Introduction to the Upper Limb; Shoulder Girdle

Acromion

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Coracoid Process

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Superior angle of the scapula

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Suprascapular notch

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Infraglenoid tubercle

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Lateral border of the scapula

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Glenoid cavity of the scapula

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Head of humerus

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Medial epicondyle

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Trochlea

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Capitulum

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Lateral epicondyle

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Radial fossa

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Coronoid fossa

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Deltoid tuberosity

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Intertuburcular sulcus

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Surgical neck

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Lesser tubercle

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Greater tubercle

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Anatomical neck

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Supraglenoid tubercle

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Suprascapular notch

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Radial groove

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Medial supracondylar ridge

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Lateral supracondylar ridge

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Olecranon fossa

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Inferior angle of the scapula

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Medial border
Infraspinous fossa

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Spine

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Supraspinous fossa

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Head of radius

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Neck of radius

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Tuberosity of radius

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Coronoid process

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Tuberosity of ulna

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Olecranon articulating with olecranon fossa of humerus

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Manubrium of sternum

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Sternal angle

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Costal Cartilage

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Xiphoid process of sternum

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Sternal end of clavicle

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Acromial end of clavicle

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Conoid tubercle of clavicle

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Trapezoid line of clavicle

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Scapulohumeral rhythm

2/1 ratio (for flexion and abduction) glenohumeral/scapulothoracic movement

Cephalic Vein

Drains into axillary vein

Basilic vein

Drains into brachial veins

Median cubical vein

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Deltoid (anterior middle and posterior)

Origin- lateral 1/3 of the clavicle, acromion, spine of the scapula
Insertion: deltoid tuberosity of the humerus
Action: Abducts arm; anterior fibers flex and medially rotate the arm; posterior fibers extend and laterally rotate the arm
Innervation: Axill

Rotator Cuff Muscles

Important shoulder stabilizers:
Subscapularis
Supraspinatus
Infraspinatus
There's Minor

Subscapularis

Origin: Subscapular fossa
Insertion: lesser tubercle of the humerus
Action: medial rotation of the arm
Innervation: upper and lower Subscapular nerves

Supraspinatus

Origin: Supraspinatus fossa
Insertion: greater tubercle of the humerus
Action: abducts the arm (initiates abduction)
Innervation: suprascapular nerve

Infraspinatus

Origin: infraspinous fossa
Insertion: greater tubercle of the humerus
Action: laterally rotates the arm
Innervation: Suprascapular nerve

Teres Minor

Origin: upper 2/3 of the lateral border of the scapula
Insertion: greater tubercle of the humerus
Action: laterally rotates the arm
Innervation: axillary nerve

Teres Major

Origin: dorsal surface of the inferior angle of the scapula
Insertion: crest of the lesser tubercle of the humerus; medial lip of the intertubercular groove
Action: adducts the arm, medially rotates the arm, assists in arm extension
Innervation: lower Sub

Pectoralis Major

Origin: medial half of the clavicle, manubrium and body of sternum and costal cartilages of ribs 2-6
Insertion: crest of greater tubercle of humerus; lateral lip of the intertubercular groove of the humerus
Action: flexes and adducts the arm, medially rot

Pectoralis Minor

Origin: ribs 3-5
Insertion: corocoid process of the scapula
Action: draws the scapula forward, medialward, and downward
Innervation: medial pectoral nerve

Subclavius

Origin: first rib and its cartilage
Insertion: interior surface of the clavicle
Action: draws the clavicle forward and downward
Innervation: nerve to subclavius

Serratus Anterior

Origin: ribs 1-8 or 9
Insertion: medial border of the scapula on its costal (deep surface)
Action: draws the scapula forward; inferior fibers rotate the scapula superiorly
Innervation: long thoracic nerve

Order of muscle insertions- shoulder extension insertion order in intertubercular / bicipital groove

Lateral to Medial
Pectoralis major
Latissimus dorsi
Teres Major

Rotator Cuff Muscle insertion order

Anterior to posterior:
Subscapularis
Supraspinatus
Infraspinatus
Teres minor

Vertebral a.

Branch of subclavian; supplies the spinal cord and brain

Subclavian a.

Receives blood from aorta; runs from aorta to lateral aspect of the 1st rib; know one branch = VERTEBRAL atery

Axillary a.

Runs from lateral 1st rub to the inferior border of the teres major tendon; gives off posterior and anterior circumflex humeral arteries

Posterior Circumflex humeral a.

Branch of the axillary artery

Anterior circumflex humeral a.

Branch of the axillary artery

Brachial a.

Runs down the arm to the antecubital space; gives off deep artery of the arm

Rotator cuff pathology

-Repetitive movements (especially overhead) are the cause of many injuries to rotator cuff
-Degeneration- with age tendon properties change and the risk of tear increases
-Trauma- fall on outstretched hand FOOSH
-Supraspinatus most injured
-Partial versus

Boundaries of the Axilla

Medial wall: ribs and serratus anterior
Lateral wall: humerus
Anterior wall: Pec major/minor
Posterior wall: scapula, lats, and teres major

Contents of the axilla

Brachial plexus
Axillary artery and branches
Axillary vein
Lymph nodes

Brachial plexus

Purpose: Motor and sensory innervation to the upper limb
Hierarchy:
Roots
Trunks
Divisions
Cords
Branches

Brachial Plexus Roots

Landmark = anterior and middle scalenes
Ventral primary rami C5-T1, but can include C4 or T2
Subclavian artery
2 named branches =
Dorsal scapular nerve - C5
(To rhomboids and lavatory)
Long thoracic nerve - C5, C6, C7 (to serratus anterior)

Brachial Plexus Trunks

Landmarks = proximal/superior to clavicle, superior to 1st rib
-Superior/Upper Trunk- C5, C6
-Middle Trunk- C7
-Lower Trunk- C8, T1
2 Named Branches =
Nerve to subclavius C5, C6
Suprascapular nerve C5, C6 (to Supraspinatus and infraspinatus)

Brachial Plexus Divisions

Landmarks = deep to clavicle / apex of axilla
Anterior division
Posterior division

Brachial Plexus Cords

-Formed from divisions
-Landmark = deep to pec minor

Lateral cord

Lateral pectoral n C5 C6 C7 (pectoral is major)

Posterior cord

Upper Subscapular n. C5, C6 (subscapularis)
Thoracodorsal n. C6, C7, C8 (lats)
Lower Subscapular n. C5, C6 (subscapularis and teres major)

Medial cord

Medial pectoral n. C8, T1 (pec major and minor)
Medial Brachial Cutaneous n. T1 (sensory to medial arm)
Medial antebrachial cutaneous n. C8, T1 (sensory to forearm)

Terminal Branches

-Musculocutaneous n. C5 C6 C7 (biceps, brachialis, coracobrachialis)
-Axillary n. C5 C6 (deltoids and teres minor)
-Radial n. C5 C6 C7 C8 T1 (triceps, posterior forearm/hand motor and sensory)
-Median n. C5 C6 C7 C8 T1 (anteriorlateral forearm/hand motor

Lesions of the Brachial plexus

-Signs/Symptoms = pain, sensory loss, motor loss
-often originates in the c/s from stenosis or disc herniation (not the BP)
-can also reflect CNS lesions

Causes of BP lesions

Trauma
Compression/traction
Trauma during surgery
Tumors
Childbirth

Lesions of BP: TRAUMA

Motor vehicle accident
BP injuries often missed due to vascular injuries being paramount
Can arise later from post traumatic/surgical edema
Clavicle and humerus fracture
Distal fractures affect terminal branches

Lesions of BP - COMPRESSION/TRACTION

Can be due to major or minor trauma
-makela et al backpack study - Axillary, long thoracic, Suprascapular
-Saturday night palsy - radial n.
-Honeymoon palsy - radial or musculocutaneous n.

Lesions of BP - TRAUMA DURING SURGERY

Shoulder surgery
Clavicle fx/surgery
Breast surgery - elective / oncological
Positioning and direct insult to a nerve
Lymph node removal
Radiation
Long thoracic or thoracodorsal n.

Lesions of the BP - CHILDBIRTH

Erb's palsy-upper trunk loss of abduction, external rotation, supination, elbow flexion, sensation in lateral shoulder region
Klumpke's Palsy - lower trunk - claw Hand deformity

Myotomes

C5 elbow flexors (biceps, brachialis)
C6 wrist extensors (extensor carpi radial is longus and brevis)
C7 elbow extensors (triceps brachii)
C8 finger flexors (distal phalanx of middle finger (flexor digitorum profundus)
T1 finger abductors - 5th finger abd