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Origin:  Ventral ramus of C5 with a frequent contribution from C4.

Course:  pierces scalenus medius, descends deep to levator scapulae and enters deep surface of rhomboids.

Distribution:  innervates rhomboids and occasionally supplies levator scapulae.

Origin:  ventral rami of c5-7

course:  descends posterior to C8 and T1 rami and passes distally to external surface of serratus anterior.

distribution:  innervates serratus anterior.

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origin:  superior trunk, receiving fibers from C5, C6 and often C4.

course:  descends posterior to clavicle and anterior to brachial plexus and subclavian artery.

distribution:  innervates subclavius and sternoclavicular joint.

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Origin: superior trunk, receiving fibers from C5 and C6 and often C4.

course:  passess laterally across posterior triangle of neck, through scapular notch under superior transverse scapular ligament.

Distribution:  innervates supraspinatus, infraspinatus and glenohumeral (shoulder) joint. 

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origin: lateral cord, receiving fibers from C5-C7

distribution:  pierces clavipectoral fascia to reach deep surface of pectoral muscles.

distribution:  primary supplies pectoralis amjor but sends a loop to medial pectoral nerve that innervates pectoralis minor.

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origin:  lateral cord, receiving fibers from C5-C7

course:  enters deep surface of coracobrachialis and descends between biceps brachii and brachialis.

Distribution:  innervates coracobrachialis, biceps brachii and brachialis, continues as lateral antebrachial cutaenous nerve.

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Origin:  lateral root is a continuation of lateral cord, receiving fibers from the from c6-c7; medial root is a continuation of medial cord receiving fibers from c8-T1.

course: lateral root joins medial root to form median nerve lateral to the axillary artery.

enters cubital fossa medial to brachial artery, passes between the heads of pronator teres, descends between flexor digitorum superficialis and flexor digitorum profundus, and passes close to flexor retinaculum as it passes through the carpal tunnel to reach hand.

distribution:  innervates flexor muscles in forearm (except flexor carpi ulnaris, ulnar half of flexor digitorum profundus) and five hand muscles.

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origin:  medial cord receiving fibers from c8-T1

course:  passes between axillary artery and vein and enters deep surface of pectoralis minor.

distribution:  innervates the pectoralis minor and part of pectoralis major.

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origin:  medial cord, receiving fibers from C8 and T1.

course:  runs between the medial side of axillary vein and communicates with intercostobrachial nerve.

distribution:  supplies skin over medial side of arm.

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origin:  medial cord, receiving fibers from C8-T1.

course:  runs between axillary artery and vein.

distribution:  supplies skin over medial side of forearm.

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Origin:  branch of posterior cord receiving fibers from C5 and C6.

course:  passes posteriorly and enters subscapularis.

distribution:  innervates superior portion of subscapularis.

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origin:  branch of posterior cord, receiving fibers from C6-C8.

course:  arises between the upper and lower subscapular nerves and runs inferolaterally along posterior axillary wall to the latissimus dorsi.

distribution:  innervates the latissimus dorsi.

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origin:  branch of posterior cord receiving fibers from C5-C6.

course:  passes inferolaterally, deep to subscapular artery and vein, to subscapularis and teres major.

distribution:  innervates inferior portion of subscapularis and teres major.

origin:  terminal branch of posterior cord, receiving fibers from c5-c6.

course:  passes to posterior aspect of arm through the quadrangular space in company with posterior circumflex hermural artery and then winds around the surgical neck of humerus; gives rise to lateral brachial cutaneous nerve.

distribution:  innervates teres minor and deltoid, shoulder joint and skin over inferior part of deltoid.[image]

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proximal attachment - short head:  tip of coracoid process of scapula.  Long head:  supraglenoid tubercle of scapula.

Distal attachment:  tuberosity of radius and fascia of foremarm via bicipital aponeurosis.

innervation:  musculocutanous nerve (c5 and c6)

main action:  supinates forearm and when it is supine, flexes forearm.

proximal attachment - distal half of anterior surface of humerus.

distal attachment - coronoid process and tuberosity of ulna.

innervation:  musculocutaneous nerve (c5and c6)

action:  flexes forearm in all positions.

proximal:  tip of coracoid process of scapula.  

distal:  middle third of medial surface of humerus.

innervation:  musculocutaneous nerve (c5,6 and 7).

action:  helps to flex and adduct the arm.

prox:  long head - infraglenoid tubercle of scapula. Lateral head:  posterior surface of humerus, superior to radial groove.

Medial head:  posterior surface of humerus, inferior to radial groove.

distal attachment:  proximal end of olecranon of ulna and fascia of forearm.

innervation:  radial nerve c6,7 and8

main action:  extends the forearm; it is chief extensor of forearm; long head steadies head of abducted humerus.

course:  terminal branches of the lateral cord of the brachial plexus. begins opposite the inferior border of the pectoralis minor, pierces the coracobrachialis and continues distally between the biceps and brachialis. 

supplies all the muscles in the anterior (flexor) compartment of the arm.  Becomes the lateral cutaneous nerve of the forearm which continues across the anterior aspect of the elbow to supply a large area of forearm skin.

proximal:  2/3rds of the lateral supracondylar ridge of humerus.

distal:  lateral surface of distal end of radius.

innervation:  radian nerve (c5/6 and 7).

main action:  flexes forearm.

The contents of the fossa, from medial to lateral side are the median nerve, brachial artery, tendons of the biceps and farther laterally the radial nerve and its posterior interosseus branch. The cubital fossa is the triangular area between pronator teres, brachioradialis and a line joining the humeral epicondyles. The ulnar artery passes deep to the deep head of pronator teres. The brachial artery enters the cubital fossa in the midline. Halfway down the fossa it divides into the radial and ulnar arteries. The radial artery usually appears to be direct continuation of the brachial artery and the bigger ulnar artery branches off at an angle

An easy way to remember the order of structures in the cubital fossa is: Really Need (radial nerve) Beer To (biceps tendon) Be At (brachial artery) My Nicest (median nerve). (from lateral to medial)

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proximal attachment:  medial epicondyle of humerus and coronoid process of ulna.

distal attachment:  middle of lateral surface of radius.

innervation:  median nerve (c6 and 7)

main action:  pronates and flexes forearm at elbow.

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proximal:  medial epicondyle of humerus.

distal:  base of 2nd metacarpal bone.

innervation:  median nerve c6 and 7.

action:  flexes and abducts hand (at wrist)

[image]proximal:  humeral head:  medial epicondyle of humerus.

ulnar head:  olecranon and posterior border of ulna.

distal attachment:  pisiformis bone and 5th metacarpal bone.

innervation:  ulna nerve (c7 and c8)

actions:  flexes and adducts hand (at wrist)

proximal:  

humeroulnar head:  medial epicondyle of humerus, ulnar collateral ligament and coronoid process of ulna.

radial head:  superior half of anterior border of radius.

distal attachment:  bodies of middle phalanges of medial four digits.

innervation:  median nerve c7, c8 and t1.

action:  flexes middle phalanges at PIP joints of medial 4 digits; acting more strongly it also flexes proximal phalanges at MCP joint and hand. 

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proximal:  proximal 3/4ths of medial and anterior surfaces of ulna and interosseous membrane.

distal:  bases of distal phalanges of medial four digitis.

innervation:  medial part ulnar nerve (c8 and T1), lateral part: median nerve (c8 and T1)

main action:  flexes distal phalanges at distal interphalangeal joints of medial four digits; assists with hand flexion.

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prox: anterior surface of radius and adjacent interosseous membrane.

distal:  base of distal phalanx of thumb.

innervation:  anterior interosseous nerve from median (c8 and t1).

main action: flexes phalanges of 1st digit (thumb)

APB, FPB, opponens policis:  common prox attachment - flexor retinaculum and tubercles of scaphoid and trapezium and innervated by recurrent branch of median nerve (c8-T1)

abductor pollicis brevis:  distal:  lateral side of base of proximal phalanx of thumb.

action:  abducts thumb and helps oppose it.

flexor pollicis brevis:  same prox and distal attachments as APB - flexes the thumb.

opponens pollicis - distal - lateral side of 1st metacarpal.  

action:  draws 1st metacarpal bone medially to oppose the thumb toward centre of the palm and rotates it medially.

superior attachment:  nuchal ligament, spinous processes of C7 - T3 vertebrae.

inferior attachment:  superior borders of 2nd to 4th rib.

innervation:  2nd to 5th intercostal nerves

- action - elevate ribs.

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proximal:  lateral supracondylar ridge of humerus.

distal: base of 2nd metacarpal.

innervation:  radian nerve (c6,7)

main action:  extend and abduct the hand at wrist joint.

prox:  lateral epicondyle of humerus (common extensor tendon)

distal:  base of 3rd metacarpal

main action:  extend and abduct the hand at the wrist joint.

proximal:  common extensor tendon.

distal:  extensor expansions of medial four digits.

innervations:  posterior interosseous nerve (c7 and C8) the continuation of deep branch of radial nerve.

action:  extends medial four digits at MCP joints, extends hand at wrist joint.

prox:  common extensor tendon.

distal:  extensor expansion of 5th digit.

(partially detached part of extensor digitorum, deep to extensor retinaculum divides into 2 slips, lateral one joined to tendon of extensor digitorum.

innervation:  posterior interosseous nerve c7 and c8, the continuation of deep branch of radial nerve.

main action:  extends 5th digit at MCP and interphalangeal joints.

ulnar artery divides into 2 terminal branches - the superficial palmar arch and the deep palmar arch.  

The superficial palmar arch -> give rise to 3 common palmar digital arteries.

the deep palmar arch (mainly radial branch) -> 3 palmar metacarpal arteries and princeps pollicis.

these anastomose to form 3 pairs of proper palmar digital arteries.

radial artery - anastomoses with deep branch of ulnar artery to form the deep palmar arch.

prox:  lateral epicondyle of humerus and posterior border of ulna.

distal:  base of 5th metacarpal.

main action:  extends and adducts the hand at wrist joint.  (integral to making a fist).

proximal:  lateral epicondyle of humerus, radial collateral and anular ligaments, supinator fossa and crest of ulna.

dist:  lateral, posterior and anterior surfaces of proximal 3rd of radius.

nerve:  deep branch of radial nerve c5,6.

action:  the prime mover in supination, rotating the radius.

- when the radial nerve reaches the distal 3rd of the humerus, it passes from the posterior to anterior fascial compartment by piercing the lateral intermuscular septum.  

- the nerve then runs between the brachialis and brachioradialis muscles across the anterior aspect of the lateral epicondyle.

- the radial nerve divides in the cubital fossa into motor (deep) and sensory (superficial) branches. The deep branch penetrates the supinator muscle to reach the posterior compartment of the forearm.

prox:  posterior surfaces of ulna, radius and interosseous membrane.

distal:  base of 1st metacarpal.

innervation:  posterior interosseous nerve (c7 and 8), the continuation of deep branch of radial nerve.

main action:  abducts thumb and extends it at the carpometacarpal joint.

prox:  posterior surface of radius and interosseous membrane.

distal:  base of proximal phalanx of thumb.

innervation:  posterior interosseous nerve (c7 and 8) the continuation of the deep branch of radial nerve.

aciont:  extends proximal phalanx at thumb at carpometacarpal joint.

prox:  posterior surface of middle third of ulna and interosseous membrane.

distal:  base of distal phalanx of thumb.

innervation:  posterior interosseous nerve c7 and 8.

action:  extends distal phalanx of thumb at metacarpophalangeal and interphalangeal joints.

- the anatomical snuff box is visible when the thumb if ully extended.  Bound by the tendons of the APL and EPB anteriorly and EPL posteriorly.

- the radial artery lies in the floor of the snuff box.

- the radial styloid process can be palpated proximally and the base of the 1st metacarpal can be palpated distally.

- scaphoid and trapezium can be felt in the floor between the radial styloid process and the 1st metacarpal.

the median nerve is the most sensitive structure in the carpal tunnel and most affected by anything that reduces the size of the carpal tunnel.

- 2 terminal sensory branches (however palmar branch superficial to flexor retinaculum).  

- 1 motor branch - supplies thenar muscles.

in CTS - progressive loss of coordination and strength of thumb.  Unable to oppose the thumb - also para/hypo or anesthesia in lateral 3.5 digits.

abductor digiti minimi - prox:  pisiform.  

distal:  medial side of base of proximal phalanx of little finger.

innervation:  deep branch of ulnar nerve

action:  abducts digit 5.

flexor digiti minimi brevis: prox:  hook of hamate and flexor retinaculum.  

same innervation and distal attachment as abductor digiti minimi.

action:  flexes proximal phalanx of digit 5.

opponens digitis minimi:

prox: hook of hamate and flexor retinaculum.  

dist:  medial border of 5th metacarpal. 

innerve:  deep branch of ulnar nerve.

action:  draws 5th metacarpal anteriorly and rotates it, bringing digit 5 into opposition with thumb.

lumbricals - flex the digits at the MCP joints and extend the interphalangeal joints.

nerve: 1 + 2 by median nerve, 3 +4 by ulnar nerve.

interossei:  dorsal abduct (DAB), palmar adduct (PAD)

nerve:  ulnar nerve.

locations:  

injuries usually occur in four places:

- posterior the medial epicondyle of the humerus.

- the cubital tunnel formed by the tendinous arch connecting the humeral head and ulnar heads of the flexor carpi ulnaris.

- at the wrist.

- in the hand.

mechanism:  

- elbow hits a hard surface - fracturing the epicondyle.

- compressed at the elbow during sleep or as an occupational neuritis in workers who rest their elbows on hard surfaces.

- guuyons canal syndrome 

- cyclists palsy

presentation:

- impaired power of adduction.

- on flexing at wrist, hand drwn to lateral side by FCR.

- difficulty making a fist because of paralysis of most intrinsic hand muscles..

- MCP joints become hyperextended and they cannot flex 4th and 5th digits at DIP joints, nor extend interphalangeal joints (claw hand).

radial nerve supplies no hand muscles.

terminal branches arise in cubital fossa.

- the characteristic handicap from radial nerve injury is inability to extend the wrist resulting from paralysis of extensor muscles of the forearm.

- the hand is flexed at the wrist and lies flaccid - wrist drop.

- the digits also remain in the flexed position at the MCP.

thoracoappendicular muscles which act indirectly on the joint.

the scapulo-humeral muscles directly

- chief flexors:  pec major (clavicular part), deltoid (anterior fibers), coracobrachialis and biceps brachii.

- chief extensor - latissimus dorsi.

- chief abductor - deltoid.

-chief adductor - pectoralis major and latissimus dorsi.

- medial rotator - subscapularis.

- lateral rotator - infraspinatus.

- stabalisers: rotator cuff, coracobrachialis, short head of biceps and long head of triceps.