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42 Cards in this Set
- Front
- Back
Define plexus.
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area of the peripheral nervous system where there is branching & interconnecting of nerves, resulting in redistribution of nerve fibres.
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What does each spinal nerve have to make up its common root?
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dorsal root = sensory root of the nerve
ventral root = motor root of the nerve |
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What does the common root of a spinal nerve branch into?
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posterior primary ramus - small, innervates trunk overlying spinal column
anterior primary ramus - has majority of nerve fibres |
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does the anterior or posterior primary ramus innervate most activity of a particular segmental nerve?
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anterior primary ramus - has the majority of nerve fibres
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name 2 areas where anterior primary rami distribution is modified as they go out to limbs.
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brachial plexus
lumbrosacral plexus |
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Which nerve roots are involved in the brachial plexus?
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C5 6 7 8 + T1
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which roots merge to become trunks?
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C5+6 - upper trunk
C7 - middle trunk C8+T1 - lower trunk |
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What parts of the brachial plexus pass behind the clavicle?
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trunks
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What does each trunk divide into as it enter the axilla?
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anterior + posterior divisions
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What do the divisions merge into to form?
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cords
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Which divisions make up the lateral, medial & posterior cords?
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lateral - 2 upper/lateral anterior divisions
medial - anterior lower/medial divisions posterior - 3 posterior divisions, in the middle of the other 2 cords |
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What do the cords become?
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branches that are peripheral nerves of the upper limb
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List the changes in name of the brachial plexus
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roots trunks divisions cords branches
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What are cords named in relation to?
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axillary artery
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What is the most vital area of the plexus anatomically and what part lies in this region?
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axilla - cords lie here
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What are the 2 branches from the roots?
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dorsal scapular nerve (C5)
long thoracic nerve (C5,6+7) |
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Only the upper trunk has branches. What are these 2?
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suprascapular nerve
insignificant nerve to subclavius |
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What branches do divisions have?
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None, they only redistribute fibres into cords
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What are branches mostly named in relation to?
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which cord they arise from
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upper middle lower or lateral medial posterior or anterior posterior, which are cords, which are divisions and which are trunks?
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trunks - upper, middle, lower
cords - lateral, medial, posterior divisions - anterior, posterior |
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What are the 3 branches coming off the lateral cord?
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lateral pectoral nerve
lateral head of median nerve musculocutaneous nerve |
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What are the 5 branches of the medial cord?
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medial pectoral nerve
2 cutaneous nerves - arm + forearm medial head of median nerve ulnar nerve |
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what are the 5 branches of the posterior cord/
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upper + lower subscapular nerve
thoracodorsal nerve axillary nerve radial nerve |
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what is the main single branch of the lateral cord?
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musculocutaneous nerve
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Describe the distribution of the musculocutaneous nerve
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arises from lateral cord
enters coracobrachialis arises deep to biceps, superficial to brachialis & supplies these elbow flexors becomes lateral cutaneous nerve lateral & proximal to elbow joint no motor function below this point |
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Name 4 functions of musculocutaneous nerve
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elbow flexor
shoulder flexor forearm supinator sensation on lateral forearm |
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what is the main nerve continuing from the medial cord?
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ulnar nerve
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describe the passage of the ulnar nerve
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branch of medial cord
passes down medial arm towards elbow posteriorly behind medial epicondyle of humerus between 2 heads of flexor carpi ulnaris (supplies) supplies medial half of flexor digitorum profundus dorsal cutaneous branch to medial 1.5 fingers posteriorly 2 branches at hand - superficial (cutaneous) & deep - between hypothenar eminence to supply intrinsic muscles of hand |
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What muscles does the ulnar nerve supply?
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flexor carpi ulnaris
medial half of flexor digitorum profundus deep branch - intrinsic muscles of heand except thenar & lateral 2 lumbricals |
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What areas does the ulnar nerve give sensation?
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dorsal cutaneous branch - medial side of hand & medial 1.5 fingers on posterior surface
superficial branch - palmar surface of 1.5 medial digits |
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what muscle does the thoracodorsal nerve supply?
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latissimus dorsi
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what is the main nerve continuing from the posterior cord?
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radial nerve
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Describe the radial nerve's passage
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branch of posterior cord
behind humerus shaft in radial groove in front of triceps - supplies 3 heads posterior & lower lateral cutaneous branches supply skin above elbow joint behind elbow then through brachialis & muscles arising from lateral epicondyle to enter forearm 2 branches - superficial cutaneous & deep posterior interosseous nerve |
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what muscles does the radial nerve supply/
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triceps
brachialis extensor muscles of forearm supinator (???) |
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what areas does the radial nerve give cutaneous supply?
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lower part of arm above elbow joint - posterior & lower lateral cutaneous nerves of arm
lateral aspect of forearm posteriorly back of hand under fingers 123 |
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What cords does the median nerve arise from?
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lateral & medial cords
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Describe median nerve passage
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follows axillary artery
into cubital fossa - medial to brachial artery under pronator teres under flexor digitorum superficialis & on top of profundus in forearm superficial towards wrist under flexor retinaculum at wrist & into hand supplies lateral 2 lumbricals & thenar eminence |
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What muscles does median nerve supply?
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all muscles of flexor origin (except flexor carpi ulnaris & medial half of digitorum profundus)
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What section of palm does median or ulnar nerve supply, & which is more important for sensory/motor function?
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median - lateral palm
ulnar - medial palm median - sensory importance ulnar - motor importance (small muscles of hand) |
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If a lesion involves a root, are dermatomes or cuteneous nerve maps more important?
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dermatomes indicate areas of skin supplied by nerve roots
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Learn cutaneous nerve map of upper limb
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Learn nerve root supply of upper limb (dermatomes)
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