Brachial plexus Flashcards
(15 cards)
Brachial plexus Roots and branches
C5-T1
My Aunt recognised by uncle
Musculocutaneous
Axillary
Radial
Median
Ulnar
Musculocutaneous
C5-C7 Lateral cord
Sensory to Lateral forarm
Motor to biceps, brachialis, coracobrachialis
Musculocutaneous impingement sites
Axillary fold or coracobrachialis
Musculocutaneous damage signs
Weakness of elbow flexion
- Loss of cutaneous sensation to anterior & lateral forearm (lateral antebrachial cutaneous nerve)
- Loss of biceps reflex
Axillary nerve
C5-6
Innervates the deltoid and teres minor
Cutaneous to Post/lat deltoid
Axillary nerve impingement sites
Quadrangular space - Teres minor/major, triceps long head, humerus
Martin gruber anastomosis – median/ulnar nerve connection - 5-10% prevalence
Axillary nerve symptoms
- Often due to fractures of the humerus and dislocations
- Weakness in deltoid & teres minor - weak abduction of arm
- Loss of cutaneous sensation to superior posterior & lateral arm
Radial nerve
C5-T1 Posterior cord
Innervating the triceps brachii, anconeus and the extensor muscles of the forearm.
Extensor carpi radialis brevis
Supinator
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Extensor indicis
Cutaneous to Post/Lateral upper limb and posterior forearm Dorsal/lateral hand and thumb
Radial nerve impingement sites and symptoms
- Triangular space - Between: Teres major, triceps (long head) and humerus
- Loss of tricep reflex
- Loss of sensation to entire posterior arm and forearm
- Loss of sensation to sensory distribution - Radial groove
- Often due to humeral fractures
- Weakness of wrist extension or wrist drop
- Loss of sensation to sensory distribution - Radial head/ supinator muscle
- Fractures to proximal radius or compression of extensor carpi radialis brevis muscle
- Weakness of thumb extension & MCP extension
Arcade of frohse, spiral groove, pec minor, scalenes, 1st rib, IVF
Median nerve
C6-T1 Lateral and medial cords
Innervates the flexors of the forearm
Pronator teres, Flexor carpi radialis, Flexor digitorum superficialis, palmaris longus.
And muscles of the hand: Abductor pollicis brevis, Flexor pollicis brevis and longus.
Cutaneous to Palmar surface of 2/3rd of hand and digits 2/3
Median nerve impingement sites and symptoms
Median nerve (C6-T1)
1. Elbow
- Weakness of forearm and wrist pronation
- Weakness of wrist flexion
- Ape hand deformity
- Loss of sensation to median nerve distribution
- Between the two heads of pronator teres
- Aching P in wrist/forearm
- Ape hand deformity
- Loss of sensation to median nerve distribution - Carpal tunnel
- Most commonly due to carpal tunnel syndrome
- Ape hand deformity
- Loss of sensation to median nerve distribution
Struthers ligament, pec minor, 1st rib, scalenes, IVF.
Ulnar nerve
C7-T1 Medial cord
Forearm: Flexor Carpi Ulnaris, Flexor Digitorum Profundus (Medial Half)
Hypothenar Muscles: Abductor digiti minimi, Flexor digiti minimi brevis, Opponens digiti minimi.
Hand: Lumbricals (Medial Two), Interossei (Palmar and Dorsal), Deep Head of Flexor Pollicis Brevis, Palmaris Brevis.
Cutaneous to anterior and posterior dorsal medial 1/3rd of hand.
Ulnar nerve impingement sites and symptoms
- Elbow
- Cubital tunnel syndrome, fractures of medial epicondyle or damage to anconeus
- Weakness of ulnar sided wrist flexion
- Claw hand deformity
- Loss of sensation to medial 1 1/2 fingers - Wrist - Tunnel of Guyon
- Caused by trauma or Swelling of the flexor carpi ulnaris
- Bishops or claw hand deformity
- Loss to sensory distribution
Flexor carpi ulnaris, arcade of Osborne, arcade of Struthers, pec minor, 1st rib, scalene, IVF.
Extra nerves on Trunks
Upper trunk 3:
- Dorsal scapula C5 (rhomboids and levator scapular)
- Nerve to subclavius (C5-6)
- Suprascapular C5/6 (Supraspinatus, infraspinatus, GH joint)
Upper and middle trunk:
Long thoracic nerve C5/7 (Serratus anterior)
Extra nerves on Cords
Posterior cord:
- Upper subscapular C5/6 (Subscapularis)
- Lower subscapular C5/6 (Subscap and Teres major)
- Thoracodorsal C6/8 (Lats)
Medial cord:
- Medial pectoral nerve C8/T1 (Pec minor and major)
- Medial brachial cutaneous C8/T1 (Post/med humerus)
- Medial antebrachial cutaneous C8/T1 (Anterior/lateral humerus down to forearm)
