Atlas ki 1h9de Il 0 magnum ○ Superior nuchal line → extends laterally from external occipital protuberance ◆ Marks the ATQ What is the point superior limit of neck posteriorly of a spinal tap when you suspectmeningitis where brain a spinal cord attach directly  ○ Inferior nuchal line → anterior to superior nuchal line and posterior to posterior rim of foramen magnum ➔ External surface of cranial base (inferior portion of cranium) ◆ Occipital bone: most posterior bone Foramen magnum (FM) → transition point between brain and spinal cord Occipital condyles → protuberances on each side of FM ○ Articulates cranium with vertebral column involved in the Condylar fossa → depression posterior to FM and containing the condylar sitting of d canal Condylar canal → contained in the condylar fossa Hypoglossal canal → anterior to occipital condyles for hypoglossal n Basilar part of occipital bone → extends forward from the FM Pharyngeal tubercle → eminence on basilar part ○ Attachment for pharyngeal wall Foramen lacerum → exist only in the diseased, dry cranium ○ Between occipital, temporal, and sphenoid bone aminimalwhenpt.is alived hydrated dehydration of Skull seenafterdeath g ◆ Temporal bone: anterolateral to occipital and posterolateral to sphenoid  TEMPORAL BONE Stylomastoid foramen → posterolateral to styloid process and anteromedially to mastoid process Carotid canal → medial to the styloid process Jugular foramen → posterior to carotid canal Mandibular fossa → anterior to external acoustic meatus opening ○ Accommodates mandibular condyles Petrotympanic fissure → anterior to external acoustic meatus opening Articular tubercle → front boundary of mandibular fossa enga e btwn Styloid a mastoid process ◆ Sphenoid bone: anterior to temporal and occipital bones, and posterolateral to maxilla Greater wings → extend laterally from body of sphenoid Medial pterygoid plate → extend inferiorly from the junction of body and wings, medial to lateral pterygoid plate Lateral pterygoid plate → extend inferiorly from the junction of body and wings, lateral to medial pterygoid plate ○ Contribute to infratemporal fossa hamulus hooked Pterygoid hamulus → small hook-shape coming off the medial pterygoid on hummus plate that serves as muscle attachment Foramen ovale → posterolateral to lateral pterygoid plate  ○ Opens into the infratemporal fossa Foramen spinosum → posterior and slightly lateral to foramen ovale Spine → posterior to foramen spinosum, it guards it ovalshaped 08000 ◆ Vomer, palatine, and maxilla connects nose to maxilla Vomer → contributes to nasal septum. Posterior to palatine bone Choanae → posterior opening of nasal cavity Palatine bone → anterior to vomer and posterior to maxilla root of mouth ○ Greater palatine foramen: posterolateral to palatine bone ○ Lesser palatine foramina: posterior to greater palatine foramen Maxilla ○ Palatine process ○ Incisive fossa: posterior to incisive teeth front teeth o D  if the back of the head is too flat the cerebrum part wont develop Ineedsto be right shape size ➔ Internal surface of cranial base (inferior portion of cranium) ◆ Divided into anterior, middle, and posterior cranial fossae that form the floor of the cranial cavity seen it you ◆ Anterior cranial fossa (formed by the frontal (anterior), ethmoid (middle), and open the skull sphenoid (posterior) frontal ethmoid a sphenoid bones Frontal bone (orbital part) remove brain ○ Frontal crest: median bony extension ○ Foramen cecum: at the base of the frontal crest where brain sits Ethmoid sits right on the nose ○ Crista galli: thick, median ridge posterior to foramen cecum ○ Cribriform plate: sieve-like structure on each side of crista galli ooking d ethmoid frontal sphenoid lesser ◆ Middle cranial fossa Sphenoid sphenoid bone only ○ Body ○ Greater wings ○ Lesser wings ○ Optic canal → located through the lesser wing ○ Sphenoidal crest → formed by the lesser wings overhanging the middle fossa anteriorly and ends medially in the anterior clinoid processes ○ Anterior clinoid process → guards hypophyseal fossa anteriorly ○ Sella turcica (Turkish saddle) ◆ Tuberculum sellae → elevation of bone, forming anterior r boundary of hypophyseal fossa hollow part mm of Skull HOUSES Pituitary gland  108M ◆ Hypophyseal fossa (pituitary fossa): median depression between the tuberculum and dorsum sellae Houses the pituitary gland suturrent ◆ Dorsum sellae: elevation of bone, forming posterior Posterior boundary of hypophyseal fossa, and ends laterally in the posterior clinoid processes ○ Posterior clinoid process → guards hypophysial fossa posteriorly * ○ Superior orbital fissure → between the greater and lesser wings of the sphenoid, and goes into the orbit ○ Foramen rotundum → posterior to medial end of superior orbital fissure ○ Foramen ovale → posterolateral to foramen rotundum ○ Foramen spinosum → posterolateral to foramen ovale ○ Foramen lacerum → posterolateral to dorsum sellae 1 0 occipital a temporal bones cerebellum o ◆ Posterior cranial fossa (lodges cerebellum, pons, and medulla) brainstem Temporal involved in nearing ○ Petrous part of the temporal bone → divides the MCF from PCF, and looks like a mountain range ○ Internal auditory meatus → on medial side the PCF ○ Jugular foramen → posteroinferior to internal auditory meatus Occipital ○ Clivus → extends posteriorly from dorsum sellae to FM  ○ Basilar part → extends anteriorly from FM until the posterior end of sphenoid bone ○ Hypoglossal canal → on lateral wall of FM ○ FM ○ Internal occipital protuberance → in the posterior part of occipital bone, related to the confluence of sinuses ○ Internal occipital crest → extends anteriorly from internal occipital protuberance O internal auditorymeatus Po jugular foramen ➔ Development of cranium ◆ Unerupted teeth no teeth ◆ Small face area compared to cranial cavity — face ~ ⅛ the size of cranial portion; ~ ⅓ in adults ◆ Mandible: no ramus at birth ◆ Mastoid and styloid processes: underdeveloped ◆ Frontal bone halves are separated ◆ Fontanels or soft spots → the last area where the bones are lay in the cranium Anterior fontanel: between frontal and parietal bones Posterior fontanel: between parietal and occipital bones Mastoid fontanel: where temporal, parietal, and occipital bones converge Sphenoid fontanel: where sphenoid, frontal, parietal, and temporal bones converge I goes w pterion in adults weak area prone to damage meeting area for bones TQ special spot in the brain where majority of bones intersect sphenoid fontanel Pterion in adults ○ Pterion in adults → one of the last areas in the skull to develop adow'M poppin pod in  NECK OSTEO Neck Osteology ➔ Bones of neck ◆ Cervical vertebrae ◆ Hyoid bone CI 07 floating bond ◆ General characteristics of vertebrae Body → cylindrical, anterior part that supports body weight Vertebral arch → posterior to vertebral body ○ Pedicles (2): short, cylindrical projecting posteriorly from body ○ Laminae (2): flat plates continuous with pedicles that join posteriorly in the midline skipped this Vertebral foramen → formed by vertebral arch and posterior surface of vertebral body but said its ○ The succession of vertebral foramina forms the vertebral canal Vertebral notches (2) → superior and inferior to each pedicle fair game for ○ Superior and inferior notches of adjacent vertebrae form the intervertebral foramina (exit for spinal nerves and accompanying quiz exam vessels) Processes (7) ○ Spinous process: median and posterior ○ Transverse processes (2): project posterolaterally from the junction of pedicles and laminae ○ Articular processes (4): 2 superior & 2 inferior, project from the junction of pedicles and laminae v ◆ Each bears an articular surface (or facet) 7 cervical vertebrae ○ C1 = Atlas, C2 = Axis, C3-7 ○ Located between crnauum and thoracic vertebrae ○ Smallest of the moveable vertebrae (bear less weight) ○ Greatest range and variety of movement of all vertebral regions ◆ Relative thickness of discs compared to the vertebral bodies ◆ Nearly hortizontal orientation of facets ◆ Small amount of surrounding body mass ➔ C1 = Atlas (atypical vertebra) ◆ Carries the cranium ◆ No body ◆ Anterior arch ◆ Anterior tubercle ◆ Articular facet for dens: on posterior surface of the anterior arch ◆ Lateral masses: bear the weight of cranium ◆ Transverse process: project laterally, and are relatively flat ◆ Transverse foramen: passage for vertebral arteries and accompanying veins v  ◆ Superior articular facet: articulates with occipital condyle ◆ Inferior articular facet: articulates with axis (C2) ◆ Tubercle for transverse ligament of Atlas: the ligament helps to hold the dens of C2 in place ◆ Posterior arch ◆ Posterior tubercle ◆ Groove for vertebral artery: allows passage for vertebral artery into cranium ➔ C2 = Axis (atypical vertebra) ◆ Strongest of cervical vertebrae ◆ Atlas (C1) carries the cranium and rotates on the Axis (C2) ◆ Body ◆ Dens: projects superiorly from the body, and articulates with the posterior surface of the anterior arch of the Atlas, forming a synovial joint Embryologically, the dens represent the remnant of the body of the Atlas ◆ Anterior articular facet: articulates with posterior surface of anterior arch of Atlas (C1) ◆ Posterior articular facet: where the dens is supported by transverse ligament of atlas ◆ Pedicles ◆ Lateral masses ◆ Superior articular facet: where the atlas (C1) rotates ◆ Inferior articular facet: articulates with C3 ◆ Transverse process: extends lateroinferior ◆ Transverse foramen: passage for vertebral arteries and accompanying veins ◆ Laminae ◆ Spinous process: bifurcated in whites, but not as common in blacks or females ➔ C3-C7 (typical vertebrae) ◆ Body ◆ Transverse process ◆ Transverse foramina: vertebral artery goes through C3 – C6, but no C7 ◆ Anterior tubercle: muscle attachment ◆ Posterior tubercle: muscle attachment ◆ Pedicles ◆ Lamina ◆ Superior articulate facet: more transverse plane to allow more articulation, gliding movement ◆ Inferior articulate facet: more transverse plane to allow more articulation, gliding movement ◆ Vertebral foramen: triangular and large, contains large portion of spinal cord ◆ Uncus of body: raised lateral margins of the superior surface of cervical vertebrae C3 – C7  ◆ Spinous process: bifurcated in whites, but not as common in blacks or females. C7 (vertebra prominens) Defines the inferior limit of the neck posteriorly* ○ Where is the superior limit of the neck posteriorly? The hard Bouperior ➔ Hyoid bone ooo palate** nuchal line ◆ Located anteriorly in the neck, at the level of C3 Suspended by muscles that connect it to the mandible, styloid process, thyroid cartilage, manubrium, and scapula ◆ U-shaped Body Lesser horn Greater horn ◆ Stylohyoid ligament: it is a fibrous cord, which is attached to the top of the styloid process of the temporal bone and the lesser cornu (lesser horn) of the hyoid bone oneach lesserhorn  Patient will present w pain ➔ Eagle syndrome ◆ Radiographic features when speaking headaches limited ROM noidental Eagle syndome: elongation of the styploid process of mineralization of the stylohyoid ligament comploex can be seen on panoramic or finding on ltaeral-jaw radiographs can be corrected w surgery x ray ➔ Joints of vertebral bodies ◆ IV discs: cartilaginous joints, connecting articulating surfaces of adjacent vertebral bodies ◆ Ligaments (support) Anterior longitudinal ligament (ALL): strong, broad fibrous band covering and connecting the anterolateral aspects of vertebral bodies and IV disks previously ○ Extends from anterior aspect of FM to pelvic surface of sacrum ○ Limits extension (only ligament that limits extension) reviewed Posterior longitudinal ligament: weaker, narrower band than ALL ○ Runs within vertebral canal along posterior aspect of vertebral bodies ○ Extends from body of C2 to sacrum ○ Limits flexion ➔ Joints of vertebral arches ◆ Zygapophysial joints: synovial joint between superior and inferior articular facets of adjacent vertebrae. Allows gliding movements. v ◆ Ligaments (accessory ligaments supporting the vertebral arches) Ligamenta flava: broad, pale yellow band of elastic tissue joining the laminae of adjacent vertebrae ○ Form posterior wall of vertebral canal. Limit flexion and separation of vertebral laminae, protecting IV disks Interspinous ligaments: weak ligaments joining adjacent spinous processes ○ Inconsequential in the cervical region Nuchal ligament: strong, broad, and thickened fibroelastic tissue ○ Extends from occipital protuberance and posterior border of FM to spinous processes of cervical vertebrae ○ Muscle attachment ➔ Craniovertebrael joints ◆ Atlanto-occipital joint: synovial joint, with thin, loose capsule between superior articular facets of the Atlas and the condyles of the occipital bone Flexion & extension (e.x. nodding) Anatomical equivalent of zygapophysial joint ◆ Ligaments Anterior atlanto-occipital membrane: extends from anterior arches of Atlas to anterior margin of FM v  ○ Merges with anterior longitudinal ligament in the center Posterior atlanto-occipital membrane: extends from posterior arches of Atlas to posterior margin of FM ○ Perforated to allow passage for the vertebral artery These two membranes are strong sheets of connective tissue that extend laterally towards the atlanto-occipital joint, and help prevent excessive movement of atlanto-occipital joint ◆ Atlanto-axial joints Lateral atlanto-axial joints (2): synovial, gliding joint, with thin, loose capsule between inferior articular facets of the Atlas (C1) and the superior articular facets of the Axis (C2). Anatomical equivalent of zygapophysial joint Ligaments ○ Anterior atlanto-axial membrane: extends from anterior arches of Atlas to anterior arches of Axis. Merges with anterior longitudinal ligament in the center ○ Posterior atlanto-axial membrane: extends from posterior arches of Atlas to posterior arches of Axis. It’s a superior continuation of Ligamenta flava, but less elastic fibers Median atlanto-axial joint (1): pivot joint between dens of C2 and anterior arch of C1 Ligaments ○ Tectorial membrane: superior continuation of posterior longitudinal ligament, starting at the body of Axis (C2) until anterior aspect of FM ○ Cruciate ligament ◆ Transverse ligament of atlas: strong band extending between tubercles on lateral masses of C1 ◆ Superior and inferior longitudinal bands: from transverse ligament to occipital bone superiorly and to body of C2 inferiorly ◆ Alar ligaments: extend superolaterally from each side of dens to lateral margin of FM ○ Check ligaments, prevent excessive rotation of the joints ➔ Movements of cervical portion of vertebral column ◆ Rotation ◆ Lateral bending ◆ Flexion ◆ Extension ➔ Temporomandibular jont (TMJ) ◆ Hinge, type of synovial joint  Only moveable joint in the cranium ◆ Movements Modified to allow gliding and slight rotation (protrusion and retrusion) Flexion (elevation) Extension (depression) ◆ Components components Mandibular fossa of temporal bone MACA I Articular tubercle of temporal bone Condylar process of mandible 12from temp bone 1 Mand Articular disc of the TMJ: separates the fibrous capsule into superior and inferior articular cavities ◆ Ligaments ligaments 1.5.5 1404 sells shells Lateral: intrinsic, strengthen the joint laterally and prevent sposterior 1 intrinsic dislocation of TMJ ATQ ○ Attaches superiorly to articular tubercle and inferior surface of 02 extrinsic zygomatic arch and inferiorly to neck of mandible Sphenomandibular: extrinsic, attaches superiorly to spine of sphenoid ligaments bone and inferiorly to lingula of mandible Stylomandibular: extrinsic, attaches superiorly to styloid process of temporal bone and inferiorly to angle of mandible