Upper Extremity Neurology Flashcards
Supraclavicular nerve
Part of cervical plexus (Anterior rami of C1-4)
Provides cutaneous innervation to skin over neck and shoulder
Has middle, lateral and medial branches
Brachial plexus
The roots of the plexus are the 5 anterior rami of C5-8 and T1, travel b/w the anterior and middle scalene muscles with the subclavian artery
Dorsal scapular nerve innervates
Rhomboid major and minor
Injury to superior part of brachial plexus
Typically affects C5/C6 anterior rami and are the result of dramatically increasing the angle between the neck and the shoulder. Patient will have adducted and medially rotated arm and an extended elbow
Also known as Erb-Duchenne palsy or “waiters tip position”
Injury to inferior part of brachial plexus
Less common than upper portion injury, usually the result of dramatically increasing the angle between the trunk and upper limb
Can result in “claw hand” when the individual tries to make a fist, also known as klumpke paralysis
The names of the posterior, lateral and medial cords are named because they are positioned posterior, lateral and medial to what
Axillary artery
Medial pectoral nerve
Pierces the pectoralis minor, innervates both pectoral muscles
Medial brachial cutaneous nerve
Sensory/cutaneous to medial aspect of the distal 2/3rds of brachium
Medial antebrachial cutaneous nerve
Travels with ulnar nerve, then travels through deep fascia with basilic vein before dividing into anterior/posterior branches
Sensory from anterior and medial aspect of antebrachium
Thoracodorsal nerve
Originates b/w upper and lower subscapular nerves
Innervates latissimus dorsi
Lower subscapular
Innervates lower portion of subscapularis and the teres major
Compression of brachial plexus
Usually results from prolonged periods of working with the upper limb extended over the head
Results in pain radiating down the arm, loss of sensation, tingling of the arms and weakness of hands
Musculocutaneous nerve travels through what
Coracobrachialis
Lateral antebrachial cutaneous nerve
Continuation of musculocutaneous nerve, sensory information from the lateral aspect of the antebrachium
Musculocutaneous nerve injury
Rare but possible with blunt force trauma
Renders anterior brachial muscles paralyzed
Axillary nerve path
Travels through quadrangular space with posterior humeral circumflex artery, produces superior lateral brachial cutaneous nerve, travels around surgical neck of humerus to deltoid
Superior lateral brachial cutaneous nerve
Branch from axillary nerve
Sensory innervation from superior half of the lateral aspect of brachium
Axillary nerve injury
Results in atrophy of the deltoid and loss of sensation over the superolateral arm
Median nerve path
Travels through brachium with brachial artery, enters cubital fossa by passing through heads of pronator teres, travels through antebrachium between flexor digitorum profundus and superficialis, travels through carpal tunnel to central compartment of palm
Anterior interosseous nerve path/muscles innervated
Travels along surface of interosseous membrane with anterior interosseous artery
Innervates lateral half of flexor digitorum profundus, flexor pollicis longus, pronator quadratus, then sends sensory fibers to innervate wrist joint
Palmar cutaneous branch of median nerve
Originates before median nerve enters carpal tunnel, travels superficial to flexor retinaculum to provide sensory innervation from central palm
Recurrent branch of median nerve
Innervates abductor pollicis, opponens pollicis, and superficial head of flexor pollicis brevis
Medial branch of median nerve
Innervates 2nd lumbrical
Forms common palmar digital nerve which give sensory innervation to palmar surface and distal dorsal surface of digits 1, 2, 3 and lateral half of 4
Lateral branch of median nerve
Innervates 1st lumbrical, becomes common palmar digital nerve which gives sensory innervation to palmar surface and distal dorsal surface of 1, 2, 3, and lateral half of digit 4
Median nerve injury
Results in adducted thumb and thenar eminence atrophy, known as Apes hand. Injury to median nerve at elbow inhibits flexion of 2nd and 3rd digits, known as hand of benediction
Ulnar nerve path
Terminal branch of medial cord, travels through medial brachium, passes through groove for ulnar nerve posterior to medial epicondyle, passes b/w two heads of flexor carpi ulnaris, travels through antebrachium b/w flexor carpi ulnaris and flexor digitorum profundus, becomes superficial as it enters hand passing over flexor retinaculum
Muscular branches of ulnar nerve innervate
Flexor carpi ulnaris and medial half of flexor digitorum profundus
Ulnar nerve provides sensory/cutaneous innervation to which parts of hand
Distal most anterior antebrachium and medial 1/3rd of palm
Dorsal aspect of 4th/5th digits
Palmar surface of medial half of 4th and 5th digits
Deep ulnar nerve innervates
Abductor digiti minimi Flexor digiti minimi Opponens digiti minimi 3rd/4th lumbrical Dorsal/palmar interossei Adductor pollicis Deep head of flexor pollicis brevis
Ulnar nerve injury
Typically occurs in one of four places: posterior to the medial epicondyle, b/w the ulnar and humeral heads of flexor carpi ulnaris (cubital tunnel), at the wrist or in the hand.
Results in extensive loss of sensory and motor control in hand, and when patient tries to make fist it appears as claw hand
Ulnar nerve compression
Can be compressed when pressure is placed on the hamulus of the hamate bone, like when riding a bike. This can produce sensory loss on the medial side of hand and weakness of intrinsic hand muscles referred to as handlebar neuropathy
Radial nerve path
Travels to the posterior aspect of the humerus with deep brachial artery (both pass through triangular interval), passes b/w lateral and medial heads of triceps, divides in cubital fossa into deep/superficial branches
Posterior brachial cutaneous and posterior antebrachial cutaneous
PBC- sensory from posterior brachium
PAbC- produces inferior lateral brachial cutaneous nerve, provides sensory from posterior antebrachium and inferior aspect of lateral brachium
Muscular branches of the radial nerve innervate
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis longus
Deep radial nerve innervates
Extensor carpi radialis brevis
Supinator
Continues on as posterior interosseous after passing through the two heads of the supinator muscle
Posterior interosseous nerve innervates
Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Extensor indicis Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis
Superficial radial nerve provides sensory/cutaneous from
Lateral half of the dorsum of the hand
Dorsal aspect of thumb
Proximal aspect of dorsum of 2nd, 3rd and lateral half of 4th digits
Injury of radial nerve
Results in “wrist drop”, impairment of elbow extension and thumb abduction/extension
Thoracic spinal nerve- intercostobrachial nerve
Lateral cutaneous branch of the 2nd intercostal nerve, travels laterally to provide sensory/cutaneous innervation to uppermost medial aspect of brachium
C5 dermatome
Over deltoid
C6 dermatome
Lateral antebrachium and hand, including thumb
C7 dermatome
Central portion of hand and posterior antebrachium, including 3rd digit
C8 dermatome
Medial hand and antebrachium, including 5th digit
T1 dermatome
Medial brachium
T2 dermatome
Anterior border of axilla
