Axilla

1. Arterial anastomoses around Scapular- Collateral circulation a. Ligation of lacerated subclavian/axillary artery

i. Axillary artery ligated btwn 1st rib and subscapular arteryii. Vascular sternosis (artherosclerotic lesion reduce bld flow)

iii. (a & b) reverse direction of bld flow in subscapular arteryb. Surgical ligation of axillary artery btwn subscapular artery and profunda brachii

i. Bld supply cut frm arm (collateral circulation inadequate although potential collateral pathways/peri-articular anastomoses exist ard shoulder joint and elbow joint)

c. Occlusion (slow) => Sufficient time for collateral circulation to developi. Ischaemia (loss of bld supply) prevented

d. Occlusion (Sudden) => insuff time for adequate collateral circulation to developi. inadequate bld supply to arm, forearm, hand

2. Dissection of Axillary Lymph Nodesa. Used to stage breast cancer to determine appropriate treatmentb. Lymphedema (swelling due to accumulated lymph esp in subcutaneous tissue)c. Nerves at risk of injury:

i. Long thoracic nerve- supplies serratus anterior 1. nerve identified and maintained against thoracic wall during surgery2. Cutting of nerve Winged scapular

ii. Thoracodorsal Nerve- supplies Latissimus Dorsi 1. damage of nerve

a. Weakened medial rotationb. Weakened adduction

2. No deformity3. Nerve may have to be sacrificed if nodes around nerve are obviously malignant.

(Nodes resected to incr likelihood of complete removal of all malignant cells)d. Recall: Mastectomies may cause damage to thoracodorsal nerve

3. Enlargement of axillary lymph nodes- Lymphangitis (inflammation of lymphatic vessels, a. Cause: infection in ULb. Result:

i. Axillary nodes tender and inflamed (humeral nodes usually first to be involved) ii. Warm, tender red streaks in skin of limb

iii. Infectious in:1. Pectoral region 2. Breast3. Superior abdomen

iv. Enlargement of axillary nodesc. In metastatic Cancer of apical group

i. Nodes adhere to axillary vein need to excise tt part of axillary veinii. Enlargement of apical nodes obstruction of Cephalic vein superior to pec minor

4. Role of Axillary Vein in Subclavian Vein Puncture a. Clinical Significance:

i. Axillary Vein lies anteriorly and inferiorly to axillary artery and brachial plexusb. Procedure:

i. Subclavian Vein puncture= Catheter placed into subclavian veinii. Punctured (point of entry) is terminal part of axillary vein

c. Risk/ Complications:i. Pneumothorax (pierces pleura and lung when not done carefully)

5. Brachial Plexus blocka. Enables surgeons to conduct surgeries using local anaesthetic vs generalised anaestheticb. How it works:

i. Anaesthetic solution injected directly into/surrounding axillary sheath disrupt conduction of impulses of peripheral nerves anaesthesia of structures supplied by peripheral nerves (branches of cords of plexus)

ii. Sensation blocked in deep structures of ULiii. Sensation blocked in Skin distal to middle of armiv. Combined w occlusive tourniquet to retain anaesthetic agent

c. Methods of procedure/Approach:i. Interscalene

ii. Supraclaviculariii. Axillary

6. Variations in Brachial Plexus- Prefixed, postfixed brachial plexus (variations can occur in all areas/ forms but end roots usually the same for plexuses tt are functioning normally)

a. Prefixed Brachial Plexus (anterior rami of C4-C8)b. Postfixed Brachial Plexus (C6-T2)

i. Inferior trunk of plexus may be compressed by first rib7. Compression of Axillary Artery – axillary artery can be palpated in inferior lateral wall of axilla

a. 3rd part of axillary artery compressed against humerus to stop profusive bleeding (eg stabbed/ bullet wound)

b. If need to be compressed at more proximal site,1st part of axillary artery is compressedi. Compressed at origin (subclavian artery crosses 1st rib)

ii. Exert downward pressure in angle btwn clavicle and inferior attachment of sternocleidomastoid muscle

8. Aneurysm of Axillary Artery (enlargement of first part of axillary artery)a. Trunks of Brachial Plexus compressed (in all areas of skin supplied by the affected nerves)

i. Painii. Anesthesia

b. At Risk: (rapid and forceful arm movements)i. Baseball pitchers

ii. Football quaterbacks9. Injuries to axillary vein- Air emboli (air bubbles in bld –dangerous) or profuse bleeding

a. Axillary Vein large and exposedb. Overlaps axillary artery anteriorly when arm fully abducted

10. Brachial Plexus Injuries(****)a. Affect:

i. Movementsii. Cutaneous sensations

b. Causes:i. Disease

ii. Stretchingiii. Wounds in lateral cervical region (posterior triangle of neck)

c. Result:i. Paralysis

ii. Anesthesiad. Test

i. degree of damage:1. Complete paralysis:

a. No movement detectable

2. Incomplete paralysis:a. Movements weak vs normal side

ii. Degree of anesthesia- Pinprick of skine. Types of Brachial Plexus injury

i. Superior part of Brachial Plexus injured (C5 and C6) 1. Cause: excessive increase in angle btwn neck and shoulder

a. Person lands on shoulder in a way that widely separates neck and shoulder (think break-dancing)

b. Shoulder usually hits something and stops but head and trunk continue to move (car accidents as well, T-bone accidents)

i. Eg thrown off motorcycle/horse and lands on shoulderc. Excessive stretching of neck during delivery (in neonates)

2. Result: SUPERIOR roots of plexus avulsed (torn) frm spinal cord or superior Brachial Plexus stretched/ ruptured

a. Erb-Duchenne Palsy/“waiter’s tip position”- Limb hangs by the side in medial rotation (UL w adducted shoulder, medially rotated arm and extended elbow)

i. Paralysis of muscles of shoulder supplied by C5 and C6 1. Deltoid2. Biceps3. Brachialis

ii. Loss of sensation in lateral aspect of forearmb. Backpacker’s Palsy – similar signs of waiter’s tip

i. Caused by carrying heavy backpack for long period of timeii. Results in:

1. Motor sensory deficits in distribution of musculocutaneous and radial nerve

2. Muscle spasms and severe disability (in hikers) c. Acute Brachial Plexus Neuritis (Brachial Plexus Neuropathy- a neurologic

disorder of unknown cause)i. Onsets after

1. Upper respiratory infection (why you so lazy Ellen?!)2. Vaccination3. Non-specific trauma

ii. Characteristic: Sudden onset of severe pain1. Around shoulder2. Pain begins at night3. Muscle weakness/neurologic amyotrophy (muscle

atrophy) follows after painii. Compression of cords of brachial plexus- Cords compressed btwn coracoid process of

scapular and tendon of pectoralis minor tendon1. Hyperabduction Syndrome (compression of axillary artery and vein)

a. Ischaemia (compression – decreased blood flow) of ULb. Distension (enlargement) of superficial veins

2. Caused by: Prolonged hyper abduction of arm (hands raised above head) eg painting ceiling

3. Neurologic symptoms:a. Pain radiating down armb. Numbnessc. Paresthesia (tingling)

d. Erythema (redness of skin caused by capillary dilation)e. Weakness of hands

iii. Inferior brachial plexus injury/Klumpke Paralysis- Claw Hand (C8-T1) (less common)

1. Cause: UL suddenly pulled superiorlya. Eg person grabs something to break a fallb. Eg baby’s UL pulled excessively during injury

2. Result: a. Roots avulsed from spinal cord short

muscles of hand affectedb. Damage to ulnar/median nerve affects literally all fingers.