Vertebral Column Flashcards
The Vertebral column has how many vertebrae?
-24 individual vertebrae
How many regions in the spine?
- Cervical
- Thoracic
- Lumbar
- Sacral
- Coccygeal
Cervical Lordosis
- Cervical ( top portion of the spine)
- 7 vertebrae
- C1 and C2 may be fused the occipital bone of the skull
- normally curved with the convexity facing anteriorly,
Thoracic Kyphosis
- 12 vertbrae (middle)
- curved facing posteriorly
Lumbar lordosis
- 5 vertebrae (near bottom)
- L5 maybe fused to the sacrum
- convexity faces anteriorly
Sacral
-Five sacral vertebrae are fused to form the sacrum
S1 maybe free (transitional vertebrae
Coccygeal
–Four coccygeal vertebrae form the coccyx
The Curves of the spine form when?
- the curves of the spine of the spine form secondarly to the development of postural reflexes about three months after birth.
Motion segement
- Each pair of individual, nonfused vertebrae, with intervening intervertebral disc, facet joints, and ligaments, constitute a motion segement, the basic movable unit of the intervebral column
Motion Segement is made up of how many joints?
- Three joints (except C1 & C2)
- a partly moveable intervertebral disc anteriorly, and a pair of gliding synovial facet (zygapophyseal) joint posteriorly
intervertral disc
- -is a martly movable fibrocartilaginous joint between two vertebrae consisting of (1) the load bearing annulus fibrosus attached to the vertebral bodies above and below, and the mosre central nucleus pulposus; it transfers the load imposed on it to the annulus.
- the discs amke possible movement betweeen the vertebral bodies.
vertebral formina
-longtitudal series of vertebral formina form the spinal (or neural or vertebral) canal, transmitting the spinal cord and related coverings, vessels, and nerve roots
annulus fibrosus
- layers of concentric, interwoven collagenous fibers integrated with cartilage cells
nucleus pulposus
- a mass of thin, degenerated collagen and proteoglycans in water
Cervical vertebrae
- support and move the head and neck, supported by intervertebral discs between C2 and T1
C1 and the occiptial bone
-The ring shape atlas of (C1) has no body; thus, there are no weight-bearing discs between the occiptal bone (occiput) of the the skull and C1, and between C1 and C2(the axis)
How is the weight of the head transfered?
- head weight is tranferred to C3 by the large articular processes and facets of C1 and C2.
Atlantoocipital joints
- in conjunction witht he C3 and -C7 facet joints permit a remarkable degree of flexion/ extension
Head movement?
- the dens of C2 projects into anterior part of the C1 ring, forming a pivot joint and enabling the head and C1 to rotate up to 80 degree. such rotation capacity is permitted by the relatively horizontal orientation of the cervical facets.
- C3-C6 vertbrae are similar
C7
- prominant spinous process easily palpated. the anteriorly directed cervical curve( convex anteriorly) and the extensive paracervical musculature generally prelude palpation of the other cervical spinous process.
vertebral arteries
vertebral arteries arise from the subclavian arties and reach the brain stem, by way of the formina of the transverse process of the upper six cervical vertebrae, and make an S-turn ino the foramen magnum. these vessels are subject to stretching injuries with extreme cervical rotation of the hyperextened neck.
What does the cervical vertebral canal do?
- it conducts the cervical spinal cord and its coverings.
what are the most mobile of the cervical region?
- The C4-C5 and C5-C6 are the most mobile of the cervical region and are partiularly prone to disc and facet degeneration with aging.
thoracic vertbrae
- 12
- characerized by long slendor spinous processes, heart shaped bodies, nearly vertically oriented facets, and eleven interverbral discs, support the chest and aticulate with ribs bilaterally. in general, each rib forms a synovial joint with two demifacets on the bodies of adjacent vertebra. Variations of these costovertebral joints are seen with T1, T11 and T12. The existance of the ribs in the thoracic region contributes to the relatively reduced range of motion in this part of the vertebral column
Lumbar vertebrae
- these five vertebrae are the most massive of all the individual vertebrae. theri thick processes secure the attachements of numerous ligaments and muscle tendons.
- significant flexion and extension of the lumbar and lumbosacral motion segments, particularly at L4-L5 and L5- S1, are possible.
- At about L1 the spinal cord terminates and cauda equina begins
cauda equina
- bundle os lumbar, sacral, and coccygeal nerve roots
lumbar intervertebral formina
- are large; tranmitting nerve roots/sheaths take up only about 50% of the forminal volume.
- occasionly L5 vertebra is partially or compleelty fused to the sacrum.- leaving only 4 vertebrae
- S1 vertebra may partially or wholly fuse to L5, resulting in essentially 6 lumbar verte brae
planes of the articular facets
-the planes of the articular facets strongly influence, but do not complelety determine, the direction and degree of motion-segment movement.
cervical facets
- the plane of the cervical facets is angled off the horizontal plane about 30 degree, giving the neck considerable freedom of motion, especially in rotation.
thoracic facets
- the thoracic facets are arranged more vertically in the coronal plane and are virtually non-weight-baring. the range of motion here is significantly limited in all planes, especially rotation.
lumbar facets
- the plane of the lumbar facets is largely sagittal, resisting rotation of the lumber spine. The L4-L5 facet joints permit the greatest degree of lumbar motion in flexion /extension. the lower lumber facets, oriented in the saggital planes as they are, are prone to reorienting toward the coronal plane under continued stress.
- this change makes it easier for L4-L5 and L5-S1 to experience disc trama by allowing more rottion than normal when rotatting the torso let or right whiel bearing loads.
sacrum
- consists of fused vertebrae: the intervertbral discs here are largely replaced by bone. the dura-lined sacral canal contians the terminal sac of the dura mater that ends at S2.
- The sacral nerve roots continue inferiorly as the cauda equina, transmiting their respective sacral intervertebral formina. This sac is relatively safe for injection into or withdrawal of cerebrospinal fluid.
what forms the sacroilliac joint?
- the sacrum joins with the ilium of the hip bone at the auricular surface, forming the sacroiliac joint.
What contributes to the wieght bearing of the hips?
- The sacrum and ilia of the hip bones form an arch for the transmission and distribution of weight-bearing forces from the spine to the heads of the femora.
Coccyx
- the tail bone
- consists of 2-4 tiny fused, rudimentary vertebrae.
- rare occasion there may be more coccygeal vertebrae
- falls are generally on of the more unpleasant experiences
