7-2. The Vertebral Column and Thoracic Cage Flashcards
vertebral column
strong, flexible rod made of 26 irregular bones called vertebrae. Extends from the skull to the pelvis. Infants have 33 bones.
What are the functions of the vertebral column?
provide attachment points for ribs and muscles of back; encloses and protects spinal cord; supports head and trunk
intervertebral disc
cushion-like pads of fibrocartilage between adjacent vertebrae that permit movement while absorbing shockq
herniated disc
ruptured disc caused by trauma to the spine
intervertebral foramen
openings between adjacent vertebrae through which spinal nerves connect to the spinal cord
spinal stenosis
narrowing of the intervertebral foramina causing the nerves to pinch
normal curves
when viewed from the side, spine is curved in 4 regions to increase strength, help maintain balance, and absorb shock
What are the four normal curves, in order?
cervical curvature
thoracic curvature
lumbar curvature
sacral curvature
Which are the primary curves?
thoracic curvature and sacral curvature (were born with them)
Which are the secondary curves?
cervical curvature and lumbar curvature (develop later)
cervical curvature
concave curve in neck, C1-C7
lumbar curvature
concave curve in lower back, L1 - L5
thoracic curvature
convex curve in chest, T1-T12
sacral curvature
convex curve between hips (5 fused vertebrae)
abnormal curves
some are congenital; others result from disease, poor posture or unequal muscle pull on spine
scholeosis
abnormal lateral curvature, usually in the thoracic region (S shaped)
kyphosis
“hunchback” - an exaggerated thoracic curve
lordosis
“sway-back” - exaggerated lumbar curve
body
thick, disc shaped anterior part of vertebrae that bears the weight
vertebral arch
forms the walls around the spinal cord - consists of 2 short, thick processes behind the body (pedicles), which unite with lamina at the back
vertebral foramen
space between the arch and the body, containing the spinal cord (all line up to form the vertebral canal)
processes
7 processes project from the vertebral arch:
1 spinous process (bumps you can feel in the back)
2 transverse processes
2 superior articular processes
2 inferior articular processes
cervical vertebrae
7 vertebrae in neck, they have small oval bodies and large vertebrral arches. Spinous process is usually bifid (cleft). Each transverse process has a transverse foramen through which blood vessels pass to brain.
atlas
C1 - lacks a body and a spinous process; articulates with occipital bone (nod head yes)
axis
C2 - has thumblike process known as dens that sticks up into atlas (shake head no)
vertebra prominens
C7 - spinous process that can be felt through skin at base of neck (“bony landmark”)
thoracic vertebrae
12 vertebrae in chest region. They are larger than cervical and have long spinous processes that point sharply down. They have facets for articulations with ribs.
lumbar vertebrae
5 vertebrae in lower back. They are the largest, thickest vertabrae, with kidney shaped bodies. The spinous process is short, flat, broad and projects straight back. The vertebral foramen is triangular.
sacrum
1 triangular bone (fusion of 5 sacral vertebrae). At the back of the pelvic girdle, between the 2 coxal bones, where it forms the sacroiliac joint. Articulates superiorily with L5 and inferiorly wiht coccyx
coccyx
1 small triangular tailbone below sacrum (4 fused vertebrae)
What the sacrum articulate with superiorily? inferiorly?
superior - L5
inferior - coccyx
thoracic cage
bony framework of thorax consisting of sternum and costal cartilage anteriorly, the ribs laterally, and the bodies of thoracic vertebrae dorsally
sternum
flat narrow bone in the anterior midline of the thorax, resulting from fusion of three bones
What are the three regions of the sternum?
manubrium - superior
body - large, middle part
xiphoid process - inferior tip
What is the last part of the skeleton to osssify?
xiphoid process - over age 40
ribs
12 pairs of flat bones that make up side of thorax. Each rib articulates posteriorily with its corresponding thoracic vertebrae (eg. rib 1 > T1, etc)
true ribs
pairs 1-7, attach directly to sternum by costal cartilage
false ribs
pairs 8 - 12, do not attach directly to sternum
floating ribs
pairs 11 and 12, anterior ends do not attach to anything, only attach posteriorly to thoracic vertebrae
What is the classification of rib pairs 11 and 12?
both false and floating
costal margin
inferior margin of ribcage, formed by costal cartilage of ribs 7 - 10