Flashcards in UL Arteries, Veins, Brachial Plexus Deck (26):
Continuation of subclavian artery
Origin, termination, parts and branches of the axillary artery:
• Axillary artery begins at the outer border of the first rib and continues as the brachial artery at the lower border of the teres major muscle.
• It is divided into three parts by the pectoralis minor muscle.
• The axillary vessels and brachial plexus of nerves are surrounded by the axillary sheath which is a continuation of the prevertebral layer of deep cervical fascia.
I part: It lies superior and medial to the pectoralis minor. It gives one branch:
• Superior thoracic artery
II part: it lies behind the pectoralis minor muscle. It gives two branches:
• Lateral thoracic
III part: It lies below the level of pectoralis minor - It gives three branches:
• Anterior circumflex humeral
• Posterior circumflex humeral
• Axillary artery is related to the cords and branches of the brachial plexus
• The cords of the brachial plexus are named as lateral, medial and posterior depending on their relationship to the second part of the axillary artery.
• Therefore second part of the axillary artery has lateral cord lateral to the artery, medial cord medial to the artery and posterior cord behind the artery.
• The third part of the axillary artery is related to the branches of the brachial plexus
• It is the continuation of the brachial vein; formed by brachial and basilic v. (latter-
after traveling along with the brachial a. and the medial cutaneous n. of the forearm to the axilla, where it merges with the accompanying veins (L. venae comitantes) of the axillary a.)
• It extends from the lower border of the teres major to the outer border of the 1st rib where it continues as the subclavian vein
-axillary v.=vessel actually punctured in a typical “subclavian” vein puncture for catheter insertion
• It lies medial to the axillary a.
• Axillary vein is joined by the 2 venae commitantes of the brachial artery little above the lower border of the teres major. Its tributaries correspond to the branches of the axillary artery.
• @terminal pt, cephalic vein is the important tributary of the axillary vein.
• Cephalic vein pierces the clavipectoral fascia and then opens into the axillary vein.
-if lacerated in axilla (large size of axillary v.), risk of producing air embolus (bubbles)
-may receive blood from the inguinal region of the body
Brachial plexus summary
• Muscles supplied by the nerve are paralyzed. This results in loss of movements at the joints
• sensory loss
extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit
-in neck extending into the axilla posterior to the clavicle
Wiki: cutaneous and muscular innervation of the entire upper limb, with two exceptions:
1) trapezius muscle innervated by the spinal accessory nerve (CN XI)
2) area of skin near the axilla innervated by the intercostobrachial nerve (T2)
• brachial plexus communicates through the sympathetic trunk via gray rami communicantes that join the plexus roots
• The terminal branches of the brachial plexus (musculocutaneous n., axillary n., radial n., median n., and ulnar n.) all have specific sensory, motor and proprioceptive functions
• It is formed by the ventral rami of lower four cervical nerves and first thoracic nerve
(No dorsal rami ever supply the skin or muscles of the limbs)
-Ventral roots- only motor;
-Dorsal roots- only sensory
-Motor and sensory roots meet to form spinal nerve, which divide into dorsal/ventral rami (rami are mixed in nature-sensory and motor)
-dorsal ramus-only supply back of trunk eg posterior primary rami of the spinal nerves innervate the erector spinae (ILS)
-ventral ramus-only supply anterior of trunk, and upper and lower limbs
Nerves in axilla come from neck region
Higher part of brachial plexus=superclavicular part; lower=infraclavicular part
• The brachial plexus has: Roots, Trunks, Divisions, Cords, and Branches
• Roots, trunks and divisions lie in the posterior Triangle of the neck (supraclavicular part)
• Infraclavicular part of the brachial plexus lies in the axilla
o Infraclavicular part includes the cords and the branches
Becomes lateral cutanoeus n. of forearm
Sensory innervation- skin of anterolateral forearm
Muscular Innervation- brachialis, biceps brachii, coracobrachialis
• Injury is rare, may be injury to flexor compartment of the arm
• Muscle paralysis: Biceps brachii, coracobrachalis, and brachialis
• Sensory loss: lateral part of the forearm
• Weak flexion of the elbow
Sensory innervation- skin of lateral portion of shoulder and upper arm
Muscular Innervation- deltoid, teres minor
• Cause: Fracture of surgical neck of the humerus or shoulder dislocation (95% of shoulder dislocations, the humerus is displaced anteriorly)
• Muscle paralysis: Deltoid & teres minor
• Sensory loss: skin over the lower lateral part of deltoid
• Abduction and lateral rotation of shoulder is affected
(C5-T1) (from 3 posterior div)
Chief nerve of extension
Sensory innervation- posterior aspect of lateral forearm and wrist; posterior arm; lateral part of dorsum of hand
Muscular Innervation- triceps brachii, brachioradialis (exception- forearm flexor), anconeus, extensor m. of posterior arm and forearm
• Common cause: Fracture of midshaft of the humerus
• Muscle paralysis: All the extensors of the upper limb (if the injury is in the axilla)
• Sensory loss: back of the arm, back of the forearm and lateral part of dorsum of the hand EXCEPT nail beds.
• Wrist drop
• Saturday night palsy
(C5-T1) (from 3 anterior div.)
Chief nerve of elbow flexion
Sensory innervation- skin of lateral 2/3 of hand, tips of digits 1-4
Muscular Innervation- forearm flexors (except flexor carpi ulnaris and the medial half of flexor digitorum profundus [both are supplied by ulnar nerve]), thenar eminence (except adductor pollicis-supplied by ulnar nerve), lumbricals of hand 1-2
• Common cause: Fracture of lower part (supracondylar) of the shaft of the humerus, dislocation of lunate, pronator syndrome, carpel tunnel syndrome, wrist slash
• Muscle paralysis: Most of the flexors of the forearm, except flexor carpi ulnaris and medial half of flexor digitorum profundus, thenar muscles except adductor pollicis; lumbricals 1-2
• Sensory loss: lateral palm, skin over lateral (thumb, index, middle and half of ring) three and half digits AND nail beds of three and half digits
• Benedict's sign /hand: Cannot flex thumb, index and middle finger ( if asked to make a fist) (named bc Pope who blessed people like so with thumb, forefinger and middle finger up)
• Ape thumb deformity/ Simian hand: loss of opposition of the thumb, apes can’t oppose! (same as how apes hold bananas)
• Ulnar deviation of wrist: due to unbalanced action of flexor carpi ulnaris in wrist flexion
• Flattening of thenar eminence
• Median claw: extension of MP joints and flexion of IP joints of index and middle finger (due to paralysis of lateral 2 lumbricals)
• In carpal tunnel syndrome, sensory loss will be in digits NOT in palm.
(C8, T1 aka musician's n.-small hand movements aka funny bone n.)
Sensory innervation- skin of palm and medial side of hand and digits 3-5
Muscular Innervation- hypothenar eminence, some forearm flexors (Flexor carpi ulnaris, medial half of FDP), thumb adductor pollicis, lumbricals 3-4, interosseous m.
• Common cause: Fracture of medial epicondyle of the humerus, cubital tunnel syndrome, Guyon’s canal syndrome, handle bar neuropathy, fracture of pisiform, wrist slash
• Muscle paralysis: Flexor carpi ulnaris, medial half of flexor digitorum profundus (ring and little finger), hypothenar muscles, adductor pollicis, palmar and dorsal interossei, medial 2 lumbricals (third and fourth)
• Sensory loss: Skin over medial part of palm, medial part of dorsum of the hand, and one and half digits including nail beds
• Ulnar claw hand: extension of MP joints and flexion of IP joints of little and ring finger (due to paralysis of medial 2 lumbricals)
• Loss of abduction and adduction of medial four digits (PAD, palmar & DAB, dorsal)
• Paper finger test for palmar interossei
• Flattening of hypothenar eminence
• If lower trunk of the brachial plexus are damaged, results in complete claw hand (all 4 lumbricals are paralyzed)
Dorsal scapular n.
Supplies the muscles attached to the dorsal aspect of the medial border of the scapula:
• Levator scapulae
• Rhomboid minor
• Rhomboid major
Long thoracic n.
Supplies serratus anterior muscle which
• When it is injured it results in winging of the scapula (elevated medial border of the scapula)
Supplies supraspinatus (initiates abduction) and infraspinatus- both attached to scapula
o If infraspinatus affected, then complete lack of lateral rotation of arm
Lower subscapular n.
Supplies inferior subscapularis, teres major
Thoracodorsal n. or middle subscapular n.
Supplies latissimus dorsi
• Erb’s point of the brachial plexus is the area on the upper trunk where six nerves meet. C5 & C6 roots join to form the upper trunk, the upper trunk divides into anterior and posterior divisions, & two nerves, suprascapular nerve and nerve to subclavius- arise from the upper trunk.
• Injury to this point occurs due to undue stretching of the head from the shoulder as in breech presentation (rump first- during birth).
• In adults it may follow a blow or fall on the shoulder.
• When upper trunk is severed it results in Erb Duchenne palsy.
• In this palsy free upper limb is pronated, adducted and medially rotated.
• Called as policeman’s or waiters tip hand.
-more common than Klumpke's
• When lower trunk is injured
• This occurs when a falling man holds on to a branch of a tree or during child birth.
• All the intrinsic muscles of the hand are paralysed.
• Results in claw hand deformity.
• Lower trunk injury may result from apical lung carcinoma (pancoast tumor) or from metastatic spread of cancer from the breast.
• Lower trunk of brachial plexus together with the subclavian artery may be angulated over a cervical rib resulting in Thoracic outlet syndrome
• Brachial plexus block: Injection of anesthetic solution into or immediately surrounding the axillary sheath produce anesthesia of the branches of the cords of brachial plexus.
Cutaneous nerves of the upper limb
• Most cutaneous nerves of the upper limb are derived from the brachial plexus which is formed by the anterior rami of the C5 – T1 spinal nerves.
• The cutaneous nerves to the shoulder are derived from the cervical plexus which is formed by the anterior rami of the C1 – C4.
• Sensory to the skin of the base of the axilla is by intercostobrachial nerve (T2), ONLY part of the upper limb which is supplied by a nerve which is NOT a branch of brachial plexus.
x Cutaneous nerves of the arm and forearm
• Supraclavicular nerves (C3, C4): branch of cervical plexus
• Posterior cutaneous nerve of the arm: branch of radial nerve
• Posterior cutaneous nerve of the forearm: branch of medial cord
• Upper lateral cutaneous nerve of the arm- branch of cervical plexus
• Lower lateral cutaneous nerve of the arm; branch of axillary
• Lateral cutaneous nerve of the forearm: branch of musculocutaneous nerve
• Intercostobrachial nerve (T2): branch of second intercostal nerve
• Dorsal venous arch on the dorsum of the hand.
• From the medial end (ulnar end) basilic vein begins, ascends superficially along the medial side of the limb and at the middle of the arm, passes deep and continues as axillary vein
• From the lateral end (radial end) vein begins, ascends superficially along lateral side of the limb, enters the deltopectoral groove, pierces the clavipectoral fascia and opens in to axillary vein
• Median cubital vein is located superficially in the cubital fossa and connects cephalic vein to basilic vein.
• Used for intravenous injections and to collect blood sample.
• It is the continuation of the axillary artery.
• Origin: It begins at the level of the lower border of the teres major
• It terminates opposite the neck of the radius by dividing into two terminal branches, radial and ulnar.
• Arteria profunda brachii (deep artery of the arm)
• Nutrient artery to humerus
• Superior ulnar collateral artery
• Inferior ulnar collateral artery
• Muscular branches
• Two terminal branches: radial and ulnar.
• Its pulsations are readily felt in the middle of the arm medial to the biceps.
• This artery is used to record the blood pressure.
• The pulse of the brachial artery is palpable on the anterior aspect of the elbow and, with the use of a stethoscope and sphygmomanometer (blood pressure cuff) often used to measure the blood pressure
• The ideal place to compress the brachial artery to control hemorrhage is the middle of the arm since the arterial anastomoses around the elbow provides adequate arterial supply to upper limb.
• However the brachial artery has to be clamped distal to the origin of the deep artery of the arm (profunda brachii) (below lower border of teres major).
• Volkmann's contracture, also known as Volkmann's ischemic contracture, is a permanent flexion contracture of the hand at the wrist, resulting in a claw-like deformity of the hand and fingers.
• Volkmann's contracture results from ischemia of the muscles of the forearm. It is caused by pressure, possibly from improper use of a tourniquet, improper use of a plaster cast or from compartment syndrome.
• It is commonly described in a supracondylar fracture where it results from the occlusion of the brachial artery
• It arises as the smaller of the two terminal branches of brachial artery at the level of the neck of the radius
• It gives a radial recurrent artery in the cubital fossa
• It is overlapped by the brachioradialis in the upper part and covered by the skin and fascia only in the lower part of the forearm
• It is covered superficially by the brachioradialis muscle
• It gives superficial palmar branch before it winds round the lower end of the radius.
• The superficial palmar branch completes the superficial palmar arch laterally.
• It winds round the lateral side of the wrist deep to abductor pollicis longus and extensor pollicis brevis.
• It lies in the anatomical snuff box
• It then passes deep to the tendon of the extensor pollicis longus
• Enters the hand by piercing the first dorsal interosseous muscle
• Before dipping to the front, it gives the first dorsal metacarpal artery
• In the palm of the hand it gives two branches
• Princeps pollicis artery
• Radialis indicis artery
• Then it passes between the two heads of adductor pollicis and forms the deep palmar arch
• The deep palmar arch is completed medially by the deep branch of the ulnar artery
• Deep palmar arch gives three palmar metacarpal arteries
• Palmar metacarpal arteries join the palmar digital arteries of the superficial palmar branch
• Superficial in the lower part of the forearm
• It can easily be slashed.
• In the forearm it is lateral to the tendon of flexor carpi radialis and medial to brachioradialis tendon.
• Check your pulse!
• It is the larger of the two terminal branches of the brachial artery
• It runs downwards and medially
• It lies deep to the deep head of the pronator teres
• It runs with the lateral side of the ulnar nerve in the middle of the forearm overlapped by FCU
• Anterior and posterior ulnar recurrent branches
• Common interosseous artery
Common interosseous artery divides into two branches:
• Anterior interosseous artery (anterior to the interosseous membrane accompanied by anterior interosseous nerve)
• Posterior interosseous artery (passes in the gap above the interosseous membrane and enters the extensor compartment of forearm posterior to the interosseous membrane)
• Ulnar artery crosses superficial to the flexor retinaculum lateral to the ulnar nerve
• It divides into superficial and deep branches
• The superficial branch continues as the superficial palmar arch
• Superficial palmar arch is completed laterally by the superficial palmar branch of the radial artery.
• Superficial palmar arch gives one proper digital branch to the medial side of the little finger and three common palmar digital arteries which divide into the corresponding proper digital arteries after reaching the web of the fingers.
• Palmar digital arteries receive the palmar metacarpal arteries of the deep palmar arch
• Pulsations of ulnar artery can be felt lateral to the pisiform bone
• Ulnar artery can also be used for some arterial punctures
• The ulnar artery enters the hand anterior to the flexor retinaculum between the pisiform and the hook of the hamate via the ulnar canal (Guyon canal)
o Ulnar a. and n. travel thru canal- get Guyon canal syndrome (common in bicyclists bc put pressure here) (Ulnar n. palsy)
• Raynaud’s disease: is a rare disease condition affecting the blood vessels in the fingers, toes, ear lobes or tip of the nose.
o The blood vessels become narrow in these regions causing paleness and blue coloration.
o When the blood flow returns, the skin becomes red and tingling sensation is felt.
o Cold weather and stress can trigger the attack. Women are more prone.
Superficial palmar arch
• It is an arterial arch situated superficially in the palm deep to the palmar aponeurosis.
• It is formed by the main continuation of ulnar artery
• It is completed laterally by joining with any one of the following arteries:
• Superficial palmar branch of radial artery
• Arteria princeps pollicis (branch of radial A)
• Arteria radialis indicis (branch of radial A)
• Its curvature touches the tangent drawn at the convexity of the hyperextended thumb.
• It lies over the long flexor tendons of the palm
• It gives 1 proper digital artery to the medial side of little finger & 3 common palmar digital arteries
• Each common digital artery divides into proper digital arteries at the web of the corresponding fingers
Deep palmar arch
• It is formed by the union of the radial artery with the deep branch of the ulnar artery.
• It lies approximately one inch proximal to the superficial palmar arch.
• It lies deep to the flexor tendons and runs with deep branch of ulnar nerve
• It gives three palmar metacarpal arteries
• Each palmar metacarpal artery joins the corresponding common palmar digital artery
• There is rich anastomosis between the radial and ulnar arteries in the palm because of the superficial and deep palmar arches.
• Therefore, whenever a vessel is cut in the palm the cut ends bleed from both sides.
• That is the reason why it difficult to stop the bleeding by just compressing the radial or ulnar artery.
• In such cases the compression of brachial artery is preferable.
• Allen test: Try it out!
-physical examination of arterial blood flow to the hands
-If color fails to return, the test is considered abnormal and it suggests that the ulnar artery supply to the hand is not sufficient. This indicates that it may not be safe to cannulate or needle the radial artery.
Deep veins of forearm
Paired radial and ulnar veins and interosseus veins accompany arteries of same name
All communicate with superficial veins and median cubital vein
Anastomosis around the scapula
Three arteries which take part in the anastomosis around the scapula
• Suprascapular artery – branch of the thyrocervical trunk of the 1st part of subclavian A
• Deep branch of the transverse cervical artery - which is a branch of the thyrocervical trunk
• Circumflex scapular artery which is a branch of subscapular artery – branch of the 3rd part of the axillary A.
• In the event of block or surgical removal of first or second part of axillary artery, blood reaches through suprascapular artery and deep branch of transverse cervical artery and goes in reverse direction in the circumflex and subscapular artery to reach the third part of axillary artery.
• Thus the anastomosis forms a collateral pathway between the 1st part of subclavian and the 3rd part of the axillary artery.