Axial skeleton includes

1. Cranium
2. Vertebral column
3. Ribs
4. Sternum
5. Sacrum

Cranium

• protection for head organs (eyes/nose/ears/mouth/brain...)
• mvt bones: occipital +temporal bones
• mastoid process: attachment point for muscles (sternocleidomastoid, upper trap, humeral head muscle)
• formal magnum: spinal cord runs in middle

Vertebrae

• good design for distributing load (arches)
• cauda equina (horsetail)
• anterior: most of the weight-bearing
• posterior: transverse processes, laminae, particular cross-section, vestibular arch
  • main protection, stability

cervical bones

C1-7/8

thoracic bones

T1-12

lumbar bones

L1-L5

ribs

• ribcage: protect internal organs (heart)
• posterior: head, neck, vestibular process, turbecle
• 2 synovial joint: costacoperal joint + costotransverse joint
• ribs articulate to vertebrae

rib's don't go out

• break or dislocate
  • might feel like going out
• levels of anatomy hold ribs in place (transverse process + scapula head)(muscles: traps, erector spinae. intercostal muscles)
• words matters to people (make people feel weak)

Sternum

• joints (from top to bottom0
  • sternoclavicular joint/clavicular facet
  • 1st sternocostal joint (costal facet)
  • manubriosternal joint

whole vertebral column

• 33 verteberal segments
  • 7 cervical. 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal segments
• Top to bottom curvatures (4)
  • cervical lordosis
  • thoracic kyphosis
  • lumbar lordosis
  • sacrococcygeal kyphosis
• insane support

Ligament

• provides insane support
• ligamentum flavum (innermost lig. in center)
• supraspinous + interspinous ligaments (between each spinous process)
• intertransverse ligaments (between adjacent transverse process, vertical way)
• anterior long. ligament: big vertical lig. on front side)
• posterior long ligment: big vertical lig. behind circle bone)

cervical vertebrae

• atypical vert: 1(no vertebral body), 2 (odontoid process/dens) , 7 (large spinous process)
  • look funny
• typical vert: 3-6
• all have transverse vertebrium (vascular blood supply to brain)

Thoracic Vertebrae

• Typical: T2-T9
• costocorporeal joints + apophyseal joint (T6-T7)
• Atypical: T1, 10, 11, 12
  • T1: full costal facet
  • T10-12: lack costotransverse joints (floating ribs attachment)

lumbar vertebrae

• big vertibral body => larger body mass (2x as cervical)
• C-spine: fully vertical

Sacrum & coccyx

• sacrum: where lumbar spine sits
  • articulate with pelvis // push compressive force out to pelvis
• coccyx: attachment to muscles (pelvis floor)

General arthrology structure (joint)

• transverse+spinous processes
  • increase moment arms for lumbar
• apophyseal joint
  • where guide intervertebral motion (railroad tracks)
• intervertebral disc
  • load absorption +dispersion

General osteokienmatics: axial rotation

• (torso rotate R/L)
• plane of motion: horizontal
• axis of rotation: vertical

General osteokienmatics: lateral flexion

• (side2side bend)
• plane of motion: frontal
• axis of rotation: anterior-posterior

General osteokienmatics: flexion +extension

• (bend forward+back)
• plane of motion: sagittal
• axis of rotation: medial-lateral

General osteokienmatics

1. flexion +extension
2. lateral flexion
3. axial rotation

what are apophyseal joints?

• 24 pairs of joints
• plane joints (slide past each other)
• mechanical blocks (anterior translation of vertebrae // V. past each other)
  • prevent cutting into spinal cord
• more horizontal = more axial rotation (CERVICAL)
  • less vertical = less axial rotation (thoracic/lumbar)

Structure of intervertebral discs

• research on dead stuff
• nucleus pulposus: gel-like (70-90% of water), hydrolic shock absorber (water hard to compress), force distribution
  • belly flops hurt
• annulus fibrosis: many layers, good with dealing with diff. motions,
• fully hydrated = can disperse pressure really well
  • dehydrated= force go into apopseal joints (??)
• endcaps / endplates: low blood flow

Jelly rant

• 15-25 collagen rings
• gum stacked between tire

Spine coupling

• When the spine moves in one plane, there exist automatic
  (obligatory) movements in another plane
  • Muscle actions
  • Articular alignment of facets
  • Preexisting posture
  • Stiffness of connective tissues
  • Geometry

Spinal coupling in the cervical spine

Craniocervical extension (80 degrees)

• convex on concave (base of skull + first vertebra) // roll + slide
• rest are planar (slide past each other)
• downward extension // decrease of space [cervical 1 upward slide of top vertebrae + top joint slides down on bottom joint+ head roll back + slide foward]

Craniocervical flexion (45-50 degrees)

• downward flexion // increase of space [cervical 1 downward slide of top vertebrae
• top joint slides up on bottom joint
• head roll foward+ slide back

Rotation (35-40 degrees each side = 80 degrees both sides)

• side you are turning to
  • turning facets drop-down slide (extension) + top facets upward slide (side turning away from)
• turn to right
  • extent on right + flex on left side

Side bending (40 degrees)

• couple with rotation (roll top + slide bottom)
• decrease space + backward slide on side you're turning to (dropping to) [extension]
• opening + upward slide of side turning away from [flexion]

ROM of joint in craniocervical region

• 45 degree rotation

Thoracic kinematics

• 15-25 degree (more vertical = not alot of movement)
• mostly flexion + extension
• more lumbar mvt

Thoracic + sacral kinematics/movement

• coupling event with sidebend+rotate
• side rotating toward (downward glide) + side rotate away (upward glide)
• not lots of rotational (rotating chest area) = protection design (facets + rib cage)

Lumbar kinematics

• no/not a lot of rotation = very verticle + facets
• spine needs to work together

Lumbar kinematics Injury

• BW creates shear force
• prevent movement L5 slide off sacrum: anterior longitudial ligament + apophyseal joints mvt (anterior side)
• common fractures by hyperextension: dancers + linemen

Lumbopelvic Rhythm

• pelvis and lumbar spine move together
  • load sharing with lumbar mvt = use whole posterior chain (ham, calve)
• stronger to lift in bent spine (use passive tension = muscles + lig. on stretch)

Spinal motion

• Flexion: happens on cervical (most) -> lumbar -> T10-12
• Rotation: shared through all // especially C1-C2
• Lateral/side bend: C2-7 (most), but used with all (not a lot tho_
• Thoracic not do much = ribcage anatomy

Sacroiliac Joint

• synovial in children = fused as adults
• articular surfaces: rough, increased interlocking
• force transfer btn trunk + legs => HEAVY ligament support

SIJ kinematics

• Nutation: BW want to create N. = help push force through system
  • anterior sacral tilt
  • posterior illiac tilt
• countemutation
  • posterior sacral tilt
  • anterior illiac tilt

SIJ is “out” you are in the ER or dead

• pelvic ring fracture (most likely) > dislocate
  • sacrum. ischium, ilium and pubic bone
  • noney pathology or fall or smt with high force (car accident)