MSK of the Back and Spine

how many bones are in the human body?

206

what percent of body weight does the skeleton contribute?

14%

how many bones are in the appendicular skeleton?

126

how many bones are in the axial skeleton?

80

how many total vertebrae are in the body?

33

what are the three classifications of ribs?

true, false, floating

what are the parts of the sternum?

manubrium, sternal angle, body, and xyphoid process

osteologic features of vertebrae

body and end plate, processes, foramina, and the arch

What are the processes of a vertebra?

spinous, transverse, and superior/inferior facets

what are the foramina of a vertebra?

vertebral, intervertebral, and transverse

laminar arch

transverse process to transverse process

pedicle

vertebral body to the transverse process

types of vertebrae

cervical, thoracic, lumbar, sacral, and coccyx

curves of the spine

lordosis and kyphosis

lordosis

convex anteriorly

kyphosis

convex posteriorly

where is there a natural lordosis in the spine?

lumbar and cervical regions

where is there a natural kyphosis in the spine?

sacral and thoracic regions

1st cervical vertebra

atlas

2nd cervical vertebra

axis

movements of atlas and axis

flexion, extension, and rotation

common features of cervical vertebrae

transverse foramen, uncovertebral joints, bifurcating spinous process, small body

why is C7 different?

A large spinous process because an artery does not pass through the transverse foramen

bodies of the thoracic vertebrae

increase in size caudally

spinous processes of thoracic vertebrae

long, slender, and directed caudally to overlap with the succeeding vertebra

movements of thoracic spine

lateral flexion and rotation

limited movements of thoracic spine

flexion and extension due to rib cage

where to the ribs attach to the throacic vertebrae?

superior and inferior costal facets of vertebral body and costal facet on transverse process

true ribs

attach directly to sternum

what are the true ribs

1-7

false ribs

attach via cartilage to the cartilage of the rib above

what ribs are false ribs

8-10

another name for false ribs

vertebrochondral ribs

floating ribs

verebrae posteriorly with no anterior attachment

what ribs are floating ribs

11-12

typical ribs

3-9

atypical ribs

1, 2, 10, 11, 12

why is the first rib atypical?

it has a single head facet and scalene tubercle

why is the second rib atypical?

two head facets and tuberosity for serratus anterior

why are ribs 10-12 atypical ribs?

one head facetand articulate with only one vertebra

why are ribs ONLY 11 and 12 atypical ribs?

no neck or tubercle

lumbar vertebra

largest and heaviest vertebrae that are wider and longer than others with short, heavy pedicles and broad spinous processes

mamillary process

spinous process

transverse process

superior articular facet of vertebra

inferior articular facet of vertebra

vertebral foramen

intervertebral foramen

transverse foramen

lamina

costal facet on transverse process

E

inferir costal facet

costal tubercle

what is the orientation of the facets in the lumbar spine?

in the sagittal plane

what is the major motion of the lumbar spine

flexion and extension

what is the minor motion of the lumbar spine

lateral flexion and extension

what is the shape of the sacrum?

wedge

superior articular processes of sacrum

auricular surface of sacrum

sacral hiatus

dorsal foramen of sacrum

anterior foramen of sacrum

where is the pelvic surface concave?

articulating with the ilium

coccyx

4 fused vertebrae

concave surface of the coccyx

anterior surface

convex surface of the coccyx

posterior surface

transverse processes of coccyx

what is the ONLY ligament to resist extension?

anterior longitudinal ligament

anterior longitudinal ligament

where is the anterior longitudinal ligament

cranium to sacrum

posterior longitudinal ligament

what does the posterior longitudinal ligament resist?

hyperflexion

where does the PLL attach?

intervertebral discs

why does the PLL attach to the intervertebral discs

prevent direct posterior herniation of the nucleus pulposus

where is the PLL?

C2-sacrum

where does the PLL turn into the tectorial membrane?

C1

intertransverse ligament

what does the intertransverse ligament resist?

lateral flexion

ligamentum flavum

what does the ligamentum flavum do?

provide constant tension in neutral and flexed spines

why is the ligamentum flavum unique?

only ligament with elasticity

where does the ligamentum flavum attach?

lamina to lamina

why do the intervertebral discs require compression from the elastic fibers in the ligamentum flavum?

increased pressure = increased sitiffness = increased support in neutral spine

interspinous ligament

what does the interspinous ligament limit?

spinal flexion

supraspinous ligament

what does the supraspinous ligament limit?

flexion

where is the supraspinous ligament?

whole spine except C spine

what is the supraspinous ligament in the c spine?

ligamentum nuchae

which is the first posterior ligament to fail?

supraspinous ligament

why is the supraspinous ligament the first to typically fail?

composed primarily of collagen

ligaments that resist flexion

supraspinous ligament, ligamentum nuchae, interspinous ligaments, ligamentum flavum, PLL

intervertebral discs

how does the thickness of intervertebral discs change?

increases caudally

annulus fibrosis

what is the annulus fibrosis made of?

fibrocartilage

how does blood supply and innervation change within the annulus fibrosis?

decreases with deeper rings

nucleus pulposus

B

what is the nucleus pulposus composed of?

mucoid material interspersed with reticular and collagen fibers