Brachial Plexus Flashcards
What are the five segments of the brachial plexus?
Roots, Trunks, Divisions, Cords, Nerves
What nerves compose the upper, middle, and lower trunks?
C5-6
C7
C8,T1
The lateral cord stems from what spinal nerves? What divisions?
C5-7
Anterior division of the upper and middle trunk
The medial cord contains nerves from what spinal roots? What divisions does it contain?
C8 and T1
Anterior division of lower trunk
The posterior cord is comprised of what spinal nerve fibers? What division does it originate from?
C5-C8
All three posterior divisions
What cord and spinal nerves does the musculocutaneous nerve arise from?
Lateral cord; C5-7
What cord and spinal nerves does the median nerve come from?
Merged lateral and medial cord
Spinal nerves C6-T1
What cord and spinal nerves results in the axillary n.?
Posterior cord
C5-6
What cord and spinal nerves results in the radial n.?
Posterior cord
C5-8
What cord and spinal nerves results in the ulnar nerve?
Medial cord
C8-T1
What spinal nerve gives rise to the dorsal scapular n.?
C5 (near trunk)
What spinal nerve gives rise to the suprascapular n.?
C5-6 (@ trunk)
What spinal nerve gives rise to the subclavian?
C5-6
What spinal nerve gives rise to the long thoracic?
C5-7
What spinal nerve gives rise to the lateral pectoral?
C5-6 of lateral cord
What spinal nerve gives rise to the upper subscapular?
C5 of posterior cord
What spinal nerve gives rise to the thoracodorsal n.?
C6-8 of posterior cord
What spinal nerve gives rise to the lower subscapular?
C6 of posterior cord
What spinal nerve gives rise to the medial pectoral n?
C8-T1 of medial cord
What spinal nerve gives rise to the medial cutaneous nerves of arm and forearm?
C8-T1 medial cord
What spinal nerve is generally responsible for abduction of the shoulder?
C5
What spinal nerve is generally responsible for extension of the wrist?
C6
What spinal nerve is generally responsible for fingers?
C7
What spinal nerve is generally responsible for wrist flexion?
C7
What spinal nerve is generally responsible for finger flexion?
C8
What spinal nerve is generally responsible for ab/adduction of fingers?
T1
What spinal nerve is tested with the biceps reflex? Brachioradialis reflex? Triceps reflex?
C5; C6; C7
What nerve’s dermatome lies on the shoulder?
C5
What nerve’s dermatome lies on the lateral lower arm, forearm, and hand?
C6
What nerve’s dermatome lies on the middle portion of the palm and middle finger, plus half of the two fingers surrounding middle; and in the middle of the posterior forearm to the elbow?
C7
What nerve’s dermatome lies on the medial hand and half of ring finger, plus the posteriomedial forearm?
C8
What nerve’s dermatome lies on the lateral forearm and posterio-lateral arm?
T1
What are the axillary nerve’s muscle branches? Sensory?
Teres minor and deltoid
Superior lateral cutaneous n.
What are the muscular and sensory branches of the musculocutaneous nerve?
Coracobrachialis, biceps brachii, brachialis
Lateral cutaneous nerve of the forearm
What are the muscular and sensory branches of the median n.?
Anterior compartment of forearm (EXCEPT flexor carpi ulnaris and 1/2 of the flexor digitorum profundus); thenar muscles of hand, first two lumbricals
1st 7 palmar digital nn (first 3 and 1/2 digits on palm)
What are the muscular and sensory branches of the ulnar nerve?
Flexor carpi ulnaris and 1/2 of the flexor digitorum profundus; intrinsic muscles of the hand (except thenar and 1st 2 lumbercals)
Common and proper palmar and dorsal digitals
What are the muscular and sensory branches of the radial nerve?
Posterior compartment muscles of arm and forearm; NONE IN HAND
Inferior lateral brachial cutaneous n., posterior cutaneous n of forearm; dorsal digitals for first 2.5 digits
What are the supraclavicular nerves? What do they innervate?
Dorsal scap- levator scapulae and romboids
suprascapular- supraspinatus and infraspinatus
subclavian- subclavius
long thoracic- serratus anterior
What are the posterior cord nerves and what do they innervate?
Upper subscapular- subscapularis
Lower subscapular- subscapularis and teres major
Thoracodorsal- latissimus dorsi
What are the median chord nerves and what do they supply?
Medial pectoral n.- pec minor and major
Medial cutaneous nerve of arm/forearm- the name says it all (think C8-T1 dermatome)
What are the nerves of the lateral cord and what muscle do they supply?
Lateral pectoral n- pec major
Severance of the axillary nerve would cause what issue?
Numbness along lateral and posterior shoulder; no abduction of shoulder joint
Severing the musculocutaneous nerve could cause what complication?
Numbness along the lateral aspect of the forearm; inability to flex at the elbow or internally rotate the glenoid fossa
Severing the median nerve can cause what complications?
Proximal severance: lack of flexion power in the forearm, inability to move thumb and digits 1 and 2 very well
Severance of the ulnar nerve results in what complications?
Limits flexion of wrist; limits mobility of fingers 4-5; numbness and tingling on fingers 4-5
Severance of the radial nerve can cause what complications?
Limits extension at elbow and forearm; numbness along posterior and lateral arm
