The Spine Flashcards
what are the three functions of the spinal cord?
sensory in from body to brain, motor from brain to body and controls reflexes
what is the spinal cord protected by?
meninges
what are meninges?
membranes that cover the spinal cord and brain
what are the layers of meninges?
Dura mater (leather like), subdural space filled with interstitial fluid, Arachnoid mater, subarachnoid space filled with CSF, pia mater (thin layer lining)
spinal cord in new born is from?
magnum foramen to L4
spinal cord in adult is from?
magnum foramen to L1
spinal nerve is composed of what two roots?
dorsal - sensory and ventral - motor
dorsal root gangion are composed of?
cell bodies of sensory neurons
what are the sensory tracts in the spinal cord?
- dorsal columns 2. spinothalamic tracts 3. spinocerebellar tracts
what is the dorsal column responsible for?
proprioception, vibration, pressure, two point discriminative, discriminative touch
what is the spinothalamic responsible for?
temperature, pain, deep pressure, crude touch
what is the spinocerebellar responsible for?
unconscious proprioception
what are the motor tracts in the spinal cord?
direct (pyramidal) pathway and indirect (extrapyramidal) pathway
what is direct (pyramidal) tract responsible for?
precise, voluntary movement
what is indirect (extrapyramidal) pathways responsible for?
programmed/automatic movement
what are intergrating centres?
found in CNS where sensory impulses are relayed to motor neurons
what are flexes?
automatice responses to environmental change
what type of reflexes are there?
stretch, tendon, cross extensor and flexor reflex
what is stretch reflex?
mono synaptic reflex, to prevent over stretching
what is tendon reflex?
when tendon stretches, muscle relaxes and antagonistic muscle contracts
what is flexor reflex?
pain signal activates motor fibre and muscle group pulls away from pain
what is cross extensor reflex?
occurs with flexor reflex, after limb pulls away, contralateral limb comes in place to maintain balance
spinal nerves is branched from?
the spinal cord through intervertebral foramina
how many pairs of spinal nerves are there?
31 pairs
how many spinal nerves are there is each category?
cervical 8, thoracic 12, lumbar 5, sacral 5, coccygeal 1
what are plexus?
network of nerves
what are the plexus of the body?
cervical (phrenic), brachial (ulnar, median, radial), lumbar (femoral), sacral (sciatic)
significance of Cervical plexus
ventral rami of c1-c5, skin and muscles of head, neck and superior shoulders and chest - phrenic nerve phrenic nerve
significance of Brachial plexus
ventral rami of c5 - T1, shoulders and upper limbs, roots from superior, middle and inferior trunk ulnar, medial, radial nerve
significance of lumbar plexus
L1-L4, innervates abdominal wall, external genitals and anterior-medial thigh femoral nerve
significance of sacral plexus
L4-S4, innervates buttocks, perineum and part of lower limb sciatic nerve
what are dermatones?
area of skin that is supplied by 1 nerve, overlapping prevents loss of sensation if 1 nerve damage
to induce local anesthetics
3 nerves needs to be blocked
