Download Document

Pamela BL
 Description
 Contents
 Clinical
application
 The
axilla(armpit, underarm) is the
pyramidal space inferior to the
scapulohumeral joint and superior to the
axillary fascia at the junction of the arm and
thorax.
 It provides passageway for vessels and nerves
to reach the upper limb.
 The
shape and size of the axilla vary
depending on the position of the arm.
 It almost disappears when the arm is fully
abducted.
 The
1.
2.
3.
axilla has:
An apex
A base
Four walls


Apex of axilla (the entrance from the neck)
lies btwn the 1st rib, clavicle and superior
edge of subscapularis.
The arteries, veins, lymphatics and nerves
pass from the neck to the axilla through the
cervicoaxillary canal-the superior opening
to the axilla, to reach the arm.
 Base
of the axilla is formed by the concave
skin, subcutaneous tissue and axillary(deep)
fascia extending from the arm to the
thoracic wall.
 Anterior wall of axilla is formed by pectoralis
major and pectoralis minor muscles, and
pectoral and clavipectoral fascia associated
with them.
 Posterior
wall of axilla is formed by scapula
and subscapularis on its anterior surface and
inferiorly by teres major and latissimus dorsi.
 Medial
wall is formed by the thoracic
wall(1st-4th rib and intercostal muscles) and
the overlying serratus anterior.
 Lateral wall of axilla is a narrow bony wall
formed by the intertubercular groove of
humerus.
 The
1.
2.
3.
4.
5.
6.
axilla contains:
Axillary artery and its branches
Axillary vein and its tributaries
A network of interjoining nerves(brachial
plexus) that pass from the neck to the
upper limb
Several groups of axillary lymph nodes
Lymphatic vessels.
Proximally these neurovascular structures
are ensheathed in a fascial sleeve, axillary
sheath.
 Axillary
artery begins at the lateral border of
the 1st rib as the continuation of the
subclavian artery and ends at the inferior
border of the teres major.
 It passes posterior to the pectoralis minor
into the arm and becomes the brachial artery
when it passes distal to the inferior border of
the teres major.
 For
descriptive purposes, the axillary artery
is divided into three parts by the pectoralis
minor.
 First part of the axillary artery-located btwn
the lateral border of the 1st rib and the
medial border of the pectoralis minor, is
enclosed in the axillary sheath and has one
branch-the superior thoracic artery.
 The
superior thoracic artery(highest thoracic
artery) arise from the first part of axillary
artery just inferior to the subclavius.
 It runs inferomedially posterior to the
axillary vein and supplies muscles in the 1st
and 2nd intercostal spaces and the serratus
anterior.
 It anastomoses with the intercostal arteries.
 Second
part of the axillary artery lies
posterior to pectoralis minor and has two
branches, the thoracoacromial and lateral
thoracic arteries, which pass medial and
lateral to the muscle respectively.
 Thoracoacromial
artery, a short wide trunk,
deep to pectoralis minor, pierces the
costocoracoid membrane(part of
clavipectoral fascia) and then divides into 4
branches-acromial, deltoid, pectoral and
clavicular deep to the clavicular head of
pectoralis major.
 The
lateral thoracic artery has a variable
origin.
 It usually arises from the second part of the
axillary artery, but it may arise from the
thoracoacromial, suprascapular or
subscapular arteries.
 It
supplies the pectoral muscles, the axillary
lymph nodes and the breast.
 It is an important source of blood to the
lateral part of the mammary glands in
women.
 Third
part of axillary artery extends from
lateral border of pectoralis minor to the
inferior border of teres major.
 It has three branches, the subscapular-the
largest branch of the axillary artery, anterior
circumflex humeral and posterior circumflex
humeral arteries.
 The
subscapular artery, the largest branch of
the axillary artery descends along the lateral
border of the subscapularis on the posterior
axillary wall.
 It then divided into the circumflex scapular
and thoracodorsal arteries and supplies the
subscapularis, teres major, serratus anterior
and latissimus dorsi muscles.
 The
circumflex scapular artery, the larger
branch of the subscapular curves posteriorly
around the axillary border of the scapula
passing btwn the subscapularis and teres
major to supply muscles on the dorsum of
the scapula.
 It participates in anastomoses around the
scapula.
 The
thoracodorsal artery continues the
general course of the subscapular to the
inferior angle of the scapula and supplies
adjacent muscles principally latissimus dorsi.
 It also participates in the arterial
anastomoses around the scapula.
 The
circumflex humeral arteries usually arise
from the third part of the axillary artery
opposite the subscapular artery and pass
around the surgical neck of the humerus to
anastomose with each other.
 The
smaller anterior circumflex humeral
artery passes laterally deep to
coracobrachialis and biceps brachii, it gives
off an ascending branch that supplies the
shoulder.
 The
larger posterior circumflex humeral
artery passes through the posterior wall of
the axilla via the quadrangular space with
the axillary nerve to supply surrounding
muscles(deltoid, teres major and minor and
long head of triceps).
 Lies
on the medial side of the axillary artery.
 Formed by the union of the brachial vein and
the basilic vein at the inferior border of the
teres major.
 It ends at the lateral border of the 1st rib
where it becomes the subclavian vein.
 The
axillary vein receives tributaries that
generally correspond to branches of the
axillary artery with a few exceptions:
 The veins corresponding to the branches of
the thoracoacromial artery do not merge to
enter by a common tributary, some enter
independently into the axillary vein but
others empty into the cephalic vein which
superior to pectoralis minor also enters the
axillary vein close to its transition to the
subclavian vein.
 The
axillary vein receives directly or
indirectly the thoracoepigastric vein(s),
which is formed by anastomoses of
superficial veins from the inguinal region
with tributaries of the axillary vein usually
the long thoracic vein-constituting a
collateral route that enables venous return in
the presence of obstruction of the inferior
vena cava.
 The
axillary artery can be palpated in the
inferior part of the lateral wall of the axilla.
 Compression of the 3rd part of axillary artery
against the humerus may be necessary when
there is profuse bleeding(trauma).
 If compression is required at a amore
proximal site, the axillary artery can be
compressed at its origin by exerting
downward pressure in the angle btwn the
clavicle and attachment of
sternocleidomastoid.
2.Arterial anastomoses around the scapula
Many arterial anastomoses occur around the
scapula.
Several vessels join to form networks on the
anterior and posterior surfaces of the
scapula-he dorsal scapular, suprascapular
and subscapular(via the circumflex
scapular).
 Slow
occlusion of axillary
artery(disease/trauma) often enables
sufficient collateral circulation to develop,
preventing ischemia.
 Sudden occlusion usually does not allow
sufficient time for a good collateral
circulation to develop, resulting into an
inadequate supply of blood flow to the arm,
forearm and hand.
 Injury
to the axillary vein
 Because of its large size and exposed position
the axillary vein is often injured.
 When the arm is fully abducted, the axillary
vein overlaps the axillary artery anteriorly.
 Its more dangerous when the wound is in the
proximal part of the axillary vein not only
because of profuse bleeding but also because
of the risk of emboli formation.
 Are
found in the fibro fatty connective tissue
of the axilla.
 They are arranged in five principal groups:
1. Apical
2. Pectoral
3. Subscapular
4. Humeral
5. Central
 Apical
lymph nodes- located at the apex of
the axilla along the medial side of the
axillary vein and the first part of the axillary
artery.
 Receives lymph from all other groups of the
axillary lymph nodes as well as from
lymphatics accompanying the proximal
cephalic vein.
 The
pectoral(anterior) lymph nodes consists
of 3-5 lymph nodes that lie along the medial
wall of the axilla, around the lateral thoracic
vein and the inferior border of the pectoralis
minor.
 They receive lymph mainly from the anterior
thoracic all including the breast.
 Efferent lymphatic vessels from these nodes
pass to the central and apical groups of
axillary nodes.
 The
subscapular(posterior) axillary lymph
nodes consist of 6-7 lymph nodes that lie
along the posterior axillary fold and
subscapular blood vessels.
 Receive lymph from the posterior aspect of
the thoracic wall and scapular region.
 Efferent lymphatic vessels pass from these
nodes to the central and apical groups of
axillary lymph nodes.
 The
humeral(lateral) axillary lymph nodes
consist of 4-6 lymph nodes that lie along the
lateral wall of the axilla, medial and
posterior to the axillary vein.
 Receive nearly all the lymph from the upper
limb except that carried by lymphatic vessels
accompanying the cephalic vein which drains
to the central and apical axillary lymph
nodes.
 The
central axillary lymph nodes consist of 34 lymph nodes situated deep to the
pectoralis minor near the base of the axilla
in association with the 2nd part of the axillary
artery.
 Receive lymph from the pectoral,
subscapular and humeral lymph nodes.
 Efferent vessels from these nodes pass to
apical lymph nodes.
 The
axillary lymph nodes may
enlarge(lymphadenopathy) and become
tender following infections of the upper
limb.
 Infections in the pectoral region and breast,
and the superior part of the abdomen can
also produce enlargement of axillary lymph
nodes.
 In
carcinoma(cancer) involving the apical
lymph nodes, the lymph nodes often adhere
to the axillary vein which may necessitate
excision of part of this vessel.
 Enlargement of apical lymph nodes may
obstruct the cephalic vein superior to the
pectoralis minor.
 Excision
and pathologic analysis of axillary
lymph nodes is often necessary for staging
and treatment of malignancy e.g. breast
cancer.
 During surgery care is taken not to injure the
long thoracic nerve, which is identified and
maintained against the thoracic wall.
 Injury to this nerve causes a winged scapula.
 Injury
to the thoracodorsal nerve results into
weakened medial rotation and adduction of
the arm, but no deformity forms.
 The
arm extends from the shoulder to the
elbow.
 Two types of movements occur btwn the arm
and forearm at the elbow joint: flexionextension, and pronation-supination.
 The muscles performing these movements
are divided into anterior and posterior
groups.
 Three
flexors(biceps brachii, brachialis and
coracobrachialis) are in the anterior
compartment.
 They are supplied by musculocutaneous
nerve.
 One extensor(triceps brachii) is in the
posterior compartment, supplied by the
radial nerve.
 The anconeus at the posterior aspect of the
elbow is essentially a distally placed
continuation of the triceps brachii.
 Biceps
brachii, located in the anterior
compartment of the arm.
 Has two heads and its two muscle bellies
unite just distal to the middle of the arm.
 When the elbow is extended, the biceps
brachii is a simple flexor of the forearm.
 When
the elbow is flexed, and more power is
needed against resistance, the biceps is the
primary(most powerful) supinator of the
forearm.
 The biceps barely operates during flexion of
the prone forearm.
 The
rounded tendon of the longhead of
biceps brachii crosses the head of the
humerus within the cavity of the
glenohumeral joint.
 The tendon surrounded by synovial
membrane, descends in the intertubercular
groove of the humerus.
A
broad band, the transverse humeral
ligament passes from the lesser to the
greater tubercle of the humerus and converts
the intertubercular groove into a canal.
 The ligament holds the tendon of the long
head of biceps brachii in the groove.
 Distally, the tendon attaches to the
tuberosity of the radius.
 The
biceps brachii continues distally as the
bicipital aponeurosis, a triangular
membranous band that runs from the biceps
tendon across the cubital fossa and merges
with the antebrachial(deep) fascia covering
the flexor muscles in the medial side of the
forearm.
 Approximately
10% of people have a 3rd head
to the biceps arising at the superomedial
part of the brachialis(with which it is
blended).
 In most, the 3rd head lies posterior to the
brachial artery.
 To
test the biceps, the elbow joint is flexed
against resistance when the forearm is
supinated.
 If acting normally, the muscle forms a
prominent bulge on the anterior aspect of
the arm which is easily palpated.
 Brachialis
is a flattened fusiform muscle that
lies posterior(deep) to the biceps brachii.
 The brachialis is the main flexor of the
forearm.
 It flexes the forearm in all positions and
during slow and quick movements.
 Because of its many functions, it is regarded
as the workhorse of the elbow flexors.
 Coracobrachialis
is an elongated muscle in
the superomedial part of the arm.
 It is a useful a landmark as the
musculocutaneous nerve pierces it, and the
distal part of its attachment indicates the
location of the nutrient foramen of the
humerus.
 Biceps
tendinitis, inflammation of the tendon
usually from repetitive microtrauma.
 Common in sports involving
throwing(baseball, cricket).
 A tight, narrow and/or rough intertubercular
groove may irritate and inflame the tendon
producing tenderness and crepitus(crackling
sound).
 Triceps
brachii, a fusiform muscle locates in
the posterior compartment of the arm.
 It has three heads: long, lateral and medial.
 it is the main extensor of the elbow joint.
 Because its long head crosses the shoulder
joint, the triceps helps stabilize the
adducted glenohumeral joint by serving as a
shunt muscle resisting inferior displacement
of the head of the humerus.
 The
triceps also aids in extension and
adduction of the arm.
 To test the triceps, the arm is abducted 90
degrees and then the flexed forearm is
extended against resistance provided by the
examiner.
 If acting normally the triceps can be seen
and palpated.
 Is
an axillary space in the arm of clinical
importance.
 In the quadrangular space, the axillary nerve
and posterior circumflex humeral artery can
be compresse or damaged due to space
occupying lesion or trauma disrupting its
normal anatomy.
 Symptoms include axillary nerve related
weakness of the deltoid muscle(in case of
significant mass lesions in the quadrangular
space).
 Boundaries:
 Bounded
superiorly by teres minor
 Inferiorly: teres major
 Medially: long head of triceps trachii
 Laterally: surgical neck of humerus.
 It transmits the axillary nerve and posterior
circumflex humeral artery.