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116 Cards in this Set
- Front
- Back
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Where does the spinal cord enter the skull superiorly?
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Foramen Magnum
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Directly superior to the foramen magnum, what does the spinal cord become?
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medulla oblongatta
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Where does the spinal cord end inferiorly, and what is it called there?
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L1/L2 vertebral, as the conus medullaris.
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Where is an epidural anisthetic given?
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It's given in the space inside the bony spinal canal but outside the membrane called the dura mater (the epidural space), usually in the mid-lumbar region, below L1, L2. It's a safe place because the spinal cord has turned into the cauda equina at this place.
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Why are there cervical and lumbar enlargements in the spine?
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Because of nerve supply to arms and legs.
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Cauda Equina
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"horse's tail", the continuation of spinal nerves below the conus medullaris. L2 to S5
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Filum Terminale
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an extension of the pia mater that extends inferiorly and anchors spinal cord to coccyx
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Conus Medullaris
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Inferior to the lumbar enlargement, the spinal cord tapers to this medullary cone, which gives rise to bundle of nerve roots called cauda equina.
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Name the order of the meninges and their spaces from the deepest to the most superficial (Hint: PAD)
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pia mater - subarachnoid - arachnoid - subdural - dura mater - epidural
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What is the memingeal space directly deep to the skull bone, but outside the dura mater?
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The epidural.
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What is the meningeal space between the arachnoid and the dura mater?
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The subdural space
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What is the meningeal space which holds the CSF (Cerebro Spinal Fluid) over the pia mater and under the arachnoid?
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Subarachnoid space
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Spinal Cord Cross-section
Horns |
gray matter in the spinal cord which forms an H (anterior, posterior and lateral horns). It is unmyelenated
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Spinal Cord Cross-section
White Matter |
Myelenated matter of the spinal cord
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Spinal Cord Cross-section
Columns |
3 pairs of White matter tracts-bundles of myelenated axons-of spinal cord (dorsal/posterior, lateral, ventral); subdivided into tracts/fasiculi.
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Spinal Cord Cross-section
Enlargements |
Cervical and lumbar
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Spinal Cord Cross-section
Ganglia |
cluster of cell bodies outside the CNS i.e. dorsal root ganglia (DRG) associated w/spinal nerves
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Spinal Cord Cross-section
Ramus |
"arms" or "bridges". After emerging from IVF (intervertebral forman) nerve divides. Dorsal Ramus branches off after dorsal root and DRG and progresses toward the posterior, Ventral merges with the spinal nerve in body anterior.
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Spinal Cord Cross-section
Rami Communicantes |
Forms autonomic system. White (inside) and gray (outside) ramus. Communicating nerve between spinal nerve and sympathetic chain ganglion)
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Spinal Nerves are mixed. What does that mean?
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They have both sensory and motor nerves
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How are the 31 spinal nerves distributed?
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8 cervical
12 thoracic 5 lumbar 5 sacral 1 coccygeal |
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How can there be 7 cervical vertebrae but 8 cervical nerves? How are they numbered?
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They start out numbered from the top, then the eighth is under C 7, on top of T1. From there on down, the nerves are numbered under their corresponding vertebrae.
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Cranial Nerves - are they sensory or motor?
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Some are sensory - I, II, VIII
Some are mixed/Both X, IX, V, VII Some are motor - III, IV, VI,XI, XII |
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How many cranial nerves are there? Wwhat numbering system do they use and why?
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12, numbered by their exit from the brain with roman numerals, so numbered as not to be confused with the cervical nerves which use arabic numbering.
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What is a good mnemonic device for remembering the cranial nerves?
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I OLd - Olfactory
II OPie - Opthalamic III OCcasionally - Oculomotor IV TRies - Troclear V TRIgonometry - Trigeminal VI - And - Abducens VII - Feels - Facial VIII - VEry - Vestibulococlear IX - GLoomy - Glossopharyngeal X - VAGUe - Vagus XI - And - Accessory XII - HYPOactive - Hypoglossal |
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What is a good mnemonic for remembering the sensory or motor status of the cranial Nerves?
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M = motor, B = Both, S = Sensory
I-Some; II-Say; III-Marry; IV-Money; V-But; VI-My; VII-Brother; VIII-Says; IX-Bad; X-Business; XI-Marrying; XII-Money |
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Dorsal Rami Innervation
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innervate the deep muscles of the back and overlying skin
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Ventral Rami Innervation
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innervates the anterolateral body wall, limbs, and skin indirectly by forming network with other spinal nerves called a plexus
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Plexus
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Nerve Network. Brainding, interconnection, overlap, motor, and sensory. However, on a later page it's listed as motor/ventral rami forming the plexi.
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Plexus
Cervical Plexus location |
C1-C4; injury debilitates depending on which vert. level. Para, hemi, quadriplegia
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Cervical Plexus Nerves
Phrenic Nerve |
Phrenic nerve (C3, 4,5) to diaphragm, then respiratory failure, inconsistencies or shut in body functions (i.e. sweating)
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Cervical Plexus Nerves
Accessory Nerve |
C1-C4 (C5) -> trapezius and sternocleidomastoid motor
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Brachial Plexus location
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C5 - C8 and T1
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Brachial Plexus Nerves
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Ulnar, Radial Median - nerve damage in specific region. Plexus of arm.
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Lumbar Plexus location and major nerve
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L1-L4, Femoral Nerve
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Sacral Plexus Location and Major Nerve
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(L4) L5, S1-S4
Sciatic nerve, Peroneal Nerve, Tibial Nerve. Foot Drop. |
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Paraplegia
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both lower linbs affected from cord injury T1-L1
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Spinal tracts
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Bundles of axons ascending and descending to carry messages up and down and in and out of spinal CNS.
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How can you tell if a spinal tract is sensory or motor from the name?
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If it starts with the word spine it is an ascending/afferent/sensory. If it ends with the word spinal, it is descending/motor/efferent.
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How can you tell if a spinal tract is sensory or motor from location?
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If it's anterior or ventral it's motor (think motor in front of car) and if it is dorsal or posterior it is sensory.
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Spinal Tracts - Sensory
Spinothalamic |
Responsible for pain, temperature. Ascending spine to brain. Also called anterolateral sometimes, but it is wired into the back of the column.
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Spinal Tracts - Sensory
Dorsal Column |
Sensory, carries all else but pain/temperature (think how dorky you'd look carrying all that stuff)
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Spinal Tracts - Sensory
Fasiculus Gracilis and Fasiculus Cuneatus |
Gracilis - think "graceful legs", Cuneatus - "cute hug with arms". Fasiculus - think fasicle and facile. 2 point discrimination, proprioception, fine touch, vibration, weight.
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Spinal Tracts - Motor Voluntary
Corticospinal Tract |
descending motor pathway, form pyramids on medulla oblongatta so called pyramidal tracts. Some decussate before FM. Finely coordinated limb movements.
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Spinal Tracts - Motor Voluntary
Corticobulbar Tract |
Precise, voluntary movements of skeletal muscles
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Extrapyramidal or Indirect Pathway - Motor automatic
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Rubrospinal, tectospinal, vestibulospinal, automatic movements like balance, tone, pisture.
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Reflexes
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Protective movements, stereotyped, meant to protect against injury
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Spinal Reflex Arc
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Receptor-->Sensory neuron (DRG)-->Posterior Horn-->Internuncial neuron-->Motor neuron-->Effector (muscle or gland response).
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Withdrawal Flexor Reflex
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3 neuron plus, polysynaptic, flexor muscles withdraw body part from painful stim. Ipsilateral (receptor to sens neuron to sp cord to interneuron to nmj to flexors to extremity withdrawal.
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Crossed Extensor Reflex
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3 neuron plus, polysynaptic, crossover to contralateral motor neuron, extensor muscles of opposite limb straighten/balance. Contralateral reflex arc.
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Cranial Reflexes - Corneal reflex
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watering eye
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Autonomic Reflexes aka. Visceral Reflexes
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effect on smooth muscle, cardiac, and glands
regulate blood pressure, respiration, digestion, defecation and urination Pupil reflex Ciliary (accommodation) reflex |
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Pathological Reflexes - Babinski
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toes in normal baby flare when bottom of foot scratched. Toes in normal adult should curl in to avoid stim.
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Dermatome
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The cutaneous branch that provides sensory input from an area of skin to the respective spinal nerve level is called a dermatome. Some neighboring dermatome's may overlap.
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Cervical Plexus location and nerves
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C1-C5 - 5 nerves - Lessesr occipital nerve, ansa cervicalis, transverse cervical nerve, supraclavicular nerve phrenic nerve.
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Brachial Plexus location and nerves
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C5-T1 - 5 nerves - musculocutaneous nerve, axillary nerve, median nerve, radial nerve, ulnar nerve
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Lumbar Plexus location and nerves
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L1-L4 - 6 nerves - Iliohypogastric, iliolinguinal, genitofemoral, lateral femoral cutaneous, femoral, obturator
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Sacral Plexus location and nerves
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L4-S4 - Superior gluteal, inferior gluteal, sciatic nerve (common peroneal, tibial, posterior femoral, pudendal)
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Where does the lumbar enlargement occur?
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T11 (think T 10 for the bellybutton on the dermatome and on the back directly below that)
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Where does the cervical enlargement occur?
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T1, first thoracic vertebrae
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Where is the anterior median fissure found?
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In the anterior white column of the spinal cord.
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What is the location of the lumbosacral plexus?
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T12 to S5
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Dermatome - Cutaneous innervation
Landmarks |
T4 - nipple; T10 - think "o" for belly button; L1 - think L = groin shape; L4 - patella/knee; S1 - lateral side, "Small 1" of the toes
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Dermatome - Cutaneous Innervation
Cranial Nerve V - Trigeminal |
V1 - Opthalamic
V2 - Maxillary V3 - Mandible Think "V" for Cranial V is Jaw shaped, then count backwards from 3 to 1 (tri - geminal - twins go together) |
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Cervical Plexus (C1-C4)
Sensory and Motor info |
Sensory - neck, scalp and ear, shoulder
Motor -0infrahyoids (ansa cervicalis) diaphragm (phrenic) |
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Brachial Plexus (C5-8, T1)
Sensory and motor info |
Sensory and motor - upper extremity, lateral chest
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Lumbar plexus (L1 - L4)
Sensory and Motor info |
Sensory and motor - abdominal wall, lower extremity
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Sacral Plexus or Lumbosacral Plexus (L4, 5, S1-4)
Sensory and motor info |
Sensory - skin of outside lower buttock, anal, upper thigh and upper calf, sex organs, front of leg
Motor - glues, tensor fascia latae, hams, intrinsic foot, biceps femoris, perineum |
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Brachial Plexus
Divisions of Upper, Middle, Lower |
Kind of braided. Upper is roots in C5,6, branches into subscapular, musculocutaneous, median. Middle is C7, branches into axillary and radial. Lower is C8 and T1 branches into ulnar and median
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Brachial Plexus
Nerve Lesions - Upper Trunk |
Upper trunk, C5,6. Lateral. Erb's Paralys - axillary suprascap, musculocutan. Loss if intrinsic shoulder musc. and anterior arm which medially rotates and abducts. Forearm extended/promated. Waiter's tip. Think waiter named Erb with a tray tipped upside down.
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Brachial Plexus
Nerve Lesions - Lower Trunk |
Lower Trunk C8-T1) Thoracic Outlet Syndrome. Forearm and hand Muscle Loss. Claw and Ape Hand. Horner's Syndrome
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Brachial Plexus
Nerve Lesions Upper Extremity Radial at Axilla |
Radial Nerve at axilla - loss of extensors elbow, wrist, digits. weakened extension shoulder, weakened supination. WRIST DROP (think drop the axe,
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Brachial Plexus
Nerve Lesions of Upper Extremity Radial at Elbow |
Radial nerve at elbow - loss of wrist digit extensors. sensory loss on posterior forearm, hand. WRIST DROP, can be from fracture of shaft of humerus, too, same result
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Brachial Plexus
Nerve Lesions of Upper Extremity Radial at Wrist |
sensory loss on posterior hand (first dorsal web space)
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Brachial Plexus
Nerve Lesions of Upper Extremity Median at Axilla or Elbow |
loss of flexion, thenar eminence musc. and lumbrirals 1/2. weakened flexion of wrist. loss of promation. sense loss on lateral palm/digits 1,2,3 and half 4. APE OR SIMIAN HAND
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Brachial Plexus
Nerve Lesions of Upper Extremity Median at Wrist |
Loss of function of thenar, lumbricals 1. sensory loss palmar srface of dig 1,2,3, 1/2 of 4. No sense loss for palm. Sign Ape or Simian Hand. Carpel Tunnel.
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Brachial Plexus
Nerve Lesions of Upper Extremity Ulnar at Elbow or axilla |
weakened, loss abduction and adduction of digits. weakened flex dig 4,5. SEnse loss 5 and 1/2 4. Claw Hand. Fracture of medial epicondyle of humerus could also damage ulnar nerve.
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Brachial Plexus
Nerve Lesions of Upper Extremity Ulnar at Wrist |
Loss of abduction and adduction of digits, sensory loss on dig 5 and 1/2 of 4. Claw hand, but less severe.
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Brachial Plexus
Nerve Lesions of Upper Extremity Axillary |
Fracture at surgical neck of humerus. Loss of abduction of arm to horizontal plane. Axillary innervates deltoid, so may affect shoulder.
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Palm Hand diagram, sensory innervation of hand
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Anterior of hand Radial nerve - thumb. M, or median nerve with the thumb, index, and middle finger. a tiny bit of ring. Ulnar makes U with 3/4 pinky and ring. On posterior hand, mostly radial, fingertips median, pinky ulnar.
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Nerve Lesions of Lower Extremity
Superior Gluteal Nerve |
loss of abduction of limb, Trendlenberg Gait. Patient can't keep pelvis level when on one leg, it drops forward.
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Nerve Lesions of Lower Extremity
Femoral Nerve |
Weakened Hip Flexion - Loss of knee extension. Sensory loss on anterior thigh, medial leg and foot. Quads.
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Nerve Lesions of Lower Extremity
Common Peroneal Nerve |
combo of deficits of lesion of deep and superficial peroneal nerves. Foot Drop (Cant dorsiflex (pull foot back)
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Nerve Lesions of Lower Extremity
Tibial Nerve |
Loss of Flexion of knee and digits, loss of plantar flexion (ballerina toes) weakened inversion. Sense loss on leg (except medial) and plantar foot.
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Nervous system basic functions
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receiving sensory input
integrating, associating, storing info transmitting motor impulses that result in movement or secretion |
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Nociceptors
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pain sensory receptors
free nerve endings |
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Things to ask about pain
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Severity 1-10 scale. Onset - acute or chronic? Location - superficial, deep, visceral (waves)? Localized - local, referred (2nd order CNS neuron stimulated)? Duration - intermittent or constant?
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Causalgia and RDS
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Pain "locked in brain" and stays there. Usually root cause can be identified. RDS - reflex Sympathetic Dystrophy - no cause identified, miserable constant pain, really bad pain
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Somatosensory pathways to cerebral cortex
3 Neurons Up - afferent 1st, 2nd, 3rd order neurons |
1st - carry signals from somatic receptor to brain stem or sp cord. 2nd - signals from spinal cord or br stem to thalamus. Decussates in sp cord or medulla. 3rd - thalamus to primary somatosensory area of cortex (postcentral gyrus)
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Postcentral gyrus
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Gyrus located directly posterior to the Central Sulcus, where conscious perception of the sensation results
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Posterior/Dorsal Column - sensory
1st, 2nd, 3rd order neurons |
1st sensory neurons, cellbodies in DRS, axons ascend in posterior column to medulla fasiculus gracilis (trunk/legs) fasciculus cuneatus (upper chest/upper body parts. 2nd order cross over in medulla. 3rd order in thalamus -= axons carry impulses to somatosensory cortex
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Spinothalamic (sensory)
1st, 2nd, 3rd order neurons |
pain and temp
1st order - sensory neurons, cell bodies in DRG. 2nd order - posterior dorsal gray horn, contralateral up to brain stem. pain/temp lateral. Anterior other. 3rd in thalamus axons carry impulses to somatosensory area of cerebral cortex of parietal lobe. |
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Homonculus
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"Little person" in brain. relative size of areas in somatosensory cortex are directoy proportional to # of specialized sensory receptors and sensitivity in each receptive part. Larger areas - lips, face, tongue, thumb.
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Cerebellum
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learning and performing, coordination, highly skilled movements, maintains proper posture and equilibrium.
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Cerebellum abnormality - ataxia
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produces drunklike weaving (think "call a taxi")
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Somatic (Body) Motor Pathways from the Cerebral Cortex
CNS motor impulses to the peripheral __________. |
effectors
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Somatic (Body) Motor Pathways from the Cerebral Cortex
Where is the Primary (PreCentral) Motor Area? |
It is located in the precentral gyrus of the Cerebral Cortex.
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Why is the Direct Pathway (Motor) also called Pyramidal?
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Pyramid shaped cell formation in medulla, directly superior to foramen magnum.
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Direct (Pyramidal) Pathway
UMN |
Upper Motor Neurons in cerebral cortex, axons pass through pyramids of medulla
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Direct (Pyramidal) Pathway
Lateral Corticospinal tracts are responsible for what kind of movement? |
skilled movement of hands and feet.
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Direct (Pyramidal) Pathway
corticobulbar tracts contain motor neurons for what kind of nerves? |
Cranial Nerves
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Direct (Pyramidal) Pathway
Anterior Corticospinal tracts are responsible for motor in what areas? |
neck and trunk
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Direct (Pyramidal) Pathway
LMN |
Lower Motor Neurons extend from motor nuclei of cranial nerves to SKELETAL MUSCLES of face/head. LMNs also extend from anterior horns of spinal cord to SKELETAL muscles of trunk/limbs.
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Indirect (Extrapyrimidal) Pathway
What do they do and where are they? |
They influence lower neurons to determine final responses, and comprise all descending tracts other than corticospinal and corticobulbar tracts.
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BASAL GANGLIA (NUCLEI) abnormalities
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abnormalities - abnormal movements or tremors by loss of inhibitory signals from the basal ganglia. 1 - Parkinson’s Disease and Chorea - Huntington’s chorea (dominant defective gene)
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Basal Ganglia
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1-help to promote habitual or automatic movements; 2-selectively inhibit other motor neuron circuits;
3-components - several groups of nuclei in each cerebral hemisphere (caudate nucleus and putamen); 4- receive input from sensory, motor, and association areas of the cerebral cortex substantia nigri |
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Where is the UMN (Upper Motor Neuron) located?
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Located in the cerebral cortex
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Where is the LMN Located?
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It is a ventral horn cell located in the spinal cord.
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What gyrus of the cerebral cortex houses the UMN?
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The precentral gyrus
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Where does the decussation of the UMN occur?
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immediately superior to the foramen magnum in the caudal medulla, spinal cord junction.
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Where does the UMN go after its decussation? Where does it synapse with the LMN? Why?
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It goes down the lateral corticospinal tract, and then synapses with the LMN in the spinal cord at the level of innervation (anteriorly) of the skeletal muscle it's effecting, for voluntary refined movements of the distal extremities.
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What is the brainstem?
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Medulla, pons, and midbrain combine to form this
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What problems would a UMN lesion cause?
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Spastic Paralysis, Hyperreflexia, Babinski sign present. If lesion in Cerebral Cortex or Brainstem problem would be contralateral. If lesion in spinal cord (after decussation in brainstem) it'd be ipsilateral.
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What problems would LMN lesion cause?
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Flaccid Paralysis, Areflexia, No Babinski. If location in Spinal cord (post synaptic and headed toward effector muscle) it would be ipsilateral.
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Where is the motor homonculus located?
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IN the pre central (sulcus) area, on the primary motor cortex of left cerebral hemisphere.
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Where is the sensory homonculus located?
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In the post central (sulcus) area in the primary sensory cortex on the right cerebral hemisphere.
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