B7.006 Spine and Back Flashcards
structure of vertebra
body - anterior to spinal cord, become larger from C2 to L5
arch - creates a cranial/caudal opening that protects the spinal cord
4 articular processes
2 transverse processes
1 spinous process
components of vertebral arch
2 pedicles
2 laminae
vertebral foramen
helps form the vertebral canal containing the spinal cord
intervertebral foramen
formed by inferior and superior vertebral notches
contains dorsal root ganglion and spinal nerves
spinous processes
extend posteriorly and inferiorly
connected by:
interspinous ligaments
supraspinous ligament
transverse process
originate from the junction of the pedicles and laminae
serve as site of muscle attachment
articular facets
at oblique angles which vary significantly up and down the spinal column
limit rotation and flexion of adjacent vertebral bodies
add stability to column
pars interarticularis
portion between the superior and inferior articular facet on each vertebra
often defective in spondylolisthesis
key difference in cervical vertebrae
have a transverse foramen for the vertebral artery in C1-C6
bump you feel on the back of your neck
C7 has an extra long spinous process (vertebral prominence)
atlas
C1 vertebrae
has no body or spinous process, but has a posterior arch and posterior tubercle
axis
C2 vertebrae
has a body and spinous process, two large superior articular facets, and one large dens process
dens process
formed during embryonic development from body of the first cervical vertebra
stabilization of atlas and axis to the skull
alar ligaments
cruciform ligaments
thoracic vertebrae (12)
very stable
articulate with ribs
have at least one or sometimes two facets for the heads of ribs on each side of the body
long thin spinous process points inferiorly
lumbar vertebrae (5)
large, kidney shaped vertebral bodies
no facets for ribs
articular processes project superior and inferior and limit rotation while permitting flexion and extension
contain an additional process of muscle attachment - mammillary process
spinout process is thicker and shorter than in the thoracic region
function of facet joints
limit movement between adjacent vertebrae
sacrum
5 fused vertebrae
support vertebral column
forms the posterior of bony pelvis
intervertebral discs
shock absorbers in between each vertebrae
make up 1/4 height of column
allow for flexion of the vertebral bodies between each other
intervertebral discs as a symphysis
fibrocartilaginous articulation between hyaline cartilage on the “end” of the bodies of vertebrae
2 parts of the intervertebral disc
annulus fibrosus- concentric layers of oblique fibers
nucleus pulposus - avascular gelatinous mass, derived from notochord
height variation throughout the day
1/4 of the length of the vertebral column is due to the intervertebral disks which are hydrated structures
in the morning, you are the tallest
most adults are 1 cm short by the end of the day
location of dorsal root ganglia
sits in the intervertebral foramen
how does an intervertebral disk respond to increased load?
bulges into intervertebral foramen, can impinge on exiting and entering spinal nerves when this occurs
at what positions is your body putting the most load on your 3rd lumbar disc
bending over
sitting
this is why standing desks are good
ligamentum flavum
extends from lamina to lamina
forms the:
1. posterior boundary of the intervertebral foramen
2. posterior wall of the spinal canal
result of hypertrophy of ligamentum flavum
spinal cord stenosis
most frequently in lumbar and cervical regions
anterior longitudinal ligament
strong, broad fibrous band running anterior to the vertebral bodies and discs from base of skull to sacrum
limit hyperextension
posterior longitudinal ligament
weaker than anterior
runs within the vertebral canal, just anterior to the spinal cord
helps stabilize vertebral bodies
called tectorial membrane when it reaches the base of the skull
causes of vertebral body (compression) fracture
osteoporosis
cancer
trauma
where do compression fractures occur
weight of body is largely anterior to the spinal column so compression fractures occur first within the anterior portion of the vertebral body
burst fractures
more severe
can put bone fragments into the spinal canal
effect of compression fractures
trap spinal nerves as they pass out in the intervertebral foramen
leads to radicular pain or loss of function
spondylolysis
defect in pars interarticularis (in between superior and inferior facets)
bone breaks, most common at L5 inferior facets, can lead to pain and instability of the vertebra
may be unilateral or bilateral
who gets spondylolysis
adolescent athletes
prevalence of LBP in 11-17 year old athletes is 30.4%
diagnosis of spondylolysis
breakage most frequent at the pars interarticularis or isthmus (neck)
may not be visible on plain films, but typically seen on MRI of thin slices and high resolution
spondylolisthesis
slipping (subluxation) of vertebra in relation to the adjacent inferior vertebra or sacrum
often secondary to spondylolysis of the L5 vertebra, allowing the vertebral column to slide forward on top of the sacrum
result of spondylolisthesis
dislocation/ subluxation of the vertebral body, typically anteriorly
compression of sacral spinal nerves and thus, leg pain
classification of spondylolisthesis
by degree of slippage, measured as percentage of the width of the vertebral body
when is surgery required in spondylolisthesis
generally 50-100% slippage
grade 3-4
primary curvature of spine
develops in utero
concave (anterior) curve
secondary curvature of the spine
occurs in cervical and lumbar regions as we learn to look around and walk
saves energy
kyphosis
anterior concave curvature of the vertebral column
most frequently in thoracic region
when severe, can limit lung function and cause digestive problems
>3 mil per year in US
lordosis
anterior convex curvature of the vertebral column
200,000 per year in US
most frequently occurs w pregnancy
scoliosis
lateral and/or rotational curvature of the vertebral column
most frequently initiates during adolescence and involves both thoracic and lumbar regions
3 mil per year in US
screening for scoliosis
having patient bend forwards looking at the height of the left and right shoulder lades
types of curves in scoliosis
thoracic - 90% on right side
thoracolumbar - 80% on right side
lumbar - 70% on left side
double major - right thoracic and left lumbar curves are equal in size
embryonic spinal cord in vertebral canal
at 8 weeks, the spinal cord fills the vertebral spinal canal and the spinal levels match the vertebral level
differential growth of the spinal cord
eventually, spinal cord slows its growth and the bones and ligaments continue to grow rapidly
in a full term newborn, cord terminates at L3
where does the cord terminate in adults
most around L1
99% by inferior end of L2
what is the spinal cord
cylindrical structure beginning in the medulla, exiting from the foramen magnum and ending at L1-2
how many spinal nerves
31
made up of ventral motor roots and dorsal sensory roots
corresponding nerves and vertebra
in cervical level, nerve exits above corresponding vertebra (C8 exits below C7)
for thorax, lumbar, and sacral levels, nerve exits below the corresponding vertebra
cervical enlargement
accommodating spinal segments C4-T1 for the brachial plexus
lumbosacral enlargement
L1-S3 spinal segments (T11-L2 vertebral segments)
tethered spinal cord syndrome
neuro disorder caused by tissue attachments that limit the movement of the spinal cord within the spinal column
usually in children
symptoms of tethered spinal cord in children
back pain
shooting pain in the legs
weakness, numbness, or problems with muscle function in the legs
tremors or spasms in the leg muscles
changes in the way the feet look, like high arches or curled toes
loss of bladder or bowel control that gets worse
scoliosis or abnormal curve of the spine that changes or gets worse
repeated bladder infections
symptoms of tethered spinal cord in adolescents
bending slightly
buddha sitting with legs crossed
baby holding (or equivalent weight) at the waist level
diagnosis and treatment of tethered spinal cord
diagnosed by MRI
treated surgically
meninges of the spinal cord
dura matter
arachnoid matter
pia matter
dura mater
tough, fibroelastic connective tissue sheath, free within the vertebral canal
ends at S2ish
what is located outside of the dura mater
fat, arteries, veins, and periosteum
between dura mater and periosteum = extradural / epidural space which is filled with fat and venous blood vessels
sacral hiatus
opening at end of spinal canal
located 1.5-2 in above the top of the coccyx
allows access to epidural space
inside the dura mater
arachnoid mater
denticulate ligament
denticulate ligament
formed of pia mater
ribbon-like structure extending laterally from the midline from each side of the spinal cord to attach to the inner surface of the dura in 21 tooth like projections
stabilizes spinal cord within the dura mater
arachnoid mater
separates pia from the dura by a fluid filled space, the subarachnoid space
applied directly to the inner surface of the dura, and sends arachnoid trabeculae through the subarachnoid space to the pia
contains CSF
pia mater
2 fused layers of loos connective tissue
encloses network of blood vessels which supply the cord
subdural space
potential space (pathologic) between dura and arachnoid mater
end of the spinal cord
ends in the conus medullaris at L1-2
dura mater and subarachnoid space end at S2
from L2-S2 is the lumbar cisterna
cauda equina
within the lumbar cisterna
spinal nerves distal to the conus medullaris
filum terminale internus
strand of connective tissue from the end of L2 to S2
attaches to the periosteum of the coccyx below the dural sac
upon flexion, pulls the spinal cord anteriorly
function of CSF
serves as mechanical and protective support for the brain
serves as an ion sink
volume of CSF
120-150 mL
95 mL within brain, 35-55 mL around spinal cord
450-500 mL produced every day
composition of CSF
clear fluid w SG = 1.007
pressure 70-180 mm
spinal tap / lumbar puncture procedure
cerebral spinal fluid is most commonly taken from the lumbar cisterna by inserting a spinal tap needle between L3/L4 or L4/L5
how to find L4
horizontal line across superior iliac crests generally falls between L3 and L4 (or on the L4 spinous process)
superficial back muscles
trapezius levator scapulae rhomboid minor rhomboid major latissimus dorsi serratus posterior superior serratus posterior inferior serratus anterior
trapezius origin
superior nuchal line on back of head down to the T12 spinous process
trapezius insertion
spine of scapula
acromion
lateral 1/3 of clavicle
innervation of trapezius
CN XI
C3, C4
action of trapezius
adduct, elevates, depresses, and rotates scapula
levator scapulae origin
transverse processes of C1-C4
levator scapulae insertion
medial border of scapula
levator scapula innervation
dorsal scapular nerve
C3,C4
rhomboid minor origin
spines of C7-T1
rhomboid minor insertion
root of spine of scapula
rhomboid minor innervation
dorsal scapular nerve
C5
levator scapulae function
elevates scapula
rhomboid minor function
adducts scapula
rhomboid major origin
spines of T2-T5
rhomboid major insertion
medial border of scapula
rhomboid major innervation
dorsal scapular nerve
C5
rhomboid major action
adducts scapula
latissimus dorsi origin
spines of T5-T12
thoracolumbar fascia
iliac crest
ribs 9-12
latissimus dorsi insertion
floor of bicipital groove of humerus
latissimus dorsi innervation
thoracodorsal nerve
latissimus dorsi action
adducts, extends, and rotates arm medially
serratus posterior superior origin
ligamentum nuchae
supraspinous ligament
spines of C7-T3
serratus posterior superior insertion
upper border of ribs 2-5
serratus posterior superior innervation
first 4 intercostal nerves
serratus posterior superior action
elevates ribs
serratus posterior inferior origin
supraspinous ligament
T-11-L3
serratus posterior inferior insertion
lower border of and spines of ribs 9-12
serratus posterior inferior innervation
last 4 intercostal nerves
serratus posterior inferior action
depresses ribs
serratus anterior origin
outer surface of ribs 1-8
serratus anterior insertion
medial border of scapula
serratus anterior innervation
long thoracic nerve
serratus anterior action
abducts and protracts scapula
triangle of auscultation
by the trapezius, lat dorsi, and medial border of the scapula
ddx of back pain
intervertebral disc rupture / herniation nerve inflammation or compression degenerative changes in the vertebral facet joints metabolic bone disease abdominal aortic aneurysm metastatic cancer myofascial disorders back strain and sprain
characterize the intermediate layer of deep back muscles
called the erector spinae group
contained within a common connective tissue sheath (thoracolumbar fascia)
what muscles are included in the intermediate layer of deep back muscles
iliocostalis (most lateral)
longissimus
spinalis (most medial)
I love spaghetti (lateral > medial)
deep layer of back muscles
collectively called transversospinalis
semispinalis
multifidus
rotatores
semispinalis
most superficial of deep back muscles
runs next to spinalis portion of erector spinae
arise from transverse processes of C4-T12 and insert onto spinous processes 4-6 segments superiorly
multifidus
deeper than semispinalis
arise from sacrum and ilium inferiorly or transverse processes more cranially
insert into spinous processes 2-4 segments superiorly
rotatores
deepest and smallest of the deep back muscles
arise from transverse processes and insert into spinous process 1 or 2 segments superiorly
back sprain
damage to back ligaments which connect vertebrae
less common than back strain
back strain
muscular problem
microscopic tears to the muscle fibers, typically due to overuse
“weekend warrior”
symptoms of back strain/sprain
may cause protective reflex tonic muscle contraction (tight back) to guard and protect the back from excessive movement and further damage
muscle guarding
protective response in muscle that results from pain or fear of movement
semi-contracted or stimulate state which may produce muscle pain and fatigue
treatment of muscle guarding
induced relaxation by using biofeedback to reduce EMG activity
injuries that can produce muscle guarding
damage to vertebrae or ligaments that connect vertebrae
damage to back muscle
muscles surrounding spine at L4 level
psoas
transversospinalis group
erector spinae group
this is why do you do sit ups to strengthen your back as well as back muscle exercises
blood supply to the spinal cord
medullary arteries reach the anterior or posterior spinal arteries of the spinal cord
radicular arteries supply non-spinal cord structures (vertebrae)
artery of Adamkiewicz
great medullar artery which provides major blood supply to the lumbar and sacral cord
origin of artery of Adamkiewicz
in 75% of people, the left side of the aorta between the T8 and L1 vertebral segments
damage to the artery of Adamkiewicz
can result in anterior spinal artery syndrome, with urinary and fecal/anal incontinence and impaired motor function of the legs
sensory function is often preserved to a degree
importance of identifying artery of Adamkiewicz
when surgically treating an AAA to prevent damage which would result in insufficient blood to the spinal cord
Batson’s venous plexus
network of valve-less veins that connect from deep pelvic veins, thoracic veins, and head and neck veins to the internal vertebral venous plexus
epidural veins
thought to allow the spread of some metastatic cancers to the vertebral column and brain
communications of batson’s venous plexus
scalp, skull, and face
thoracoabdominal wall
azygous, pulmonary, and caval venous systems
pelvic, prostatic, and sacral veins
lifetime risk of disc herniation
2-4%
more common in males
epidemiology of disc herniation
most frequently occurs during middle ages
- younger individuals may not be strong enough to lift weight sufficient to cause herniation
- as individuals age the nucleus pulposus tends to dry out and herniate less frequently
what spinal nerves are at risk during herniation
spinal nerve BELOW level of herniation
disk herniation usually occurs in either cervical or lumbar regions
L4 herniation symptoms
rare
pain: lower back, hip, posterolateral thigh, anterior leg
numbness: anteromedial thigh, knee
weakness: quad
atrophy: quad
reflexes: knee jerk
L5 herniation symptoms
pain: SI joint, lateral thigh and leg
numbness: lateral leg, web of great toe
weakness: dorsiflexion
atrophy: minor
reflexes: none
S1 herniation symptoms
common
pain: SI joint, hip, posterolateral thigh and leg to heel
numbness: back of calf, lateral heel, foot and toe
weakness: plantarflexion
atrophy: gastroc and soleus
reflexes: ankle jerk
function of sacral hiatus
used to gain access to caudal epidural space
injection of steroid into the fat and venous blood within the sacral canal
used for birthing pain relief
C5
lat deltoid
C6
thumb
C7
middle finger
C8
little finger
L1
inguinal ligament
L4
knee cap (patella)
medial malleolus
side of big toe
L5
lateral knee
top and sole of foot
S1
lateral malleolus
back of thigh
S2,3,4
external genitalia and perineum
C2-3
upper neck
C5
clavicle
T4
nipple
T7
xiphoid
T10
umbilicus
hip movement
flexion: L2,3
extension: L4,5
knee movement
extension: L3,4
flexion: L5,S1
ankle flex/extend movement
dorsiflexion: L4,5
plantarflexion: S1,2
ankle inversion/eversion movement
inversion: L4
eversion: L5,S1
3 most common nerve roots damages in disc herniation
C7
L5
S1
myotome of C7
tricep
extension of forearm
myotome of L5
extensor hallicus longus
dorsiflexion of great toe
myotome of S1
gastrocnemius
plantarflexion
ankylosing spondylitis
chronic inflammatory disease of the axial skeleton
manifested by back pain and progressive stiffness of the spine
inflammation around the enthesis (site of ligament insertion onto bone)
epidemiology of ankylosing spondylitis
peak onset in 20s
prevalence 0-1.4% depending upon ethnic group
HL-B27 association
ankylosis
fibrous or bony bridging of oint
other sponyloarthropathies
reactive arthritis
psoriatic arthritis
juvenile spondyloarthropathy
IBD associated arthropathy
diagnosis of ankylosing spondylitis
suggestive clinical features and evidence of sacroiliitis by radiological imaging
characteristics of identifying inflammatory back pain
onset before 40 insidious persistence for 3 months morning stiffness improvement with exercise
chest expansion
measured at 4th intercostal space
should be >5cm
less than 2.5 cm is abnormal
causes of cauda equina syndrome
severe / massive ruptured disc in the lumbar area (most common)
narrowing of spinal canal
spinal lesion or tumor
spinal infection, inflammation, hemorrhage, or fracture
complication from a severe lumbar spine injury
AV malformation
symptoms of cauda equina syndrome
occur suddenly severe low back pain pain, numbness, or weakness in legs that causes stumbling or trouble arising from a chair loss of or altered sensation in legs, butt, inner thighs, external genitalia, back of legs, feet bladder/bowel dysfunction sexual dysfunction absent Achilles reflex absent anal reflex
diagnosis of cauda equina syndrome
MRI or CT
treatment of cauda equina syndrome
usually surgical
often laminectomy
epidemiology of spinal canal stenosis
common, gradual onset
8% of people
occurs in people > 50
males and females equally
symptoms of spinal canal stenosis
pain, numbness, weakness in the legs and arms
gradual in onset
improve with bending forwards
classification of spinal canal stenosis
cervical, thoracic, lumbar
lumbar most common followed by cervical
causes of spinal canal stenosis
ligamentum flavum hypertrophy facet joint hypertrophy disk bulging posterior longitudinal ligament thickening RA spinal tumors trauma Paget's scoliosis spondylolisthesis achondroplasia
