Axial Skeleton Flashcards
1
Q
Vertebral Column (What we call it, 4 details)
A
- together with ribs and sternum we call this the “trunk”
A. represents the framework on which our entire skeleton is suspended. (central pillar of the body)
B. possesses ability to bend all directions
C. supports the head, provides attachment for ribs and articulates with the pelvic bones, to which it transmits the weight of the head and trunk
D. composed of irregular bones = vertebrae - separated by fibrocartilage disks - intervertebral discs
2
Q
Vertebral Column (How many Vertebrae and Groups)
A
consists of 33 vertebrae divided into 5 groups.
- 7 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral - in adult - fused into 1 bone - sacrum
- 4 coccygeal - may be fused - collectively called the coccyx
3
Q
Vertebral Column (Curves)
A
in the adult - the vertebral column has 4 curves
(obvious when viewed from the lateral side)
- thus adult one sees 4 curves: (in saggital plane)
a. cervical
b. thoracic same divisions as vertebral types
c. lumbar
d. sacral - from the front these appear as alternately concave and convex. (e.g. curve toward the viewer or away from the viewer).
- in fetus - only 1 curve is present - concave anteriorly due to fetal position.
- cervical curve develops in 3rd-4th month of postnatal life when child can raise and maintain head erect.
- lumbar curve develops when child is able to stand and walk erect.
- since the thoracic and sacral curves actually do not change from the fetus - they are concave anteriorly - are called primary curves.
- since the cervical and lumbar curves are opposite of the fetal curvature - they are convex anteriorly - they are called secondary curves.
note: in later months of pregnancy - increased size and weight of fetus cause women to increase the lumbar curvature (lordosis).
also: in old age intervertebral discs atrophy, resulting in loss of height and a gradual return to a continuous anterior concavity like the fetus.
4
Q
Vertebral Column (Abnormal Curvatures) *3
A
- scoliosis - lateral bending - usually in thoracic region.
- kyphosis - “hunch back” - exaggeration at thoracic curve (mild kyphosis = round shouldered)
- lordosis - “swayback” - exaggeration of lumbar curve
5
Q
Characteristics of different vertebrae (6)
A
A. all vertebrae will have:
- body
- vertebral arch (made up of pedicle and lamina)
- vertebral foramen (which united form the vertebral canal (spinal canal)
- transverse processes
- spinous processes (spine)
- superior and inferior articular processes (the two of these from adjacent vertebra form the intervertebral foramina)
6
Q
different vertebrae: Cervical Vertebrae (4 details)
A
- smaller in size, but with larger vertebral arches
- spinous processes of 2nd - 6th are bifid.
- each transverse process contains a foramen = transverse foramen (foramen transversarium)
- first, second, and seventh cervical vertebrae are atypical
a. first: Atlas - named for support of head
- basically just an anterior and posterior arch - no body or spinous processes
- lateral masses have superior articular surfaces that articulate with occipital condyles of skull - permits nodding of head.
b. second: Axis - does not have a true body
- tooth like or peg like structure called odontoid process or dens
- permits lateral rotation of head.
c. seventh: Vertebra Prominens - longest spinous process of cervical vertebrae.
- spinous process - not bifid.
- smaller transverse foramen.
7
Q
different vertebrae: Thoracic Vertebrae (5 details)
A
- larger than cervicals
- long spinous process - points in inferior direction
- longer and heavier transverse processes also
- costal facets are present on the sides of the bodies where the heads of the ribs articulate, and on the transverse processes where tubercles of ribs articulate (note Tll and T12 have no facets on transverse processes)
- may have facets or demi-facets
8
Q
different vertebrae: Lumbar Vertebrae (3 details)
A
- largest and strongest of the entire column
- spinous processes are square looking
- superior articular processes face medially while the inferior articular processes face laterally
9
Q
different vertebrae: Sacrum (7 details)
A
- triangular bone formed by union of 5 sacral vertebrae
- located between 2 hip bones of posterior of pelvic cavity
- anterior side has 4 transverse lines
- anterior side has 8 pelvic foramina - correspond to intervertebral foramina
- sacral canal = continuation of vertebral canal
- sacral promontory - anteriorly projecting superior border
- auricular surface - area articulating with ilium
10
Q
different vertebrae: Coccyx (1 detail)
A
- triangular bone formed by fusion of coccygeal vertebrae (tailbone)
11
Q
different vertebrae: Intervertebral disc (4 details)
A
- responsible for 1/4 length of vertebral column
- thickest in cervical and lumbar regions where most movement occurs - absent below lumbar region
- serve as shock absorbers - fluid nucleus pulposus allows it to change shape - rock forward or back
- with advancing age, water content in discs decreases - discs become thinner and less elastic - nucleus becomes indistinguishable from annulus
12
Q
Sternum (Where, 3 parts)
A
- breastbone
A. overlies heart - anterior thoracic wall
B. divided into 3 parts:
1. Manubrium - superior portion - triangular - articulates with 1st and upper part of 2nd costal cartilage
2. Body - middle largest portion - articulates with manubrium via a fibrocartilage joint - this joint forms the sternal angle (angle of Louis)
3. Xyphoid Process - inferior smallest portion - hyaline cartilage that becomes ossified thru life
C. jugular (suprasternal) notch - depression on superior surface of manubrium
D. clavicular notches - each side of jugular notch - articulate with clavicles
13
Q
Costal Cartilages (2 details)
A
- bars of hyaline cartilage connecting the superior 7 ribs to the edge of the sternum, and the 8th, 9th, and 10th to the cartilage immediately above.
- Cartilage of the 11th and 12th simply end in abdominal musculature
14
Q
Ribs (3 details)
A
A. twelve pair of ribs - form the sides of the thoracic cavity.
B. all attach to the vertebral column posteriorly
C. increase in length from the first thru the seventh, and then decrease in length to the 12th
15
Q
true ribs
A
1st - 7th - attach directly via cartilage to sternum
