Costal facets
· essential characteristic
· pair of demifacets on each side
· on upper and lower borders of posterior body
· on morphological neural arch cf. centrum
· make synovial joint with facet of head of rib
Body
· concave circumference
· left-sided excavation
· from descending aorta
· heart-shaped outline
· anterior body sharply convex
· posterior body concave
· resultant round central canal
· upper and lower surfaces
· ring of cortical bone (fused ring apophysis)
· central cancellous bone
· covered with hyaline cartilage
· 2 foramina on posterior surface
· for basivertebral veins
Pedicles
· project back from upper half of body
· upper border level with upper surface of body
· curve upwards to superior articular process
· form small superior vertebral notch
· curve downwards to inferior articular process
· form deep inferior vertebral notch
· margin is pars interarticularis
· adjacent pedicles enclose intervertebral foramen
Laminae
· slope down from pedicles
· unite posteriorly
· form deep notch between them
· grooved for attachment of ligamentum flavum
· back of upper surface
· front of lower surface
Facet joints
· superior articular process projects backwards and laterally
· inferior articular process projects forwards and medially
· form synovial joints
· joints lie on arc of circle
· permit rotation
· ligamentum flavum extends between joints
Spinous process
· slopes down from junction of vertebrae
· tips connected by supraspinous ligament
· base receives rotator spinae from vertebra below
· shaft receives multifidus, semispinalis and spinalis
Transverse processes
· project backwards and laterally
· from junction of pedicle and lamina
· anterior ends carry costal facet
· attachments
· tip attaches lateral costotransverse ligament
· root gives origin to rotator spinae to vertebra above
· lower margin gives origin to levator costae muscle
· lower margin recieves superior costotransverse ligament
· posterior surface attaches erector spinae attachments
· broad oval body
· large round facet superiorly for head of 1st rib
· demifacet inferiorly for part of head of 2nd rib
· pedicle attached below upper margin of body
· attachments
· longus colli attached to anterior convexity
· single costal facet on upper part of body
· stunted transverse process
· single costal facet on lower part of body
· transverse process projected into
· upper mamillary body
· lower accessory tubercle
· posterior ramus of T11 lies in groove between them
· superior articular facet typically thoracic
· lower articular facet typically lumbar
· attachments
· upper limit of psoas major attached to lower body
Body
· kidney-shaped
· posterior surface flat
· resultant triangular central canal
· attachments
· psoas attached to upper and lower borders
Pedicles
· attach to upper body
Laminae
· less sloped
Spinous process
· horizontal
· hatchet-shaped
· upper border straight
· lower border curves down
· attachments
· borders attach interspinous ligaments
· posterior border attaches supraspinous ligament
· surface attaches interspinales and multifidus
Transverse process
· variable length
· 4th is longest
· spatulate
· attachments
· vertical ridge on anterior surface for attachment of psoas and anterior layer of lumbar fascia
· psoas attached medial to ridge
· quadratus lumborum attached lateral to ridge
· tip attaches middle layer of lumbar fascia
· posterior surface attaches erector spinae
Articular processes
· upper facets face posteromedially
· are concave and cylindrical
· lower facets face anterolaterally
· are convex and cylindrical
· pars interarticularis is ridge between facets
· morphological transverse process forms two processes separated by groove
· mamillary process
· projects from superior articular process
· behind margin of facet
· accessory tubercle
· lies at root of transverse process
· groove between them
· for medial branch of posterior ramus of lumbar nerve above
· characteristic pyramidal transverse process
· more anterior on body
· inferior facets face posteriorly
· fusion of 5 vertebrae and costal elements
· carries whole body weight via ligaments
· upper surface slopes down at 30o
· superior articular facets vertical
· prominent anterior lip of 1st sacral body called sacral promontory
· 4 ridges mark lines of ossification
· represent intervertebral discs
· lateral to this are 4 anterior sacral foramina
· bone between them represents costal processes
· bone lateral to foraminae called lateral mass or ala
· neurovascular
· lateral mass grooved by anterior rami of S1-S4
· median sacral vessels lie in sacral hollow
· sacral sympathetic trunk lies medial to foramina
· sacral plexus lies lateral to foramina
· lateral sacral vessels lie lateral to foramina
· attachments
· piriformis arises from the 3 ridges that separate the foramina and adjoining lateral mass
· closed by fusion of laminae
· leaves 2 hiatuses
· superior hiatus closed by ligamentum flavum
· inferior hiatus from lack of fusion of S5
· spinous processes fused to form midline ridge
· called median sacral crest
· superior articular facet for L5
· remaining articular facets fused to form ridge medial to posterior foramina
· called intermediate sacral crest
· projected inferiorly as sacral cornu
· transverse processes fused to form ridge lateral to posterior foramina
· called lateral sacral crest
· auricular surface is for articulation with ilium
· postauricular surface is rough area between lateral crest and auricular surface
· inferior to this is triangle where lateral crest meets lateral border of sacrum
· ala of sacrum projects laterally from upper border of S1
· neurovascular
· sympathetic trunk crosses base of ala
· ala crossed by (M to L) lumbosacral trunk, iliolumbar artery and obturator nerve
· attachments
· erector spinae between median and lateral crests
· posterior layer of lumbar fascia attached to both
· sacroiliac ligaments attached to postauricular surface
· part of sacrotuberous ligament attaches to triangle inferior to postauricular area
· sacrospinous ligament and cocccygeus attach to lateral border of sacrum inferior to triangle
· ventral sacroiliac ligament attaches to ala
· triangular
· closed in front and behind
· contains meninges down to S2
· each DRG lie inside its intervertebral foramen
· filum terminale runs down and blends with periosteum of coccyx
· S1-S4 emerge from sacral foramina
· S5 emerges from foramen formed by sacral cornu and coccyx
· completed by lateral SC ligament
· may be ossified
· represents tail
· fusion of 4 pieces
· sacrococcygeal joint is symphysis with fibrocartilagenous disc
· may be synovial joint
· reinforced by
· ventral SC ligament
· deep dorsal SC ligament
· lateral SC ligament
Body
· kidney-shaped
· projected upwards into posterolateral lip (uncus)
· reciprocal bevel on lower surface
· these represent neural arch contribution to body
Pedicle
· attached to midbody
· below uncus
Transverse process
· attached to pedicle laterally
· in front of articular processes
· perforated by foramen transversarium
· contains vertebral artery
· posterior bar ends in posterior tubercle
· anterior bar ends in anterior tubercle
· of C6 is carotid tubercle (of Chassaignac)
· tubercles joined by intertubercular lamella
· syn. costotransverse bar
· true transverse process forms proximal part of posterior bar
· costal element forms
· anterior bar and tubercle
· intertubercular lamella
· posterior tubercle
· attachments
1. anterior tubercle gives rise to
· longus capitus
· scalenus anterior
· longus colli
2. posterior tubercle gives rise to
· scalenus medius
· levator scapulae C3,4)
· scalenus posterior (C5,6,7)
Laminae
· enclose large triangular intervertebral foramen
Articular processes
· at junction of pedicle and lamina
· form cylindrical column
· upper facets face up and back
· lower facets face down and forward
· joints in same plane
Spinous process
· bifid
· attachments
· inferior concavity for semispinalis cervicis
· spinous process not bifid
· rounded tubercle
· foramen does not transmit vertebral artery
· transmits posterior vein when vein double
· anterior tubercle smalll
· lacks a centrum
· vertebral arch forms lateral mass on each side
· joined by anterior and posterior arch
Lateral mass
· carries articular facets
· upper facets
· kidney-shaped
· deeply concave
· lower facets
· round
· gently concave
· hilum of each kidney has tubercle
· for attachment of transverse ligament
· anterior ramus of C1 passes behind facet joint
· attachments
· lateral mass attaches rectus capitis anterior and lateralis
Transverse process
· projected from lateral mass
· perforated by foramen transversarium
· foramen transmits vertebral artery
· internal jugular vein lies on transverse process
· attachments
· obliquus capitis superior and inferior
· splenius cervicis
· levator scapulae
Anterior arch
· short
· posterior surface has facet for dens
· attachments
· anterior tubercle attaches longus colli
· upper border attaches anterior alanto-occipital membrane
Posterior arch
· semicircle
· upper surface grooved at root
· for vertebral artery and C1
· odontoid process (dens) projects up from body
· flanked by weight-bearing facets on lateral mass
Dens
· anterior cylindrical facet
· makes synovial joint with anterior arch of atlas
· smooth posterior surface
· bursa between it and transverse ligament
· attachments
· tip of apex attaches apical ligament
· sides of apex attach alar ligaments
Body
· typical inferior surface
· anterior surface projects down a little
· upper surface carries pair of large facets
· slope down from dens and extend
· posteriorly over pedicle
· laterally over lateral mass
· attachments (posterior)
· vertical limb of cruciate ligament
· tectorial membrane
Transverse process
· prominent tubercle
· represents posterior tubercle
· foramen directed up and out
· attachments
· scalenus medius
· splenius cervicis
· levator scapulae
Articular facet
· typical inferior facet extends from junction of pedicle and lamina
Spinous process
· large
· upper surface ridged
· lower surface bifurcated
· attachments
· semispinalis capitis inserts into concavity
· rectus capitis posterior major and inferior oblique attach to sides