Arm and Cubital Fossa

1) Bicipital Myotatic Reflexa. Confirm integrity of Musculocutaneus nerve (C5 and C6 spinal cord segments)

i. Relaxed limb passively pronated and extended at elbowii. Examiner place thumb over biceps tendon

iii. Reflex hammer briefly tapped at base of nail bediv. involuntary contraction of Biceps, jerk-like flexion of elbow

b. Excessive, diminished, prolonged(hung) response =>i. CNS disease

ii. PNS diseaseiii. Metabolic disorder eg Thyroid Disease

2) Venipuncture in Cubital Fossaa. Medial cubital vein (merged cephalic and basilica vein) used because of

its prominence and accessibilityb. Uses:

i. Sampling ii. Blood transfusion

iii. IV injectionsiv. Cardiac Catheters- Coronary Angiography

c. Procedure:i. Tourniquet placed ard midarm (to distend veins in cubital fossa)

ii. Vein puncturediii. Tourniquet removed (prevent excessive bleeding when needle

removed)3) Variation of veins in Cubital Fossa

a. Varies in 20% of pplb. Median antebrachial vein divides into median basilic vein and medial cephalic vein (M formation)

(these veins join back to their main veins respectively)c. Ideal for drawing bldd. NOT ideal for injecting drugs (may pierce brachial artery)

i. Brachial artery separated from medial basilic/cubital vein by bicipital aponeurosise. In obese ppl- fatty tissue overlies vein

4) Interruption of bld flow in brachial artery- Hemostasis (stopping bleeding through manual/surgical control)a. Best place to compress brachial artery to control haemorrhage:

i. Middle of arm medial to humerus1. Arteriole anastomoses ard elbow ensures ulnar and radial arteries receive sufficient

bld flow ( functionally and surgically impt collateral circulation) Same as scapulab. Ischemic (restriction of blood supply) compartment syndrome/ volkman/ischemic contracture

i. Sudden occlusion/laceration of brachial artery1. Surgical emergency: Ischemia of elbowparalysis of muscles

a. muscles and nerves tolerate up to 6 hours of ischaemia before fibrous scar replaces necrotic tissue

2. Loss of hand powera. Flexion of fingers and wrist loss of hand power due to irreversible

necrosis of forearm flexor muscles

b.5) Biceps Tendinitis

a. Cause: (common in sports)i. Repetitive microtrauma

1. Throwing eg baseball, cricket2. Tennis/racquet sports

ii. Irritation of tendon1. Tight, narrow intertubercular sulcus2. Rough intertubercular sulcus

b. Result: i. Tendon inflamed due to wear and tear of constant movement

ii. Tendernessiii. Crepitus (cracking sound)

c. Anatomy basis:i. Tendon of long head of biceps enclose by synovial sheath can move back and forth in the

intertubercular sulcus/bicipital groove of humerusii. Wear and tearshoulder pain

6) Dislocation of Tendon Long head of Biceps Brachiia. Partial or complete dislocationb. In young:

i. Traumatic separation of proximal epiphysis of humerus (see slide on humerus fracture)c. Older ppl:

i. Hx- Biceps tendinitisd. Characteristics:

i. Painii. Sensation of popping or catching during rotation of arm

7) Rupture of Tendon of Long Head of Biceps Brachiia. Cause:

i. Wear and tear of inflamed tendon (moves back and forth in intertubercular sulcus of humerus) => usually occurs in ppl >35 years old

ii. Forceful flexion of arm against excessive resistance eg lifting weightsiii. Tendon weakened by prolonged tendonitisiv. Repeated overhead movements eg swimmers and baseball pitchers (weakened tendon in

intertubercular sulcus torn)b. Result:

i. Popeye deformity – detached muscle belly forms ball at distal part of anterior arm1. Tendon torn from attachment to supraglenoid tubercle of scapular @ Origin2. Dramatic rupture3. Associated w snap/pop

8) Fracture of Humeral Shafta. Midhumeral Fracture

i. Radial nerve in radial groove injuredii. X paralyse triceps (nerves originate higher than 2 heads of biceps)

b. Supra- epicondylar fracture (distal humerus fracture)i. Shortened limb

1. Brachialis and triceps pull distal fragment over proximal one (distal bone fragment may be displace anteriorly or posteriorly)

c. Nerves or branches of brachial vessels related to humerus may be injured by bone fragments

9) Injury to Musculocutaneous Nervea. Uncommon (musculocutaneous nerve is in protected area)b. Causes:

i. Knife stabc. Result:

i. Paralysis of :1. Coracobrachialis2. Brachialis3. Biceps

ii. Weakened flexion of GH jointiii. Weakened flexion and supination of forearm

1. WEAK flexion and supination possible by brachioradialis and supinator-supplied by radial nerve

iv. Loss of sensation @ lateral surf of forearm 1. supplied by lateral antebrachial cutaneous nerve, a continuation of

musculocutaneous nerve10) Injury to Radial Nerve in Arm –Wrist Drop- Wrist partially flexed (due to unopposed tonus of flexor muscles

and gravity )(inability to extend wrist and fingers at metacarpalphalangeal joints)a. Injury superior to origin of branches to triceps brachii

i. Paralysis of:1. Triceps2. Brachioradialis3. Supinator4. Extensor muscles of wrist and fingers

ii. Loss of sensation in areas supplied by radial nerveb. Injury in radial groove

i. Triceps weakened (not completely paralysed)1. Only medial head of triceps affected

ii. Muscles in posterior component of forearm (supplied by more distal branches of nerve) paralysed