back and spine - gross anatomy

8/11/2019 Back and Spine - Gross Anatomy

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The BackVertebrae, Ligaments, Joints and Deep Muscles of the Back



Vertebrae



Vertebral Column

• 7 cervical vertebra

• 12 thoracic vertebra

• 5 lumbar vertebra

• 5 sacrum vertebra

•

4 coccyx vertebra



•

Round vertebral body anteriorly•Vertebra arch posteriorly

• Pedicle

• Lamina

• 7 processes• Spine process (1)

• Transverse process (2)

• Articular process (4)

•Vertebral foramen



• Foramen transversarium - for the passage of thevertebral artery and veins (C1 to C6 only)

• The spines are small and bifid.

• The body is small and broad from side to side.

• The vertebral foramen is large and triangular.

• The superior articular processes have facets thatface posteriorly and superiorly

• The inferior processes have facets that faceinferiorly and anteriorly.



1st Cervical Vertebra(Atlas)

• No body

• No spinous sprocess

• Anterior and posterior arch

• Lateral mass on each side forarticulation with the occipitalcondyles (atlantooccipital joints)

• Articular surface on the inferiorside for articulation with the 2nd cervical vertebra (axis)



• Odontoid process (Dens)



• Has the longest spinous process

• No bifid

• Has large transverse process

• Small foramen transversarium

• Does not transmit the vertebral arteryor vein



• The body is medium size and heart shaped.

• The vertebral foramen is small and circular.

• The spines are long and inclined downward.

• Costal facets are present on the sides of the bodies for articulationwith the heads of the ribs.

• Costal facets are present on the transverse processes for articulationwith the tubercles of the ribs (T11 and 12 have no facets on thetransverse processes).

• The superior articular processes bear facets that face posteriorly andlaterally

• The inferior articular processes face anteriorly and medially.

• The inferior articular processes of the 12th vertebra face laterally, asdo those of the lumbar vertebrae.



• The body is large and kidney shaped.

• The pedicles are strong and directed backward.

• The laminae are short in a vertical dimension (important whenperforming a spinal tap.)

• The vertebral foramina are triangular.

• The transverse processes are long and slender.

•

The spinous processes are short, flat, and quadrangular and projectposteriorly.

• The articular surfaces of the superior articular processes facemedially, and those of the inferior articular processes face laterally.



Sacrum

• 5 rudimentary vertebra fusedtogether

• Wedges shaped, concaveanteriorly

• Upper base articulates with L5

• Lower apex articulates with coccyx

• Articulates with the Iliac bone onthe lateral sides

• S1 anterior border forms thesacral promontory



Sacrum

• Sacral canal formed by vertebralforamina

• Sacral hiatus due to absence of4th/5th lamina

• Sacral canal contain the anteriorand posterior roots, filum

terminale and fibrofatty material• Subarachnoid space goes down as

low as the S2 vertebra

• 4 foramina on each side, on bothanterior and posterior surface



Coccyx

• 4 fused vertebra to form onesmall triangular bone.



Important Variations

• Cervical rib

• 1st lumbar vertebra mayhave a rib

• 5th lumbar vertebra may befused with the sacrum

• Partial fusion of the S1

• Spines of Sacrum may fail tofuse



Joints and Ligaments of the Verte



• Synovial joints

• Between occipital condyles and lateral mass of atlas

• Ligaments• Anterior atlanto-occipital membrane

• Continuation of ALL and connects the anterior arch to the anteriormargin of the foramen magnum

• Posterior atlanto-occipital membrane

• Similar to ligamentum flavum• Continues to the posterior arch to the posterior margin of the

foramen magnum

• Movement• Flexion, extension and lateral flexion.



• 1 - alar ligament

• 2 - occipital bone

• 3 - occipital condyle

• 4 - atlantooccipital joint

• 5 - the transverse process of atlas

• 6 - the lateral mass of atlas

•7 - Atlanta cruciate ligament

• 8 - Lateral atlantoosevoy joint

• 9 - the body of cervical vertebra II



• Synovial joint

• Between odontoid process andanterior arch of the atlas

• Between the lateral masses ofthe bones

• Encapsulated

• Ligaments

• Apical ligaments –

apex ofodontoid process to the anteriormargin of the foramen magnum

• Alar ligaments – odontoidprocess to medial sides of theoccipital condyles



Atlantoaxial Joint

• Cruciate ligaments• Transverse part – odontoid

process to the inner aspect ofthe lateral masses

• Vertical part – posterior surfaceof the body of axis to theanterior margin of the foramenmagnum

•

Membrana tectoria• Upper continuation of the PLL,

to the foramen magnum

• Covers the odontoid process,apical, alar and cruciateligaments

• Movements – rotation



• Between the inferior surface and superior

surface of adjacent vertebrae withIntervertebral disc of fibrocartilage in between

• Between the superior articulating process andinferior articulating process of the lamina



• Starts from C2 to S1

• Responsible for ¼ of vertebral columnheight

• Thickest at the cervical and lumbarregions

• Serve as a shock absorber

• Two parts

• Anulus fibrosus –

fibrocartilage arrange inconcentric layers

• Inclination of the fibers are arranged inreversed direction at each layer.

• Nucleus pulposus – ovoid gelatinousmaterial containing large amount of water.



Intervertebral Disc

• Function

• Nucleus pulposus allows it tochange shape

• Compression load causes it toflatten and absorb energy

• Excessive load causes the ruptureof the annulus fibrosus

• Tears in the annulus fibrosuscauses the nucleus pulposus toherniate and cause impingementof the roots, spinal nerves or cord.

• Losses water content with age



• Ligaments

• Anterior longitudinal Ligaments• Wide and strongly attached to the front and

sides of the vertebral body and disc

• Posterior longitudinal ligament

• Weak and narrow and attached to theposterior border of the disc



• Supraspinous Ligament – between tips

of adjacent spines

• Interspinous Ligament – between theadjacent spines

• Ligamentum Nuchae – thickenedsupraspinous and interspinous ligamentson the cervical region (occipitalprotuberance to the C7)

• Intertransverse ligaments –

betweenadjacent transverse processes

• Ligamentum flavum – betweenlaminae of adjacent vertebra



Nerve supply of VertebralJoints

• Small meningeal branches of theeach spinal nerve

• Arises from the spinal nerves as itexits the intervertebral canal

• Supplies meninges, ligaments andintervertebral disc

• Posterior rami of spinal nerves

• Articular process



• As fetus – one continuous anterior concavity

• At birth –

cervical lordosis develops as child raises his head

• At one year old – lumbar lordosis develops as child learns to stand and walk.

• Lateral curvatures

• Minor curvatures due to predominant use of one limb. With compensatory curves above curvature.



Muscles of the Back



• The superficial muscles connected with the

shoulder girdle.• The intermediate muscles involved with

movements of the thoracic cage.

• The deep muscles or postvertebral musclesbelonging to the vertebral column.



• Superficial Vertically Running Muscles

• Erector spinae• iliocostalis

• longissimus

• spinalis

• Intermediate Oblique Running Muscles

• Transversospinalis

• Semispinalis

• multifidus

• Rotatores

• Deepest Muscles• Interspinales

• Intertransversarii



• Splenius capitis

• Origin: Lower part of ligamentum nuchae andupper four thoracic spines

• Insertion: Superior nuchal line of the occipitalbone and mastoid process of the temporalbone

• Splenius cervicis

• Origin: Lower part of ligamentum nuchae and

upper four thoracic spines• Insertion: transverse process of the upper

cervical vertebrae

• Nerve supply: posterior rami of the spinalnerves



• Auscultatory Triangle

• Boundaries: latissimus dorsi, trapezius, medial border of scapula• For breath sounds

• Lumbar triangle

• Boundaries: latissimus dorsi, posterior border of the externaloblique muscle of abdomen and iliac crest

• Pus may emerge from abdominal wall



• Between 12th ribs to the iliac crest

• Originate from the transversus abdominisaponeurosis

• Divides into three lamella

• Attached to the tips of the spinous process

• Covers the deep muscles of the back

• Attached to the tips of the transverse process

• Between the deep muscles of the back and

quadratus lumborum• Attached to anterior surface of the transverse

process

• Anterior to the quadratus lumborum



• Cervical region

• Occipital artery –

br. External carotid• Vertebral artery – br. Subclavian

• Deep cervical artery – br. Costocervicaltrunk

• Thoracic Region – from posteriorintercostal arteries

• Lumbar Region – subcostal and lumbar

arteries

• Sacral Region – iliolumbar and lateralsacral arteries (br. Internal iliac artery)



• External vertebral venous

plexus• External and surrounds the

vertebral column

• Internal vertebral venousplexus

• Within the vertebral canal butoutside the dura mater of thespinal cord

• Receives tributaries frombasivertebral veins

• Drained by the intervertebralveins



Spinal Cord and its Blood Supply



• Posterior rami of 31 spinal nerves

• C1, C6, C7, C8, L4 and L5 nerves supply by the deep muscle of the back and not t

• Scalp supplied by C2 (greater occipital nerve)



• Cylindrical, grayish, white structure

• Begins above the foramen magnum

• Continuous with medulla oblongata

• Terminates at the level of lower border of first lumbarvertebra (adult) or upper border of 3rd lumbar vertebra(child)

• Cervical and Lumbar enlargements due to brachial and

lumbar plexus

• Inferior ends tapers down into conus medullaris

• Filum terminale – extension of the pia mater to attachedto coccyx



• Anterior median fissure

• Posterior median sulcus

• Motor roots (anterior)

• Sensory roots (posterior)

• Posterior root ganglion

• Spinal Nerves – fusion of anteriorand posterior roots and exits thruthe intervertebral foramen.

• Becomes longer due to discrepancyof spinal cord and column lengths

• Cauda equina – group of spinalnerves beyond the cords length.



• One anterior spinal artery – from vertebral

arteries• Two posterior spinal artery – from vertebral

arteries

• Radicular arteries

• Venous drainage into the internal vertebralvenous plexus



Meninges



• Dura Mater

•Continuous from the meningeallayer of dura covering the brain

• Ends in the filum terminale

• Separated from the wall of thespinal column by the extradural(epidural space)

• Continues on the spinal nervesas the epineurium

• Separated from the arachnoidmater by subdural space.



• Arachnoid Mater

•Delicate impermeablemembrane

• Between the pia mater anddura mater

• Separated from the pia materby the subarachnoid space.(filled with CSF)

• Continuous with above the

foramen magnum and ends inthe filum terminale



• Pia mater

•

Vascular membrane closelycovering the spina cord

• Ligamentum denticulatum – thickening on the lateral sides

• Suspends the cord in the middle ofthe dural sheath.



Conditions involving the Spine



• Chance Fracture

•A fracture through an entirevertebra.

• During rapid deceleration, the

spine flexes, Fracture plane

begins at the spinous process and

travels through the vertebra.

• Ligaments involved includes• Supraspinous

• Interspinous

• Ligamentum flavum

• Posterior longitudinal



Spondylosis

is a congenital defect or an acquiredstress fracture of the lamina thatpresents with no slippage ofadjacent articulating vertebrae



Spondylolisthesis

• Anterior displacement of theSuperior body and transverseprocess while the posteriorfragment (vertebral laminae andspinous process) remains inproper alignment over thesacrum.

•This defect has the radiographicappearance of a Scotty dog witha broken neck Pressure on spinalnerves often leads to low backand lower limb pain.



Scotty Dog Collar

• Lumbar Oblique view



Herniated Disc



Pott’s Disease



Lumbar Puncture andSpinal Anesthesia

• Lumbar puncture• A spinal needle is inserted into

the subarachnoid space of thelumbar cistern in the midlinebetween either the L3 to L4 orL4 to L5 vertebral spinousprocesses. Because the spinalcord ends at approximately L1or L2, the needle will not

pierce or damage the cord.• Epidural Anesthesia

• Administration of an anestheticagent into the epidural spacedirectly affects nerve roots ofthe cauda equina and is acommon form of anesthesiaused during childbirth.



Spina Bifida

back and spine - gross anatomy

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