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