Human Anatomy - Chapter 7

How many bones does the adult have?

How many bones does the adult have?

two hundred and six; eighty in the axial skeleton and one hundred and six in the appendicular skeleton

What does the axial skeleton contribute to homeostasis?

protects many of the body’s organs​; support the storage and release of calcium

What are the five main shapes of bone?

long, short, flat, irregular, and sesamoid

What are sutural bones?

small, extra bone plates located within the sutures of cranial bones

What are the two major types of surface markings?

depressions/openings (passage of soft tissue, form joints) and processes (projections that form joints, attachment points for ligaments and tendons)

What are the five types of depressions and openings and their description?

fissure: narrow slit between bones for passage of blood vessels or nerves

foramen: hole for passage of blood vessels, nerves or ligaments

fossa: shallow depression

sulcus: furrow on a bone for passage of blood vessel, nerve or tendon

meatus: tube-like opening

What are the eleven types of processes and their description?

condyle: rounded projection with a smooth articular surface

facet: rounded articular process supported on a neck

head: smooth, flat, slightly concave articular surface

crest: prominent ridge or elongated process​

epicondyle: roughened projection on a condyle​

line: long, narrow ridge or border

spinous process: sharp, slender projection

trochanter: large projection found only on the femur​

tubercle: variably sized rounded projection​

tuberosity: variably sized projection with rough, bumpy surface

How many bones are in the skull?

twenty-two (not including the three middle ear bones in both ears)

What are the groups of the skull bones?

cranial bones (8) and facial bones (14)

What is a paranasal sinus?

skull bones containing mucous membrane-lined cavities

What is the only moveable bone of the skull?

mandible

What is the function of the cranial bones?

protect the brain; stabilize the positions of the brain, blood vessels, and nerves; protect and support the special sense organs

What is the function of the facial bones?

protect and support the nerves and blood vessels in the area; protect and support the special sense organs

What are the six cranial bones?

frontal, parietal, temporal, occipital, sphenoid, and ethmoid

What is the sphenoid bone?

keystone of the cranial floor because it articulates with all the other cranial bones

What is the ethmoid bone?

forms part of the anterior portion of the cranial floor, the medial wall of the orbits, the superior portion of the nasal septum, and most of the superior side walls of the nasal cavity; major superior supporting structure of the nasal cavity

What are the 14 facial bones?

two nasal bones, two maxillae, two zygomatic, mandible, two lacrimal, two palatine, two inferior nasal conchae, and vomer

What does the maxillae articulate with?

every bone in the face except for the mandible

What is the largest and strongest facial bone?

mandible

What is the nasal septum?

a vertical partition that divides the nasal cavity into right and left sides

What bones form the orbit?

frontal, sphenoid, zygomatic, maxilla, palatine, ethmoid, and lacrimal

What are sutures?

immovable joints found only between skull bones and hold skull bones together​

What are the four sutures of the skull?

coronal, lambdoidal, squamosal, and sagittal

What are fontanels?

dense connective tissue membrane-filled spaces between the cranial bones of fetuses and infants

What are the two major functions of fontanels?

enable the fetal skull to modify its size and shape as it passes through the birth canal and permits rapid growth of the brain during infancy

What is the hyoid bone?

supports the tongue and provides an attachment site for some muscles of the neck and pharynx​; does not articulate with any other bone

How many vertebrae does the vertebral column?

twenty-six; seven in the cervical, twelve in the thoracic, five in the lumbar, one as the sacrum (5 fused), and one as the coccyx (4 fused)

What are the four normal vertebral curves?

cervical and lumbar (anteriorly convex curves) and thoracic and sacral (anteriorly concave curves)

How does the spine develop as we age?

fetus: one single, anteriorly, concave curve

child: develops cervical curve to hold head up

child: lumbar curve develops to begin walking

What are intervertebral discs?

located between the bodies of the vertebrae from the second cervical to the sacrum

What are intervertebral discs made of?

an outer ring of fibrocartilage and an inner, soft nucleus with a layer of hyaline cartilage

what do intervertebral discs do?

Absorb shock and separate the vertebrae

What are the first and second cervical vertebra?

atlas (supports the skull) and axis (side-to-side rotation)

What are the largest and strongest vertebrae?

lumbar

Picture of difference of vertebra.

Picture with vertebra diagram.

What makes up the bones of the thorax?

ribs, sternum, and costal cartilage

What is the purpose of the thoracic cage?

protects the organs in the thoracic and superior abdominal cavities; provides support for the bones of the shoulder girdle and upper limbs

What are the three segments of the sternum?

manubrium, sternal body, and the xiphoid process

How are the 12 ribs divided?

first seven (vertebrosternal) are true ribs, next five (vertebrochondral) are false ribs, and the last two of the false ribs are called floating ribs

Picture of rib diagram.

What causes a herniated disc?

may occur due to trauma or sometimes is simply associated with aging​

What are the three curve-related pathologies of the spine?

scoliosis (lateral curvature), kyphosis (thoracic curve), and lordosis (lumbar curve)

What is spina bifida?

a congenital defect caused by failure of the vertebral laminae to unite at the midline

What vertebra are most commonly fractured?

C1, C2, C4-T, and T12-L2