Skeleton - Bones and Joints Flashcards
Name 5 functions of bones.
- framework for body
- protection of organs
- movement
- storage of mineral salts
- formation of blood cells
How many bones are their in an adult?
206
What are the divisions of the skeleton?
- axial (head and trunk)
- appendicular (extremities including girdles)
What are the 4 bone shapes?
- flat
- short
- irregular
- long bones
What are some examples of flat bones?
- ribs
- cranium
- scapula
What are some examples of short bones?
- carpals of wrist
- tarsals of ankle
- patella
What are some examples of irregular bones?
- vertebrae
- facial bones
What are some examples of long bones?
- humerus
- femur
- other long bones of arms & legs including phalanges
What are the 3 components of long bone structure?
- diaphysis (long narrow shaft composed of compact bone; hollow centre filled with yellow bone marrow)
- epiphysis (ends of long bones irregularly shaped, distal and proximal)
- epiphyseal line (remnant of the cartilage growth plate found in children’s long bones; site of growth in bone length; closes by end of puberty and replaced with bone)
What is the diaphysis of long bones?
- long narrow shaft composed of compact bone
- hollow centre filled with yellow bone marrow
What is the epiphysis of long bones?
- ends of the long bones irregularly shaped
- distal (far end) and proximal (near end)
What is the epiphyseal line in long bones?
- remnant of the cartilage growth plate found in children’s long bones
- site of growth in bone length
- closes by end of puberty and replaced with bone
What is the hard, dense, outer, strong layer of all bones called?
compact bone
What is the main component of the shaft of long bones?
compact bone
Describe the structure of compact bone.
- rings of mineralized collagen forming Haversian Systems (osteon)
- osteocytes (mature cells that maintain living bone tissue)
- lacunae (spaces around osteocytes)
- blood vessels found in Haversian and Volkmann canals
What are osteocytes?
mature cells that maintain living bone tissue
What are lacunae?
spaces around osteocytes
What is the functional unit of compact bone?
Haversian System of osteon (long cylinder of rings of mineralized collagen)
Where are nerves and blood vessels contained in compact bone?
- central (Haversian) canal (rings formed around)
- Volkmann canals
What do blood vessels and nerve fibres do in compact bone?
- blood vessels supply oxygen and nutrients to bone tissue
- nerve fibres inform us of damage to bone
Where are osteocytes found in compact bone?
in spaces (lacunae) between the rings (formed around central canal) - when living, extend many small processes out into radiating channels
What is another name for spongy bone?
cancellous bone
Which type of bone is less dense with more spaces?
spongy (cancellous bone)
Where is spongy bone found?
within the ends of long bones (epiphyses) and at the centre of short, flat, and irregular bones
What is spongy (cancellous bone) made of?
- a meshwork of small, bony plates filled with red bone marrow (location of blood cell production)
- not composed of osteons
- still has osteocytes, mineralized collagen fibers
What are the two types of bone marrow? Where are they found?
- red; found within spongy bone (at the ends of long bones and the centre of other bones)
- yellow (in the hollow, central cavity (diaphysis) of long bones)
What type of bone marrow manufactures red and white blood cells?
red
What type of bone marrow is composed mainly of fat (for energy storage)
yellow
What is the function of red bone marrow?
manufactures red and white blood cells
What is the function of yellow bone marrow?
composed mainly of fat, energy storage
What are the connective tissue membranes of bone?
- periosteum
- endosteum
What is the periosteum (location/structure/function)?
- membrane of bone that covers outside except at joint
- has outer fibrous layer and inner cellular layer
- inner layer contains osteoblasts which are essential for repair
- contains blood vessels and nerves
What is the endosteum (location/structure/function)?
- membrane of bone that is the thin, inner layer
- lines the marrow cavity
- contains cells for growth and repair
What is the embryonic skeleton composed of?
almost entirely composed of cartilage (can grow in both width and length)
What is ossification? When does it occur?
- bone formation
- begins during second and third months of embryonic life
What bones form directly without cartilage template (embryo)?
- skull bones
- ribs
- pelvic bones
- shoulder blades
- vertebrae
What bones replace cartilage template (embryo)?
long bones
What 3 cells are involved in bone growth and repair?
- osteoblasts
- osteocytes
- osteoclasts
What are osteoblasts?
- bone building cells
- manufacture the matrix (located between the cells)
- matrix contains large amount of collagen protein fibres
- calcium compounds deposited within matrix
What cells manufacture bone matrix (bone building cells)?
osteoblasts
What are the mature cells that maintain the living bone?
osteocytes
What are osteoclasts?
- bone cells that breakdown (resorb) bone
- regulated by hormones (from parathyroid gland) (calcium transferred to bloodstream)
Why are osteoclasts important (breakdown and resorb bone)?
- necessary for remodelling and repair (grown & after injury)
- important when minerals needed by body
What is blood calcium homeostasis important for?
- skeletal muscle contractions
- nerve function
- blood clotting
What hormones are involved in blood calcium homeostasis and what do they do?
- vitamin D (promotes absorption of dietary calcium)
- hormones from thyroid and parathyroid glands regulate blood levels of calcium which in turn regulate calcium deposition into bone
- calcitonin (thyroid gland) produced when blood calcium levels are high; acts on osteoblasts (calcium from blood to bone)
- parathyroid hormone (parathyroid gland) produced when blood calcium low; acts on osteoclasts (break down bone and release calcium into blood)
What are the 2 types of bone markings?
- projections
- depressions
What are projections?
raised areas that help to form joints or serve as points for muscle attachments
What are 6 types of bone projections?
- epicondyle
- head
- process
- condyle
- crest
- spine
What is an epicondyle (with one example)?
a small projection above a condyle (eg on humerus)
What is a head projection (with one example)?
rounded end separated from the rest of the bone by a slender region called the neck (eg femur)
What is a process (with one example)?
large projection of bone (eg transverse process of vertebrae)
What is a condyle (with one example)?
rounded projection; joint surface (eg femur)
What is a crest (with one example)?
border or ridge (eg iliac crest)
What is a spine (projection) (with one example)?
sharp projection from the surface of a bone (eg spinous process of vertebrae)
What are depressions?
various holes that allow the passage of nerve and blood vessels
What are 4 types of depressions?
- foramen
- sinus
- fossa
- meatus
What is a foramen (with example)?
hole that allows vessels and nerves to pass through or between bones (eg vertebral foramen containing spinal cord; nutrient foramen in long bone diaphysis)
What is a sinus (with example)?
an air space found in some skull bones (paranasal sinuses for warming air)
What is a fossa (with example)?
depression on a bone surface (scapula)
What is a meatus (with example)?
- short channel or passageway (eg external auditory meatus or channel in temporal bone of skull leading to the inner ear)
What are the paranasal sinuses?
spaces in skull bones lined with mucosa to filter, warm, and moisten incoming air
What are the 4 paranasal sinuses called?
- frontal
- ethmoidal
- sphenoidal
- maxillary
How many bones in each division of the skeleton?
- axial 80 bones
- appendicular 126 bones
Which division of the skeleton includes the bones of the head (skull/cranium) and the trunk (vertebrae, sternum, ribs)?
axial
Which division of the skeleton includes the shoulders, hips, and extremities?
appendicular
What is the rounded chamber of fused, flat bones that encloses and protects the brain calle?
the cranium
What are the 8 distinct bones of the cranium?
- frontal
- parietal x 2
- temporal x 2
- occipital
- ethmoid
- sphenoid
Where is the frontal bone (cranium)?
forms the forehead and anterior roof of the skull (paranasal sinuses communicate with nasal cavities)
Where are the parietal bones (cranium)?
form most of the top and the side walls of the cranium
Where are the temporal bones (cranium)?
form part of the sides and some of the base of the skull; each contains mastoid sinuses
Where is the ethmoid bone (cranium)?
- fragile bone located between the eyes forming part of the eye orbit and most of the nasal cavity roof (a thin plate-like extension forms much of the nasal septum)
- sensory nerves from nose pass through into brain
Where is the sphenoid bone (cranium)?
compound bone forms part of the eye socket
Where is the occipital bone (cranium)
- forms the posterior and part of the base of the skull
- foramen magnum is located at the base of the occipital bone and is a large opening through which the spinal cord emerges
What are sutures of the skull?
lines joining bones of skull that are composed of immovable joints
What are the four sutures of the skull? Where are they located?
- coronal (joins frontal and parietal bones)
- sagittal (joins two parietal bones)
- lambdoid (joins parietal bones and occipital bone)
- squamous (joins temporal bone to parietal bone on lateral surface of cranium)
Where are the mandible and maxillary bones located?
skull (facial bones)
What is the lower jaw bone called (only moveable bone in skull)?
mandible
What are the maxillary bones?
- form upper jaw bone (fuse in midline) including front part of hard palate
- each maxilla contains maxillary sinus (communicates with nasal cavity)
What bones form the cheekbones?
zygomatic bones
What bones (lying side by side) form the bridge of nose?
nasal bones
Where are the lacrimal bones?
near inside corner of eye in front part of medial wall of orbital cavity (each the size of a fingernail)
Where is the vomer and what is its shape?
- forms lower part of nasal septum
- shaped like blade of plow
Where are the palatine bones?
form back part of hard palate
Where are the inferior nasal conchae?
extend along sides of nasal cavities to increase surface area
Where are the ossicles located and how many are there? What do they do?
- in the middle ear
- three
- transmit sound waves
What is the hyoid bone?
attachment for tongue and other muscles
What are fontanels?
- spaces in infant skull due to incomplete formation of bone and sutures
- allows skull to compress and change shape during birth and permits rapid brain growth
What is the largest fontanel? When does it close?
- anterior fontanel
- around 18 months of age
What are the functions of the vertebral column?
- supports trunk and head
- protects spinal cord from mechanical injury
- provides attachment for hip bones
How many bones are in the adult vertebral column?
26
How many cervical vertebrae are there?
C1 through C7
What is the atlas (vertebral column)?
C1 cervical vertebrae - skull rocks on atlas when nodding
What is the axis (vertebral column)?
C2 cervical vertebrae - shaking head side to side (rotation); dens projects upward and serves as pivot
What is the uppermost section of the spine called?
cervical spine
What is the upper section of the spine below the cervical spine called (largest section)?
thoracic spine
What is the bottom section of the spine called (above sacral vertebrae)?
lumbar spine
How many thoracic vertebrae are there?
T1 through T12
Where is the thoracic spine? What attaches to it?
- longer spinous process below cervical vertebrae
- ribs and muscles attach here
How many lumbar vertebrae are there?
L1 through L5
Where is the lumbar spine? What does it do?
- small of back
- supports weight
- largest and heaviest vertebrae (not longest section of spine, vertebrae themselves are big)
How many sacral vertebrae are there?
5 separate bones in children fused in adults to just 1
Where is the sacral vertebrae?
sacrum area (above tailbone, below small of back)
What is another name for the tailbone?
coccyx
How many bones are in the coccyx (tailbone)?
4 or 5 in children and fused in adults to just 1
List structural aspects of vertebrae.
- centrum
- intervertebral discs of cartilage
- vertebral foramen
- spinous process
- transverse processes
- intervertebral foramen
What is the centrum of the vertebrae?
drum-shaped body anteriorly located (weight bearing)
What are the intervertebral disks (vertebrae)?
- cartilage that lies between vertebrae
- act as shock absorbers
What is the vertebral foramen (vertebrae)?
hole in which the spinal cord travels (protective)
What is the spinous process (vertebrae)?
projects posteriorly from vertebrae for muscle attachment
What are the transverse processes (vertebrae)?
- lateral, paired for muscle attachments
- holes in cervical ones (transverse foramen) for blood vessels and nerves supplying the head and neck
What are the intervertebral foramen (vertebrae)?
lateral openings from which spinal nerves emerge from the spinal cord
What is the thorax?
cone-shaped ribcage (includes sternum and ribs)
What are the components of the sternum (breast bone)?
- manubrium (clavicular notch site where it joins clavicle)
- body (ribs 2-7 attach; sternal angle elevated landmark)
- xiphoid process (CPR landmark; toward bottom)
Are the true ribs above or below the false ribs?
above
How do the ribs attach to the vertebrae?
posteriorly
What are the spaces between ribs that contain muscles, blood vessels, and nerves called?
intercostal spaces
What are the true ribs?
first 7 paris that attach anteriorly directly to sternum by costal cartilage
What are the false ribs?
- bottom 5 pairs (8-12)
- 8,9,10 attached to the cartilage of ribs above
- 11/12 are floating ribs (no anterior attachment)
What are the two divisions of the appendicular skeleton and what do they include?
- upper: shoulder (girdle), arm, forearm, wrist, hand, fingers
- lower: hip (pelvic girdle), thigh, leg, ankle, foot, toes
List the bones of the upper extremity (arm).
- humerus (upper arm)
- radius/ulna (forearm)
- carpals (wrist)
- metacarpals (palm)
- phalanges (fingers/digits)
What does the shoulder girdle consist of?
- clavicle
- scapula
What is the clavicle?
- bone that joins sternum anteriorly and scapula laterally
- helps support shoulder
- most frequently broken bone
What are the components of the scapula?
- spine: raised ridge for muscles that move arm (muscles sit in fossa)
- glenoid cavity: forms socket of the ball-and-socket joint with humerus
- coracoid process: for muscle attachment
- acromion: process that joins the clavicle; can be felt as the highest point of the shoulder
What is the humerus? What are its components?
- proximal bone of the arm
- head forms ball-and-socket joint with glenoid cavity of scapula
- medial and lateral epicondyles (tendon attachments at elbow)
What is the ulna? Name a component.
- medial side of lower arm
- aligns with little finger
- olecranon process (elbow/funny bone; forms joint with humerus)
What is the radius?
- lateral side of lower arm
- aligns with thumb/radial artery
What is the olecranon?
funny bone
What does the elbow joint consist of?
trochlea of humerus sitting in trochlear notch of ulna
What are the bones of the wrist and hand and how many are there per hand?
- carpal bones x 8 (make up wrist)
- metacarpal bones x 5 (framework for palm)
- phalanges x 14 (each known as phalanx; 3 per finger; 2 for thumb)
What are the 2 divisions of the lower division of the skeleton and what do they include?
- pelvis (hip, pelvic girdle)
- lower extremity (femur - upper leg/thigh; patella - knee cap; tibia/fibula - lower leg; tarsals - ankle; metatarsals - foot; phalanges - toes/digits
What are the three pairs of bones that make up the pelvis? Where are they fused?
- ilium (iliac crest; anterior superior iliac spine - landmark)
- ischium (lowest & strongest; ischial spine - landmark for childbirth; ischial tuberosity - sit bones)
- pubis (anterior part; pubic symphysis)
- fused at pubic symphysis
What is the pelvic girdle?
dorsal enclosure completed by the coccyx and sacrum plus a pair of three fused pelvic bones (ilium, ischium, pubis) (one on each side)
What is the acetabulum?
- fused ilium, ischiu, pubis on one side
- deep socket that holds the head of the femur to form the ball-and-socket hip joint
What is the obturator foramen?
- pelvic foramen
- largest in body; partially covered by a membrane
- passageway for blood vessels and nerves
What is the largest foramen in the body?
obturator foramen in pelvis
What are the differences between the male and female pelvises?
- female adapted for pregnancy and childbirth: lighter in weight; iliac crests wider & more flared; pubic arch wider; pelvic opening/outlet wider and more oval or heart shaped; sacrum & coccyx shorter and less curved
What is the upper leg bone?
femur (thigh bone)
Describe the femur.
- thigh bone
- largest & strongest bone
- large ball shaped head
- medial and lateral condyles (forms joint surface with tibia)
- medial epicondyle (tendon/ligament attachment)
- greater trochanter (tendon/ligament attachment at hip)
What bone is the kneecap?
patella
What is the tibia?
- shin bone
- sharp anterior crest
- weight bearing
- medial malleolus makes up inner “ankle”
What is the fibula?
- one of two lower leg bones
- lateral malleolus - outer “ankle”
- does not reach knee joint
- not weight bearing
What are the bones of the ankle and foot and how many are there per side?
- medial malleolus
- lateral malleolus
- tarsal bones x 7 (ankle) (weight bearing)
- calcaneous (heel)
- metatarsal bones x 5 (form instep and balls of feet)
- phalanges x 14 (3 in each toe and 2 in great toe)
What is the medial malleolus? Lateral malleolus?
- ankle bones
- medial is projection of tibia
- lateral is projection of fibula
What is osteoporosis?
- the significant loss of bone tissue which can lead to fractures, especially of the head of femur (hip fracture)
- postmenopausal women most susceptible as estrogen levels decline
What are the three abnormal spine curvatures?
- kyphosis (hunchback or exaggeration of thoracic curve; associated with osteoporosis)
- lordosis (swayback or excessive lumbar curve)
- scoliosis (lateral curvature; occurs during rapid growth during teenage years; more in girls)
What are the three main types of articulations or joints based on material that joins them?
- fibrous joint (fibrous connective tissue)
- cartilaginous joint (cartilage)
- synovial joint (fluid-filled joint cavity)
What are the three main types of joints based on degree of movement?
- synarthrosis (immovable)
- amphiarthrosis (slightly moveable)
- diathrosis (freely movable)
What are fibrous joints with example?
- bones held together by fibrous connective tissue
- eg sutures between skull bones (occipital and parietal bones)
- synarthrosis (immovable)
What are fibrous joints with example?
- connected by cartilage
- eg pubic symphysis joins the two pubic bones anteriorly in pelvis; intervertebral discs found between the bodies of vertebrae (when damaged cause herniated discs)
- amphiarthrosis (slightly moveable)
What are synovial joints with example?
- space between two bones of joint (joint cavity) filled with synovial fluid (nourishes the articular cartilage (hyaline) on the ends of the bones forming joint)
- eg femur and tibia - joints between long bones
- diarthrosis (freely moveable)
- most common type
- ligaments join bone to bone
- bursa prevent rubbing of tendons and ligaments
What are 6 types of movements of synovial joints?
- flexion (decreases angle between bones)
- extension (increases angle between bones)
- abduction (movement away from midline of body)
- adduction (movement toward midline of body)
- circumduction (circular - combining abduction, adduction, flexion, extension; eg arm rotation)
- rotation (twisting or turning of a bone on its own axis; eg twisting at waist)
What are the movements of the forearm?
- supination (turning palm up or forward)
- pronation (turning palm down or backward)
What are the movements of the ankle?
- inversion (turning sole inward)
- eversion (turning sole outward
- dorsiflexion (foot bent upward at ankle)
- plantar flexion (toes point downward flexing arch of the foot)
What are the types of synovial joints with examples?
- all diarthroses but range of motion varies
- gliding joint (wrist, ankle)
- hinge joint (between femur and tibia)
- pivot joint (proximal radius and ulna)
- condyloid joint (finger)
- saddle joint (opposition of thumb)
- ball-and-socket (shoulder joint and hip joint)
What are herniated discs?
- intervertebral discs composed of outer fibrocartilage ring (joint) and inner nucleus pulposus (gel-like, shock absorbing)
- repetitive stresses wear down fibrocartilage and nucleus pulposa bulges out
- can press on spinal nerve root exiting intervertebral space
- leads to sciatica or nerve pain down the leg
- treatment can involve surgery to remove disc then spinal fusion
What are three disorders of joints?
- herniated disc
- osteoarthritis
- rheumatoid arthritis
What is osteoarthritis?
- age-related degenerative joint disease affecting one or a few joints
- formation of bone spurs at edges of articular surfaces
- thickening of synovial membrane
- atrophy of the cartilage
- joint could fuse (immovable)
- caused by obesity or repeated injury (wear and tear)
- locations: weight bearing joints (hips, knees, vertebral column), digits
What is rheumatoid arthritis?
- swelling of multiple joints primary of hands/feet
- due to chronic inflammation of synovial membranes
- inflammatory chemicals destroy articular cartilage
- joint cavity develops adhesions and scar tissue
- joints stiffen and become non-functional
- permanent joint deformities result
- flare-ups and remisions
- cause: autoimmune with genetic predisposition
- immune cells make abnormal antibodies that circulate in the blood and attack the body’s own tissue
- treatment: removal of antibodies and anti-inflammatory medications
What are some skeletal changes in aging?
- loss of calcium salts (osteoporosis)
- decrease in amount of protein formed
- reduction of collagen in bones as well as in tendons, ligaments, and skin
- thinning of intervertebral discs (loss of height - 1.2 cm or .5 inches each 20 years beginning at 40)
- decrease in chest diameter (rib cartilage loses flexibility as it calcifies)
What are 3 steps towards healthy bones?
- well balanced diet (calcium, protein, vitamins C and D, magnesium and phosphorus; limit phosphorus as depletes bone calcium)
- weight bearing exercises (stronger, denser skeleton)
- healthy lifestyle (smoking, alcohol, high caffeine levels may deplete skeleton of calcium)
