Chapter 7: The Skeletal System: The Axial Flashcards Preview

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Flashcards in Chapter 7: The Skeletal System: The Axial Deck (144)
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How many bones do adults have?



What are the 2 main divisions of the skeleton?

Axial (80 bones) and appendicular (126)


What is the axial skeleton and what are some examples?

Consists of bones that lie around the longitudinal axis of the body. Examples: skull bones, auditory, ossicles (earbones), hyoid bones, ribs, sternum, bones of the vertebral column


What is the appendicular skeleton and what are some examples?

Bones of the upper and lower limbs (extremities and appendages). Plus bones forming the girdles that connect limbs to the axial skeleton.


What are the 5 types of bones based on shape?

Long, flat, short, irregular and sesamoid


What is long bone and what are some examples?

Greater in length than width, have a shaft and variable number of extremities or epiphyses (ends). Slightly curved for strength (a curved bone absorbs stress of the body's weight at several points so it's easily distributed). Compact bone tissue in diaphysis and lots of spongy bone tissue in epiphyses. Includes femur (thigh bone), tibia, tibula (leg bones), humerus (arm bone), ulna and radius (forearm bones) and phalanges


What are short bones and what are some examples?

Cube shaped. Legnth=width. Mainly spongy bone except at surface which is thin layer of compact bone tissue


What are flat bones and what are some examples?

Thin and composed of 2 nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue. For protection and provides extensive areas for muscle attachment. Examples: Cranial bones, sternum, ribs, and scapulae.


What are irregular bones and what are some examples?

Complex shapes and can't be grouped into any of the previous categories. Examples: Vertebrae, hipbones, certain facial bones, and the calcaneus.


What are sesamoid bones and what are some examples?

Develop in certain tendons where there's lots of friction, tension and physical stress (Ie palms and soles). Varies in number from person to person, not totally ossified, only a few mm in diameter (except for the 2 patallae), protects tendons from wear and tear. Change direction of pull of a tendon which improves the mechanical advantage at a joint.


What are sutural bones?

Small bones located in sutures (joints) between certain CRANIAL BONES


Where is red bone marrow found?

Flat bones (ribs, sternum, skull), irregular bones (vertabrae and hip bones), long bones (proximal epiphyses of femur and humerus) and some short bones.


What are surface markings of bones?

Structural features adapted for specific functions


What can cause surface markings?

Tension (new bone may be deposited resulting in raised or roughened areas) and compression (can result in depression of bone)


What are the 2 main types of surface markings?

1) Depressions + openings: Allows passage of soft tissues like blood vessels, nerves, ligaments and tendons or it forms joints. 2) Processes: Projections/outgrowths that either help form joints or serve as attachment points for connective tissues (like ligaments and tendons)


How many bones does the skull contain and what are the 2 categories they are grouped in?

22 bones. They are grouped in either cranial bones or facial bones


What are the cranial bones?

Forms the cranial cavity (encloses and protects the brain). 8 cranial bones: 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, and 1 ethmoid


What are the facial bones ?

14 bones: 2 nasal, 1 ethmoid, 2 zygomatic, 1 mandible, 2 lacrimal, 2 palatine, 2 inferior nasal conchae, and 1 vomer


What is the frontal bone?

Forms the forehead, roof of the orbits (eye sockets) and most of the anterior part of the cranial floor.


What is the frontal squama?

Scale-like plate of bone that forms the forehead of the skull.


What is the parietal bone?

Forms the greater portion of the sides and roof of the cranial cavity. The internal surfaces of the parietal bones contain. Many protrusions and depressions that accommodate the blood vessels that supply dura matter (the superficial connective tissue covering the brain).


What do the parietal bones form?

The internal surfaces of the parietal bones contain many protruions and depressions that accomodate the blood vessels that supply the dura mater (the superficial connective tissue covering the brain).


What do the temporal bones form?

Inferior lateral aspects of cranium and part of cranial floor. Temporal squama is thin, flat and forms the anterior+superior part of the temple (the region around the ear). Zygomatic processes project from the inferior portion of the temporal squama and articulates with the temporal process of the zygomatic bone to form the zygomatic arch


What is the mandibular fossa?

On the inferior posterior surface of the zygomatic process of each temporal bone. ANterior to the mandibular fossa is the articular tubercle. The mandibular fossa and articular tubercle articulate with the mandible (lower jaw) to form the temporomandibular joint (TMJ).


What are mastoid air cells?

Located in the mastoid portion and communicates with the hollow space of the middle ear


What is mastoiditis?

A painfull inflammation caused by middle ear infection that goes untreated and spreads into the mastoid air cells


What does the mastoid process do?

Point of attachment for several neck muscles


What does the internal auditory meatus do?

Opening where the facial (VII) and vestibulocochlear (VII) nerve pass


What does the styloid process do?

Point of attachment for muscles and ligaments of the tongue and neck


What does the atylomastoid foramen do?

Between the styloid process and mastoid process. The facial (VII) nerve and stylomastoid artery pass through