Axial Skeleton Ch. 7 Flashcards
1
Q
The Skeleton
- consists of
- bones grouped into two divisions called
A
- bones, joints, cartilage, ligaments
has 206 bones - -axial skeleton: 80
-appendicular skeleton: 126
2
Q
The Axial Skeleton
A
- Formed from 80 named bones
* Consists of skull, vertebral column, and bony thorax
3
Q
The Skull
A
- Formed by cranial and facial bones
- Body’s most complex bony structure
- Skull: formed by cranial and facial bones
- 8 Cranial bones: frontal, occipital, parietal (2), temporal (2), ethmoid, sphenoid
- 14 Facial bones: mandible, vomer, inferior nasal conchae (2), lacrimal (2), maxilla (2), nasal (2), palantine (2), zygomatic (2)
4
Q
Facial bones
A
- Form framework of face
- Form cavities for sense organs of sight, taste, and smell
- Provide opening for passage of air and food
- Hold teeth
- Anchor facial muscles
5
Q
Cranium
A
- Encloses and protects brain
* Provides attachment for head and neck muscles
6
Q
Cranial Fossae
A
- Internally, prominent bony ridges divide skull into distinct fossae
- Anterior cranial fossa: frontal lobe of cerebrum
- Middle cranial fossa: temporal lobe of cerebrum
- Posterior cranial fossa: cerebellum
7
Q
Small Cavities of Skull
A
- Middle and inner ear cavities in lateral aspect of cranial base
- Nasal cavity lies in and posterior to the nose
- Orbits house the eyeballs
- Air-filled sinuses occur in several bones around the nasal cavity
8
Q
Skull contains approximately 85 named openings
A
- Foramina, canals, and fissures that provide openings for important structures e.g.
- Spinal cord
- Blood vessels
- Cranial nerves
9
Q
Cranial Bones
A
•Formed from eight bones
–Paired bones include
•Temporal bones
•Parietal bones
–Unpaired bones include
•Frontal bone
•Occipital bone
•Sphenoid bone
•Ethmoid bone
10
Q
Parietal Bones & associated Sutures
A
- Parietal bones form superior and lateral parts of skull
- Coronal suture—runs in the coronal plane and is located where parietal bones meet frontal bone
- Squamous suture—occurs where each parietal bone meets a temporal bone inferiorly
- Lambdoid suture—occurs where parietal bones meet the occipital bone posteriorly
- Sagittal suture—occurs where right and left parietal bones meet superiorly
11
Q
Sutural Bones
A
- Small bones that occur within sutures
- Irregular in shape, size, and location
- Not all people have sutural bones
12
Q
Frontal Bone
A
- Forms the forehead and roofs of orbits
- Supraorbital margin is superior margin of orbits
- Glabella is smooth part of frontal bone between superciliary (eyebrow) arches
- Squamous part of frontal bone makes up forehead
- Frontal sinuses within frontal bone
- Contributes to anterior cranial fossa
13
Q
Occipital Bone
A
- Forms the posterior portion of the cranium and cranial base
- Articulates with the temporal bones and parietal bones
- Forms the posterior cranial fossa
14
Q
Occipital Bone structures
A
- Superior and inferior nuchal lines
- Occipital condyles
- Hypoglossal canal through which CN XII runs
- Foramen magnum located at its base
15
Q
Temporal Bones
A
- Lie inferior to parietal bones
- Contributes to the middle and posterior cranial fossae
- Form the inferolateral portion of the skull
16
Q
Regions of Temporal Bones
A
- Squamous region flat area of bone which contains bar-like zygomatic process; zygomatic process projects anteriorly to meet zygomatic bone of face and contributions of these two bones to make up the zygomatic arch
- Zygomatic process
- Mandibular fossa
- Tympanic region surrounds the external acoustical meatus (= external ear canal)
- Styloid process extends down from inferior temporal bone and is muscle attachment site
- Mastoid region can feel it behind the ear
- Petrous region
17
Q
The Temporal Bone
A
•Mastoid region/mastoid process
–Site for neck muscle attachment
–Contains air sinuses
•Petrous region
–Projects medially, contributes to cranial base
–Appears as a boney wedge
between occipetal bone
posteriorly and sphenoid
bone anteriorly
–Houses cavities of middle
and internal ear
18
Q
Foramina of Temporal Bone
A
- Internal & external acoustic meatus
- Jugular foramen (at boundary with occipital bone)
- Carotid canal
- Foramen lacerum (at boundary with sphenoid bone and occipital bone)
19
Q
The Sphenoid Bone
A
- Spans the width of the cranial floor
- Resembles a butterfly or bat
- Has a body
- Has three pairs of processes •Contains five important openings
- Is the “keystone”of the cranium and forms a central wedge that articulates with multiple other cranial bones44
20
Q
The Sphenoid BoneBody
A
- The superior part of the body bears a saddle-shaped prominence called a sella turcica
- The seat of this “saddle” contains the hypophyseal fossa, which holds the pituitary gland (= hypophysis)
21
Q
The Sphenoid Bone Processes
A
- Greater wings
- Lesser wings
- Pterygoid processes
22
Q
Sphenoid Bone Openings
A
- Superior orbital fissure :long slit between greater and lesser wings
- Optic canal: lies just anterior to sella tursica
- Foramen rotundum: in medial part of greater wing
- Foramen ovale: posteriolateral to foramen rotundum
- Foramen spinosum: posteriolateral to foramen ovale(at boundary with temporal bone)
- Foramen lacerum (at boundary with temporal bone and occipital bone)
23
Q
The Ethmoid Bone
A
- Lies between nasal and sphenoid bones
- Forms most of the medial bony region between the nasal cavity and orbits
- Superior and middle nasal conchae extend medially from lateral masses
24
Q
The Ethmoid Bone
A
- Crista galli is attachment site for falx cerebri, the large vertical sheet of connective tissue that lies in between cerebral hemispheres
- Cribriform plate is superior surface of the ethmoid bone; contain olfactory foramina
- Perpendicular plate forms superior part of nasal septum
- Lateral masses contain air
25
Q
Facial Bones
- ) Unpaired bones
- ) Paired Bones
A
1.)Unpaired bones
–Mandible
–Vomer
2.)Paired bones
–Maxillae
–Zygomatic
–Nasal
–Lacrimal
–Inferior nasal conchae
–Palatine
26
Q
Mandible
A
•The lower jawbone is the largest and strongest facial bone
•Composed of two main parts
–Horizontal body
–Two upright rami
27
Q
Mandible
A
- Mandibular condyle
- Temporomandibular joint: interface of mandibular condyle with mandibular fossa of temporal bone
- Mandibular notch
- Coronoid process
- Ramus of mandible
- Mandibular angle
- Body of mandible
- Alveolar margin
- Mental foramen
- Mandibular foramen
