axial skeleton part 2 Flashcards
What is the vertebral column?
spine
What does the vertebral column consist of?
24 single bones (vertebrae) and 2 fused bones (sacrum & coccyx)
What are the functions of the vertebral column?
axial support and weight bearing, transfers weight to lower limbs, surrounds & protects spinal cord
When are spinal curves developed?
all 4 are developed by age 10
When are primary curvatures present?
at birth
What are the primary curvatures?
thoracic curve & sacral curves; give the baby “C” posture
When do the secondary curvatures develop?
after birth
What are the secondary curvatures?
cervical curve & lumbar curve
When does the cervical curve develop?
as infants learn to balance the weight of their head on their neck
When does the lumbar curve develop?
with the ability to stand; balances the weight of the trunk over the lower limbs
What are the abnormal spinal curvatures?
kyphosis, lordosis, and scoliosis
What is kyphosis?
the thoracic curve becomes exaggerated posteriorly, producing a rounded-back or “humpback”
What is lordosis?
an anterior exaggeration of the lumbar curve; bending backward or “swayback”
What is scoliosis?
abnormal lateral curvature of the spine; most common distortion of the spinal curvature
What is the vertebral body?
rounded central portion; transfers weight along the axis of the vertebral column
What are characteristics of the vertebral body?
connected to adjacent vertebrae by ligaments; have intervertebral discs
What are intervertebral discs?
fibrocartilage pads that separate vertebrae & absorb shock
What is the vertebral foramen?
where spinal cord passes through
What is the spinous process?
the part you can feel & see on your back
What is the transverse process?
two lateral projections; sites for muscle attachments & may articulate with the ribs
What are the intervertebral foramina?
gaps between the pedicles of successive vertebrae; permit nerves to pass to & from the spinal cord
What are pedicles?
connect the body with the transverse processes
What are lamina?
connect the transverse processes with the spinous process
What are the cervical vertebrae?
of the neck; C1-C7 (7 vertebrae)
What is the atlas?
C1; lacks a body & spinous process; the articulation with the occipital condyles of the skull allows you to nod your head “yes”
What is the axis?
C2; acts as a pivot for rotation of the atlas & skull; joint between C1 & C2 allows you to rotate your head to say “no”
What is the odontoid process (dens)?
part of the axis; large vertical process that is the pivot point
What are C3-C7?
the smallest, lightest vertebrae; spinous process divided into 2 branches (“split tip”); transverse processes have transverse foramina where vertebral arteries pass to the brain
What is C7?
vertebrae prominens
What are the thoracic vertebrae?
T1-T12 (12 vertebrae)
What are costal facets?
on the thoracic vertebrae; articulating surfaces on each side that articulate with the ribs
What are characteristics of the thoracic vertebrae?
body is larger than cervical & somewhat heart-shaped; spinous process is long with a sharp downward angle; vertebral foramen is circular
What are the lumbar vertebrae?
L1-L5 (5 vertebrae)
What are the characteristics of the lumbar vertebrae?
large body; oval-shaped; vertebral foramen is triangular; short, thick, hatchet-shaped spinous processes; sturdiest because they are subjected to the most stress
What is the sacrum?
5 fused vertebrae; forms the posterior border of pelvis
What is the median sacral crest?
remnants of the spinous process of the fused vertebrae
What is the ala?
wing-like projections that articulate with hip bones (sacroiliac/SI joint)
What is the sacral promontory?
the prominent ridge on the anterior side of the 1st sacral vertebrae
What are the sacral foramina?
openings for passage of the sacral nerves
What is the coccyx?
4 fused vertebrae (3-5 bones); remnant of the tail
What is the bony thorax/thoracic cage?
composed of sternum, ribs, & thoracic vertebrae; forms protective cage surrounding the heart, lungs, etc.
What is the sternum/breastbone?
flat bone; fusion of 3 bones: manubrium, body, & xiphoid process
What is the manubrium?
articulates with clavicles (collar bones) and the cartilages of the 1st ribs
What is the body?
where ribs 2-7 attach
What is the xiphoid process?
where the diaphragm and rectus abdominis muscle attach
What is the area where the manubrium articulates with the clavicle?
sternoclavicular/SC joint
How many pairs of ribs are there?
12; all articulate posteriorly to the vertebral column
What are true ribs?
the 1st 7 pairs; attach directly to the sternum by individual costal cartilages
What are false ribs?
the next 5 pairs; pairs 8-10 have indirect cartilage attachments to the sternum; the last 2 pairs are floating ribs (no sternal attachment)