Week 8 Intro to Skeleton Flashcards
What the 3 classifications of bones
- microscopic anatomy [compact & spongy bone]
- porosity
- gross anatomy - size & shape
What are the 4 classification of bones based on shape+size
long bines
short bones
flat bones
irregular bones
Describe structure of long bones
- longer than wide
- tubular shaft (diaphysis,body)
- expanded articular ends (epiphyses)
- head - expanded upper end
- neck - narrowing adjacent to head
Describe structure of short bones
- cube-shaped, ± equal length & width
Describe strucutre of flat bones
thin plate-like
Describe structure of irregular bone
no definable shape
Describe what are sesamoid bones
- short bones
- develop within tendons subjected to pressure
- increase lever function of muscles
- patella(kneecap) largest sesamoid bone
What are articular surfaces
where ever bones form a joint [articulate/articulation]
What are facets
smaller, forming distinct flat areas
What is bone lined with
articular [hyaline] cartilage
What are condyles
‘knuckle-shaped’ projections
What are epicondyles
small projections adjacent to condyles
How many bones are in the body
206 bones in body [sesamoid & sutural bones]
What are the 2 major components of the skeleton
bones & joints [cartilage & other connective tissues]
What are the 2 major divisions of skeleton, and describe each
- Axial skeleton
- bones of head and trunk
- forms longitudinal axis of body
- Appendicular skeleton
- bones that support the limbs
How amny bones in the axial skeleton and 4 main components
- 80
- skull
- bones associated with the skull
- thoracic cage
- vertebral collumn
How many cranial and facial bones in skull
8 cranial bones and 14 facial bones
How many bones in bones associated w skull
6 auditory ossicles and 1 hyoid bone
How many ribs in thoracic cage
1 sternum and 24 ribs
How many bones in vertebral collumn
24 vertebrae, 1 sacrum, and 1 coccyx
What are the 4 functions of the axial skeleton
- supports and protects organs in body cavities
-provides points of attachment for muscles that
->adjust positions of head, neck, and trunk
->perform breathing movements
->stabilize parts of appendicular skeleton
What is the function of the vertebral column(spine), how many bones
- protects the spinal cord
- supports the head and body
- 26 bones =24 vertebrae, the sacrum, and the coccyx
What are the 4 spinal curves
cervical curve
thoracic curve
lumbar curve
sacral curve
What are the Thoracic and sacral curves, functon
called primary curves
- present during foetal development
- accommodate internal organs
What are the Cervical and lumbar curves, function
- called secondary curves (compensation curves)
- appear after birth
- shift body weight to permit upright posture
How many cervical vertebrae in neck
seven cervical vertebrae
How many thoracic vertebrae in upper back
- 12 thoracic vertebrae
- each articulates with one or more pairs of ribs
How many lumbar vertebrae in lower back
five lumbar vertebrae
What 3 parts does each vertebra consist of
vertebral body
vertebral arch
articular processes
What is vertebral body
- transfers weight along the spine
- forms anterior margin of each vertebral foramen
What is vertebral arch
- forms posterior margin of each vertebral foramen
- walls are called pedicles
- laminae form roof
What are articular processes
lateral projections between laminae and pedicles
What is a spinous process
posterior projection from where vertebral laminae fuse
What is a transverse processes
projections from where laminae join pedicles
What are superior and inferior articular processes
have articular facets
-for articulations with neighboring vertebrae
What are Intervertebral discs
pads of fibrocartilage
- separate adjacent vertebral bodies
What are Intervertebral foramina, function
- gaps between pedicles of adjacent vertebrae
- for nerve connections to & from spinal cord
What are Vertebral canal
- formed by vertebral foramina of successive vertebrae
- encloses the spinal cord
What are the 5 regions of the vertebral collumn
- Cervical (C)
- Thoracic (T)
- Lumbar (L)
- Sacral (S)
- Coccygeal (Co)
What is the cervical vertebrae
- C1 to C7
- small body (support only head)
- large vertebral foramen (largest part of spinal cord)
- concave superior surface
- anterior edge is inferior to posterior edge
Describe the strucuture of the atlas
- (C1)
- articulates with occipital condyles of skull
- has no body or spinous process
- has a large, round vertebral foramen within anterior and posterior arches
Describe the structure of the axis
(C2)
- articulates with the atlas
- heavy spinous process for muscles of head and neck
- bodies of axis & atlas fuse during development to form the dens
What are Thoracic vertebrae (T1–T12)
- have heart-shaped bodies
- larger bodies and relatively smaller vertebral foramina than those in cervical vertebrae
- long, slender spinous process
- dorsolateral surfaces of body have costal facets
- articulate with heads of ribs
Describe the T1–T8 thoracic vertebra
- each articulate with two pairs of ribs
at superior and inferior costal facets
Describe the T9–T11 thoracic vertebra
articulate with one pair of ribs
Describe the T10-T12 thoracic vertebra
transition to lumbar vertebrae
What are the Lumbar vertebrae (L1–L5)
- largest vertebrae
- thick, oval-shaped bodies
- no costal facets or transverse costal facets
- triangular vertebral foramen
- superior articular processes face medially
- inferior articular processes face laterally
- slender transverse processes project dorsolaterally
- massive spinous processes for attachment of lower back muscles
Describe the sacrum, function, attaches what?
- L5 articulates with the sacrum
- sacrum articulates with the coccyx
- curved, more so in males than in females
- protects reproductive, urinary, and digestive organs
-attaches
->axial skeleton to pelvic girdle
->broad muscles that move the thigh
What is the adult sacrum
-consists of five fused sacral vertebrae
->sacral canal
->median sacral crest
->lateral sacral crest
->sacral cornua
->sacral hiatus
-fusion occurs between puberty and ages 25–30
-leaving transverse lines
What is the sacral canal
- passageway that extends the length of the sacrum
- contains nerves and membranes
What is the median sacral crest
- ridge formed from fused spinous processes
- 4 pairs of sacral foramina open to either side
What is the lateral sacral crest
- ridge formed from fused transverse processes
- attaches to muscles of lower back and hip
What is the sacral cornua
- ridges formed from laminae of 5th sacral vertebra
- laminae do not meet at midline
What is the sacral hiatus
- opening at inferior end of sacral canal
- bordered by sacral cornua
- covered by connective tissues
What is the mature coccyx
consists of three to five fused coccygeal vertebrae
attaches ligaments and a constricting muscle of the anus
What is the thoracic cage and the 4 things it consists of
- the skeleton of the chest
- consists of
- thoracic vertebrae
- ribs
- costal cartilages
- sternum
What are the 2 functions of the throacic cage
- protects organs of the thoracic cavity
->including heart, lungs, and thymus - provides attachment for muscles involved in
->breathing
->maintaining position of vertebral column
->moving pectoral girdles
What are ribs
- 12 pairs of long, curved, flat bones
- extending from thoracic vertebrae
What are 2 types of ribs
true ribs
false ribs
How many of the ribs are true ribs, describe
Ribs 1–7
- vertebrosternal ribs
- connected to sternum by costal cartilages
How many of the ribs are false ribs, describe
Ribs 8–12
- do not attach directly to sternum
- vertebrochondral ribs (Ribs 8–10)
->costal cartilages fuse together
-> merge with cartilages of rib 7 before reaching sternum
- floating or vertebral ribs (Ribs 11–12)
- have no connection with the sternum
- connect only to vertebrae and muscles of body wall
What are the 4 structures of the ribs and describe each
- Head (capitulum) at vertebral end of rib
->has superior and inferior articular facets - Neck - short area between head and tubercle
- Tubercle - a small dorsal elevation
->has an articular facet that contacts transverse process of thoracic vertebra (at t1–t10 only) - Shaft - attaches muscles of pectoral girdle and trunk
->attaches intercostal muscles that move the ribs
What is the sternum and 3 parts of the sternum
- a flat bone in anterior midline of thoracic wall
- three parts of the sternum
->manubrium
->body
->xiphoid process
What is the manubrium
- superior portion of sternum
- broad, triangular shape
- articulates with clavicles (collarbones)
- articulates with cartilages of first rib pair
- jugular notch, a shallow indentation between clavicular articulations
What is the sternal body
- tongue-shaped
- attaches to manubrium
- attaches to costal cartilages of rib pairs 2–7
What is the xiphoid process
- smallest part of the sternum
- attaches to sternal body
- attaches to diaphragm and rectus abdominis muscle
What is flexion
bending, decreases angle between bones
What is extension
opposite of flexion - straighten joint back to anatomical position
- increases angle between bones
What is abduction
movement of bone/body part away from midline of body
What is adduction
opposite of abduction - movement back towards midline of body
What is rotation
‘spinning’ around own axis
What is medial rotation
body part [limb] moves inward
What is lateral rotation
returns limb to anatomical position
What is circumduction
body part ‘draws circle’
What are 3 types of joints, describe each
(i) fibrous joints - synarthroses (Gk: syn- together, arthrosis – joining)
->lack space (joint cavity) between bones of joint
-> immovable
(ii) cartilaginous joints-amphiarthroses
->also lack joint cavity, slightly moveable
(iii) space/cavity between bones of joint, movable - diarthroses or synovial joints – the most common
What are the 6 types of synovial joints
- ball and socket
- hinge
- pivot
- plane
-saddle - condylar
What is a multiaxial joint
- shoulder joint has three degrees of freedom or axes of rotation
- some joints are monoaxial [uniaxial] or biaxial
What do long bones act as in lever system
act as levers to enhance speed or power of limb movements
What is a lever
any elongated, rigid object that rotates around a fixed point called fulcrum
When does resistance occur
when effort applied overcomes resistance (load) at some other point
What are 3 types of levers
- first class leverl
second class lever
third class lever
What is a first class level
- fulcrum in the middle between effort & resistance (EFR)
- Atlanto–occipital joint lies between muscles on back of neck (applying effort) & weight of the face (resistance)
->eg.opening mouth - loss of muscle tone occurs when you nod off in class
What is a second clas lever
- resistance between fulcrum & effort (FRE)
E.g. when bouncing a baby on your knee, hip is fulcrum, baby’s weight is resistance, and effort is applied at the tibia
What is a third class lever
- effort between the resistance & the fulcrum (REF)
- most joints of the body
- effort of a biceps curl is applied to the forearm between the elbow joint (fulcrum) & the weight in the hand (resistance)
What is range of motion
- degrees through which a joint can move
- aspect of joint performance -> physical assessment of a patient’s joint flexibility
What is ROM determined by 3 things
- structure of the articular surfaces
-> elbow - olecranon of ulna fits into olecranon fossa of humerus - strength & tautness of ligaments & joint capsules
->stretching of ligaments increases range of motion - action of the muscles & tendons
->nervous system monitors joint position & muscle tone
->muscle tone - state of tension maintained in resting muscles
