· direct continuation of posterior cord (C5,6,7,8)
· passes behind 3rd part of axillary a
· in front of subscapularis
· passes through triangular space
· teres major, humerus, long head of triceps
· with profunda brachii
· enters extensor compartment
· spirals around medial head of triceps
· lies on shaft of humerus in spiral groove
· deep to lateral head of triceps
· pierces lateral intermuscular septum 2/3 down arm
· enters flexor compartment
· held from bare bone by brachialis
· descends between brachialis and brachioradialis
· passes anterior to lateral elbow joint
· enters radial tunnel
· gives off posterior interosseous branch
· remnant is purely sensory
· cutaneous (post arm) ]
· triceps (long) ] axilla
· triceps (med) __________ ]________
· triceps (lat) ]
· triceps (med) ] radial
· cutaneous (lower lat arm) ] groove
· cutaneous (post forearm)___ ]________
· B ]
· BR ] flexor
· ECRL ] comp
· post inter ]
· ECRB / sup
· EDC / EDM / ECU
· APL / EPB / EPL
Posterior cutaneous nerve of arm
· contains all of radial n T1 fibres
Muscular branches
· long head of triceps
· medial head of triceps
· runs close to ulnar n
· often called ulnar collateral n
Muscular branches
· lateral head of triceps
· medial head of triceps
· also supplies anconeus
Lower lateral cutaneous nerve of arm
Posterior cutaneous nerve of forearm
Muscular branches
· brachialis
· small branch to lateral part
· brachioradialis
· ECRL
Posterior interosseous nerve
· spirals around lateral side of upper end of radius
· passes between 2 heads of supinator
· enters extensor compartment
· crosses APL
· dips down to interosseous membrane
· runs to back of wrist
· in cubital fossa, supplies
· supinator
· ECRB
· in extensor compartment, supplies
· extensors from common extensor origin EDC, EDM and ECU
· thumb muscles APL, EPB and EPL
· sensory to
· interosseous membrane
· periosteum
Superficial terminal branch
· runs down flexor compartment of forearm
· under cover of BR
· lateral to radial a
· descends on
· supinator
· pronator teres
· FDS
· FPL
· winds down lower end of radius deep to BR
· crosses
· APL
· EPB
· EPL
· sensory to
· snuffbox
· dorsum of radial 3 1/2 digits
· direct continuation of medial cord (C8,T1)
· picks up C7 fibres from lateral cord in axilla
· fibres are for FCU
· runs down medially and behind brachial a
· pierces medial intermuscular septum at middle of arm
· descends along medial head of triceps
· lies on shaft of humerus between medial epicondyle and olecranon
· enters forearm between 2 heads of FCU
· descends on FDP under cover of FCU
· joined by ulnar a (n lies ulnar to a)
· both emerge from under medial side of tendon of FCU just above wrist
· cross flexor retinaculum next to pisiform
· at this point, divides into 2 branches
Muscular branches
· to
· FCU (C7)
· ulnar half of FDP (C8, T1)
Palmar cutaneous branch
· arises in middle of forearm
· pierces deep fascia above flexor retinaculum
· supplies hypothenar eminence
Dorsal cutaneous branch
· given off 5 cm above wrist
· winds around distal ulna deep to tendon of FCU
· crosses triquetral bone
· supplies dorsal 1 1/2 fingers and corresponding dorsum of hand
Superficial branch
· runs distally beneath palmaris brevis
· supplies palmaris brevis
· divides into 2 digital branches
· one for ulnar side of litle finger
· one for 4-5 cleft and adjacent fingers
· nerve to 4-5 cleft sends branch to median digital n
Deep branch
· accompanied by deep branch of ulnar a
· passes deeply
· between AbDm and FDM
· perforates ODM
· crosses palm in concavity of deep palmar arch
· supplies
· all 3 hypothenar muscles
· ulnar 2 lumbricals
· all interossei
· AdP
· FPB (often)
· arises from branches from
· lateral cord (C6,7)
· medial cord (C8,T1)
· branches unite in front of 3rd part of axillary a
· starts lateral to brachial a
· then slopes in front of brachial a and crosses it
· descends on its medial side to cubital fossa
· at elbow lies on brachialis under bicipital aponeurosis
· just medial to artery
· enters forearm by passing between 2 heads of PT
· crosses over ulnar a
· separated from it by deep head of PT
· passes beneath fibrous arch of FDS
· lies on FDP but adheres to deep surface of FDS
· emerges on radial side of FDS
· lies between FCR and PL
· enters carpal tunnel
· divides into two branches
· passes into hand
· vascular branches to brachial a
· no motor or sensory
Muscular branches
· muscular branches given off proximally
· branches to
· PT
· FCR
· FDS
· PL
Anterior interosseous nerve
· given off when passes between heads of PT
· descends on interosseous membrane to wrist
· with anterior interosseous a
· gives muscular branches to
· radial 1/2 of FDP
· FPL
· pronator quadratus
· sensation to
· interosseous membrane
· periosteum
Palmar cutaneous branch
· given off short distance above flexor retinaculum
· pierces deep fascia above flexor retinaculum
· supplies skin over thenar eminence
· lies lateral to tendons of FDS
Muscular branch
· syn. recurrent, thenar
· first branch of median n
· arises distal to flexor retinaculum
· may arise in carpal tunnel and pierce retinaculum
· curves laterally and proximally
· crosses and supplies
· FPB
· AbPB
· OP
Digital branches
· divides into 5 common palmar digital branches
· may first divide into medial and lateral branches
· thumb nerves may arise from common stem
· 2 branches pass to thumb
· one for radial side crosses in front of tendon of FPL
· 1 branch passes to radial index finger
· also supplies 1st lumbrical
· 2 branches pass to 2-3 and 3-4 clefts
· divide into proper digital nn for adjacent sides of fingers
· nerve for 2-3 cleft supplies 2nd lumbrical
· nerve for 3-4 cleft receives twig from ulnar n