MSK 1 Upper Limb Flashcards
What spinal nerve roots enter the brachial plexus?
C5, C6, C7, C8, T1
Which nerves form the ‘M’ structure across the Axillary nerve?
Musculocutaneous
Median
Ulnar
What spinal nerve root(s) form the Dorsal scapular nerve?
C5
Which spinal nerve roots form the Long Thoracic nerve?
C5, C6, C7
Which spinal root(s) form the suprascapular and subclavian nerves?
C5, C6
Which nerves branch form the ‘trunks’ section of the brachial plexus?
Suprascapular nerve
Subclavian nerve
Which nerves branch from the ‘roots’ section of the brachial plexus?
Long thoracic nerve
Dorsal scapula nerve
Which nerve branches from the lateral cord of the brachial plexus?
Lateral pectoral
Which nerves branch from the posterior cord of the brachial plexus?
Lower Subscapular
Medial Subscapular
Upper Subscapular
Which nerves branch from the Medial cord of the brachial plexus?
Medial cutaneous nerve of the arm
Medial cutaneous nerve of the forearm
Medial pectoral nerve
What are the 5 main branches of the brachial plexus?
1) Musculocutaneous nerve
2) Axillary nerve
3) Radial nerve
4) Median nerve
5) Ulnar nerve
What are the spinal nerve roots of the Musculocutaneous nerve?
C5, C6, C7
What are the spinal nerve roots of the Axillary nerve?
C5, C6
What are the spinal nerve roots of the Radial nerve?
C5, C6, C7, C8, T1
What are the spinal nerve roots of the Median nerve?
C5, C6, C7, C8, T1
What are the spinal nerve roots of the Ulnar nerve?
C8, T1
What does the Musculocutaneous nerve innervate?
Brachialis muscle
Biceps Brachii muscle
Coracobrachialis muscle
Skin of the lateral forearm (via Lateral cutaneous nerve of forearm)
Which nerve innervates the coracobrachialis?
Musculocutaneous nerve
Which nerve innervates the skin on the lateral edge of the forearm?
Lateral cutaneous nerve of the forearm (branch of the Musculocutaneous nerve)
What does Axillary nerve innervate?
Glenohumeral joint
Teres minor muscle
Deltoid muscle
Skin over the regimental patch area
Which nerve innervates Teres minor muscle?
Axillary nerve
Which nerve innervates the Deltoid muscle?
Axillary nerve
What does the Medial nerve innervate?
1st and 2nd Lumbricals Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis Palmar skin Anterior forearm EXCEPT FCU and ulnar 1/2 of FDP: -Pronator teres -Flexor carpi radialis -Palmaris longus -Flexor digitorum superficialis -Medial 1/2 of Flexor digitorum profundus -Pronator quadratus -Flexor pollicis longus
Which nerve innervates the 1st and 2nd Lumbricals?
Medial nerve
Which nerve innervates the Palmar skin?
Medial nerve
Which intrinsic muscles of the hand are innervated by the Median nerve?
1st and 2nd Lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
What does the Radial nerve innervate?
Skin of posterior upper limb Posterior compartments of the upper limb muscles: - Triceps brachii - Brachioradialis - Supinator - Anconeus - Extensor digitorum - Extensor pollicis longus - Abductor pollicis longus - Abductor pollicis brevis - Extensor carpi ulnaris - Extensor carpi radialis longus - Extensor carpi radialis brevis - Extensor digiti minimi - Extensor indici
Which nerve innervates the Extensor carpi ulnaris muscle?
Radial nerve
What does the Ulnar nerve innervate?
Medial 1/2 of palmar and dorsal skin (of hand) Flexor carpi ulnaris Ulnar 1/2 of FDP Dorsal and Palmar interossei 3rd and 4th Lumbricals Adductor pollicis Hypothenar muscles: - Opponens digiti minimi - Abductor digiti minimi - Flexor digiti minimi brevis
Which nerve innervates the dorsal and palmar interossei of the hand?
Ulnar nerve
Which nerve innervates the hypothenar muscles?
Ulnar nerve
What is the name of an upper brachial plexus injury (to C5-6 nerve roots)?
Erb’s palsy
Which nerve roots are damaged in Erb’s Palsy?
C5
C6
What are some possible causes of an Erb’s palsy?
Difficult birth (small birth canal, large baby, pulled out)
Trauma ie Motorcycle collision
= Extended angle between head and neck
How will someone present if they have Erb’s Palsy?
- Extended, adducted and medially rotated arm
- Flexed wrist
Why does Erb’s Palsy cause arm to be adducted?
Damaged nerve roots of Supraspinatus nerve and Axillary nerve,
= Loss of Supraspinatus and Deltoid muscles, which are responsible for the first 90’ of abduction
= unopposed adduction
What is the name of a lower brachial plexus injury (to C8/T1 nerve roots)?
Klumpke’s palsy
Which nerve roots are damaged in Klumpke’s Palsy?
C8
T1
What are some possible causes of Klumpke’s Palsy?
Fall from tree and catch branch
Difficult birth (pulled out by arm)
= Hyperextension of arm
How will someone present if they have Klumpke’s Palsy?
‘Claw hand’
- Extension of wrist
- Hyperextension of metacarpophalangeal joints
- Flexion at interphalangeal joints
Why does Klumpke’s Palsy cause hyperextension of metacarpophalangeal joints?
Damage to Median and Ulnar nerves causes loss of the lumbricals in the hand, allowing unopposed extension of MCP joints.
Which nerves are at risk during a stab wound to the axilla?
Axillary nerve
Musculocutaneous nerve