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7. Upper Limb 2, Nerves, Vessels, Lymph

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Upper Limb 2
Nerves, Vessels and Lymph
Learning Objectives
1. Describe the anatomy of the brachial plexus from its origin in the neck to its
terminal branches.
2. Describe the course of neurovascular structures lying in close relation to the
bones and joints of the upper limb. Identify those that are at risk of injury and
predict what the functional effects of such injury might be.
3. Describe the sensory innervation to the upper limb.
4. Describe the origin, course and distribution of the major arteries and their
branches that supply the shoulder, arm, forearm and hand. Identify common
sites of injury. Palpate pulse points.
5. Describe the course of the main veins of the upper limb. Identify the common
sites of venous access and describe their key anatomical relations
6. Describe the anatomy of the axillary lymph nodes. Explain their importance in
the lymphatic drainage of the breast and upper limb, and in the spread of
tumours.
NERVES- Upper Limb
• Brachial plexus
• Extensor compartment
• Flexor compartment
• Hand
• Dermatome distribution/Sensory innervation
Brachial Plexus
Nerves to the upper limb originate at the levels C5 to T1.
The exit the spine as roots, join together in communal
fascial sheaths to form trunks, reorganise themselves at
the axillary artery into an anterior and posterior division.
The anterior division supplies the flexors in the anterior
compartment of the upper limb, the posterior division
supplies the extensors in the posterior compartment of
the upper limb.
The organisation of the nerves then changes into 3
cords- lateral, medial, posterior.
The lateral and medial cords supply the anterior (flexor)
compartment. The posterior cord supplies the posterior
(extensor) compartment.
The cords give rise to the named nerves supplying motor
and sensory innervation.
Anterior division- lateral and medial cords
ARM
The lateral and medial cords
lie anterior to the axillary
artery.
The musculocutaneous,
median and ulnar nerves
come from these two cords
and pass down through the
anterior compartment of the
arm to supply the flexors
NECK
Posterior division- posterior cord
ARM
The posterior cord sits
posterior to the axillary artery.
The radial and axillary nerves
come from this cord and pass
down through the posterior
compartment of the arm to
supply the extensors
NECK
Upper Limb Dermatomes
Lateral Shoulder (Regimental Badge)
Radial forearm, thumb, forefinger
Medial forearm, middle finger
Ulnar forearm, little and ring fingers
Medial arm
Axilla (deodorant)
C5
C6
C7
C8
T1
T2
Flexion of the arm- Musculocutaneous nerve
All motor and sensory functions in
the flexor compartment of the
arm are supplied by the
musculocutaneous nerve.
The nerve passes with the
brachial artery in a fascial plane
that lies between brachialis and
biceps brachii, sending off
branches superior and inferior to
innervate the muscles either side
of it.
Muscles involved in flexion of the
arm are biceps brachii, brachialis,
corocobrachialis.
Dermatome is C5/6
Arm with biceps brachii cut and reflected showing:
NCB- nerve to corocobrachialis
NBB- nerve to biceps brachii
NB- nerve to brachialis
LCNF- lateral cutaneous nerve to the forearm
MN- median nerve
Flexion of the wrist and hand - Ulna nerve
The ulna nerve passes straight through
the arm to innervate the flexors of the
forearm and medial hand.
The ulna nerve passes medial to the
medial epicondyle (‘funny bone’)
supplying flexor carpi ulnaris, and the
medial part of the muscle bulk of flexor
digitorum profundus. It passes into the
hand through Guyons canal under the
hook of the hamate to innervate the
medial two fingers and most of the
intrinsic muscles of the hand. Damage
gives rise the distinctive ‘ulnar claw’.
Dermatome is C8, T1
Ulnar claw
Ulnar nerve supply
involved in ‘hitting
your funny bone’
Flexion of the wrist and hand- Median nerve
The median nerve passes
through the centre of the
cubital fossa to supply the
superficial flexors of the wrist
and fingers. It passes into the
hand under the flexor
retinaculum in the carpal
tunnel. 80% of the nerve fibres
are sensory nerves carrying
information from the palm,
thumb, index, middle and
lateral half of the ring finger
back to the brain.
It can be compressed at the
wrist ‘carpal tunnel syndrome’.
Dermatomes C6/7
Median nerve
To
Hand
To
Head
Cubital fossa
showing median
nerve with brachial
artery
Ulnar and radial
sensory
distribution
Extensors- Axillary nerve
The axillary nerve passes from
the posterior division of the
brachial plexus behind the
humerus to supply deltoid and
teres minor muscles.
The area immediately over the
deltoid known as the ‘regimental
badge’ is used to test for sensory
muscle damage in a shoulder
dislocation.
Dermatome C5/6
Extensors- Radial nerve
The radial nerve comes off the
posterior division of the brachial plexus
to pass behind the humerus and curves
around it in the ‘spiral groove’- a
distinct groove visible on the humeral
bone.
It supplies triceps in the arm, and the
extensors of the forearm.
It passes through the cubital fossa
lateral to the median nerve and passes
into the extensor compartment of the
forearm.
It supplies sensory information from
the entire posterior of the arm and the
lateral part of the dorsum of the hand.
Dermatome C5/6/7/8/T1
Sensory distribution in the hand
Red- ulnar
Yellow- median
Blue- radial
Nerve Dance
https://www.youtube.com/watch?v=ZXLhwF2ptl0 (fun version)
Upper Limb Myotomes
Abduct the Shoulder
Adduct the Shoulder
Flex the Arm
Extend the Arm
C5
C6,7,8
C5,6
C7,8
Supinate
Pronate
Flex and Extend the Wrist
Flex and Extend the Fingers
C5,6
C7,8
C6,7
C7,8
Vessels
ArteriesSubclavian, Scapular branches, Axillary, Brachial, Radial, Ulnar
VeinsCephalic, Basilic, Median cubital, Subclavian
Subclavian artery and scapular blood supply
The left subclavian artery comes directly off the arch of
the aorta. On the right hand side the brachiocephalic
artery comes off the arch of the aorta, giving rise to the
right carotid artery and the right subclavian artery.
The first vessel to come off the subclavian is the
internal thoracic (mammary) artery. This descends
along the chest wall to supply the anterior portion of
the ribcage and the mammary gland.
The scapula is supplied the via the thyrocervical trunk,
with the suprascapular branch passing posteriorly
through the suprascapular notch to supply
supraspinatus and infraspinatus muscles, and the artery
to subscapularis passing anterior. These blood vessels
anastamose (join up) to form a circuit around the
scapula
Thyrocervical
trunk
Brachiocephalic
artery
Internal thoracic
(mammary) artery
Right subclavian artery
Blood supply
to the scapula
Axillary artery
The axillary artery is a continuation of the
subclavian artery. It starts at the lateral
border of the first rib and ends at the lower
border of teres major where it becomes
the brachial artery.
It gives rise to branches supplying the
acromion, the shoulder joint capsule and
the circumflex humeral artery which wraps
around the neck of the humerus.
Circumflex
humeral artery
Right axillary artery
Brachial artery
The brachial artery is a continuation of the
axillary artery. It begins at the lower border
of teres major and is the main blood supply
to the anterior (flexor) compartment of the
arm.
The profunda brachii artery passes
posteriorly into the extensor compartment
of the arm to supply triceps
Radial and Ulnar arteries
At the elbow the brachial artery divides into
the radial artery which follows the radial
bone, and the ulnar artery which follows
the ulna bone.
The radial pulse is felt at the wrist before
the artery passes posterior to the thumb on
the dorsum of the hand to pass back
through into the palm of the hand between
the muscles in the first webspace between
the thumb and the forefinger to form the
deep palmar arch.
The ulna artery passes directly into the
hand underneath the bony hook of the
hamate carpal bone. This forms the
superficial palmar arch. The deep and
superficial palmar arches anastomose to
form a circuit in the hand.
Pulse point
Radial
Deep palmar arch
Ulnar
Superficial palmar
arch
Pulse taking exercise
https://www.youtube.com/watch?v=yP672n9U1Ew
Work with a partner to find a pulse at
Axilla
Brachial
Cubital
Radial
Ulna
https://www.youtube.com/watch?v=0BSv4iN8T2E
Work with a partner to perform Allens test
Subclavian vein
The left and right subclavian veins drain into the
brachiocephalic trunks on each side. The
brachiocephalic veins both drain into the
superior vena cava which drains into the right
atrium of the heart.
The subclavian veins become the
brachiocephalic veins at the point where the
jugular vein joins, draining the head.
The vein sits superior to the subclavian artery,
travelling in the same fascial sheath.
It is often used for inserting a ‘central line’ a
cannula that is inserted into the subclavian vein
that then travels through the brachiocephalic
trunk and into the right atrium. This line is used
to deliver large quantities of fluid and/or drugs
directly into the circulatory system.
Positioning of a
central line
inserted into the
right subclavian
vein
Cephalic and Basilic veins
The cephalic and basilica veins drain the
arm. The basilic vein drains into the
brachial vein.
The cephalic vein travels in a groove
formed between the deltoid and pectoralis
major muscles called the deltopectoral
groove. It drains directly into the subclavian
vein just inferior to the clavicle.
The median cubital vein runs between
them at the elbow and is an often used site
for drawing blood.
The venous return in the hand is found on
the dorsum. This is because veins are easily
compressed and so they would not
function on the palm of the hand,
particularly in 4 footed animals.
LYMPH
The lymph nodes in the axilla drain the arm and most
of the breast. They travel with the blood vessels and
drain particular parts of the breast.
For this reason they are key in the diagnosis and
treatment of breast cancer.
In the early stages of a tumour in the breast the
lymph node draining that area will become enlarged,
but the rest of the lymph will remain normal. The
affected node is called a ‘sentinel’ node.
Radioactive dye is injected into the lump which will
track back to the sentinel node.
Both the cancerous lump and the associated lymph
node can be removed without the necessity for a
mastectomy.
This appreciation of the anatomy of the lymph
draining the breast has revolutionised the care of
breast cancer which has the highest incidence of any
cancer, affecting 1 in 8 women in the UK.
Learning Objectives
Nerves:
Describe the anatomy of the brachial plexus from its origin in the neck to its terminal
branches. Describe the course of neurovascular structures lying in close relation to the
bones and joints of the upper limb. Identify those that are at risk of injury and predict what
the functional effects of such injury might be. Describe the sensory innervation to the
upper limb.
Vasculature:
Arteries- Describe the origin, course and distribution of the major arteries and their
branches that supply the shoulder, arm, forearm and hand. Identify common sites of injury
and pulse points.
Veins- Describe the course of the main veins of the upper limb. Identify the common sites
of venous access and describe their key anatomical relations
Lymph:
Describe the anatomy of the axillary lymph nodes and explain their importance in the
lymphatic drainage of the breast and upper limb, and in the spread of tumours.
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