Nerves and Arterial Supply of the Upper Limb
Secret Study Sheet by Jonathan
Note: This study sheet is designed to breakdown the pathways of the nerves and arteries
Axillary Artery
Artery Branch
Supreme Thoracic
Thoraco-acromial
Lateral Thoracic
Subscapular
Anterior Circumflex
Humeral
Posterior Circumflex
Humeral
Supplies
1st &2nd intercostal space/superior
part of seratus anterior.
-Pectoral muscles/axillary lymph
nodes.
Circumflex Scapular: Dorsum of
Scapula.
Thoracodorsal: Latissmus Dorsi.
Ascending branch supplies
shoulder.
Deltoid/Triceps brachii.
Other stuff
-Divides into: acromial, deltoid,
pectoral, clavicular artery
Larger in women-supplies the lateral
part of mammary gland.
Largest branch of Axillary.
Passes around the surgical neck of
humerus/Anastomoses with PCH
Passes around the surgical neck of
humerus/Anastomoses with ACH.
(Through Quadrangular Space)
Collateral Circulation
 Important when the axillary artery is ligated anywhere between the thryocervical trunk and the
subscapular artery.
 The important concept here is the fact that blood flow will reverse in the subscapular and scapular
circumflex branches to reach the brachial artery in the arm.
The axillary artery ends at the inferior border of the teres major muscle, where it passes into the arm and
becomes the brachial artery.
Brachial Artery
 The main artery that provides the principal arterial supply to the arm. (Anterior Compartment of Arm)
 First lies medial, then anterior to the humerus.
 Anterior to the triceps and brachialis muscle.
 Overlapped by the coracobrachialis and biceps muscles.
 Passes inferiorly and slightly laterally starting to accompany the median nerve, which crosses anterior
to the artery in the middle of the arm.
 In the cubital fossa, the bicipital aponeurosis covers and protects the median nerve and the brachial
artery.
 Branches:
-Profunda brachii artery (supplies the posterior compartment of the arm), largest branch.
 Clinical Correlate:
-Laceration of brachial artery results in paralysis due to ischemia of flexor pollicis longus and
flexor digitorum profundus. Can tear when elbow is fractured.
-For those of you who forgot, this is the artery that the blood pressure is measured from.
The brachial artery divides at the distal end of the cubital fossa into the Ulnar Artery and Radial Artery.
Radial Artery
 A terminal branch of brachial artery.
 Supplies lateral part of forearm in both the extensor and flexor compartments(basically the posterior
compartment of forearm).
 Continues on the lateral side of the forearm to the hand to be the primary blood supply.
 Pulse rate!
 Crosses the floor of the anatomical snuff box.
 Ends by completing the deep palmar arterial arch in conjunction with the ulnar artery.
 Deep Palmer Arch
-Continuation of radial artery.
-Deep to long flexor tendons in central compartment.
-Arch completed by deep branch of ulnar artery. (Note the anatomical description here!-branch
vs. arch).
-Supplies lateral side of digit 2 and the thumb (via princeps pollicis artery).
Ulnar Artery
 Begins near the neck of the radius
 Supplies the posterior compartment of forearm.
 Passes deep to pronator muscle, and then passes between the ulnar and radial heads of the flexor
digitorum superficialis. Ending on the flexor digitorum profundus.
 Common Interosseous Artery
-Immediately branches into anterior and posterior.
-Anterior Interosseous Artery
-Passes distally on the interosseous membrane to join carpal arch.
-Posterior Interosseous Artery
-Passes just proximal to the interosseous membrane to supply adjacent muscles.
 Superficial Palmer Arch
-Continuation of ulnar artery.
-Arch completed by the superficial palmer branch of the radial artery.
-Supplies the medial side of digit 2 via digital arteries.
-Supplies the medial and lateral sides of digits 3-5.
Veins of the Arm and Cubital Fossa
 The cephalic(lateral) and brachial(lateral) veins communicate in the cubital fossa by way of the
median cubital vein.
 Here it lies anterior to the bicipital aponeurosis(accessibility).
 Hence, venipuncture!
Nerves of the Upper Limb
Median Nerve
 Combination of lateral and medial cords of brachial plexus.
 Runs distally in the arm on the lateral side of the brachial artery until it reaches the middle of the arm
where it cross to its medial side and contacts the brachialis muslce.
 Further descends into the cubital fossa where it lies deep to the bicipital aponeurosis and the median
cubital vein.
 No branches in the axilla or arm.
 Supplies Anterior Compartment of forearm.(All flexors except flexor carpi ulnaris and medial half of
the flexor digitorum profundus.)
 Damage:
-Loss of flexion of the proximal interphalangeal joints of ALL digits.
-Loss of flexion of the distal interphalangeal joints of the 2 nd and 3rd digits.
-Flexion of the 4th and 5th digits is not affected.
-Loss of sensation to lateral palm, and tips to first 4 digits.(Palmer Cutaneous Branch)
Ulnar Nerve
 Continuation of medial cord of brachial plexus.
 Passes distally, anterior to the triceps on the medial side of the brachial artery.
 Around the middle of the arm it pierces the medial intermuscular septum and descends between it and
the medial head of the triceps muscle.
 Passes between the medial epicondyle of the humerus and the olecranon to enter the forearm. (You
may think that’s funny-I don’t!)
 Runs on the medial side of the forearm to the hand.
 Supplies Flexor carpi ulnaris and ulnar half of flexor digitorum profundus(basically some of the
posterior compartment of forearm).
 Damage:
-Impaired flexion and adduction of wrist
-Impaired movement of the 1st, 4th, and 5th digits-resulting in poor grasp.(CLAW HAND)
-Inability to abduct or adduct medial four digits due to loss of interosseous muscles.
-Loss of sensation to 5th and ½ of 4th digit on palm side.
-Loss of sensation to 5th, 4th(minus the tip), 3rd(minus the tip).
Musculocutaneous Nerve
 Continuation of lateral cord of brachial plexus.
 Begins opposite the inferior border of the pectoralis minor muscle.
 Pierces the coracobrachialis muscle and then continues distally between the biceps and brachialis
muscles.
 At the lateral border of the tendon of the biceps it becomes the lateral antebrachial cutaneous nerve.
 Supplies coracobrachialis, biceps, and brachialis muscles(Basically anterior compartment of arm).
 Damage:
-Flexion of elbow joint and supination of forearm weakened.
-Loss of sensation on the lateral surface of the forearm by way of lateral antebrachial cutaneous
nerve.
Radial Nerve
 Continuation of posterior cord of brachial plexus.
 Largest branch of brachial plexus.
 Supplies the posterior compartment of arm.
 Enters the arm posterior to the brachial artery, medial to the humerus, anterior to the long head of the
triceps muscle.
 Passes inferolaterally with the profunda brachii artery around the body of the humerus in the radial
groove.
 Then pierces the intermuscular septum and continues inferiorly between the brachialis and
brachioradialis to the lateral epicondyle of humerus where it divides.
 Divides into deep(muscular) and superficial(sensory) branches at the lateral epicondyle of the of the
humerus.
 Deep turns into the posterior interosseous nerve to supply the posterior compartment of forearm.
 Basically supplies the posterior compartment of forearm.
 Damage:
-Deep branch damage results in paralysis of (posterior compartment) triceps, brachioradialis,
supinator, extensors of wrist and digits.(Hard to grasp stuff).
-Superficial branch damage results in loss of sensation on posterior hand on first 2 ½ digits(minus
the tips). In addition, lateral posterior of arm and forearm by way of posterior brachial cutaneous
and posterior antebrachial cutaneous, respectively.
-Wrist Drop:
-Clinical sign of radial nerve injury usually in the radial groove.(i.e., humerus
fracture/shoulder joint dislocation).
-Wrist drop occurs because the triceps is not completely paralyzed.
-“Saturday Night Palsy”-for those of you that pass out after med-school parties and
compress your radial nerve (presents as wrist drop).
Axillary Nerve
 Through quadrangular space.
 Winds around surgical neck of humerus.
 Supplies the teres minor and deltoid muscles.
 Damage:
-Pressure from crutch, forward dislocation of shoulder joint, or humerus fracture.
-Teres minor and deltoid weakend, shoulder numbness and lateral side of proximal arm present.
-Impaired abduction of arm (only supraspinatus works).
-Deltoid atrophies rapidly.
Long Thoracic Nerve
 Innervates serratus anterior muscle.
 Damage:
-Carrying heavy object on shoulder, weight lifting, injury to posterior triangle of neck.
-Winged Scapula
-Paralyzed serratus anterior muscle allows the scapula to move out like a wing.
-Difficulty in flexing or abducting the arm above 45degrees, because the scapula
normally rotates when arm is abducted fully.
Damage To Brachial Plexus
Upper Brachial Plexus Injury (Erbe-Duchenne Palsy)
 Stretch or tear to C-5/C-6 roots.
 Results from excessive separation of the neck an shoulder (i.e., motorcycle accident, football injury)
 Also can occur during delivery if the child’s neck is excessively stretched.
 Deltoid and teres minor(axillary nerve)=loss of abduction and lateral rotation at shoulder joint.
 Biceps brachii and brachialis(musculocutaneous nerve)=loss of flexion at elbow and supination of
forearm.
 Supraspinatus and infraspinatus(suprascapular nerve)=loss of lateral rotation at shoulder joint.
 Loss of sensation on lateral side of arm.
 Patient Presents as: Limb that hangs limply, is medially rotated(unopposed subscapularis) and
forearm pronated(unopposed pronators).
Lower Brachial Plexus Injury (Klumpke Palsy)
 Stretch or tear to T-1 root.
 Results from a forceful pull of an infant’s shoulder during birth, grasping something to break a fall.
 Loss of sensation on medial side of arm.
 Damages roots in ulnar and median nerves that innervate the small intrinsic muscles of the hand which
become paralyzed.