Anatomy & Physiology 34A Lecture
Chapter 7 - The Skeletal System: Axial Skeleton
I.
Overview
A. Introduction to the axial skeleton
B. Skull
C. Vertebral Column
D. Thoracic Cage
E. Disorders
II. The ________ Skeleton forms the axis of the body & consists of 80 major bones in the skull,
vertebral column, and rib cage (bony thorax)
III. The ______ - composed of 22 bones in the 2 major sets of bones: the cranium and the facial
bones
A. __________ - encloses and protects the brain; divided into 2 major areas: the ___________
forming the superior, lateral, and posterior walls of the skull, and the cranial ______,
forming the skull base.
1.
The cranium has several cavities & fossae
a.
b.
Cranial cavity is the largest, surrounds the ________
c.
________ cavity is formed by both cranial and facial bones and is separated into two
chambers by a nasal __________
d.
Paranasal ___________ (4) are located within the bones surrounding the nasal area
(______ = frontal, ethmoidal maxillary, and sphenoidal)
e.
Middle & inner _____ cavities within the temporal bone, house the organs of
hearing and balance
f.
__________ (2) for the eyeballs are formed by facial and cranial bones
Cranial __________ in the floor of the cranial cavity
1) ____________ fossa – formed by the lesser wings of the sphenoid, frontal, and
ethmoid, bones; houses frontal lobes
2) ___________ fossa – formed by the greater wings of sphenoid and temporal bone;
houses temporal lobes
3) ___________ fossa – formed by the occipital bone; houses cerebellum
2.
____________ (soft spots) are soft, membranous spots between the incompletely formed
cranial bones of a fetus or embryo; allow skull compression and expansion, and include
the ______:
a. __________ – in temple area where frontal, parietal, and sphenoid bones join
b. _________ – at medial junction of parietal & occipital bones
c. __________ – at medial junction of frontal and parietal bones
d. __________ – at posterior junction of occipital, parietal, and temporal bones
e. Ossification of these spots is not complete until around __-__ months old
3.
____________ - interlocking immovable joints that join all but one of the bones of the
cranium (the mandible is attached by a moveable joint). Major cranial sutures include:
a.
____________ S. - joins frontal and parietal bones
2
b.
c.
d.
4.
____________ S. - joins parietal bones
______________ S. - joins occipital and parietal bones
____________ S. - joins parietal and temporal bones
Eight large, flat bones construct the __________
a.
___________ (forehead) bone - anterior cranium; includes roof of eye orbit and
frontal sinuses
b.
___________ bones (2) - superior, lateral bones of cranium; bordered by all 4 cranial
sutures
c.
___________ bones (2) - inferior to parietal bones; parts are:
1) ___________ (flat) portion and _________ (rock) portion
2) Processes - zygomatic, styloid, __________
3) Fossa – ____________
4) Foramina – jugular, carotid canal, stylomastoid, ________
5) _________ – external auditory and internal auditory
d.
_________ bone - posterior, inferior bone of cranium; parts:
1) Processes – occipital ___________, external occipital proturberance
2) Foramina – foramen __________, hypoglossal canals
e.
__________ bone - bat-shaped bone forming anterior plateau of middle cranial
fossa; parts:
1) Greater & lesser _________
2) ______ ___________ (seat of the pituitary gland) includes anterior & posterior
clinoid processes
3) Foramina – __________, rotundum, ovale, spinosum
f.
_____________ bone - anterior to sphenoid
1) _________ ________ with olfactory foramina and crista galli found in medial,
anterior cranial cavity
2) Perpendicular plate forms upper nasal ___________
3) Superior & middle nasal ________ found in nasal cavity
B. __________ bones - 12 paired bones plus one mandible and vomer
1. _____________ - lower jaw; only movable bone of skull; parts:
a. _____--_-, ramus, angle, notch
b. Processes – coronoid, condyle, __________
c. Foramina – ___________, mandibular
2.
________________ (2) - upper jaw; parts:
a. Processes – alveolar, ____________ (anterior hard palate)
b. Infraorbital __________
3.
4.
5.
6.
7.
_____________ (2) - posterior hard palate
_______________ (2) - cheek bones; art. with temporal bone
_____________ (2) - has lacrimal fossa, beneath tear ducts
_________ (2) - bridge of nose
__________ - inferior part of nasal septum in median plane of nasal cavity
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8. Inferior Nasal __________ (turbinates) - lateral wall of nasal cavity
C. Auditory _______ – malleus (hammer), incus (anvil), stapes (stirrup)
D. _________ bone - not part of skull but lies inferior to mandible
IV. ___________ (spinal) Column - extends from skull to pelvis; forms body’s major axial
support; surrounds and protects spinal ______
A. ____________ vertebrae - __ neck vertebrae (C1-C7)
1. ________ - has lateral processes with facets that receive the occipital condyles of the
skull; joint allows head to ____
2.
________ - inferior to atlas; has a large process called a _____ that allows the skull to
pivot (indicating “___”)
3.
4.
Vertebra __________ – 7th cervical with long spinous process
Transverse processes contain ______________ through which vertebral arteries pass
to brain.
B. ____________ Vertebrae - ___ vertebrae (T1-T12) posterior to rib cage; have ________
for rib tubercles on transverse processes.
C.
________ Vertebrae - 5 vertebrae (L1-L5) with large, block-like bodies and short, thick
spinous processes extending directly backward.
D. ________ - 5 fused vertebrae; articulates with L5 superiorly, with ilium laterally, and
connects to coccyx inferiorly. Parts:
1. Body, ____
2. Articular - Superior articular process, ____________ surface
3. Processes – promontory, median _______
4. Foramina – sacral _______, sacral foramina
E. Coccyx (__________) - 3-5 fused bones.
F. Typical vertebrae have the following features:
1. _______ - central rounded portion
2. Vertebral ____ - junction of all posterior projections; includes the _______ (bet.
spinous & transverse processes) and _______ (attachment of arch to body)
3.
4.
5.
6.
Vertebral ________ - large hole through which the spinal cord passes
7.
_____________ foramina - notches on the superior & inferior surfaces of the pedicels
that allow spinal nerves to exit the spinal cord
_____________ processes - two lateral projections from the vertebral arch
____________ process - single medial, posterior projection from the vertebral arch
Superior & Inferior articular ______________ - paired projections lateral to the
vertebral foramen that enable articulation with adjacent vertebrae
G. Vertebrae are separated by intervertebral discs of ______ cartilage that are composed of
two regions:
1.
Nucleus ___________ - a central gelatinous area that behaves like a fluid and is
surrounded by the
2.
Annulus __________ - an outer ring of collagenous fibers that stabilizes the disc
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3.
In a ___________ _______, the nucleus pulposa herniates through the annulus and
compresses adjacent nerves
V. Thoracic (rib) _______ - composed of sternum, ribs, and thoracic vertebrae; encloses and
protects heart & lungs
A. ___________ (breast bone) - 3 fused flat bones
1. ______________ - articulates with clavicles (collarbone) at the clavicular notches and
ribs 1 & 2; has medial jugular notch
2.
______ - forms majority of sternum; joins manubrium at sternal angle,costal facets
articulate directly or indirectly with ribs 2-10
3.
____________ process - inferior end of sternum; at level of 5th intercostal space; no
ribs, but some abdominal muscles attach
B. Ribs - ___ prs. of ribs form the thoracic cage:
1. ________ (vertebrosternal) ribs - 1st __ pr. ribs, all increasing in length; attach directly
to sternum via their costal cartilage
2.
________ (vertebrochondral) ribs - next __ pr. Ribs; attach indirectly via hyaline
cartilage to sternum
3.
4.
5.
__________ (vertebral) ribs – 2 pr. have no sternal attachment
_____________ spaces are found between the ribs
A typical ____ (#3-9) has the following features:
a.
b.
c.
Head & ____________ articulate with thoracic vertebra
_______ - distal to the head
Body (______) - long, straight part of the rib, curves at angle
VI. Spinal Curvatures & Disorders of the Axial Skeleton
A. ________ spinal curves include primary and secondary curvatures
1. ____________ curvatures
a. Present at _________
b. Found in the __________ and _________ regions
2. _____________ curvatures
a. Develop ________ birth
b. _________ curve develops as baby begins to lift his/her head
c.__________ curve occurs when baby begins to stand and walk
B. _______________ spinal curvatures include:
1. ___________ - lateral curvature of more than 10, usually in the thoracic region; may
result from legs of unequal length
2.
____________ (humpback) - dorsal curvature of the thoracic region; most common in
older women due to osteoporosis
3.
____________ (swayback) - accentuated lumbar curvature; may result from
osteomalacia or overweight
B. ________________ - incomplete formation of the vertebral arches surrounding the spinal
cord; may result in paralysis; may be prevented by taking folic acid during pregnancy
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C. ________________ - congenital abnormality in which the right & left palate fail to join
medially; also prevented by taking _________ acid during pregnancy