compensatory - cause by a short leg or hip disease
abnormal curvatures of the back
kyphosis
lordosis
scoliosis
typical cervical vertebrae
C3 - C6
body with uncinate process
bifid spinous process
two transverse processes with transverse foramen
four articular processes - superior articular facets face posterior and superior; inferior articular facets face anterior and inferior
C7
vertebra prominens
spinous process is NOT bifid, very large, and easily palpable
transverse foramen small or absent - does NOT transmit the vertebral artery (only accessory vertebral vein)
C1
atlas
no body
anterior tubercle
posterior tubercle - attachment for suboccipital triangle muscles; groove for vertebral artery
superior articular surfacearticulates with occipital condyles (base of skull)
C2
axis
dens/odontoid process - body of C1 developmentally
bifid spinous process
uncovertebral joints
an articulation in the five lower cervical vertebral bodies, formed by the space between one vertebral body and the uncinate process that projects superiorly from the vertebral body immediately below it
synovial joint
typical thoracic vertebra
long spinous processes
costal facets on sides of body
costal facets on transverse processes of T1-T10
costovertebral joints
costotransverse joints
costovertebral joints
synovial joint between head of rib and vertebral body
costotransverse joints
synovial joint between tubercle of rib and transverse process of T1 - T10
typical lumbar vertebra
vertebral bodies get progressively larger as your proceed inferiorly
NO costal facets
NO transverse foramina
superior articular process has a rounded mamillary process
short horizontal spinous processes
superior articular facets face medially
inferior articular facets face laterally
Scotty Dog
oblique radiograph of lumbar vertebral column
ear = superior articular process
eye = pedicle
front leg = inferior articular process
back leg = spinous process + inferior articular process
neck = pars interarticularis
spondylolysis
a defect or fracture of the isthmus or pars interarticularis
no anterior displacement of the vertebral body
radiographs show that the Scotty dog appears to be wearing a collar at the site of the fracture
Spondylolisthesis
a unilateral or bilateral defect or fracture of the pars interarticularis
accompanied by anterior displacement of the vertebral body
radiographs show the head of the Scotty dog appears to be separated from the body
most common between the L5 vertebra and the sacrum
may stretch roos of lumbosacral spinal nerves in the cauda equina
patients have bilateral lower back pain that radiates into both lower limbs and weakness in muscles of the legs
cervical vertebrae: orientation of facets
superior facets = sup/post
inferior facets = inf/ant
cervical vertebra: movement allowed
flexion/extension
lateral bending
rotation
thoracic vertebrae: orientation of facets
superior facets = post/lat
inferior facets = ant/med
arc centered around vertebral body
thoracic vertebrae: movements allowed
lateral bending
rotation
flexion/extension
lumbar vertebrae: orientation of facets
superior facets = medial
inferior facets = lateral
lumbar vertebrae: movements allowed
flexion/extension
NO rotation
anterior longitudinal ligament
anterior to vertebral bodies
posterior longitudinal ligament
posterior to vertebral bodies and inside vertebral canal
anterior to spinal cord
ligamentum flavum
between adjacent laminae (posterior of vertebral canal)
appears yellowish in real life
interspinous ligaments
between vertebral spines
supraspinous ligament
posterior to vertebral spines
very thick in cervical regions - ligamentum nuchae (attachement for trapezius muscle)
intervertebral discs
form cushion between two adjacent vertebrae
highly innervated
central nucleau pulposus
peripheral annulus fibrosus
two layers of cartilage that cover the superior and inferior aspects of the disc
annulus fibrosus
composed of concentrically arranged lamellae made of collagen fibers
surrounds the nucleus pulposus of intervertebral discs
helps to stabilize the adjacent vertebral bodies
acts as a to limit excessive motion
nucleus pulposis
semi-fluid consistency
consists of chondrocytes, collagen fibers, and ground substance
avascular and not innervated
fluid consistency of the nucleus deforms under pressure (transmits pressure in all directions)
herniated discs
herniation of the nucleus pulposus through a defect in the annulus fibrosus
discs affected are in the mobile regions of the vertebral column (cervical and lumbar)
central protrusion
herniation in the midline under the posterior longitudinal ligament
lateral protrusion
herniation at the side of the posterior longitudinal ligament close to the intervertebral foramen
suboccipital triangle
deep to the trapezius and the semispinalis capitis muscles
suboccipital triangle borders
superiomedially - rectus capitis posterior major
superolaterally - obliquus capitis superior
inferolaterally - obliquus capitis inferior
floor - posterior atlantooccipital membrane and posterior arch of C1
roof - semispinalis capitis
rectus capitis posterior major
origin = spinous process of C2
insertion = lateral part of inferior nucal line
rectus capitis posterior minor
origin = posterior tubercle of posterior arch of C1
insertion = medial part of inferior nuchal line
obliquus capitis inferior
origin = spinous process of C2
insertion = transverse process of C1
obliquus capitis superior
origin = transverse process of C1
insertion = occipital bone between the superior and inferior nuchal lines
vertebral artery
first branch of subclavian artery
passes through transverse foramina of C6 through C1
winding course suboccipital triangle
passes through the dura and the arachnoid to enter the foramen magnum
suboccipital nerve
innervates the muscles of the suboccipital triangle
dorsal ramus of the C1 spinal nerve
spinal cord
part of the CNS
continuation of the medulla oblongata
extends from the foramen magnum in the skull through the vertebral column in the vertebral canal
42-45 cm in length
occupies the upper 2/3 of the vertebral canal
terminates inferiorly at the level of L1/L2 intervertebral disc as the conus medullaris
spinal cord segment
that portion of the spinal cord that gives rise to a single spinal nerve
spinal nerve
arises as dorsal and ventral roots from a single spinal cord segment
each spinal nerve exits through its own intervertebral foramen
number of spinal nerves
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
31 TOTAL
spinal nerve exits
C1 through C7 spinal nerves exit above the vertebra with the same name
C8 spinal nerve exits below C7 vertebra
Beginning with the T1 spinal nerve, spinal nerves exit below the vertebra of the same name
To approximate the spinal cord segment at a particular vertebral level
add one to the vertebral level in lower cervical region
add two in the upper thoracic region
add three in the lower thoracic region
to determine the level of spinal nerve clinically (determine vertebral level entrance for surgery)
subtract one from the cord segments in lower cervical region
subtract two in the upper thoracic region
subtract three in the lower thoracic region
cervical disc herniations
less common than lumbar herniation
discs between C5 and C6 & C6 and C7 are the most susceptible
lateral protrusions - cause pressure on spinal nerve or its roots
central protrusions - press on the spinal cord
lumbar disc herniations
more common than cervical
discss between the L4 and L5 & L5 and S1 are usually affected
region of the cauda equina
sciatica
pain distribution down the back and lateral side of the leg, radiating to the sole of the foot
caused by pressure on the sensory roots of the L5 and S1 spinal nerves
L4/L5 herniated disc
L5 motor root impaired
weakness in dorsiflexion of the ankle
L5/S1 herniated disc
S1 motor root impaired
weakness of plantar flexion of the ankle
diminished or absent ankle jerk reflex
spinal cord enlargements
cervical enlargement (C4 through T1)
lumbrosacral enlargement (L2 and S3)
cervical spinal cord enlargement
C4 through T1 spinal cord segments
innervation of the upper limb - brachial plexus
lumbrosacral spinal cord enlargement
L2 through S3 spinal cord segments
innervation of the lower limb - lumbar and sacral plexus
differential growth effects on spinal cord
in the first trimester, the spinal cord extends the length of the entire body
in the fetus, the spinal nerves exit the spinal cord horizontally
the vertebral column grows faster than the spinal cord and the spinal nerves are anchored to their targets
nerves just elongate as the body develops
nerves stream vertically at the inferior portion of the spinal canal (cauda equina)
lumbar cistern - enlargement of the subarachnoid space containing the nerve roots of the cauda equina
spinal meninges
dura mater + arachnoid mater + pia mater surrounding the spinal cord
dura mater
outermost covering of the spinal cord
composed of dense fibrous and elastic tissue
completely surrounds the spinal cord forming a sac within the vertebral canal = dural sac/thecal sac
continuous with the endosteal layer of cranial dura at the foramen magnum
extends down to S2 where it is continuous with the coccygeal ligament
extends laterally as dural sleeves of nerve roots and spinal ganglia
epidural space
external to the dura mater
space between the periosteum of the vertebrae and the dura
connected to pia mater by very delicate tissue strands called atachnoid trabeculae
follows the dural sac to its termination at S2
subarachnoid space
between arachnoid and pia
contains cerebrospinal fluid (CSF)
contains the cauda equina and the filum terminale
lumbar cistern
enlarged part of subarachnoid space caudal to the conus medullaris
extends from L2 to S2
pia mater
innermost covering of the spinal cord
ensheathes the spinal arteries
gives rise to the denticulate ligament
consists of 20 to 22 toothlike process
attaches to the inner surface of the dura
spinal cord is suspended within the dura by the denticular ligament
extends from foramen magnum to between the T12 and L1 nerve roots
anterior spinal artery
from vertebreal arteries
supplies anterior 2/3 of the spinal cord
75% of the blood supply to the spinal cord is from the ASA
posterior spinal arteries
from posterior inferior cerebellar arteries
supply posterior 1/3 of the spinal cord
radicular arteries & segmental arteries
branches of vertebral, intercostal, and lumbar arteries
Artery of Adamkiewicz [great anterior segmental medullary artery]
most commonly arises at T10 on the left side
origin is variable (usually T9-T12; left > right)
vertebral venous plexus
external and internal vertebral venous plexus
thin walled
incompetent valves or valveless
dependent upon pressure differential, venous blood can flow between the vertebral plexuses and skull, neck, thorax, abdomen, and pelvis
pathway for metastasis of prostate cancer to the vertebral column and cranial cavity
lumbar puncture
to obtain CSF from the lumbar cistern for laboratory examination (appearance, protein, sugar, serology, cell count, bacterial or fungal cultures)
to administer medications into the subarachnoid space
to perform myelography
to measure for evidence of increased intracranial pressure
lumbar puncture procedure
patient bends forward to increase intervertebral space
palpate iliac crest to know where L4 vertebral level is
insert needle below L4/L5 vertebrae
- spinal cord ends at L1/L2 disc in adults, L3 in children
What layers does the needle pass through when doing a lumbar puncture?
skin
superficial fascia
supraspinous ligament
interspinous ligament
infraspinous ligament/ ligamentum flavum
epidural space (containing fatty areolar tissue and the internal vertebral venous plexus)
dura mater
subdural space
arachnoid mater
subarachnoid space
CSF in lumbar cistern
epidural/ caudal block
performed by administering anesthetic through the sacral hiatus, which diffuses through the meninges and anesthetizes the roots of the sacral and coccygeal spinal nerves in the cauda equina
saddle block
anesthetic is injected directly into the subarachnoid space at L4
neuron
functional unit of the nervous system
components of a neuron
dentrites
cell body
axon
synaptic terminals
dendrites
stimulated by environmental changes or the activities of other cells
increase surface area for impulses and synapses to occur
small processes conduct impulses toward neuronal cell body
cell body
contains the nucleus, mitochondria, ribosomes, etc. of neuron
axon
conducts nerve impulses (action potentials) away from the neuronal cell body
long process - can be many feet long
synaptic terminals
affect another neuron or effector (muscle, glands, etc)
types of neurons
unipolar
bipolar
multipolar
unipolar neuron
pseudounipolar
two processes coming from cell body - dendrite (peripheral) and axon (central)
ex - found in dorsal root ganglion adjacent to spinal cord
myelinated
bipolar neuron
two processes continuous with cell body
dendrite goes toward cell body; axon coming out of cell body
not very common
ex - retinal ganglion, vestibular cells, cochlear cells
multipolar neuron
most common type
many dendrites enter the cell body but only one axon exits
myelinated
ex - skeletal muscle
CNS
consists of the brain and spinal cord
nucleus
collection of cell bodies in CNS
ganglion
collection of cell bodies outside of CNS
peripheral nervous system
consists of cranial nerves and spinal nerves
autonomic nervous system
consists of SNS and PNS
vertebral column
houses the spinal cord and spinal nerves
intervertebral foramina get bigger toward inferior end of vertebral column
how many spinal nerves?
31 pairs
how many cranial nerves?
12 pairs
where does the spinal cord end?
at the disc between L1 and L2 vertebrae
afferent
sensory
stimulus from periphery runs from receptor to CNS
efferent
motor
impulse goes away from CNS and to an end organ (muscle, etc.)
dorsal root
purely sensory (afferent)
cell bodies housed in dorsal root ganglion
ventral root
purely motor (efferent)
cell bodies are in ventral horn of spinal cord
spinal nerve
union of dorsal and ventral roots
divides into dorsal ramus and ventral ramus
dorsal ramus
sensory and motor
innervates deep muscles of the back
goes toward back of body
ventral ramus
sensory and motor
innervates the superficial muscles of the back & appendages
goes toward front of body
bigger than dorsal ramus (innervates more of the body)
dorsal root ganglion
most located in intervertebral/neural foramina
exception - in sacrum, located in vertebral canal
nerve pathway
route followed by a series of nerve impulses from their origin in one part of the body to their arrival elsewhere in the body
simplest nerve pathway
reflex arc
reflex arc
simplest nerve pathway
a rapid, automatic unconscious response to a situation in an attempt to maintain body homeostasis
direction of stimulus in a reflex arc
stimulus travels from receptor - dorsal root - synapses with association neuron - ventral root - impulse travels through motor neuron - effector (muscle)
type of reflexes
monosynaptic reflex
polysynaptic reflex
monosynaptic reflex
single synapse
ex - knee jerk reflex
when tapped, the patellar tendon stretches (also stretches Golgi fibers in muscle)
sends impulse through ventral ramus - dorsal root ganglion - dorsal root - synapses with motor cell body in ventral horn - causes action potential with nerve in muscle - knee joint extends
polysnaptic reflex
flexor/withdrawal reflex
ex - touching a hot stove
multiple synapses
an association neuron connects the afferent and efferent neurons in the spinal cord
finger touches stove - impulse through sensory fiber (nerve in ventral ramus) - association neuron - motor fiber in ventral ramus - biceps cause hand to jerk away (triceps relax)
functional nerve components
general somatic afferent
general somatic efferent
general visceral afferent
general visceral efferent
general somatic afferent (GSA)
nerve that conducts sensory impulses/ modalities
pain, touch, temperature, proprioception
general somatic efferent (GSE)
nerves that carry motor impulses
contraction of skeletal muscles
general visceral afferent (GVA)
impulses from organs
stretch pains, visceral reflexes
ex - menstrual cramps, getting kicked in the groin, stomach aches
nonspecific pain
general visceral efferent (GVE)
autonomic nervous system
motor
special somatic afferent
hearing
vision
special visceral afferent
smell
taste
special visceral efferent
pharyngeal arch musculature
denticulate ligament
lateral extension of the pia
separates the dorsal roots from the ventral roots
anchors the cord to the dura between successive nerve roots
lateral cutaneous branches of ventral rami
innervate skin
anterior cutaneous branches of ventral rami
sensory innervation of skin
superior medial branches of dorsal rami
innervate skin (cutaneous)
superior lateral branches of dorsal rami
innervate deep back muscles
inferior medial branches of dorsal rami
innervate deep back muscles
inferior lateral branches of dorsal rami
innervate skin
greater occipital nerve
medial branch of dorsal ramus of spinal nerve C2
somatic afferent (sensory) nerve fibers (GSA)
sympathetic fibers (GVE)
suboccipital nerve
somatic efferent (motor) nerve
nerve plexus
network of nerve fibers
site where nerve fibers intermingle and from which a new set of multisegmented peripheral nerves emerge
formed by ventral rami
contain motor and sensory nerves
cervical plexus
C1 - C4
brachial plexus
C5 - T1
lumbar plexus
T12 - L4
sacral plexus
L4 - S4
dermatome
area of the skin that is supplied by a single spinal nerve
important dermatomes
T4 - nipple
T10 - umbilicus
L1 - groin
peripheral nerve field
area of skin supplied by a peripheral nerve (more than one spinal nerve)
types of fascia
superficial
deep
subserous
superficial fascia
separates skin from subcutaneous tissue and fat
veins, arteries, nerves and lymphatics travel through here
"a surgeon's friend"
deep fascia
keeps muscle fibers bound together
separates muscles into compartments
also keeps nerves and vessels bound to muscle
subserous fascia
outside of serous membranes (pleura, peritoneal cavity)
autonomic nervous system
visceral motor system (GVE)
effector cells - smooth muscle, cardiac muscle, and glands
two neuron chain - pre- and post-ganglionic
effector cells of ANS
smooth muscle: digestive tract, vessels, duct systems, uterus, arrector pili muscles in skin, bronchi, genital organs
cardiac muscle
glands: sweat glands, salivary glands
preganglionic neurons
before synapse
from CNS
myelinated - look white
postganglionic neuron
after synapse in ganglion
unmyelinated - look grey
Are sympathetic and parasympathetic systems always found together?
NO
two components of autonomic nervous system
sympathetic
parasympathetic
general somatic efferent system
one neuron from CNS synapses on effector cell (skeletal muscle)
general visceral efferent
preganglionic axon from CNS synapses on cell body in ganglion
postganglionic axon from ganglion synapses on effector cell (smooth muscle, cardiac muscle, glands)
sympathetic nervous system
origin - thoracolumbar region of CNS (segments T1-L2)
short preganglionics
long postganglionics (EXCEPTION - splanchnic nerves)
fight or flight response
parasympathetic nervous system
origin: cranial-sacral area of CNS (CN 3,7,9,10 & segments S2-S4)
long preganglionics
short postganglionics
rest & digest
types of sympathetic ganglia
sympathetic chain ganglia (paravertebral)
prevertebral ganglia
prevertebral ganglia
in the abdomen -
celiac
superior mesenteric
inferior mesenteric
aorticorenal
sympathetic chain ganglia
paravertebral: on both sides of the body
runs the entire length of the spinal cord
swellings within the chain are caused by cell bodies of postganglionic sympathetic fibers
only 3 sympathetic chain ganglia in head/neck
lateral horn
intermedial lateral cell column
"bump" extending from side of grey matter in spinal cord segments T1-L2
accumulation of cell bodies
sends out axons through ventral roots (along with somatic motor fibers)
intermedial lateral cell column
site of cell bodies for preganglionic sympathetic fibers (VME)
white ramus communicans
communication between ventral ramus and sympathetic chain ganglia
myelinated (appears white)
more distal or lateral from spinal cord
gray ramus communicans
communication between postganglionic sympathetic fiber back to ventral ramus
unmyelinated (appears grey)
more medial to spinal cord
preganglionic sympathetic axon pathways
ascend up the chain before synapsing at higher ganglion (no lateral horns at cervical level)
descend down the chain before synapsing at lower level
pass through chain without synapsing (splanchnic nerves)
synapse at same level it enters the chain
True or False: All spinal nerves are associated with gray rami communicans but only those in the thoracic and upper lumbar regions are associated with white rami communicans.
TRUE
greater splanchnic nerve
composed of sympathetic fibers that did not synapse in sympathetic chain
travels down through diaphragm to ganglia in the abdomen
pain originating in one location in the body but perceived by the patient as coming from another location in the body
referred pain: ischemia in the heart
inadequate blood supply to myocardium
patient experiences severe pain over sternum radiating to left shoulder and arm or both shoulders and even root of neck and lower jaw
GVAs ascend into cardiac nerves and pass via spinal ganglia into cord at levels T1-T4/5
pain in the arm is accounted for by intercostobrachial nerve (T2) while spread of nervous system accounts for pain in jaw
referred pain: acute appendicitis
visceral pain due to spasm and distension reaches the T10 segment via the lesser splanchnic nerve
pain is referred to the umbilical region
later the pain becomes somatic over the T12 & L1 cutaneous region because of the irritation of parietal peritoneum by appendicicit
upper limb segments
shoulder: connected by joints grossly in the shoulder region
brachium (arm):connected by joints grossly in the elbow and shoulder region
antebrachium (forearm): connected by joints grossly in the wrist and elbow regions
manus (hand): connected by numerous joints
pectoral girdle
scapula, clavicle, and articulation to sternum
needed to attach upper limb to axial skeleton at glenohumeral joint
clavicle
S-shaped
convex over medial 2/3
concave over lateral 1/3
only bony attachment of the upper appendicular skeleton
to axial skeleton
movable strut
transmits all of the forces applied to upper limb
most frequently broken bone in human body
frequency of clavicular fractures
5%
1 out of 20
clavicular fractures
medial fracture: less common (2-3%)
midshaft fracture: most common (70-82%)
distal fracture: somewhat common (30%)
scapula
triangular, flat bone
extends from 2nd to 7th rib
posterior scapula features
spine
supraspinatus fossa - superior, smaller, more concave
infraspinatus fossa - inferior, larger, flatter
acromion process - enlargement of the spine as it moves laterally
lateral scapula features
glenoid cavity: pear shaped cavity on lateral border
where the head of the humerus articulates
anterior scapula features
coracoid process - beak like process projecting anteriorly from the superior border; important for ligament and muscle attachment
subscapular fossa
superior scapula features
superior transverse ligament: spans the suprascapular notch; houses the suprascapular nerve
superior transverse scapular ligament
suprascapular artery travels OVER
suprascapular nerve travels UNDER
Army goes over the bridge, Navy goes under the bridge
humerus
head - articulates with scapula at glenohumeral joint
neck - anatomic vs surgical
shaft
greater tubercle - attachment for supraspinatous,
infraspinatous, and teres minor
lesser tubercle
deltoid tuberosity
intertubercular groove/sulcus
Hilton's law
moveable joint is innervated by articular branches of the nerves that supply the muscles acting on the joint and that also supply the skin covering the joint
properties of joints
bony surfaces are rarely in direct continuity
covered by hyaline cartilage
exception - acromioclavicular & sternoclavicular joints are covered by fibrous tissue
motor: all but 1 and 1/2 muscles of anterior compartment of forearm; intrinsic thumb muscles; 1st and 2nd lumbricals
sensory: thumb half of palm, palmar aspect of thumb and 2 and 1/2 fingers and nail beds
ulnar nerve
C8-T1
motor: 1 and 1/2 muscles of anterior compartment of forearm (flexor carpi ulnaris and ulnar half of flexor digitorum profundus); most intrinsic muscles of the hand
sensory: digiti minimi half of palmar and dorsal aspect of hand; 1 and 1/2 fingers and nail beds
pisotriquetral: between individual carpal in proximal & distal rows
midcarpal: between proximal & distal rows
capsule is continuous with carpometacarpal joint capsules (except 1st joint capsule)
which joint capsules are continuous with intercarpal joint capsules?
carpometacarpal joint capsules
NOT radiocarpal joint capsules - infections will not likely spread to wrist
carpometalcarpal & intermetacarpal joints
between distal carpal row & carpal surface of 2nd-5th metacarpal bases
between adjacent metacarpals on radial & ulnar aspects of bases
common capsule with intercarpal joints (except 1st joint)
ligaments of carpometacarpal & intermetacarpal joints
dorsal CMC ligament
palmar CMC ligament
dorsal IMC ligament
palmar IMC ligament
interosseous intermetacarpal ligament
superficial transverse metacarpal ligament (part of palmar aponeurosis)
deep transverse metacarpal ligament
saddle joint
first carpometacarpal joint
synovial joint
has separate cavity from intercarpal & CMC joint capsules
between trapezium & base of 1st metacarpal
few ligaments - unrestricted movement
movement at 1st CMC joint
most mobile, all motions of thumb
flexion & extension: occur in coronal plane
abduction & adduction: occur in sagittal plane
opposition & reposition: pinching 1st & 2nd digit together
circumduction
rotation: during opposition
metacarpophalangeal joints
knuckles
synovial condyloid joint: movement in many directions
between head of metacarpal & base of proximal phalanges
each has its OWN synovial cavity
movement at 1st metacarpophalangeal joint
pure hinge
flexion & extension ONLY
movement at 2nd-5th MCP joints
flexion & extension
abduction & adduction
circumduction
interphalangeal joints
synovial hinge joints
located between head of proximal phalanges & base of middle phalanges AND between head of middle phalanges & base of digital phalanges
movement limited to flexion & extension
1st digit has only one IP joint
two IP joints in 2nd-5th digits
each joint has its own capsule
ligaments of MCP & IP joints
collateral ligaments: cordlike; slack during extension, taut during flexion (prevents dislocation)
palmar ligaments: thick fibrocartilaginous plates; site of attachment for extensor expansion
deep transverse metacarpal ligament: narrow fibrous band attached to fibrocartilaginous plates; runs across palmar surfaces of 2nd-5th metacarpal bones
fascia of the palm
continous with with antebrachial fascia & fascia of dorsum of hand
12 pairs of ribs & associated costal cartilages: lateral
sternum
manubrium: anterior
xiphoid process: inferior
musculature of thoracic walla
extend between the ribs; are of hyaxial origin (derived from hypomere)
innervated by ventral rami
- external intercostal muscles
- internal intercostal muscles
- innermost intercostal muscles
external intercostal muscles
from tubercles of ribs to costochondral junctions
fibers run superior lateral to inferiomedial
muscles of inspiration - elevate the ribs
external intercostal membrane: semitransparent membrane that continues from the external intercostal muscles to sternum
internal intercostal muscles
lie deep to external intercostal muscles
extend from sternum to angles of ribs
fibers run superior medial to inferiolateral
muscles of inspiration
intercostal internal membrane: runs from medial border of ribs (at vertebrae) to costal angles
innermost intercostal muscles
lie deep to internal intercostal muscles
fibers run in same direction as internal intercostal muscles (superiomedial to inferiolateral)
separated from internal intercostal muscles by intercostal nerve, artery & vein
vasculature of thoracic wall
arteries coming off of the thoracic aorta
internal thoracic artery
posterior intercostal artery
internal thoracic artery
branch off subclavian artery
runs parasternally (posteriorly on sides of sternum)
gives rise to anterior intercostal arteries
divides inferiorly to superior epigastric artery (abdominal wall) and musculophrenic artery (diaphragm)
can be used in coronary artery replacement
posterior intercostal artery
branch directly off of thoracic aorta
runs in intercostal spaces (except below T12)
anastomoses with anterior intercostal arteries
venous drainage of thoracic wall
internal thoracic vein: drains into brachiocephalic veins, then superior vena cava
intercostal veins: drain into internal thoracic veins or into azygos system
Azygos system: venous drainage of thoracic cage/body wall; drains into superior vena cava at Angle of Louis (T4 level)
intercostal spaces contents
intercostal veins, arteries, and nerves run between the innermost & internal intercostal muscles in a costal groove (superior to inferior... vein, artery, nerve)
intercostals give off collaterals, which run off surface of superior border of rib below
collateral run in inverted order - nerve, artery, vein
intercostal nerves come from ventral rami of corresponding spinal nerve
intercostal nerves
come from ventral rami of corresponding spinal nerves
gives off lateral cutaneous branch at axillary line (anterior and posterior branches continue on anteriorly)
anterior branch of cutaneous branch will give off a lateral & medial branch
thoracic spinal nerves ONLY supply the costal area
thoracocentesis
used to drain fluid from pleural cavity
place needly centrally in intercostal spaces inferior to rib ( avoid both intercostal bundles)
pus, blood, fluid
intercostal nerve block
done to numb area for incisions and fractured ribs
place needle near the nerve to deliver anesthetic
true ribs
ribs 1-7 attach directly to the sternum through their own costal cartilages
false ribs
ribs 8-10
attach indirectly to sternum through the cartilage of the rib above
floating ribs
ribs 11-12
have no connection to sternum
embedded in musculature posteriorly
typical ribs
ribs 3-9 (share general structure)
head articulates with head of numberically corresponding vertebra & vertebra superior to it via demifacets
tubercle: articulation with transverse process of numerically corresponding vertebra
relatively sharp bend in rib (angle)
costal-chondral junction
inferior aspect has costal groove for intercostal neurovasculature bundle
atypical ribs
ribs 1-2, 10-12
1st rib
single facet for articulation with T1 vertebra ONLY
short, flat superiorly and inferiorly
scalene tubercle: attachment for anterior scalene muscle; separated groove for subclavian artery & groove for subclavian vein on superior surface of rib
2nd rib
two facets for articulation with T1&T2 vertebrae
tuberosity for serratus anterior muscle (superior surface)
10th, 11th, 12th ribs
only one facet on heads for articulation with numerically corresponding vertebral body
typical articulation of ribs with vertebrae
only on thoracic vertebrae
two demifacets on head of rib articulate with numerically corresponding vertebra and with vertebra superior to it (synovial joint supported by various ligaments)
tubercle of rib articulates with transverse process of numerically corresponding vertebra (synovial costotransverse joint supported by lateral costotransverse ligament, costotransverse ligament, & superior costotransverse ligament)
inspiratory respiratory movement
thoracic cavity increases in volume during inspiration (inhale)
bucket-handle movement: middle parts of lower ribs elevate laterally increasing the lateral diameter of the thorax
pump-handle movement: upper ribs elevate increasing the anteroposterior diameter of the thorax
main movement - diaphragm contracts and pulls down increasing the superior/inferior diameter of the cavity
exterior & interior intercostal muscles pull up on ribs
expiratory respiratory movemtns
mostly elastic recoil
accessory respiratory muscles
accessory respiratory muscles
pectoralis major
serratus anterior
scalene muscles
serratus posterior superior
serratus posterior inferior
levatores costarum
hemothorax
accumulation of blood in thorax
pneumothorax
accumulation of air in thorax
divisions of intraembryonic coelem
pericardial cavity
peritoneal cavity
two pleural cavities
embryonic origin of lungs
endoderm
visceral pleura
from splanchnic mesoderm
the part of the pleural cavity immediately adjacent to lung (attached to lung surface)
pleural cavity
space between the visceral pleura and parietal pleura
only a little bit of serous fluidin cavity, NOTHING ELSE
the lung is NOT inside the pleural cavity, it pushes out into it
parietal pleura
from somatic mesoderm
outermost surface of pleural cavity
4 parts - cervical, costal, diaphragmatic, mediastinal
parts of parietal pleura
cervical pleura: runs along cervical region (above 1st rib)
costal pleura: runs along & inside of ribs
diaphragmatic pleura: runs along superior surface of diaphragm
mediastinal pleura: runs along mediastinum; superior & inferior to hilum
endothoracic fascia
layer of fascia between parietal pleura & thoracic wall
fat, loose areolar CT
hilum
root of lung
where parietal & viscerl pleura are continuous
pleural reflections
where pleura folds back upon itself & projects on thoracic wall
anterior costomedial reflection
where parietal pleura folds back over as mediastinal pleura
occurs posterior to sternum
to left side is the cardiac notch (bare area of pericardium)
bare area of pericardium
area of the heart not covered by pleura
where anterior portion of pericardium meets the sternum
costal lines of pleural reflection
parietal pleura: crosses 8th rib at midclavicular line; crosses 10th rib at midaxillary line
lungs/visceral pleura: cross midclavicular line at 6th rib; cross midaxillary line at 8th rib
vertebral lines of pleural reflection
parietal pleura: crosses paravertebral line at 12th rib
lungs/visceral pleura: cross paravertebral line at 10th rib
pleural recesses
costomediastinal recess: formed to due reflections between costal & mediastinal pleura; posterior to pericardium
costodiaphragmatic recess: costal pleura coming down sides of pleural cavity to diaphragm & turning into diaphragmatic pleura; where fluids will collect (site of thoracocentesis)
innervation of costal pleura
innervated by branches of the intercostal nerves
may cause reffered pain to the dermatomes supplied by the respective intercostal nerve
mediastinal & diaphragmatic pleura innervation
central diaphragmatic pleura innervated by branches of phrenic nerve (C3,C4,C5)
peripheral diaphragmatic pleura innervated by intercostal nerves (sensory)
phrenic nerve
motor innervation to central tendon area of diaphragm
sensory innervation to mediastinal pleura & diaphragmatic pleura over central tendon
innervates peritoneum on inferior surface of diaphram
referred pain to neck and shoulder - dermatome regions of C3,C4,C5
left lung: lateral surface
two lobes: upper & lower lobes separated by oblique fissure
upper lobe: cardiac notch on anterior aspect; lingula (homologous to middle lobe of right lung); mostly anterior
lower lobe: mostly posterior
left lung: medial surface
organs leave impression on lungs - sulcus for aortic arch, sulcus for subclavian artery, cardiac notch, esophageal sulcus
hilum: root of lung; where primary bronchus, pulmonary vein and arteries will enter & exit lung; where visceral & parietal pleura are continuous
pulmonary ligament: extension of visceral pleura below hilum
right lung: lateral surface
three lobes: upper and middle lobes separated by horizontal fissure; middle and lower lobes separated by oblique fissuresharp anterior surface (apex)
obtuse posterior surface
right lung: medial surface
hilum: pulmonary artery & vein, etc.
sulcus for superior vena cava
sulcus for azygos vein
sulcus for subclavian artery
cardiac impression
eparterial bronchus: supplies the superior lobe of the right lung; arises above the level of pulmonary artery (visible in hilum, differential characteristic)
pulmonary ligament
visualizing lung surface anatomy
horizontal fissure of right lung: 4th costal cartilage
oblique fissures of both lungs: 6th costal cartilage
parietal pleura: 8, 10, 12th ribs
visceral pleura: 6, 8, 10th ribs
x rays of lungs
air-filled lungs look black
oblique fissure: major fissure to radiologists
middle fissure: minor fissure to radiologists
lower lobe is pimarily posterior
respiratory tree
trachea: divides into two primary bronchi
primary bronchi: enter lung at hilum
right primary bronchus - more vertical, shorter, wider (foreign bodies are more likely to lodge here)
secondary bronchi: lobar bronchi; go into different lobes of lung; three on right, two on left
pyramidal shaped segment of the lung served by a single segmental bronchus
smalled unit that can be identified and excised (isolated tumors)
separated from each other by connective tissue septae
supplied by tertiary branch of pulmonary artery
innervation of visceral pleura
pain free
no nerves of general sensation
innervation of lung
anterior & posterior pulmonary plexuses
parasympathetic: fibers from CN X (Vagus nerve) to smooth muscle of bronchial tree; cause bronchoconstriction, vasodilation & autonomic increased secretion of glands