Section 2 -- Osteology

Unit 1 Kinesiology

number of bones in the adult human skeleton

206

number of bones in the axial skeleton

80

number of bones in the appendicular skeleton

126

skeletal functions

• protection of heart, lungs, brain…

• support to maintain posture

• movement by serving as points of attachment for muscles and acting as levers

• mineral storage such as calcium and phosphorus

• hemopoiesis - in vertebral bodies, femurs, x, ribs & sternum

what is hemopoiesis

process of blood cell formation in the red bone marrow

long bones

• composed of a long cylindrical shaft with relatively wide, protruding ends

• shaft contains the medullary canal

long bone examples

phalanges, metatarsals, metacarpals, tibia, fibula, femur, radius, ulna & humerus

short bones

small, cubical shaped, solid bones that usually have a proportionately large articular surface in order to articulate with more than one bone

short bone examples

carpals and tarsals

irregular bones

include bones throughout entire spine, & ischium, pubis & maxilla, ethmoid, ear ossicles

sesamoid bones

• small bones embedded within tendons

• provides protection

• improved mechanical advantage of musculotendinous units: patella, 1st metatarsophalangeal, 1st metacarpophalangeal

diaphysis

long cylindrical shaft

cortex

hard, dense compact bone forming walls of diaphysis

periosteum

dense, fibrous membrane covering outer surface of diaphysis

endosteum

fibrous membrane that lines the inside of the cortex

medullary (marrow) cavity

between walls of diaphysis, containing yellow or fatty marrow

articular (hyaline) cartilage

covers the epiphysis… cushioning effect and reduces friction

longitudinal growth continues if _____ plates are open

epiphyseal

plates disappear and close shortly after ____

adolescence

most close by age ___, but some may be present until ___

18, 25

growth in diameter continues throughout ____

life

Wolff’s Law

• bone size and shape are influenced by the direction and magnitude of forces that are habitually applied to them

• bones reshape themselves based upon the stresses placed upon them

• bone mass increases over time with increased stress

processes that form joints

• condyle

• facet

• head

processes to which ligaments, muscles or tendons attach

• crest

• epicondyle

• line

• process

• spine (spinous process)

• suture

• trochanter

• tubercle

• tuberosity

cavities (depressions)

• facet

• foramen

• fossa

• fovea

• meatus

• sinus

• sulcus (groove)

factors affecting stability and mobility of diarthrodial joints

• bones

• cartilage

• ligaments & connective tissue

• muscles

• proprioception and motor control

bone factor

• very similar in bilateral comparisons within an individual

• actual anatomical configuration at joint surfaces may vary significantly between individuals

cartilage factor

• cartilage structure assists in joint congruency & stability

• may vary between individuals in size & configuration

ligaments & connective tissue factor

• provide static stability to joints

• variances exist b/w individuals in degree of restrictiveness of ligamentous tissue

muscles factor

• dynamic stability

• minimal static stability

• strength & endurance are significant in stabilizing joints

• muscle flexibility affects the total range of joint motion possible

proprioception

subconscious mechanism by which body is able to regulate posture & movements by responding to stimuli originating in proprioceptors imbedded in joints, tendons, muscles, and inner ear

motor control

process by which body actions & movements are organized and executed

proprioception & motor control factor

To determine the appropriate amount of muscular forces and joint activations needed:
- sensory info from environment & body must be integrated and coordinated
- muscle strength and endurance are not very useful in providing joint stability unless activated precisely when needed

Which of the following is NOT a primary function of the skeletal system?
a. production of internal organs
b. production of hormones
c. mineral storage
d. hemopoiesis

b

Which of the following is classified as a sesamoid bone?
a. femur
b. patella
c. vertebra
d. scapula

d

Longitudinal bone growth continues as long as which structure remains open?
a. diaphysis
b. medullary cavity
c. epiphyseal cavity
d. periosteum

c

According to Wolff’s Law, bone mass increases over time in response to:
a. aging
b. nutritional intake
c. increased stress
d. hormonal changes

c