Vertebrae Anatomy

Trunk Bones - The Axial Skeleton

• The axial skeleton consists of 26 connected vertebrae and is flexible and ridged
• As one ages, 50% of mobility in vertebral column is lost
• Muscles in vertebral column help maintain spinal curve
• Vertebrae increase in size descending down vertebral column because there is more pressure to withstand
• The vertebral column consists of three pillars (vertebral column)

3 Pillars of Vertebral Column:

• Major Pillar: anterior, stacked vertebral bodies and weight bearing part of vertebrae
• Minor Pillars: posterior left & right, stacked articular processes

Intervertebral Discs

• Intervertebral discs primarily consist of cartilage between each vertebrae, holding the vertebrae together, are shock absorbent and increase stability/strength.

Herniation

• Herniation consists of jelly/watery substance in the middle of disc that slides and bulges out
• If bulging goes into intervertebral foreman, that is also considered a herniation.
• When bulging is too much, it fills up foreman and compresses the nerve.
• Herniation worsens if untreated, starts with pins & needles/ numbness/ burning sensation and leads to weakness of muscle and possibly paralysis if nerve gets completely compressed/cut.

Typical Vertebra

• Consists of 2 parts:
  • Vertebral body (anterior)
  • Vertebral arch (posterior)

Common features to all vertebrae:

• Vertebral body - large, thick base
• Vertebral arch - Arch of vertebra inside foramen - without body
  • Floor: back of vertebra
  • Walls: pedicles
  • Roof: where laminae join
• Vertebral foramen: the hole made between the body and vertebral arch that houses the spinal nerve which branches off spinal cord
  • the spinal nerve is named by the vertebral sitting above them
    • foreman of L1 (& upper L2): nerve would be called "Spinal Nerve L1”
• Spinal cord contained inside vertebral foremen and canal
• Canal has multiple foramen stacked together.
• 2 Pedicles are arms branching off the body
  • Superior vertebral notch forming lower margin of intervertebral foreman
  • Inferior vertebral notch forming upper margin of intervertebral foreman
• 2 Laminae are arms branching off the pedicles
• 1 Spinous process: two lamina coming together creating sharp process on midline (posterior)
• 2 Transverse processes: one pedicle and one lamina coming together forming long process
• 4 Articular processes (superior/ inferior) act as hands on the junctions of pedicles/laminae holding onto the adjacent vertebrae's above/below
  • Articular facet facet covered by cartilage on each end of articular process

Joints

• Disc joint is located between two adjacent bodies @ intervertebral discs and is less mobile than Z-joint
• Zygo-pophyseal joint (Z joint) is between articular facets of articular processes and is responsible for majority of movement in spine

Spinal curves (curvatures)

• Spinal curves are developmental and gradually take on weight of the body as we grow
• Primary curve: Fetus born with one single spinal curve convexity (Kyphosis curvatures)
  • Thoracic curve remains unchanged,
  • Sacral curve remains unchanged
• Secondary curves develop as baby grows (Lordosis curvatures)
  • Cervical curve: appears at 2-3 months
  • Lumbar curve: appears at 1 year (once baby starts walking)

Abnormal curves

• Scoliosis primarily consists of abnormal curves in Thoratic/ Cervical/ Lumbar to right or left
  • Can be due to poor posture OR Congenital (born with it)
  • if severe... must be fixed with surgery
  • if mild....can be fixed with a splint
• Hyper-Kyphosis - Exaggerated curve in Thoracic spine (posterior convexity) —hunchback
  • Fix with surgery —must break bones and put rod inside
  • can't fix in elderly due to osteoporosis
• Hyper-Lordosis - Exaggerated curve in Lumbar spine (posterior concavity) —bum stick-out
  • Result of weakness of core muscles
  • Typically temporary; from posture
  • Common in pregnant women

Cervical Vertebrae (Neck region) (7)

• Cervical vertebrae in region
• Typical = C3,C4,C5,C6
• Atypical = C1,C2,C7
• Most mobile region (#1)
• Convex forward
• Small body
• Triangular vertebral foramen

Typical features of Cervical vertebrae:

• Bifurcated spinous process split end (except #1, #7)
• Transverse foramen a hole on transverse process making 2 arms (biggest tell of C-spine)
  • Vertebral artery contained inside transverse foremen and is an important artery for brain blood supply
• Uncus (Uncinate process) - 2 Lips / edges on superior lateral body
• Anterior / Posterior tubercles tubercles on transverse processes lateral to the foremen
• Articular facets superior and inferior

Joints:

• Uncovertebral joint: consists of 2 Uncus joining together
• Z- joint consists of a transverse-oblique orientation
• Disc Joint is located between intervertebral discs

Atypical features of Cervical Vertebrae (C1,C2,C7)

• C1 Vertebrae: Atlas
  • No body (No... laminae / pedicles / uncus
  • No spinous process
  • Large vertebral foremen
  • Anterior arch Smaller
    • Anterior tubercle - in mid point of arch
    • Articular surface for Dens - inside anterior arch - opposite to tubercle
  • Posterior arch Bigger
    • Posterior tubercle - in mid point of arch
  • Lateral masses 2; on either side
    • Articular surface for occipital condyle on superior/inferior surfaces
    • Superior articular facets - large bean shaped (occipital bone rests on facet)
    • Inferior articular facets - smaller circular
• Atlanto occipital joint skull & superior-articular-facet joining; for movement of flexion/extension (nodding "yes") of head

C2 Vertebrae: Axis

• Dens (Odontoid process) - Tooth-shaped tubercle on body below anterior arch of atlas -acts as a pivot and allows rotation of atlas on axis hone
  • If dens dislocates, it will cut spinal cord (partially or completely)
  • Injury of dense means everything below neck is paralyzed
• Anterior articular facet on dens for anterior arch of atlas
• Posterior articular facet on dens for transverse ligament of atlas
• Lateral masses two on both sides:
  • Superior articular facets are larger for atlas
  • Inferior articular facets are smaller for C3
  • Tubercle are Fused Tubercles on transverse processes and there is no anterior/posterior side

Joint

• Atlanto axial joint Dens joins with anterior arch of atlas for movement of rotation ("no" nod) of head (dens dislocation)

C7 Vertebrae:

• Spinous process is NOT bifurcated
• Size is larger than the rest of the cervical spine
• Transverse foramen is smaller than the rest of the cervical spine and does not transmit vertebral artery
• Vertebral prominent: C7 is typically the longest (sometimes T1)-important to locate to use as a reference to count and find the other vertebrae (flex neck to prove which vertebrae)

Thoracic Vertebrae (Mid region)

• (12) Thoracic vertebrae in region (TI - TXII)
  • Typical = T2,T3,T4,T5,T6,T7, T8
  • Atypical = T1,T9,T10,T11,T12,
  • Least Mobile region (#3) (Ribs & Z-joints)
  • Concave forward

Typical features of Thoracic vertebrae:

• Costal facet rigged ridge on the sides of the vertebral body where head of ribs articulate
  • 4 on body: two Right and Left and Superior and Inferior
• Semi-Costal facet half facets (Ribs articulate with 2 semi facets [above & below] to = 1 full facet)
• Transverse-Costal facet on each transverse process articulation Rib tubercles
• Spinous process Sharp pointy long, inclined downward
• Rib attach to body & transverse process
• Body - heart-shaped and increase in size from above downward
• Vertebral foramen Round, small (size of middle finger)
• Facet of Superior articular process face backward and laterally
• Facet of Inferior articular process face forward and medially.

Joints

• Z-joint - Frontal plane (side-flexion: mobile ... flexion/extension/rotation: limited)
• Disc Joint between intervertebral discs

RIB ARTICULATION

• with two ribs: 1 of same T#, 1 of the T# below Articulates with superior semi-costal facet of T5 and inferior semi-costal facet of T6.
• The tubercle of rib also articulates with transverse process of T6

Atypical features of Thoracic Vertebrae

• T1 Vertebrae:
  • Articulates with 4 ribs
  • Superior facet: FULL for head of Ribs#1
  • Inferior facet: SEMI for upper half of head of Ribs#2
  • Body broad transverse; concave upper surface, lipped on both sides.
  • Spinous process thick, long, horizontal
  • YES transverse costal facet
• T9 Vertebrae articulates with two ribs:
  • Superior facet: SEMI for head of Ribs #9
  • No semi-facets below
  • YES transverse costal facet
• T10 Vertebrae:
  • Articulate with 2 ribs
  • Articular facet: FULL -for head of Ribs#10
  • No semi-facets below
  • YES transverse costal facet
• T11 Vertebra:
  • Articulate with 2 ribs
  • Articular facets: FULL for head of Ribs#11 large, above pedicles
  • No semi-facets below
  • NO transverse costal facet (no articulation with rib 11)
• T12 Vertebra:
  • Articulate with 2 ribs
  • Articular facet: FULL -for head of Ribs#12
  • No semi-facets below
  • NO transverse costal facet (no articulation with rib 12)
  • Inferior articular Facet -faces laterally

Lumbar Vertebrae (Lower region)

• Lumbar vertebrae in region (LI - LV)
• Convex anteriorly
• Largest vertebrae
• All Typical!
• Moderately Mobile region (#2)
• L5 has the most pressure/ weight/ compression very thick
• Discs absorb lots of shock/pressure/force
• These discs are more at risk of injury thick and strong
• Has no facets for articulation with ribs and no foramina in transverse processes (Obviously!).

Common features of Lumbar vertebrae:

• Body massive & bean-shaped.
• Pedicles strong & directed postero-laterally.
• Laminae - thick
• Vertebral foramina large & triangular
• Transverse processes long & slender.
• Articular processes sagital plane
• short, flat, rectangle-shaped; projects directly backward
• Accessory process Bump on root of transverse process; posterior surface
• Mammillary process bump on posterior part of the superior articular processes
• Superior articular facet face medially
• Inferior articular facet face laterally
• Inter-vertebral foreman -stacking 2 adjacent foreman; making a hole in between body & inferior articular processes (& superior articular surface of bottom vertebrae)
  • Foreman reduced in size when disc is compressed
  • Made by: Inferior vertebral notch / Superior vertebral notch
• Z-joint sagittal plane orientated (side-flexion/rotation: limited... flexion/extension: very mobile)
• Disc Joint between intervertebral discs

Sacral Vertebrae (bottom region)

• (5) vertebrae in sacral region (SI - SV)
• 4-5 vertebrae fused together one single wedge-shaped bone
• Concave anteriorly
• Triangular shape
• Disc last disc in vertebral column L5 - S1
• Injury is very common, lots of pressure

Common features of Sacral vertebrae:

• Upper border; articulates with the body of L5 vertebra
• Anterior surface smooth
• Inferior surface Curved, convex, bumy
• Lateral joints with 2 hip bones, these are called sacroiliac joints
• The Sacral Canal is inside anterior surface and formed by vertebral foramina
• All sacral nerves are found inside the canal.
• Quada equina (horse tail) are nerves inside the sacral canal, this relates to how sacral ridge/crest crests on posterior surface: median (1) / intermediate (2) / lateral (2)
• Median Sacral Crest one middle bony ridge
• Remnants of spinous processes of embryonic segments
• Intermediate Sacral Crest (medial crest) two bony ridges and is the left/right sides of medial sacral crest
• Remnant of articular processes
• Lateral sacral crest consists of 2 bony ridges lateral to the 4 pairs of posterior sacral foramina
• Sacral foramina holes; 4 on right/4 left sides
• they aid the passage for posterior rami of Sacral nerves and are connected together by transverse ridges and
• Represent the remnant-of intervertebral discs
• Promontory of sacrum anterior edge of the body of S1 and bulges out like big rock
• Sacral ala (wing) consists of two triangular flat surfaces (left/right) superior side of S1 lateral to the promontory
• They also helps form the 'Superior Aperture'
• Sacral hiatus Bottom of sacral canal; Laminae of S5, sometimes S4 too, fails to meet in the midline
• Last part of nerves exit through here
• Sacral Cornu connects with coccygeal horn by ligaments
• Disc Last disc in vertebral column L5 - S1

Joints:

• Z-joint: the last Z-joint in vertebral column
• Lumbo-Sacral joint between L5 and S1 disc Sacroiliac joints between sacrum

Coccygeal Vertebrae (last region)

• (4) Coccygeal vertebrae region (TI - TXII)
• 3-4 vertebrae fused together; 1 single bone
• Bones were separated as fetus
• Small triangular bone
• 1st coccygeal vertebra commonly un-fused ( or partially fused ) with sacral vertebra
• Transverse process on both sides of 1st coccygeal segment
• Coccygeal Cornu two processes arising from 1st coccygeal segment toward sacrum

Ribs

• (12) Ribs in axial skeleton
• Long, twisted, flat bone
• Attached to vertebrae ( the hody & transverse proccss)
• articulates and attaches with rib on Sternum
• Superior border rounded, smooth
• Inferior border sharp, thin which has costal groove
• Lateral surface convex (on outside, can touch)
• Medial surface concave (on inside, toward lung)

Typical rib:

• Head attaches to costal facet of body of T- spine (2 semi -facets for articulation with * corresponding vertebral body
• Neck constricted portion between the head tubcrcle
• Tubercle -tubcrcle articulates transvcrse process of vcrtebras
• Articular portion - facet tor articulation transwrse process of corresponding vertebra

-Shaft Body - thin, flattened, twisted on long axis.

• Anterior End - attached to corresponding costal cartilage Posterior End - has curvature with the head and facets
• Costal Angle -

Atypical Rib

• 1st Rib - close to brachial pleuxs & main vessels
• Scalenc Tubcrcle - on superior surface; cIoae to medial boarder (2) Grooves- (house subclavin vein a artery

Hip (coxal) bone

• Coxal
  • Flat bone
  • Borders in difterenet palnes
  • Composed of ,4 7 bones
• 8 bones ecompletely fused after puberty
• Anterior border - ASIS
• oeteruor border l:ioardccr bo;ow ÿrcate sciatic nOtc Iliac Crest
• Deep fossa on lateral surface of body 4 for leg - big
• Greater sciatic Notch deep notch berinning the noeteriox border
• Ischial tuberosity: part ot Ischium; botton bone protuberance "sit bone"
• Anterior Supeaior lliac 3pine (43r;S)
• S,imphrsis l ubis tough articular aurtaee 4 anterior hipbones ; below 'I uheicle Joints:
• symphss pubs joints join tohetber anteriorly

Sacroiliac joint both his bones jain with sacrum noseeriody at ar: 45-50 in mak

Thoratic Apertures

• Superioa Thorotic A eature thesk to chest
• bony ting comprised af iugular notch, clavicular nateh 4 Borders
• Posterior-Bsd of H2
• Later C1ascd dphragm

Test your knowledge of vertebral anatomy, features, and spinal curves. Explore the structures and functions of the vertebrae, joints, and processes contributing to spinal movement and stability. Understand the causes and effects of spinal conditions like scoliosis and disc compression.