A2 - protection of the CNS 3 Flashcards
how many spinal nerves does the vertebral column have?
31 pairs
how is the vertebral column divided?
cervical - 7
thoracic - 12
lumbar - 5
sacral - 5
coccygeal - 4 (fused)
what forms the vertebral arch?
the pedicals and laminae
functions of the vertebral column
- supports the body’s frame and connects the head to the rest of the body
- serves as protection for the spinal cord
- involved in posture and locomotion
- supports the weight of the body above the pelvis
describe the curvatures of the vertebral column
cervical
thoracic — primary
lumbar
sacral — primary
functions of vertebral curvatures
increase the strength of the vertebral column, its flexibility and its ability to absorb shock
what is a primary curvature?
concave anteriorly — thoracic and sacral
what are 3 abnormal curvatures?
- KYPHOSIS = an exaggerated thoracic curve. may result from osteoporosis
- LORDOSIS = an exaggerated lumbar curve. often seen in obesity and pregnancy
- SCOLIOSIS = an exaggerated lateral curve. most often seen in girls and may be associated with a. growth spurt
identify the parts of a typical vertebra
A = spinous process
B = lamina
C = vertebral foramen
D = transverse process
E = body
F = superior articular facet
G = pedicle
what are intervertebral discs?
- fibrocartilage pads that are sandwiched between adjacent vertebral bodies
- responsible for 25% the length of the vertebral column
where are iv discs not found?
C1-C2 and after S2
what are A and B?
A = nucleus pulposis — forms a gelatinous mass that is compromised of water, a few collagen fibres and some cartilage cells
B = annulus fibrosis — made of many sheets of fibrous connective tissues that are layered in rings around the nucleus pulposis
what are 3 functions of iv discs?
- increase size of vertebral column
- act as shock absorbers
- permit movement
describe cervical vertebrae and their distinct features
- 7
- have the smallest and thinnest intervertebral discs
- the most mobile
- have distinct features like : transverse foramina, 2 tubercles (anterior and posterior) and split (bifid) spinous processes, large, triangular vertebral foramen, small body
which cervical vertebrae are typical?
C3-C6
what do the transverse processes of cervical vertebrae end laterally in?
an anterior tubercle and a posterior tubercle — provide attachment for levator scapulae and scalenes
what is between the tubercles on the transverse processes of cervical vertebrae?
grooves for spinal nerves
describe the atlas (C1)
- consists of 2 arches (anterior and posterior) and contains 2 lateral masses
- has neither a body nor a spinous process
- the masses articulate with the occipital condyles of the skull, supporting its weight
- has a groove for the vertebral artery
describe the axis (C2)
- has an upward tooth-like projection (dens or odontoid process) and 2 superior articular facets
- it encircles both the dens and the spinal cord inside its coverings (meninges)
- it lies anterior to the spinal cord and serves as the pivot about which head rotation occurs
what does the dens of the axis articulate with?
the anterior arch of the atlas
what holds the dens in place against the anterior arch of the atlas?
the transverse ligament of the atlas
what cervical vertebra has the longest spinous process?
C7 = vertebra prominens
how is C7 atypical?
only transmit small accessory veins — thus the transverse foramina are smaller, and occasionally they are absent
what passes through the transverse foramina of the cervical vertebrae?
the vertebral arteries and their accompanying veins