Nervous System Flashcards
What are the 6 reflexes tested, and which nerve roots do they test?
BIceps (C5-6) Brachioradialis (C5-6) Triceps (C7-8) Patellar (L3-4) Tibialis posterior (L4-5) Achilles (S1-2)
Which actions can be used to test the nerve root supply to the lower limb?
L2 - hip flexion L3 - knee extension L4 - ankle dorsiflexion L5 - great toe extension S1 - ankle plantarflexion and eversion, hip extension S2 - knee flexion
Which actions can be used to test the nerve root supply to the upper limb?
C1-2 - Cx flexion / extension C3 - Cx sidebending C4 - shoulder elevation C5 - shoulder abduction C6 - elbow flexion, wrist extension C7 - elbow extension, werist flexion C8 - finger flexion, ulnar deviation T1 - finger abduction / adduction
What are the 8 nerves of the cervical plexus, including their nerve root and function?
4 sensory nerves: C2 - lesser occipital C2-3 - greater auricular C2-3 - transverse cervical C3-4 - supraclavicular
1 mixed:
C3-5 - phrenic
3 motor:
C1 - nerve to geniohyoid
C1-3 - ansa cervicalis (infrahyoid mm)
C1-5 - spinal accessory (upper traps and SCM)
What are the 5 terminal branches of the brachial plexus, their nerve roots, and their functions?
Musculocutaneous (C5-7)
- motor anterior arm
- cutaneous anterolateral forearm
Axillary (C5-6)
- motor deltoid and teres minor
Radial (C5-T1)
- motor posterior arm and posterior forearm
Median (C6-T1)
- motor anterior forearm (except medial half of FCU, and FDP)
- motor thenar mm and lateral 2 lumbricals
- sensory: palmar surface of hand except medial one and a half digits and corresponding skin, tips of digits 1-3
Ulnar: (C8-T1)
- motor medial half of FCU, FDP
- motor intrinsic hand (except thenar and lateral 2 lumbricals)
- cutaneous medial one and a half digits and corresponding skin (palmar and dorsal)
Describe the distribution of cutaneous peripheral nerve innervation and dermatomal innervation of the hand
Peripheral:
- ulnar: medial one and a half digits and corresponding skin (palmar and dorsal)
- median: palmar surface (except medial one and a half digits and hypothenar eminence); dorsal tips of digits 1-3
- radial: dorsum of hand except tips of digits 1-3; and medial one a half digits and corresponding skin
Dermatomal:
- C6: lateral two digits and corresponding skin
- C7: middle digit and corresponding skin
- C8: lateral two digits and corresponding skin
Which 4 hand signs can be used to test the peripheral nerve supply to the hand?
Thumbs up - radial
Peace - ulnar
OK - median (anterior interosseous branch)
Fist - median
What are the common sites of compression for the ulnar, median and radial nerves?
Ulnar:
- cubital tunnel
- ulnar tunnel
Median:
- carpal tunnel
- between the heads of pronator teres
Radial:
- between the heads of the supinator
What are the 11 non-terminal branches of the brachial plexus, and their function?
- dorsal scapular - rhomboids, levator scapulae
- nerve to subclavius
- suprascapular - supraspinatus, infraspinatus
- long thoracic - serratus anterior
- lateral pectoral - pec major
- medial pectoral - pec mino, medial half of pec major
7, 8, 9: subscapular nerves (upper, middle, lower) - subscapularis, teres major
10: thoracodorsal - lat dorsi
11: medial cutaneous nerves (pectoral, arm, forearm)
Briefly describe the course of the radial nerve
- Ventral roots C5-T1
- continuation of posterior cord of brachial plexus
- passes through triangular space between teres major and long head of triceps
- wraps around head of humerus laterally
- descends in spiral groove between lateral and medial heads of triceps
- reaches lateral arm 5cm below deltoid tuberosity
- enters anterior compartment of arm and descends between brachioradialis and brachialis
- enters cubital fossa and divides into deep (motor) and superficial (cutaneous) branches
Briefly describe the course of the ulnar nerve
C8-T1
- continuation of medial cord of brachial plexus
- descends through medial arm
- passes through cubital tunnel posterior to medial epicondyle of elbow
- enters anterior forearm between two heads of FCU
- descends through forearm between FDS and FDP
- enters hand through ulnar tunnel (lateral to pisiform)
Briefly describe the course of the musculocutaneous nerve
C5-7
- lateral cord of brachial plexus
- pierces coracobrachialis
- descends between biceps brachii and brachialis
What are the 6 nerves of the lumbar plexus, their nerve roots, and their functions?
Iliohypogastric
- L1
- lateral to psoas
- motor to IO, TA
Ilioinguinal
- L1
- lateral to psoas
- motor to IO, TA
Genitofemoral
- L1/2
- through psoas
- cutaneous upper thigh
Lateral femoral cutaneous
- L2/3
- cutaneous lateral thigh
Obturator
- L2/4
- motor to adductors
- cutaneous upper medial thigh
Femoral
- L2/4
- motor to anterior thigh
- cutaneous anterior thigh
What are the 6 major nerves of the sacral plexus?
Superior gluteal
- L4/S1
- glute med and min, TFL
Inferior gluteal
- L5/S2
- glute max
Sciatic
- L4/S3
- motor posterior thigh, all leg and foot
- cutaneous leg and foot
Posterior femoral cutaneous
- S1/3
- cutaneous posterior thigh
Perforating cutaneous
- S2/3
- cutaneous over glute max
Pudendal
- S2/4
- mm of pelvic floor, external urethral and anal sphincters
- cutaneous to genitals and perineum
Briefly describe the course of the sciatic nerve
L4-S3
- exits pelvis via greater sciatic foramen
- descends under piriformis and long head of biceps
- divides into tibial and fibular nerves in popliteal fossa
Tibial nerve:
- descends posterior to tibia
- passes through tarsal tunnel posterior to medial malleolus
- splits into medial and lateral plantar nerves
Fibular nerve:
- spits in popliteal fossa into superfical and deep fibular nerves
- deep fibular (motor): crosses interosseous membrane to supply anterior leg mm
- superficial fibular (mixed): wraps around neck of fibula, descends through lateral compartment of leg
