14 Pectoral and Axilla

axillary artery -beginning -end -how many segments of axillary artery?

(subclavian artery) (axillary artery) lateral border of 1st rib --> lateral border of teres major (brachial artery) 3 segments of axillary artery

breast anatomy mammary glands -how many lobules? -how many lactiferous ducts per lobule? -what is a lactiferous sinus?

-mammary glands: functional tissue that produce milk -15-20 lobules -1 lactiferous duct per lobule -dilated portion of duct just deep to areola (stores milk)

breast anatomy compartments -what divides breast into compartments? -this structure also does what? -what can the compartments prevent?

-suspensory ligaments (bands of tissue) divide breast into compartments -suspensory ligaments anchor breast to overlying skin -can prevent spread of infection

five groups of axillary lymph nodes

1) lateral (humeral) nodes 2) posterior axillary (subscapular) nodes 3) anterior axillary (pectoral) nodes 4) central nodes 5) apical nodes

the scapular anastomosis is formed by branches from these (this) artery:

1. Dorsal scapular 2. Suprascapular (from the thyrocervical trunk) 3. Circumflex scapular (from the subscapular) 4. Thoracodorsal (also from the subscapular)

3 main sites that you can compress the brachial plexus (and axillary artery/vein) as they pass from trunk into axilla and cause entrapment syndromes

1. costoclavicular space (1st rib --> clavicle) 2. interscalene space/triangle (anterior scalene --> middle scalene) 3. intrapectoral space (under pec minor tendon and coracoid process)

carcinomas of the breast can result in a number of important signs that may be recognized clinically

1. skin dimpling 2. nipple retraction 3. peau d'orange sign 4. abnormal contours

pectoralis major action

ADduction IR Flexion/Extension (depending upon where your starting position is) Inspiration when shoulder is fixed

waiter's tip position:

ADduction of shoulder medial rotation of arm extension of elbow

injury to superior brachial plexus (C5-C6) (upper trunk of brachial plexus)

Erb's Palsy

injury to the long thoracic nerve or serratus anterior muscle results in...

a "winging scapula" "C5, 6, 7, wing your way to heaven"

the breast may also show ______________ __________________, and it may become fixed to the thoracic wall if the tumor has invaded the underlying pectoral fascia and pectoralis major m. (normally the retromammary space is filled with loose connective tissue that allows the breast some mobility on the thoracic wall)

abnormal contours (4)

tumors of the breast can metastasize through these 3 lymph groups -lymphatic drainage drains through these 3 groups

anterior (pectoral) central apical

1. lymphatic drainage from the lateral quadrants of the breast is to the __________________________ group of axillary nodes. 2. from here, lymph passes to the ______________ group of axillary nodes, and then to the ___________ group of axillary nodes lymph eventually enters the venous system at the right (or left) venous angle via the... 3. lymph drainage from the medial quadrants of the breast is to the __________________________ nodes. 4. some lymph vessels communicate with those of the opposite breast and with those of the anterior abdominal wall

anterior (pectoral) central apical right lymphatic duct or thoracic duct parasternal (internal thoracic)

surface anatomy of axilla -anterior axillary fold- what muscle makes it up? -posterior axillary fold- what muscles make it up? -axillary lines -digitations of which muscle?

anterior axillary fold - pectoralis major posterior axillary fold - latissimus dorsi and teres major anterior, mid, posterior digitations of serratus anterior

a small branch which winds around anterior aspect of surgical neck of humerus

anterior circumflex humeral artery

3rd part of axillary artery: Branches

anterior circumflex humeral artery posterior circumflex humeral artery subscapular artery

pyramidal space deep to the axillary fossa (armpit)

axilla

the cords of the brachial plexus are named based on their relationship to the...

axillary artery

contents of axilla

axillary artery axillary vein axillary lymph node part of brachial plexus fat (lots of it to protect the neurovasculature)

target the terminal branches it is also used for lower arm, elbow, forearm, wrist, and hand surgeries

axillary blocks

motor to deltoid and teres minor mm.; sensory to skin over deltoid

axillary n.

axillary fascia underlying the armpit stretches b/w axillary folds

base

axillary vein is formed by the union of what 3 veins?

basilic vein (superficial) cephalic vein (superficial) brachial veins (deep)

loss of function for the serratus anterior prevents the scapula from... this is especially evident when the patient presses against a wall with outstretched arms

being held against the thoracic wall

why does erb's palsy result in the waiter's tip position? myotomes -paralysis of elbow flexors:

biceps brachii (C5,C6) brachialis (C5,C6) brachioradialis (C5-C7)

what artery is a continuation of the axillary artery? at what landmark does it change names?

brachial artery teres major

2 major superficial cutaneous veins that are carrying blood up the UE towards the shoulder

cephalic and basilic veins cephalic - lateral (ceiling) basilic - medial (basement)

apex of axilla, triangular opening

cervicoaxillary canal

winds around lateral border of scapula to reach infraspinous fossa where it participates in scapular anastomosis

circumflex scapular artery

subscapular artery branches

circumflex scapular artery thoracodorsal artery

cervicoaxillary canal -anterior border -medial border -posterior border

clavicle 1st rib superior border of scapula

thoracoacromial artery branches

clavicular acromial pectoral deltoid (cadavers are dead people)

anterior approach to shoulder surgery w/o cutting through muscle

cut along the deltopectoral groove retract the deltoid and pec major and cephalic vein

why does erb's palsy result in the waiter's tip position? myotomes -paralysis of shoulder ABductors:

deltoid (C5,C6) supraspinatus (C5,C6)

cephalic vein runs superficial up the arm then lies in the groove b/w which 2 muscles before diving deep to reach axillary vein?

deltoid and pec major (deltopectoral groove)

pectoralis minor action

depress (move down), protract (full forward) scapula optimizes position of scapula for overall movements of the shoulder inspiration (with fixed scapula) (helps serratus anterior)

traction on/shortening of suspensory ligaments (of Cooper), which are fibrous septa that attach to the skin of the breast, results in ...

dimpling of the skin (1)

branches in distal segment of subclavian and joins dorsal scapular nerve supplies levator scapulae and rhomboids

dorsal scapular artery

relevant branches of the subclavian artery

dorsal scapular artery thyrocervical trunk transverse cervical artery suprascapular artery

motor to levator scapulae and rhomboid mm.

dorsal scapular n.

lymph drainage of breast

drain lymph from breast area, chest area, entire UE

Erb's Palsy results from:

excessive increase in angle b/w head and shoulder literally stretches the C5-C6 nerve roots -ex: accidental pull of baby's head to one side during delivery, falling onto neck/shoulder

axillary vein runs (inferior, superior) to artery

inferior

target the cords which are also in close proximity and can all be potentially affected by anesthesia this block is used for lower arm, elbow, forearm, wrist and hand surgeries

infraclavicular blocks

brachial plexus blocks -ultrasound guided local administration of anesthesia to brachial plexus (for surgery, reduces need for opioids after surgery)

interscalene block supraclavicular block infraclavicular block axillary block

target the C5-C7 roots as they pass between the anterior and middle scalene mm. it usually does not anesthetize the C8-T1 roots this block is typically performed for shoulder surgeries

interscalene blocks

walls of axilla -lateral

intertubercular groove of humerus

what is the significance of the jagged edges on anterior surface of the medial border of the scapula?

it is the place where the serratus anterior attaches to the scapula origin = ribs 1-8 insertion = anterior surface of medial border of scapula

motor to pectoralis major m.

lateral and medial pectoral n.

3 parts of the axillary artery: 1st segment -where is it located? -how many branches?

lateral border of 1st rib --> medial border of pec minor 1 branch

3 parts of the axillary artery: 3rd segment -where is it located? -how many branches?

lateral border of pec minor --> lateral border of teres major 3 branches

axillary vein begins at... as a continuation of what vein?

lateral border of teres major as continuation of basilic vein

breast anatomy: largely adipose-filled organ -bed of breast

lateral edge of sternum --> midaxillary line 2nd --> 6th ribs

which pectoral nerve descends in the plane b/w pec major and minor?

lateral pectoral n. -runs on medial side of pec minor

pectoral nerves (name them) -named for what?

lateral pectoral nerve medial pectoral nerve -the cord of brachial plexus they arise from

supplies lateral thoracic wall and muscles

lateral thoracic artery

motor to serratus anterior

long thoracic n.

innervates serratus anterior

long thoracic nerve (C5-C7)

motor to subscapularis and teres major mm.

lower subscapular n.

in current practice, often only the tumor and surrounding tissue is removed --- a ___________________--- followed by radiation therapy.

lumpectomy

history of mastectomy does put people at risk of developing...

lymphedema of the upper limb because you can have occlusions of the axillary nodes

sensory to medial forearm

medial antebrachial cutaneous n.

sensory to medial arm

medial brachial cutaneous n.

motor to pectoralis major and minor mm.

medial pectoral n.

which pectoral nerve pierces pec minor?

medial pectoral n.

motor to all but 1.5 muscles in anterior forearm; motor and sensory to lateral half of palm

median n.

motor to lattisimus dorsi m.

middle subscapular (thoracodorsal) n.

when the long thoracic nerve comes off the brachial plexus, it descends down the *superficial* surface of serratus anterior...this makes it

more easily injured

motor to anterior arm; sensory to lateral forearm

musculocutaneous n.

motor to subclavius m.

n. to subclavius

axilla is a conduit for

neck and chest --> UE

interference w/lymphatic drainage of the skin results in thickened skin, called

peau d'orange sign (3)

lateral pectoral n. innervates

pec major

walls of axilla -anterior

pec major and minor

medial pectoral n. innervates

pec major and minor "medial does more"

breast anatomy -underlying muscles

pec major/minor serratus anterior

when you are winded and hold onto something or put your hands on your knees (fix shoudler, closed chain), this muscle helps with inspiration by lifting the ribcage up (helps serratus anterior)

pectoralis major

muscles of the chest

pectoralis major pectoralis minor serratus anterior

3 parts of the axillary artery: 2nd segment -where is it located? -how many branches?

posterior (deep) to pec minor 2 branches

a much larger branch which passes posteriorly through quadrangular space (with axillary n.) and winds around posterior aspect of surgical neck of humerus. Supplies deltoid m. and shoulder joint; anastomoses with ant. circumflex humeral a

posterior circumflex humeral artery

serratus anterior action *SA is one of Brooks' favorites

protracts scapula and holds against thoracic wall rotates glenoid cavity superiorly

motor to all of posterior arm and forearm; sensory to much of posterior arm, forearm, hand

radial n.

(simple/radical) mastectomy involves removal of the breast, pectoral muscles and fascia, fat, and as many axillary lymph nodes as possible

radical

traction on lactiferous ducts can result in a...

retracted nipple (2) note: it is important to determine if the retracted nipple is of recent onset, suggesting cancer of the breast, vs. long-standing retraction, which could be a congenital deformity

walls of axilla -medial

ribs 1-4, serratus anterior

walls of axilla -posterior

scapula, subscapularis, latissimus dorsi

on the ground doing a push up (closed chain) your body weight + the force of the ground is going to force the scapula into retraction how do you counteract that?

serratus anterior muscle -conteracts the forces on your upper limb so that you don't get pushed into scapular retraction

(simple/radical) mastectomy involves removal of the breast down to the retromammary space

simple

in football, this can give you a minor version of an erb's palsy injury

stinger when you tackle someone and your helmet goes to one side of your neck

axillary artery is a continuation of what artery? at what landmark does it change names?

subclavian artery 1st rib

largest branch of axillary a.

subscapular artery

supplies muscles of posterior wall of axilla ends by dividing into two branches: 1) circumflex scapular a 2) thoracodorsal a.

subscapular artery

1st part of axillary artery: Branches

superior thoracic artery

supplies first and second intercostal spaces

superior thoracic artery

breast divided into quadrants...most tumors (about 60%) arise from

superolateral quadrant -axillary extension of this quadrant

subclavius action

supports clavicle, SC joint -protects subclavian vessels and brachial plexus when clavicle is fractured -PT's dry needle this muscle

target the trunks which are in close proximity and can all be affected by the anesthesia this block is most useful for surgeries of the arm, elbow, and forearm

supraclavicular blocks

joins suprascapular nerve and supplies supraspinatus and infraspinatus mm.

suprascapular artery

motor to supraspinatus and infraspinatus mm.

suprascapular n.

why does erb's palsy result in the waiter's tip position? myotomes -paralysis of lateral rotators:

teres minor (C5,C6) infraspinatus (C5,C6)

what artery runs in the middle of the brachial plexus?

the axillary artery literally runs in the middle of the brachial plexus

hyperabduction syndrome

the subclavian and axillary vessels and the brachial plexus are compressed as they move behind the pectoral muscle and beneath the coracoid (intrapectoral syndrome) ex: occupation where the arms are ABducted for long periods of time

short trunk which immediately divides into 4 small branches that diverge to supply neighboring structures

thoracoacromial artery

2nd part of axillary artery: Branches

thoracoacromial artery lateral thoracic artery

runs with nerve of same name to latissimus dorsi m.

thoracodorsal artery

short branch that divides to give rise to transverse cervical and suprascapular arteries

thyrocervical trunk

what does the cervicoaxillary canal do?

transmits neurovasculature b/w neck and UE

joins spinal accessory nerve and supplies trapezius muscle

transverse cervical artery

only muscle of upper limb that brachial plexus does not innervate -superficial back, pectoral region, upper limb

trapezius (spinal accessory nerve innervates it)

T/F: mastectomy is not as common as it once was.

true

motor to 1.5 muscles in anterior forearm; motor and sensory to medial half of palm

ulnar n.

motor to subscapularis m.

upper subscapular n.

clinical outcome of weakness in serratus anterior

winged scapula