Brachial Plexus (Midterm) Flashcards
Which roots make up the superior trunk of the brachial plexus?
test q
C5 and C6
Which roots make up the middle trunk of the brachial plexus?
test q
C7 only
Which roots make up the inferior trunk of the brachial plexus?
test q
C8 and T1
The brachial plexus is formed by the….
anterior rami of C5-T1
Each trunk of the brachial plexus divides into anterior and posterior divisions. The anterior divisions of the trunks supply anterior (_________) compartments of the upper limb, and posterior divisions of the trunks supply posterior (______________) compartments
flexor, extensor
The anterior divisions of the superior and middle trunks of the brachial plexus unit to form the ___________ cord
lateral cord
The anterior division of the inferior trunk of the brachial plexus continues as the ___________ cord
medial
The posterior divisions of all 3 trunks of the brachial plexus unit to form the ____________ cord
posterior
What is the origin root of the dorsal scapular n.?
C5
What does the dorsal scapular n. innervate?
-levator scapulae
-rhomboid major and minor
What is the origin root of the long thoracic n.?
C5, C6, and C7
What does the long thoracic n. innervate?
serratus anterior
What is the origin root of the subclavian nerve (nerve to subclavius)?
superior trunk (C5 and C6, and sometimes C4)
What does the subclavian nerve (nerve to subclavius) innervate?
subclavius and sternoclavicular joint (accessory phrenic root innervates the diaphragm)
What is the origin root of the suprascapular n.?
superior trunk (C5 and C6, and sometimes C4)
What does the suprascapular n. innervate?
-supraspinatus and infraspinatus muscles
-glenohumeral joint
What is the origin root of the lateral pectoral n.?
lateral cord (C5, C6, and C7)
What does the lateral pectoral n. innervate?
pec major and minor
What is the origin root of the musculocutaneous n.?
lateral cord terminal branch
Which nerve pierces the coracobrachialis?
musculocutaneous n.
What does the musculocutaneous n. innervate?
-coracobrachialis
-biceps brachii
-brachialis
The contribution to the median nerve starts where?
lateral cord
What is the origin root of the upper subscapular n.?
posterior cord C5
What does the upper subscapular n. innervate?
superior subscapularis
What is the origin root of the middle subscapular n. (also known as thoracodorsal n.)?
posterior cord C6, C7, and C8
What does the middle subscapular n. (also known as thoracodorsal n. innervate?
latissimus dorsi
What is the origin root of the lower subscapular n.?
posterior cord C6
What does the lower subscapular n. innervate?
inferior subscapularis and teres major
What is the origin root of the axillary n.?
-terminal branch C5
-C6
What does the axillary n. innervate?
-teres minor
-deltoid
-glenohumeral joint
-skin of superolateral arm
What is the origin root of the radial n.?
terminal branch of the posterior cord
What is the largest branch of the brachial plexus?
radial n.
What does the radial n. innervate?
(a whole lot of muscles)
-triceps
-anconeus
-brachioradialis
-extensor carpi radialis longus + brevis
-extensor digitorum
-extensor digiti minimi
-extensor carpi ulnaris
-supinator
-extensor indicis
-(deep radial) abductor pollicis longus
-extensor pollicis longus + brevis
What does the superficial radial n. innervate?
the skin of the posterior and inferolateral arm, posterior forearm, and dorsum of the hand lateral 3.5
What is the origin root of the median n.?
-lateral and medial cords
-lateral roots of median nerve is a terminal branch of lateral cord C6 and C7
-medial root of median nerve is a terminal branch of medial cord C8 and T1
What does the median n. innervate?
-muscles of the anterior forearm compartment except for flexor carpi ulnaris and ulnar half of flexor digitorum profundus
-flexor carpi radialis
-pronator teres
-palmaris longus
-flexor digitorum superficialis
-lateral (radial) half of the flexor digitorum profundus
-flexor pollicis longus
-pronator quadratus
-oppenens pollicis
-abductor pollicis brevis
-flexor pollicis brevis superficial head
-1st and 2nd lumbricals
-sensation to skin of palmer and distal dorsal aspects of lateral 3.5 digits and adjacent palm
The recurrent (thenar) branch of the median n. arises from the median nerve as soon as it has passed distal to the….
flexor retinaculum
What does the recurrent (thenar) branch of the median n. innervate?
-abductor pollicis brevis
-opponens pollicis
-superficial head of flexor pollicis brevis
The lateral branch of the median n. arises as lateral divisions of the median nerve as it enters the….
palm of the hand
What does the lateral branch of the median nerve innervate?
-1st lumbrical
-skin of palmer and distal dorsal aspects of the thumb and radial half of 2nd finger
The medial branch of the median nerve arises as a medial division of the median nerve as it enter the….
palm of the hand
What does the medial branch of the median nerve innervate?
-2nd lumbrical
-skin of palmer and distal dorsal aspects of adjacent sides of 2nd-4th fingers
The palmer cutaneous branch of the median nerve arises from the median nerve just proximal to the….
flexor retinaculum
What does the palmer cutaneous branch of the median nerve innervate?
skin of central palm
What is the origin root of the medial pectoral n.?
medial cord C8-T1
What does the medial pectoral n. innervate?
-pec minor
-sternocostal part of pec major
What is the origin root of the medial cutaneous n. of the arm?
medial cord C8-T1
What does the medial cutaneous nerve of the arm innervate?
skin of medial side of arm, as far distal as medial epicondyle of humerus and olecranon of ulna
What is the origin root of the medial cutaneous nerve of the forearm?
medial cord C8-T1
What does the medial cutaneous nerve of the forearm innervate?
skin of medial side of the forearm, as far distal as the wrist
What is the origin root of the ulnar n.?
larger terminal branch of the medial cord, receiving fibers from C8, T1, and often C7
What does the ulnar n. innervate?
-flexor carpi ulnaris and ulnar half of flexor digitorum profundus (forearm)
-deep branch hypother muscles like the abductor, flexor and opponens digiti minimi
-adductor pollicis
-dorsal and palmer interosseous
-deep head of flexor pollicis brevis
-lumbricals 4 and 5
-superficial branch of palmaris brevis
-sensation to skin of palmer and distal dorsal aspects of medial (ulnar) 1.5 digits and adjacent palm
What does the palmer cutaneous branch of the ulnar n. innervate?
skin on the base of medial palm, overlying the medial carpals
What does the dorsal branch of the ulnar nerve innervate?
skin of medial aspect of dorsum of hand and proximal portions of little and medial half of ring finger (occasionally also adjacent sides of proximal portions of ring and middle fingers)
NOTE: this class is basically MSK on repeat- KNOW nerves and what specific muscles they innervate for midterm!!!!
