Spinal Anatomy Final Review

where does the lumbar lordosis begin and end

begins at T12 and ends at L5

where is the most prominent part of the lumbar lordosis

L3-L5

why is the L5 vertebral body smaller

it has to fit in between the iliac crests

what are the ossification centers of the lumbar spine

primary: body and each vertebral arch (3)

secondary: endplates (2), tips of TPs (2), tip of SP (1), mammillary process (2)

total secondary: (7)

what is the shape of the lumbar vertebrae

kidney shaped

do lumbar vertebrae get good blood supply

vertebral bodies have extensive blood supply

what structures attach to the lumbar vertebral bodies

anterior: ALL

posterior: PLL

Lateral: L1-L3 has right and left crus of the diaphragm

posterolateral: psoas major

what is the crus of the diaphram

a tendon that anchors the diaphragm to the lumbar spine

where is the pars interarticularis

in between the superior and inferior articular processes

what are the attachments of the TPs in the lumbar spine

anterior: psoas major, quadratus lumborum, and anterior layer of thoracolumbar fascia

medial and lateral arcuate ligaments of the diaphragm at L1

apex: middle layer of thoracolumbar fascia and iliolumbar ligament (L5)

superior and inferior border: lateral intertransversarii

posterior surface: deep back muscles

what direction do mammillary processes project

posterior for the attachment of the multifidus lumborum

what is facet tropism and where is it most common

noticeable asymmetry between right and left facets

most commonly seen at L5-S1

what degrees is the lumbar facets and what way do they face

90 degrees from vertical

inferior facet faces laterally, superior facet medially

what kind of joints are the facets

synovial planar

what innervates the facet joints

medial branch of the dorsal primary rami

what is the synovial fold aka Meniscoid fold

provides fluid and lubrication for facets

what do the facets limit

range of motion

where does the cauda equina start

about L1/L2

does motion increase or decrease as you go down the lumbar spine

increase

what does flexion vs. extension do for the lumbar spine

flexion: more CFS circulation; increases canal space

extension: less CSF circulation; decreases canal space

what is the lumbar cistern

a large arachnoid space

what are the borders of the IVF

inferior and superior vertebral notches,

articular pillars

vertebral bodies and IVDs

lateral border surrounded by attachment of the psoas major

what shape are the lumbar IVFs

inverted pear shape or inverted teardrop

how much of the IVF does the spinal nerve take up

1/3 and it is close to the superior pedicle

Kemp’s test

forcefully laterally flex and rotate until feet are off the floor, indicates whether pathology is in facets or not

flexion: incr height of IVD, decr IVD buldge, decr thickness of ligamentum flavum

extension: decr height and width of IVD, incr pressure within IVF

how does the lumbar nerve root exit

ex. L4 root enters Dural sleeve just beneath L3-4 disc the goes inferior and lateral to exit the L4-5 IVF

Scottie dog

visualization of pars interarticularis on oblique x-ray

nose= TP

eye= pedicle

ear= superior articular facet

front leg= inferior articular facet

neck= pars interarticularis

body= lamina

what does the black line at the neck of the Scottie dog mean

the patient likely has a fracture of the pars interarticularis

spondylosis

degenerative changes in the spine

spondylolysis

a defect of the lamina between the superior and inferior processes (pars)

spondylolisthesis

bilateral compromise of the pars which allows the vertebra to slide forward

spondyloptosis

complete anterior slippage of L5 off the sacrum

what is the grading of spondylo

called the meyerding scale, grades the degree of slips or translational displacement

grade 1: less than 25%

grade 2: 25-50%

grade 3: 50-75%

grade 4: 75-100%

grade 5: L5 completely off the sacrum

lumbosacral junction

most movable are of spine: 5 unilateral rotation, 3 lateral bending, 10 flexion, 10 extension (these are the percentages of TOTAL ROM of the lumbar spine; so 5 degrees of total lumbar unilateral rotation happens at the lumbosacral junction

sacralization

L5 starts to look like the sacrum so it looks as though there are only 4 lumbar

lumbarization

S1 fails to fuse with the rest of the sacrum so it appears that there are 6 lumbar

ligaments of the lumbar spine

interspinous, supraspinous, ligamentum flavum, PLL, ALL, iliolumbar

what direction does a disc herniation usually go

posterior and lateral because PLL is partially attached to IVD

dural sac aka thecal sac

area of dura mater where the cauda equina is

what does the recurrent meningeal nerve aka Sinu vertebral nerve innervate

PLL, facets, and meninges

what does the iliolumbar ligament attach to

to TPs of L5 to sacrum and iliac crest

what is imbibition

how the nucleus pulposus receives nutrients

movement

how many layers does the outer annulus have

15-20 layers

is the inner portion of disc innervated

no there is no neural supply so there is no pain until the nucleus pulposus breaks to the outer 1/3 of the annulus which is highly innervated

what ligaments are involved when a patient presents with pain with standing, sitting, and walking

standing: iliolumbar

sitting: sacrospinous

walking: sacrotuberous

what is normal range of motion of the lumbar spine

flexion: 60 degrees (39-55 in L1-4, 14-19 in L5)

extension: 20 degrees

lateral flexion: 25-20 degrees

axial rotation": 10-15 degrees

what exactly does the recurrent meningeal nerve innervate

the posterior IVD, PLL, periosteum of posterior vertebral bodies, epidural venous plexus, and anterior aspect of spinal dura mater

where does the dural sac end

at S2 then becomes the filum terminale externa

dorsal root ganglion

pseudounipolar sensory neurons

sacral base and apex shape

sacral base: wider and superior

sacral apex: smaller and inferior

difference of sacrum in men and women

males: slightly taller

women: slightly wider

when do the secondary ossification centers of the sacrum ossify

by 25 years of age

where is the sacral promontory

the anterior lip of the sacral body

what is the sacral canal a continuation of

the vertebral canal which is triangle shaped

the lamina in the sacrum fuse together to form what

the sacral tubercles

what muscle attaches to the sacral ala

psoas major

what fused to make the medial sacral crest

sacral spinous

what fused to make the lateral sacral crest

TPs and costal elements

what fused to form the intermediate sacral crest

articular pillars

what are the transverse lines on the sacrum

remnants of the sacral IVDs

what is at the level of S2

PSIS

is there a disc between the sacrum and coccyx

yes, sometimes its a synovial joint and other times its fused

where is the filum terminale/coccygeal ligament

it passes through the sacral hiatus to attach to the coccyx

what meninge is the filum terminale interna

pia mater only

what is special about S5

end of sacral hiatus

what ends at S2

dural sac and arachnoid and dura mater end here

what are the 5 distinct joints in the pelvic ring

right and left lumbosacral facet joints

anterior lumbosacral joint (L5-S1 IVD)

right and left coxal (hip joints)

right and left SI joints

pubic symphysis

how much do bones in the pelvis move

about 2 degrees or 2 millimeters

pelvic outlet borders

anterior= pubic symphysis

posterior= tip of coccyx

lateral= ischial tuberosities

nutation and counternutation

nutation: anteroinferior movement of sacrum (flexion)

counternutation: posterosuperior movement of the sacrum (extension)

what does the nervous system consist of

CNS and PNS nerves that control the systems of the body

what is the structural classifications of nerves

multipolar, pesudounipolar, unipolar, and bipolar

what are the parts of a neuron

cell body, dendrite, axon, synaptic cleft, myelin sheath, nodes of ranvier

three types of neurons

afferent, efferent, interneurons

what type of neuron makes up the most of the CNS

interneurons

classification of nerves

general (all over the body) vs. specific (in special areas)

somatic (skin/skeletal muscle) vs. visceral (organs/smooth muscle)

afferent (to the brain) vs. efferent (from the brain)

how would you classify CN II

SSA

CNS vs. PNS neuroglia

CNS: oligodendrocytes, astrocytes, ependymal cells, microglia

PNS: Schwann cells, satellite cells

what are cell bodies called in the CNS

nucleus

what are axons in the CNS called

tracts

what are cell bodies in the PNS called

ganglions

what are axons in the PNS called

nerves

how many spinal nerves are there

31 pairs

how many cranial nerves are there

12 pairs

are cranial nerves a part of the CNS or PNS

PNS

cranial nerve 1

I= olfactory (S)

cranial nerve 2

II= optic (S)

cranial nerve 3

III= oculomotor (M)

cranial nerve 4

IV= trochlear (M)

cranial nerve 5 and branches

V= trigeminal (B)

V1= ophthalmic (S)

V2= maxillary (S)

V3= mandibular (M/S)

cranial nerve 6

VI= abducens (M)

cranial nerve 7

VII= facial (B)

cranial nerve 8

VIII= vestibulocochlear (S)

cranial nerve 9

IX= glossopharyngeal (B)

cranial nerve 10

X= vagus (B)

cranial nerve 11

XI= spinal accessory (M)

cranial nerve12

XII= hypoglossal (M)

what are the two criteria for naming spinal nerves

a. spinal cord segment they arise from

b. the IVF they exit from

are named different depending on level of the spine

what happens when the ligamnetum flava affects the dorsal nerve root ganglion

patient has sensory issues but muscles are fine

where do cell bodies of the dorsal root ganglion come from

neural crest