Clinical correlates/notes from lecture Flashcards
sensory nervous system
afferent information conveyed from receptors in the periphery to the CNS
Motor nervous system
efferent information conveyed from the CNS to the skeletal, smooth and cardiac muscle
Somatic
body surface and musculoskeletal structures
Visceral
vessels, glands or organs containing smooth or cardiac muscle (ANS)
Efferent systems
Motor systems:
1) anatomically distinct sets of neurons
2) somatic is innervation of skeletal muscle
3) autonomic (Visceral) relates to innervation of smooth or cardiac muscle
Afferent systems
Sensory system
1) characterized by automically overlapping sets of neurons
2) somatic sensations are well localized
3) visceral sensations are poorly localized
LMN
have cell body in CNS and axon in PNS to innervate muscle fibers
Primary sensory neurons
have cell body in PNS with proximal process axon in CNS and distal process in PNS
Glia
the supportive cells
1) astrocytes in CNS
2) oligodendrocytes in CNS
3) microglia in CNS
4) Schwann cells in PNS
what are oligodendrocytes
Glia in CNS
myelin forming cells of the CNS
what are schwann cells
myelin forming cells of the PNS
Layers of the meninges
(closest to spinal cord) 1) pia mater
2) arachnoid matter (and subarachnoid space (CSF)
3) Dura Mater (underneath is potentail subdural space)
4) Epidural space for fat and veins
5) vertebra
Where are primary sensory neurons located in spinal cord?
Dorsal root (not cell bodies though)
What is the collect of PSC bodies located
Dorsal root ganglion
What is a spinal nerve?
combination of lower motor nuerons and primary sensory neurons.
what is the blood supply for the spinal cord?
Radicular arteries
Flexor withdrawal reflex
1) touch stimuli with primary sensory neuron
2) signal travels back to dorsal horn of spinal column
3) signal transfers to internuron that connects PSN to LMN in ventral horn
4) the LMN innervates the biceps to flex and withdraw hand
Fascicle
bundle of fibers by connective tissue
Epineurium
thick connective tissue that encloses the fascicles of the nerve
Endoneurium
delicates connective tissue the surrounds the nuerilemma cells
Perineurium
dense connective tissues that surround the axons of a single fasiicle. formed by flattened fiberglass like structures that act as a good barrier; tight junctions
what do the perinureim and epienurim form
a root sheath, or continuous barrier to the nerve bundles
what surrounds the ventral root in real life?
the dorsal root ganglion
Meningitis - possible diagnosis
patient refuses to raise leg
why is painful leg raising sign of meningitis?
raise leg you are stretching the sciatic nerve and also the epirnuerium and dura mater. you are tugging the dura matar. And in meningitis, the dura matar is inflamed.
The developing spinal cord
spinal cord is same length as developing vertebrate.
but when fetus grows, vertebrate grows and spinal cord stays same length. thus there is a relative downward displacement of the nerves
What would damage at L2 do?
damage all nerves inferior to L2, but not L2 itself
white vs grey matter
depends on the number of neurons. increased neurons = increased white matter.
white matter increases from sacral to cervial
Grey matter increases in the areas where there are extremities. (cervial and lumbar)
dermatome
area of skin innervated by a single spinal nerve
t4 dermatome
Nipple
t10
level of umblicus
Shingles
herpes virus, blood borm. infects skin and primary sensory neruons
transported by axoplastic transport to various areas of the skin, thus only certain segments appear and banded infections appear
Gray matter
Cell bodies
White matter
extended myelinated fibers
Cervical enlargement
C3-T2
lumbar enlargment
L1-S2
Spinal cord developent
neural plate (epidermis) flows and grows into a tube and gives rise to spinal cord and brain.
What do nueral crest cells give rise to?
primary sensory nuerons and schwann cells
If there is damage in dermatome (DRG), what would you expend in upper arm?
sensory loss along that single dermatome
If there is damage in periphery, what would you expect in upper arm?
if there is damage to both medial and lateral side of the skin. thus it is not damage to spinal cord.
sensory cutaenous field
when an area of skin is innervated by a single peripheral nerve, ie. lateral cutaneous femoral, which has nerve roots from multiple spinal levels.
myotome
the unilateral muscle mass receiving innervation from the fibers conveyed by a single spinal nerve
stretch reflex
hitting the tendon, stretches the tendon, muscle and spindle. Monosynpatic
1) this pulls the receptors springlike attachment appart and sends signal through primary sensory neuron through dorsal horn to ventral horn
3) synapases with lower motor neuron in ventral horn
4) signal transmits to bichep and causes muscle contraction
Calcaneal tendon spinal location
S1-2
Patellar tendon spinal location
L3-4
Biceps tendon spinal location
C5-6
Triceps tendon spinal locations
C7-8
Joint innervation
muscle or tendon crosses a joing, then the nerve that innervates the muscle also innervates the joint
what is referred pain?
when one area of the body is damaged, but pain occurs in other areas. This is due to joint innervation. For example, the knee is innervated by the obturator n. because of its contact with the gracilis. But the obturator also innervates the hip joint, so it could be referred pain with hip joint.
Organization of ANS
Two neuron chain from CNS to target structure
2) preganglionic neuron will cell body in CNS
3) post ganglionic nueron with cell body in PNS
always motor neurons
innervates smooth or cardiac muscle
where do post-ganglionic neurons come from?
Neural crest
Where do pre-ganglionic neurons reside in the spinal cord
lateral horn
sympathetic vs parasympathetic
sympathetic is fight or flight
parasympathetic is vegetative state
where do sympathetic nervous system exit spinal cord
T1-L2
where do parasympathetic nerves exit spinal cord
brainstem
where does sympathetic NS axon originate?
lateral horn of spinal cord
What is the path of a sympathetic NS signal?
origiantes in the lateral horn, passes through spinal nerve into ventral Sympathetic Chain Ganglion. synapses on post-ganglionic sympathetic neuron, where it joints and splits with the appropriate ventral and dorsal rami to innervate smooth or cardiac muscle.
what is white ramus?
sympatheic NS path from spinal nerve to sympathetic chain ganglion.
myelinated axons.
what is grey ramus?
past from sympathetic chain ganglion to ramus branches. (post-ganglion neuron)
unmyelinated
Which is faster LMN or sympatheic nervous system
LMN becuase axons are myelinated
Post-Ganglionic axons have unmeylinated areas in gray ramus.
where do preganglionic neurons originate
T1-L2 and migrate either upward or downward to synapse in sympathetic chain ganglia
Parasympathetic NS
cranial and sacral outflow
Erb- Duchenne palsy
upper brachial plexus injury (C5-C6)
increased angle between neck and shoulder
limb hangs to side in medial rotation, adducted shoulder, extended elbow
paralysis of deltoid, biceps, brachialis
Klumpke paralysis
injury to lower brachial plexus
when limb is pulled upward
damage to C8 T1
claw hand
Long thoracic nerve injury
serratus anterior pralysis
medial border of scapuls moves laterally and posteriorly from thoracic wall, winged appearance
Spinal accessory nerve injury
ipsilateral weakness when shoulders are elevated
thoracosdorsal nerve injury
nerve innervating latissimus dorsi
unable to raise trunk with upper limbs (climbing)
suprascapular n. injury
due to fractures of clavial.
loss of lateral rotation of humerus
arm appears medially rotated, unable to abduct
axillary n. injury
deltoid atrophies
types of bones
Compact (cortical) or spongy bone
cartilagineous bone
earliest bone structure
primary ossification center
also known as diaphysis.
blood vessels along shaft that turns to cartilage
secondary ossification center
epiphysis
osification at parts after birth.
right around epiphysial plate
traction epiphysis
when growth happens outward due to the pulling of a muscle
Synovial joint components
1) a fibrous joint capsule
2) synovial membrane lines joint
3) hyaline cartilage surrounds the bones in that area for protection
4) there is sometimes an articular disc between bones (meniscus)
Provides free movement and locomotion
Plane joint:
gliding or sliding
hinge joint
flextion or extension only, single axis
elbow joint
saddle joint
abduction, adduction, flexion and extension, 1 planes (carpometacarpal joint)
ball and socket joint
multiple axis and plans, AA, ML rotation, FE
differences between skeletal, smooth, and cardiac muscle
skeletal: multinucleated, striated, voluntary contraction quick
cardiac, strong quick, involuntary contraction, intercalated discs
smooth: weak, slow, involuntary contraction
skeletal muscle functions
stabalize joints, movement, generate heat
perimysium of muscle
surrounds muscle fascicle
epimysium
deep fascia that sorrounds groups of fascicles
parallel arramgement
transverse cross-section for individual fibers
pennate arrangement
oblique cross section
sex differences of pelvis
females have wider pelvis., so they have a narrower femoral notch.
males have narrower pelvis with a wider femoral notch
When does the innominate bone fuse?
ischiopubic ramus at 7-8 years
full fushion at 15-25 years
what stabalizes the SI joint?
sacrospinous ligament, sacrotuberous ligament
greater sciatic foramen boundaries
anterior sacroiliac lig.
sacrotuberous lig.
sacrospinous lig.
greater sciatic notch
lesser sciatic foramen boundaries
spine of sichium, sacrotuberous lig., tuberosity of ischium
contents of greater sciatic foramina
piriformis, sciatic n., posterior femoral cutaneous, superior gluteal vessels n., inferior gluteal n., internal pudendal vessels, pudendal n.
contents of lesser sciatic foramen
obturaor internus, internal pudendal vessels, pudendal n.
what is the covering on the acetabulum
lunate surface
Genu valgum
knock knee,
genu varum
bow-legged
normal angle of inclination for hip joint
125° between neck of femur and shaft of femur
coxa valga
inclination of hip joint greater than 125°
leads to genu varum
lengthens lower extremity
increased load on femoral head, decreases load on femoral neck
coxa vera
angle below 125°
leads to genu valgum
shortens lower extremity
increased load on femoral neck
Q angle
quadriceps angle
angle betwen shaft of femur and tibia.
Q angle men vs women
Men is 12° and women is 17°
angle of torsion
axis of femoral head compared to femoral condyles at knee.
noraml is 8-15°
anteversion
increased angle of torsion, (anteriorly rotated) pigeon toed
retroversion
decreased angle of torsion (postierly rotated) duck feet.
hip disloaction
most commonly posteriorly due to MVA. could impact the sciatic nerve!
Trendelenburg gait
weaked or ineffective gluteal medius or minimus muscle
if small weakness, pelvis tilts towards in swing leg.
if persistent weakness, shift center of gravity to overcompensate for weakness
blood supply to femur neck
children is through obturator
adults through MCF
what ligament does genu valgum stress?
Medial collateral lig.
what ligament does genu varum stress?
lateral collateral lig.
Menisci blood supply
blood supply is greatest in pheirpheral 1/3
compartment syndrome
due to trauma, overuse, hemorrhage, or infection to produce edema or hemorrage within compartments
increased pressure on nerves and vessels
fasciotomy is performed
anterior compartment syndrome
weakness in dorisflexion or toe extension, parasthesias over dorsum of foot
ankle sprains
90% are inversion injuries
grade 1, 2, 3
1: ligament streth
2: partial tear
3: complete rupture
plantar fascitis
inflammaion by overuse or overstretch
glenohumeral disloaction
inferior (anterior) joint capsule is not reinfrced by rotator cuff, so its is most vulnerable
could affec the art. n. and v. of brachial plexus
olecranon bursitis
inflammed brusa around elbow
colles fracture
fracture of distal radius and broken off styloid process of ulna
volkmann’s sichemis contracture
results of compartment syndrome in hand if not releived.
scaphoid fracture
most common carpal fracture
carpal tunnel
median n. entrapment neuropathy
what does the median recurrent innervate?
abductor pollicis brevis, flexor pollicis brevis, opponens brevis
what nerves are at risk during axillary node removal
Lateral thoracic n. and thoracodorsal n.
