Chapter 7 Study Skills: Key Terms
Body system composed of bones, cartilages, joints, and ligaments
How much body mass does the skeleton make up?
About 20 percent of total body mass
Portion of the skeleton structured from 80 bones segregated into three major regions: the skull, the vertebral column, and the thoracic cage
What are the three major regions of the axial skeleton?
Skull, vertebral column, thoracic cage
What is the general function of the axial skeleton?
Forms longitudinal axis of the body, supports the head, neck, and trunk, protects the brain spinal cord, and the organs in the thorax
interlocking joints within the bones; suture lines have saw-toothed or serrated appearances
Body's most complex bone structure; formed by cranial and facial bones
How many bones make up the skull?
22 in all
What are the functions of the facial bones?
Form the framework of the face, contain cavities for the special sense organs of sight, taste, and smell, provide openings for air and food passage, secure the teeth, and anchor the facial muscles of expression (which we use to show our feelings)
Forms the superior, lateral, and posterior aspects of the skull as well as the forehead
Forms the skull's inferior aspect
Shell-shaped bone that fors the anterior cranium
Thickened superior margins of teh orbits that lie under the eyebrows
Anterior Cranial Fossa
Supports the frontal lobe of the brain
Allows the supraorbital artery and nerve to pass to the forehead
Smooth portion of the frontal bone
sinuses in the area lateral to the glabella
Curved, rectangular bones that form most of the superior and lateral aspects of the skull
Suture where the prietal bones meet the frontal bone anteriorly
Suture where the parietal bones meet superiorly at the cranial midline
Suture where the parietal bones meet the occipital bone posteriorly
Suture where a parietal and temporal bone meet on the lateral aspect of the skull
Forms most of the skull's posterior wall and base
Posterior Cranial Fossa
Formed by the occipital bone and supports the cerebellum of the brain
Hole through which the inferior part of the brain connects with the spinal cord
Atriculate with the first vertebra of the spinal column to permit a nodding motion of the head
Medially and superiorly to each occipital condyle, canal through which a cranial nerve passes
External Occipital Protuberance
Protrusion just superior to the foramen magnum
Best viewed on teh lateral skull surface; lie inferior to the parietal bones and meet them at the squamous suture
Part of the temporal bone that ends at the squamous suture
Barlike process that meets the zygomatic bone of the face anteriorly
Spans the width of the middle cranial fossa, considered the keystone of the cranium because it forms a central wedge that articulates with all other cranial bones
Lies between the sphenoid and nasal bones of teh face; most deeply situated bone of teh skull, forms most of the bony area between the nasal cavity and the orbits
Tiny, irregularly shaped bones or bone clusters that occur within sutures, most often in the lambdoid suture
Indicates where the two mandibular bones fused during infancy
Maxillae; fused medially; form the upper jaw and the central portion of the facial skeleton
Cheekbones; form the prominence of the cheeks and part of the inferolateral margins of the orbits
Thin, basically ectangular bones that are fused medially and form the bridge of the nose
Delicate, fingernail-shaped bones that contribute to the medial walls of each orbit
L-shaped bones that ar fashioned from two bony plates and have three important articular processes
Slender, plow-shaped bone that lies in the nasal cavity and forms part of the nasal septum
Inferior Nasal Conchae
Thin, curved boens that project medially from the lateral walls of the nasal cavityf
Bone that lies in the anterior neck just inferior to the mandible; does not articulate directly with any bone
Cone-shaped, bony cavities in which the eyes are firmly encased and cushioned by fatty tissue
Constructed of bone and hyaline cartilage
mucosa-lined, air-filled sinuses that cluster around teh nasal cavity
Johnny was vigorously exercising the only joints in the skull that are freely movable. what do you think he was doing?
Eating or speaking
What bones are the keystone bones of facial expression?
The maxillae bones
The perpendicular plates of the palatine bones and the superior and middle conchae of the ehtmoid bone form a substantial part of the nasal cavity walls. which bone forms the roof of that cavity?
The cribriform plates of the ethmoid bone form the roof of the nasal cavity
What bone forms the bulk of the orbit floor and what sense organ is found in teh orbit of a living person?
The maxillae form the bulk of the orbit floor; the eye is housed in the orbit
What process leads to the formation of most of the skull bones?
consists of 26 irregular bones connected in such a way that a flexible, curved structure results
33 separate bones that form the vertebral column
Seven vertebrae of the neck
12 vertebrae inferior to the cervical vertebrae
5 vertebrae inferior to the thoracic vertebrae
5 fused vertebrae inferior to the lumbar vertebrae
Terminus of the vertebral column
Cushionlike pad of an inner gelatinous nucleus pulposus surrounded by the anulus fibrosus
Houses the spinal cord
What are the five major regions of the vertebral column?
The cervical, thoracic, lumbar, sacral, and coccygeal regions
In which two regions is teh vertebral column concave posteriorly?
The cervical and lumbar regions are concave posteriorly
Besides teh spinal curvatures, which skeletal elements help to make the vertebral column flexible?
The fibrocartilage discs between the vertebrae
What is the normal number of cervical vertebrae? of thoracic vertebrae?
Seven cervical, twelve thoracic
How can you distinguish a lumbar vertebra from a thoracic vertebra?
A lumbar vertebra is heavier and its massive body is kidney-shaped. a thoracic vertebral body is generally heart-shaped and its spinous process is long, sharp, and points downward, and its transverse processes have facets for articulating with the ribs
Bone that lies in the anterior midline of the thorax
True (Vertebrosternal) Ribs
the superior seven pairs of ribs that attach directly to the seternum
Five pairs of inferior ribs that attach indirectly or not at all to the sternum
Vertebral (Floating) Ribs
Eleventh and twelfth pairs of ribs that have no anterior attachments
How does a true rib differ from a false rib?
A true rib connects to the sternum by its own costal cartilage. a false rib connects to the sternum via costal cartilages of other ribs or not at all
What is the sternal angle and what is its clinical importance?
The sternal angle is a ridge across the front of the sternum where the manubrium joins the sternal body. it acts as a hing allowing the sternum to swing anteriorly when we inhale. Because it is aligned with the second rib, it is a handy cue for finding that rib and then counting the ribs during a physical exam
Bones of the limbs and their girdles
Shoulder girdle; consists of the clavicle anteriorly and the scapula posteriorly
What two bones construct each pectoral girdle?
The clavical and the scapula
Where is teh single point of attachment of the pectoral girdle to the axial skeleton?
The pectoral girdle attaches to the sternal manubrium of the axial skeleton via the medial end of its clavicle
Where is the major shortcoming of the flexibility allowed by the shoulder joint?
A consequence of its flexibility is that it is easily dislocated
SOle bone of the arm
The longer of the two forearm bones; main responsibility for forming the elbow joint with the humerus
Shorter of the two forearm bones
The "true" wrist; proximal part of the had
Eight small bones that form the carpus