Axial Skeleton Flashcards
5 components of the axial skeleton
Skull Hyoid Bone Auditory Ossicles Vertebral Column Thorax
How many bones in skull?
22- 8 cranial and 14 facial
Frontal Bone
Roof of orbits and anterior part of cranial floor
Frontal Squama
Forehead- Coronal suture to top of orbits
Supraorbital Margin
Thickening of frontal bone above orbits
Supraorbital foramen
On supraorbital margin, for supraorbital nerve and artery
Supraorbital Notch
Incomplete supraorbital foramen
Frontal sinuses
Hollow spaces on frontal squama
Parietal Bones
Sides and roof of cranial cavity
Saggital Suture
Holds parietal bones together
Temporal Bones
Inferior/ lateral part of cranium and part of cranial floor
Temporal Squama
Thin, flat portion of temporal bone forms temple
Zygomatic Process
On temporal Bone- articulates with temporal process of zygomatic bone
Zygomatic Arch
Anterior to ear- Zygomatic and temporal processes
Mandibular Fossa
Socket on zygomatic process
Articular Tubercle
Rounded elevation on zygomatic process
Temporomandibular Joint
Mandibular fossa and articular tubercle articulate with mandible
Mastoid Portion
Contains mastoid air cells which communicate with hollow air space in inner ear- posterior and inferior to ear canal
External Auditory meatus
Ear canal- directs sound waves into ear
Mastoid process
Rounded projection on mastoid portion- attachment point for neck muscles
Internal Auditory Meatus
Opening for facial and vestibulochlear nerves to pass
Styloid process
Attachment point for muscles and ligaments of tongue and neck- projects inferiorly from temporal bone
Stylomastoid foramen
Between styloid and mastoid processes- Facial nerve and stylomastoid artery
Petrous Portion
Between sphenoid and occipital bones- houses internal and middle ear
3 auditory ossicles of middle ear
Incus
Malleus
Stapes
Cartoid Foramen
In middle ear- Passage for cartoid artery
Occipital bone
Posterior part and base of cranium
Foramen Magnum
Medulla oblongata connects with spinal cord - passage for vertebral and spinal arteries an accesory nerve
Occipital condyles
Two oval, convex surfaces on either side of foramen magnum
Atlanto-occipital joints
Occipital condyles articulate with atlas
Hypoglossal canal
Superior to occipital condyle- passage of hypoglossal nerve and pharyngeal artery
External Occipital Protuberance
Prominent midline projection superior to foramen magnum
Ligamentum nuchae
Ligament extends for external occipital protuberance to C7
Superior Nuchal Lines
Two curved lines extending laterally from protuberance
Inferior nuchal lines
Area of muscle attachment
Sphenoid bone
butterfly- Floor, side walls and rear walls of orbit
What cranial bones does the sphenoid articulate with?
All Cranial bones
Sphenoidal Sinus
Middle portion of butterfly that is hollow
Sella Tursica
Ridgy structure on superior body of sphenoid
3 parts of the Sella Tursica
Tuberculum Sellae
Hypophyseal Fossa
Dorsum Sellae
Tuberculum Sellae
Anterior ridge of the sella tursica
Hypophyseal Fossa
Depression in between ridges of the sella tursica- houses pituitary gland
Dorsum Sellae
Posterior ridge of the sella tursica
Greater Wings
Project laterally from body of sphenoid- inferior to lesser wings
Lesser Wings
Ridge of bone superior to greater wings of the sphenoid bone
Optic Foramen
At joint between lesser wing and body of sphenoid- passage of optic nerve and opthalmic artery
Superior Orbital Fissure
Between greater and lesser wings of sphenoid. Elongated slit for passage of blood vessels and cranial nerves
Pterygoid Processes
Project from bottom of sphenoid body- Mandible muscle attachment
Foramen Ovale
Medial to foramen spinosum on wings of sphenoid- Trigeminal Nerve
Foramen Spinosum
Base of greater wing of sphenoid- meningeal blood vessels
Foramen Lacerum
Joint between sphenoid, temporal and occipital bones- pharyngeal artery and emissary veins
Foramen Rotundum
Above pterygoid process- trigeminal nerve
Ethmoid Bone
Anterior part of cranial floor between orbits- partitions nasal cavity
Lateral Masses
Wall between nasal cavity containing ethmoidal sinuses
Ethmoidal sinuses
In the lateral masses of ethmoid bone- composed of ethmoidal cells
Perpindicular Plate
Nasal Septum- Long projection in the middle of the ethmoid bone
Cribiform Plate
Horizontal plate in ethmoid bone- forms roof of nasal cavity
Olfactory Foramina
On cribiform plate of ethmoid bone- passage of olfactory nerves
Crista Gali
Projection on top of ethmoid bone- Attachment for falx cerebri which seperate brain hemispheres
Nasal bones
Two, small, flat rectangular bones form bridge of nose
Function of nasal bones
Protect upper entry of nasal cavity and provide muscle attachment points used for facial expression
Lacrimal Bones
Resemble fingernails. Lateral to nasal bones and form medial wall of orbit
Lacrimal Fossa
Formed with maxilla. Houses lacrimal sac
Palantine Bones
Two L shaped bones form posterior hard palate and walls of nasal cavity
Horizontal Plates of Palantine bone
Seperate nasal and oral cavities
Inferior Nasal Conchae
Inferior to middle nasal conchae of the ethmoid- seperate from ethmoid
Vomer
Triangular bone on floor of nasal cavity
What bones does the vomer articulate with?
Perpindicular plate of ethmoid, body of sphenoid, maxilla, palantine
Maxilla
Floors of orbits, lateral walls of nasal cavity, most of hard palate
What facial bones does the maxilla articulate with?
All except mandible
Hard palate
Palantine processes of maxilla and horizontal plates of palantine bones
Maxillary Sinus
Hollow body of maxilla
Alveolar Processes
Ridge like arch on maxilla that contains alveoli
Alveoli
Sockets for maxillary teeth
Palantine processes
Horizontal projection on maxilla makes 3/4 of hard palate anterior
Infraorbital Foramen
On maxilla. Infraorbital blood vessel/ nerve and the trigeminal nerve
Incisive Foramen
Posterior to incisor teeth. Palantine blood vessel and nasopalantine nerve
Inferior Orbital Fissure
Between greater wing of sphenoid and posterior maxilla
Zygomatic Bone
Cheek bone
What bones do the zygomatic bones articulate with
Frontal, maxilla, temporal and sphenoid
Temporal Process
Projects posteriorly and articulates with zygomatic process
Zygomaticofacial foramen
Near centre of zygomatic. Zygomaticofacial nerve and vessels
Mandible
Lower jaw bone
What is the largest and strongest facial bone?
Mandible
Body of Mandible
Horizontal, curved portion
Ramus
Perpindicular portion of mandible
Angle of mandible
Area where the body and the ramus meet
Condylar Process
Posterior part of ramus articulates with mandibular fossa and articular tubercle of temporal bone
Temporomandibular Joint
Where mandible articulates with temporal bone
Coronoid Process
End of ramus where temporalis muscle attaches
Mandibular Notch
Depression between condylar and coronoid processes
Mental Foramen
Inferiro to 2nd premolar- Mental nerve
Mandibular Foramen
Medial side of ramus
Mandibular Canal
Runs obliquely to ramus and anteriorly to body- Alveolar nerves/ vessels
Nasal Septum
Vertical partition of nasal cavity
3 components of nasal septum
Vomer
Perpindicular plate of ethmoid
Septal cartilage
Bony Nasal Septum
Perpindicular plate of ethmoid and the vomer form the posterior side of nasal septum
Septal Cartilage
Hyaline cartilage articulates with bony nasal septum to form the anterior of nasal septum
How many bones form the orbital cavities?
7
What cranial bones form the orbital cavities?
Frontal, sphenoid, ethmoid
What facial bones form the orbital cavities?
Palantine, zygomatic, maxilla, lacrimal
What bones form the orbit roof?
Frontal, sphenoid
What bones form the orbit lateral wall?
Zygomatic, sphenoid
What bones form the orbit medial wall?
Maxilla, lacrimal, ethmoid, sphenoid
What bones form the orbit floor?
Maxilla, zygomatic, sphenoid
Location of optic foramen
Junction of roof and medial wall of orbit
Location of superior orbital fissure
Back, centre of orbit
Location of inferior orbital fissure
Junction of lateral wall and floor of orbit
Location of supraorbital foramen
Medial side of supraorbital margin of frontal bone
Location of lacrimal fossa
Medial side of orbit on the lacrimal bone
Sutures
Immovable joint that holds together most skull bones
Coronal Sture
Joins frontal and parietal bones
Saggital Suture
Joins parietal bones
Lamboid Suture
Joins parietal and occipital bones
Where do sutural bones grow?
At the lamboid suture
Squamous Suture
Join parietal and temporal bones
4 bones with paranasal sinuses
Frontal
Ethmoid
Sphenoid
Maxilla
2 functions of paranasal sinuses
Allow skull to change in size but not mass
Resonating chambers intensify vocals
Cranial Fossae
3 distinct regions of the floor of the cranium
Bones that form Anterior cranial fossa
Frontal, ethmoid, sphenoid
Bones that form middle cranial fossa
Sphenoid, temporal, parietal
Bones that form inferior cranial fossa
Occipital, temporal
4 Sex differences in muscle attachment sites
Temporal lines
External Occipital Protuberance
Nuchal lines
Mastoid Process
6 Sex differences in Bone Prominence
Angle of mandible Frontal squama Supraorbital ridge Glabella Teeth Mental Eminence (chin)
Hyoid bone
Suspended from styloid process of temporal bone by ligaments and muscle
What bone is fractured during strangulation
Hyoid
Function of hyoid bone
Attachment for tongue, neck and pharynx muscles
Vertebral Column
Bone and connective tissue that surrounds and protects spinal cord
How many of each vertebrae are there?
26 total 7 cervical 12 thoracic 5 lumbar 1 sacrum 1 coccyx
Normal curves
4 slight curves in spine
What portions of the spine are convex
Cervical and lumbar
Intervertebral Discs
Between bodies of vertebrae from C2- sacrum
What % of spine length is from discs?
25%
2 components of intervertebral discs
Annulus Fibrosus
Nucleus pulpous
Annulus Fibrosus
Outer fibrocartilage ring of intervertebral discs
Nucleus pulpous
Inner, soft substance in intervertebral discs
Vertebral Body
Anterior block mass of bone
Vertebral Arch
Posterior side of spinal cord
Pedicle
Short thick processes form base of the vertebral arch
Laminae
Flat portions just before spinous process form posterior side of vertebral arch
Vertebral Foramen
Contains spinal cord and meningeal coverings
Vertebral Notches
Indentations in pedicles
Intervertebral Foramen
Vertebral notches stacked form opening permitting passage of spinal nerve
Transverse process
Postlaterally project from both sides of vertebrae
Spinous Process
Posteriorly projects from junction of laminae
2 vertebral processes that are muscle attachment points
transverse
spinous
Superior articular process
Join with inferior articular surface of vertebrae above
Inferior articular process
Join with superior articular process of vertebrae below
Vertebral facet
Surface of articulating processes covered in hyaline cartilage
where is the vertebral foramen the biggest?
Cervical vertebrae
What vertebrae have transverse formamen?
Cervical
What spinous processes are bifid?
C2- C6
Atlas
C1- Ring of bone with posterior and anterior arches and large lateral masses
Which vertebrae lacks a vertebral body and a spinous process
Atlas
What allows us to nod our head
Atlanto- occipital joint in atlas
Axis
C2- Has a peg like dens
Ondontoid Process
Dens
Atlanto- axial joint
Articulation of atlas and dens of axis
Vertebra Prominens
C7- has a large non bifid spinous process
Costal Facet
Articular surface for ribs
Which vertebrae articulate with ribs
T1- T10
What articulates with the head of the ribs?
Body of thoracic vertebrae
What articulates with the tubercles of the ribs?
Costal facets of the thoracic vertebrae
Demifacet
Head of rib articulates with body of two adjacent vertebra
Which vertebrae have both a superior and inferior costal demifacet?
T2- T8
Vertebrocostal Joints
Articulation between thoracic vertebrae and ribs
Sacrum
Triangular bone formed by fusion of 5 sacral vertebrae
What age does the sacrum fuse together at?
16-30
Transverse Lines
4 ridges that mark joining of sacral vertebrae
Anterior sacral foramina
4 pairs of holes in the sacrum
Sacral Ala
Lateral wings on the top of the sacrum
Median Sacral Crest
Fused spinous processes form a ridge down the middle
Lateral Sacral Crest
Fused transverse processes form lines down the sides
Posterior Sacral Foramina
4 pairs of holes on the back side
Sacral Canal
Continuation of vertebral canal
Sacral Hiatus
Laminae of S5 fail to meet and leave a gap on the bottom of posterior side
Sacral Cornu
Inferior articular process of S5 connects with coccyx
Apex
Narrow portion on the bottom of sternum
Base of sternum
Broad portion at the top of the sacrum
Sacral Promontory
Border of base used for pelvis measurement
Auricular Surface
Depression on posterior wings of sacrum join with ilium of hipbone
Sacroiliac Joint
Auricular surface of sacrum and ilium of hip bone
Sacral Tuberosity
Depressions on auricular surface for ligament attachment
Superior articular process of sacrum
Bumps on top that join with L5
Lumbosacral Joint
Sacrum joins with lumbar
Coccyx
Co1- Co4- Terminal end of vertebral column
When does the coccyx fuse
Age 20-30
Coccygeal Cornu
Connected by ligaments to sacral cornu
Thoracic Cage
Sternum, ribs and thoracic vertebrae
Superior Thoracic Aperture
Opening for structures in neck to pass through
Sternum
Flat bone in centre of thorax
3 parts of the sternum
Manubrium
Body
Xiphoid Process
Manubrium
Top of sternum
Xiphoid Process
Bottom of sternum