Back and Vertebral Column

the vertebral column extends from

the skull to the tip of the coccyx

the vertebral columns main functions are (5)

1. manatins posture

2. absorbs shock and transmits body weight

3. assist with locomotion

4. provides mobile framework

5. protects spinal cord and spinal nerves

how many cervical vertebrae

7

how man thoracic vertebrae

12

how many lumbar vertebrae

5

how many sacral vertebrae

5 fused

how many coccygeal vertebrae

4 fused

which regions are primary curvature (present before birth)

thoracic and sacral

primary curvatures are called

Kyphotic curves (concave posteriorly)

which regions are secondary curvature (present after birth)

cervical and lumbar

secondary curvatures are called

Lordotic curves (concave anteriorly)

excess curvature of the thoracic vertebrae is called

kyphosis (hunch back)

kyphosis is caused by

degenerative disease, developmental problems, erosion or fracture of anterior part of vertebra, posture component

excess curvature of the lumbar vertebrae, with anterior rotation of pelvis is called

lordosis (sway back)

lordosis is caused by

weak trunk muscles, obesity, pregnancy, compression fractures

increased lateral curvature of the spine with vertebrae rotation is called

scoliosis

scoliosis is caused by

weakness of back muscles, poor posture, congenital defects in vertebrae development, inequity of lower limb length

unique/distinctive features of cervical vertebrae (4)

1. small body

2. large vertebral foramina

3. transverse foramina

4. bifid (split into two) spinous process

cervical vertebrae motions

flexion, extension, and lateral flexion

unique/distinctive features of thoracic vertebrae (4)

1. costal facets

2. long transverse process

3. long spinous process

4. small vertebral foramen

thoracic vertebrae motions

rotation and some lateral flexion

unique/distinctive features of lumbar vertebrae (3)

1. large bodies

2. large vertebral foramen

3. no costal facets

lumbar vertebrae motions

flexion and extension, some lateral bending and limited rotation

what is the name of C1 vertebrae

atlas

what movement does the atlas (C1) provide

flexion and extension of head (“yes” movement)

what joint does C1 form with the skull

atlanto‑occipital joint

what is the name of C2 vertebrae

axis

what movement does the axis (C2) provide

lateral rotation of head (“no” movement")

what is the name of the joint the axis (C2) forms with the atlas (C1)

atlanto‑axial joint

how are intervertebral disc named

named for the two vertebrae that it is between (ex: L1 and L2 → disc is L1/L2)

main function of intervertebral disc

flexible shock absorbers

what is the inner part of the intervertebral disc called

nucleus pulposus (gelatinous material)

what is the outer part of the intervertebral disc called

anulus fibrosus (concentric layers of fibrocartilage)

invertebrate disc have a high content of

water (H2O)

how does a herniated disc happen

the nucleus pulposus protrudes through a weakened or torn annulus fibrosus

what is disc degeneration

gradual deterioration of invertebral disc over time

main cause of disc degeneration is

natural stress & minor injuries

what happens to disc water content in degeneration?

gradually loses water content, causes disc to shrink

which structure weakens during disc degeneration

annulus fibrosus

what are the 5 vertebral ligaments

1. anterior longitudinal ligament

2. posterior longitudinal ligament

3. supraspinous ligament

4. interspinous ligament

5. ligamentum flavum

name the ligaments (pink, blue, green)

pink = anterior longitudinal ligament

blue = posterior longitudinal ligament

green = suoraspinous ligament

during whiplash which ligament resists hyperextension

anterior longitudinal ligament (would tear if stretched to far)

during whiplash which ligament resists hyperflexion

posterior longitudinal ligament (would tear if stretched to far)

name the muscle (green)

Trapezius

trapezius innervation

spinal accessory nerve (CN XI)

trapezius action

elevates, retracts and depresses scapula

name the muscle (purple)

latissimus dorsi

latissimus dorsi innervation

thoracodorsal nerve

latissimus dorsi action

adducts, extends, and medially rotates humerus

what is the arrow pointing to and why is this structure important

triangle of auscultation - spot on back where you can listen to the lungs the best

name the muscle (teal)

levator scapula

levator scapula action

evelates and downward rotation of scapula

name the muscle (pink and purple)

pink = rhomboid minor

purple = rhomboid major

rhomboid major and minor innervation

dorsal scapular nerve

rhomboid major and minor action

retracts and downward rotation of scapula

name the muscle (orange)

serratus posterior superior

serratus posterior superior innervation

2nd-5th intercostal nerves

serratus posterior superior action

elevates ribs (respiration)

name the muscle (red)

serratus posterior inferior

serratus posterior inferior innervation

9th-12th intercostal nerves

serratus posterior inferior action

depresses ribs (respiration)

what muscles are considered accessory respiratory muscles

serratus posterior superior and serratus posterior inferior

name the muscle (purple)

splenius

splenius innervation

posterior rami of cervical spinal nerves

splenius action (unilateral and bilateral)

unilateral - laterally flexes and rotates the head and neck

bilateral - extends the head and neck

name the muscle and its 3 subsections (green, blue, red)

erector spinae

green = spinalis

blue = longissimus

red = illicostalis

erector spinae innervation

posterior rami of spinal nerves

erector spinae action (unilateral and bilateral)

unilateral - laterally flexes the vertebral column

bilateral - extends vertebral column and head

what are the 3 muscle enclosed in the transversospinalis muscle

semispinalis, rotatores, multifidus

transversospinalis muscle action

Cause rotational & lateral bending movements between adjacent vertebrae and stabilize the vertebral column

name the muscle (green)

semispinalis

semispinalis action

extends head and vertebral column. rotates contralaterally head and vertebral column

name the muscle (purple)

multifidus (spans 2-4 vertebral levels)

multifdus action

stabilizes vertebrae during local movements of vertebral column

name the muscle (red)

rotatores (spans 1-2 vertebral levels)

cervical vertebra movement

flexion, extension, lateral flexion

thoracic vertebra movement

rotation

lumbar vertebra movement

flexion, extension, and lateral flexion

sacral vertebra movement

no movement

how does a strain happen

occurs when muscle fibers are abnormally stretched or torn (especially in erector spinae muscles)

most common cause of lower back pain is

due to a strain

how does a sprain happen

occurs when ligaments are torn from their attachments – due to excessive extension or rotation

what is a back spasm

sudden involuntary muscle contraction

what causes back spasms

occurs after injury or in response to inflammation