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Anatomy Of Axilla And Shoulder
Dr. Fadel Naim
Orthopedic Surgeon
Faculty of Medicine
IUG
SURFACE ANATOMY
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ACROMION
CLAVICLE
DELTOID ( IM INJECTIONS)
HUMERUS
BICEPS MUSCLE
BICIPTAL GROOVE
BRACHILA PULSE( BLOOD
PRESSURE)
TRICEPS
OLECRNON PROCESS( PT OF
THE ELBOW)
MEDIAL /LATERAL EPICONDYLES
TRIANGLE
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CUBITAL FOSSA
MEDIAN CUBITAL VEIN- IV
CEPHALIC VEIN
ULNA
RADIUS
STYLOID PROCESS
RADIAL ARTERY( PULSE)
ULNAR ARTERY
ANATOMICAL SNUFF BOX
THENAR EMINENC
HYPOTHENAR EMINENCE
CARPAL TUNNEL
CUBITAL FOSSA
STYLOID PROCESS
Axilla(Arm pit)
AXILLA
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A pyramid-shaped
space between the
upper part of the arm
and the side of the
chest through which
major neurovascular
structures pass
between neck &
thorax and upper
limbs.
Axilla has an apex, a
base and four walls.
Axillary Walls
Bones
Anterior
Posterior
Medial
Lateral
Clavicle
Scapula
Ribs
Humerus
Muscles
Anterior
Posterior
Medial
Lateral
Pectoralis
Subscapularis
teres minor
teres major
latissimus dorsi
Serratus
anterior
Tendon of long
head of biceps
major
pectoralis minor
subclavius
Contents Of The Axilla
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Axillary artery
Axillary vein
Cords of brachial plexus
Axillary lymph nodes
Fat
Axillary sheath
Pectoralis Major
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Origin
– Clavicular head:
• Medial half clavicle.
– Sternocostal head:
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Lateral manubrium
Sternum
Six upper costal cartilages
External oblique aponeurosis
INSERTION
– Lateral lip of bicipital groove of humerus
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Action
– Clavicular head:
• Flexes and adducts arm.
– Sternal head:
• Adducts and medially rotates arm .
• Accessory for inspiration
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Nerve
– Medial pectoral nerve (from medial cord)
– Lateral pectoral nerve (from lateral cord)
Subclavius
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Origin
– Costochondral junction of 1st rib
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INSERTION
– Subclavian groove on inferior surface of middle third of
clavicle
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Action
– Depresses clavicle and steadies it during shoulder
movements
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Nerve
– Nerve to subclavius (upper trunk of brachial plexus)
Pectoralis Minor
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Origin
3, 4, 5 ribs
INSERTION
– Medial and upper surface of coracoid process of scapula
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Action
– Elevates ribs if scapula fixed
– Pulls shoulder downward and forward
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Nerve
– Medial pectoral nerve (from medial cord of brachial plexus)
Subscapularis
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Origin
– Medial two thirds of subscapular fossa
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INSERTION
– Lesser tuberosity of humerus
– Upper medial lip of bicipital groove
– Capsule of shoulder joint
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Action
– Medially rotates arm
– Stabilizes shoulder joint
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Nerve
– Upper and lower subscapular nerves (from posterior cord of brachial
plexus)
Teres Major
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ORIGIN
– Lower third of lateral side of inferior angle of scapula below teres minor
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INSERTION
– Medial lip of bicipital groove of humerus
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ACTION
– Medially rotates and adducts arm.
– Stabilizes shoulder joint
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NERVE
– Lower subscapular nerve (from posterior cord of brachial plexus)
Latissimus Dorsi
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ORIGIN
– Spine T7
• spinous processes and supraspinous ligaments
of all lower thoracic, lumbar and sacral vertebrae
– lumbar fascia
– posterior third iliac crest
– last four ribs (interdigitating with external oblique
abdominis)
– inferior angle of scapula
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INSERTION
– Floor of bicipital groove of humerus after spiraling
around teres major
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ACTION
– Extends, adducts and medially rotates arm.
– Costal attachment helps with deep inspiration
and forced expiration
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NERVE
– Thoracodorsal nerve (from posterior cord of brachial
plexus)
Serratus Anterior
 ORIGIN
– Upper 8 ribs and anterior intercostal
membranes from midclavicular line.
 INSERTION
– Inner medial border scapula
• 1 and 2: upper angle
• 3 and 4: length of costal surface
• 5-8: inferior angle
Serratus Anterior
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Action
– A strong protractor of the scapula that is used when
punching or reaching anteriorly ("boxer's muscle")
– Inferior part rotates the scapula, elevating its glenoid cavity
so the arm can be raised above the shoulder
– Holds the scapula against the thoracic wall when doing
push ups or when pushing against resistance
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Nerve
– Long thoracic nerve
Trapezius
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Origin
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Medial third superior nuchal line on the occipital bone
External occipital protuberance
Ligament nuchae
Spine of 7th cervical vertebra
Spinous processes and supraspinous ligaments to T12
 INSERTION
– Upper fibers to lateral third of posterior border of
clavicle
– Middle fibers to medial acromion and superior lip of
spine of scapula
– Lower fibers to medial end of spine of scapula
 Action
– Laterally rotates, elevates and retracts scapula.
– If scapula is fixed, extends and laterally flexes neck
 Nerve
– Motor fibers form spinal accessory nerve (Cranial
nerve XI)
– Sensory fibers spinal nerves C3 and C4
Levator Scapulae
 Origin
– Posterior tubercles of transverse processes of C1-4
 INSERTION
– Upper part of medial border of scapula opposite the
supraspinous fossa
 Action
– Raises medial border of scapula
– In conjunction with middle fibers of trapezius and rhomboids,
pulls the scapula medially and upward
 Nerve
– Anterior primary rami of C3 and C4 and dorsal scapular
nerve (C5)
Rhomboid Minor
 Origin
– Lower ligamentum nuchea
– Spines of C7 and T1
 INSERTION
– Small area of posteromedial border of scapula at level of
spine, below levator scapulae
 Action
– Elevates the medial border of the scapula and pulls it
medially
 Nerve
– Dorsal scapular nerve (C5)
Rhomboid Major
 Origin
– Spines of T2-T5 and supraspinous ligaments
 INSERTION
– Lower half of posteromedial border of scapula,
opposite the infraspinous fossa
 Action
– Elevates the medial border of the scapula and
pulls it medially
 Nerve
– Dorsal scapular nerve (C5) (from root )
Deltoid
 ORIGIN
– Anterior fibers: Lateral third of clavicle
– Middle fibers: Acromion
– Posterior fibers: spine of scapula to
deltoid tubercle
 INSERTION
– Deltoid tuberosity
– Middle of lateral surface of humerus
 ACTION
– Abducts arm
– anterior fibers flex and medial rotate
– posterior fibers extend and lateral rotate
 NERVE
– Axillary nerve (C5, 6) (from posterior
cord)
Forms the rounded
contour of the
shoulder
Supraspinatus
 Origin
– Medial three quarters of supraspinous fossa of scapula
– Upper surface of spine
 INSERTION
– Superior facet on greater tuberosity of humerus
– Capsule of shoulder joint
 Action
– Abducts arm
– Stabilizes shoulder joint
 Nerve
– Suprascapular nerve
Infraspinatus
 Origin
– Medial three quarters of infraspinous fossa of scapula
 INSERTION
– Middle facet of greater tuberosity of humerus
– Capsule of shoulder joint
 Action
– Laterally rotates arm
– Stabilizes shoulder joint
 Nerve
– Suprascapular nerve
Teres Minor
 Origin
– Middle third lateral border of scapula above teres major
 INSERTION
– Inferior facet of greater tuberosity of humerus (below
infraspinatus)
– Capsule of shoulder joint
 Action
– Laterally rotates arm
– Stabilizes shoulder joint
 Nerve
– Axillary nerve
Rotator Cuff Muscles
 Four of the scapulohumeral muscles
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Supraspinatus
Infraspinatus
Teres minor
Subscapularis
 Referred to as SITS muscles
 Called rotator cuff muscles because they
form a musculotendinous cuff around the
glenohumeral joint {Dynamic stabilizers
(“cuff”)}
 All except the supraspinatus are rotators of
the humerus
 The tendons of the muscle
blend with the fibrous capsule of
the glenohumeral joint to form a
musculotendinous rotator
cuff, which reinforces the
capsule on three sides:
– Anteriorly
– Superiorly
– Posteriorly
 The cuff is weakest anteroinferiorly, making shoulder
dislocation most common in this
direction.
 The pectoral girdle involves the:
 SC joint
 AC joint
 Glenohumeral joint
 Generally, these joints move at the same time
 Functional defects in any of the joints impair
movements of the pectoral girdle.
Sternoclavicular Joint
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The only articulation between the upper limb and the axial
skeleton
A saddle type of synovial joint functions as a ball and socket
joint
The sternal end of the clavicle articulates with the manubrium
of the sternum and the 1st costal cartilage
Can be palpated because the sternal end of the clavicle lies
superior to the manubrium of the sternum
Ligaments of the SC Joint
 Anterior and posterior SC ligaments:
 The interclavicular ligament
 The costoclavicular ligament
Articular Disc
Articular
disc
Divides the SC joint into two compartments
The articular disc serves as a shock
absorber of forces transmitted along the
clavicle from the upper limb
Movements of the SC Joint
 Although the SC joint is extremely
strong, it is significantly mobile to allow
movements of the pectoral girdle and
upper limb
 Mobility of the clavicle at the
sternoclavicular joint is essential for the
freedom of movement of the upper
limb.
 During full elevation of the limb, the
clavicle is raised to approximately a 60 °
angle.
 The SC joint moves up to 25 to 30 ° along
its long axis in several direction:
– anteriorly
– Posteriorly
– Inferiorly
Acromioclavicular Joint
The AC joint is a plane type of synovial joint
It is located 2 to 3 cm from the point of the
shoulder formed by the lateral part of the
acromion
The acromial end of the clavicle articulates
with the acromion
The articular surfaces, are separated by an
incomplete wedge-shaped articular disc.
Ligaments of the AC Joint
 The integrity of the joint is maintained by extrinsic
ligaments, distant from the joint itself.
 The superior and inferior AC ligament:
The coracoclavicular
ligament
 The coracoclavicular ligament:
1.
The conoid ligament
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2.
Trapezoid ligament
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Its wide attachment is to the conoid tubercle on the inferior
surface of the clavicle
extends laterally to the trapezoid line on the inferior surface of
the clavicle.
provides the means by which the scapula and free limb
are (passively) suspended from the clavicular strut
The rotatory movements of the scapula occur at this
important ligament
Glenohumeral (Shoulder) Joint
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A ball-and-socket type of
synovial joint
Relatively unstable
The large, round humeral head
articulates with the relatively
shallow glenoid cavity of the
scapula
The glenoid is deepened slightly
but effectively by the ringlike
glenoid labrum
The glenoid cavity accepts little
more than a third of the humeral
head, which is held in the cavity by
the tonus of the rotator cuff
muscles
Both articular surfaces are covered
with hyaline cartilage.
 The inferior part of the articular
capsule is the only part not
reinforced by the rotator cuff
muscles
 Its weakest area.
 Here the capsule is particularly lax
and lies in folds when the arm is
adducted
 It becomes taut when the arm is
abducted.
Ligaments of the
Glenohumeral Joint
The glenohumeral ligaments:
– Superior , middle and inferior
The coracohumeral ligament
 The transverse humeral ligament
The Coracoacromial Arch
 An extrinsic, protective
osseoligamentous
structure formed by:
– The smooth inferior
aspect of the acromion
– The coracoid process of
the scapula
– The coracoacromial
ligament
 Overlies the head of the
humerus, preventing its
superior displacement
 The supraspinatus muscle
passes under this arch
Movements of the Glenohumeral Joint
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The glenohumeral joint has more freedom of movement
than any other joint in the body.
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This freedom results from:
1.
2.
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The glenohumeral joint allows movements around three
axes and permits:
1.
2.
3.
4.
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the laxity of its articular capsule
the large size of the humeral head compared with the small size
of the glenoid cavity.
Flexion-extension
Abduction-adduction
Rotation (medial and lateral) of the humerus
Circumduction.
Circumduction is an orderly sequence of flexion,
abduction, extension, and adduction or the reverse.
Glenohumeral motions
Glenohumeral motions
Glenohumeral motions
Scapular motions
Scapular motions
Protraction – Retraction
Scapular Motions
Rotational Elevation Of Glenoid Cavity
Rotational Depression Of Glenoid Cavity
•Elevation
Shoulder
Girdle
Movements
•Adduction
•Abduction
•Depression
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The supraspinatus initiates abduction and the
deltoid takes over once the humerus is abducted
past 15 degrees
During full abduction of the arm we have to
laterally rotate our humerus to move the
greater tuberosity out of the way.
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Even with this maneuver, space is too limited to
allow for the range of motion that is seen in a
normal individual.
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The remainder of the range of motion is made
possible by scapular rotation.
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Once we have abducted the arm past 20 degrees
or 30 degrees, for every 3 degrees of abduction at
the glenohumeral joint, 1 degree occurs at the
scapulothoracic surface and only 2 degrees
occurs at the glenohumeral joint.
Bursae Around the Glenohumeral Joint
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Several bursae containing synovial fluid
Bursae are located where
– Tendons rub against bone, ligaments, or
other tendons
– Where skin moves over a bony prominence.
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Some of them communicate with the joint
cavity (the subscapular bursa)
opening a bursa may mean entering the
cavity of the shoulder joint.
Subacromlal Bursa
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Large bursa lies between the deltoid, the
supraspinatus tendon, and the fibrous capsule
of the glenohumeral joint.
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The subacromial bursa is located inferior to the
acromion and coracoacromial ligament, between
them and the supraspinatus.
Subdeltoid Bursa
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This bursa lies between the deltoid muscle
and the fibrous joint capsule over the head
of the humerus.
Subscapular
Bursa
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Located between the neck of the scapula and
the subscapularis muscle
Often communicates with the glenohumeral
joint cavity through an opening in the fibrous
joint capsule