Upper Limb 2 - MEDIUM

Cubital Fossa

• Depression on the anterior part of the elbow.

Borders

• Superior: Imaginary line connecting the epicondyles.
• Medial: Pronator teres muscle.
• Lateral: Brachioradialis muscle.
• Floor: Brachialis and supinator muscles.
• Roof: Deep fascia and bicipital aponeurosis.

Contents

• Brachial artery and commencement of its terminal branches, which are the ulnar and radial arteries.
• Deep veins following the arteries.
• Tendon of biceps brachii muscle.
• Median nerve.
• Radial nerve divides into its superficial and deep branches.

Radial Nerve Injuries

• May occur as the nerve passes along the radial groove of the humerus following fractures.
• Can result from prolonged pressure on the back of the arm, such as on an operating table.
• Branches to the triceps are spared, allowing forearm extension.
• Paralysis of long extensors leads to wrist drop, where the wrist and fingers cannot extend.
• There is a loss of sensation over a small area on the dorsal surface of the hand.
• Interphalyngeal joints can be weakly extended due to intact lumbricals and interossei muscles.
• Injuries superior to the origin of the branches to the triceps brachii result in triceps paralysis.
• Inability to extend the forearm.
• Sensory loss at the posterior parts of the arm and forearm.

Median Nerve Injuries

• Common at the forearm and wrist (most common at the carpal tunnel).
• Carpal tunnel is a passageway between the flexor retinaculum and carpal bones.
• The median nerve travels with long flexor tendons through the carpal tunnel to the hand.
• Long flexor tendons are enclosed by synovial sheaths.
• Compression of the median nerve in the carpal tunnel.
• Results from a lesion reducing the size of the carpal tunnel.
• Inflammation of the synovial sheaths, infection, or anterior dislocation of carpal bones can compress the median nerve.
• Excessive finger exercise may also cause swelling, may cause swelling of their tendons and synovial sheaths around them.
• Compression causes paresthesia (tingling), hypoesthesia (diminished sensation), or anesthesia (loss of sensation) in the lateral 3.5 digits.
• Sensation of the central palm is spared because the palmar branch passes superficial to the flexor retinaculum.
• Thenar muscles are affected, leading to atrophy and difficulty opposing the thumb, resulting in wasting of the thenar eminence.
• The thumb remains adducted due to paralysis of the abductor pollicis brevis.
• Paralysis of the 1st and 2nd lumbricals causes hyperextension of the 2nd and 3rd digits at the metacarpophalangeal joint and flexion at the interphalangeal joint and is called ape hand.

Clinical Notes on Flexion in Median Nerve Injuries

• Flexion at the interphalangeal and metacarpophalangeal joints remains possible due to intact flexor digitorum superficialis and profundus muscles.
• Injury at the elbow, the median nerve is vulnerable due to its superficial position.
• Flexion of the interphalangeal and metacarpophalangeal joints will be impossible.
• Sensory loss involves the palm.
• Note on the medial part of the flexor digitorum profundus is intact.
• Observe thenar atrophy, inability to oppose the thumb, and thumb adduction.

Ulnar Nerve Injuries

• ~30% of all upper limb nerve lesions affect the ulnar nerve.
• The most common injury site is where the nerve passes posterior to the medial epicondyle of humerus.
• Injury at the wrist leads to anesthesia in the medial part of the hand and medial 1.5 digits.
• Paralysis is caused by of 3rd and 4th lumbricals
• The 4th and 5th digits remain in hyperextended position at the metacarpophalyngeal joint, and in flexed position at the interphalyngeal joint
• The thumb remains abducted position due to the paralysis of adductor pollicis, and is called claw hand

Ulnar Nerve Injury at the Elbow

• Results in weakness of hand adduction.
• Wrist flexion draws the hand to the lateral side due to the flexor carpi radialis, as the flexor carpi ulnaris is normally balanced.

Biceps and Elbow Tendinitis

• Common in tennis players due to repetitive microtrauma to the tendons, also know as Lateral epicondylitis

Synovial Cyst of the Wrist

• Presents as a small swelling, often on the dorsum of the wrist.
• Reason unknown
• Painful in some cases.

Dupuytren Contracture of Palmar Fascia

• Disease of the palmar fascia.
• There is progressive shortening, thickening, and fibrosis of the palmar fascia and aponeurosis.
• Cause is unknown.
• Progressive shortening of the palmar aponeurosis, mostly on the medial side pulls the 4th and 5th digits into partial flexion at the metacarpophalyngeal and proximal interphalyngeal joints.
• Nodular thickenings are palpable and raised ridges at the palmar skin is visible

Arteries of the Upper Limb:

• The axillary artery begins at the lateral border of the first rib as a continuation of the subclavian artery.
• It terminates at the inferior border of the teres major muscle, continuing as the brachial artery.
• Divided into three parts based on its relation to the pectoralis minor muscle.

Parts and Branches of the Axillary Artery:

• 1st part: Superior thoracic artery.
• 2nd part: Thoracoacromial and lateral thoracic arteries.
• 3rd part: Subscapular, anterior, and posterior circumflex humeral arteries.
  • Subscapular artery branches include the circumflex scapular and thoracodorsal arteries.

Clinical Notes on the Axillary Artery

• To compress the axillary artery may be necessary during profuse bleeding in the upper limb.
• Can easily compress against the humerus.

Brachial Artery:

• Begins at the inferior border of the teres major muscle.
• Pulsations can be palpated along the medial lower part of the arm.
• Terminates at the cubital fossa, opposite the neck of the radius.
  • It gives its two terminal branches, the Ulnar and the Radial.

Branches:

• Deep artery of the arm (deep brachial artery): Radial collateral and middle collateral arteries.
• Superior ulnar collateral artery.
• Inferior ulnar collateral artery.
• Ulnar artery, terminal branch.
• Radial artery, terminal branch.
• Interruption of blood flow during profuse bleeding may require the artery to compress
• Can be easily compressed against the humerus on its medial aspect.
  • Distal compression means the deep artery of the arm, the ulnar and radial arteries still receive blood through the anastomoses around the elbow.
• However, the collateral circulation through anastomoses provide only temporary protection.
• Prolonged and complete occlusion results in ischemia, especially in the flexor part of the arm; muscles and nerves can tolerate ischemia for up to 6 hours.
• Continuing ischemia leads to necrosis and replacement with fibrotic tissue.
• This affects the flexor muscles and causes a flexion deformity.
• Resulting condition known as ischemic compartment syndrome, referred to as Volkmann ischemic contracture.
• A sfigmomanometer is used to measure the arterial blood pressure, usually from the right arm.

Ulnar Artery

• Pulsations are palpable lateral to the flexor carpi ulnaris tendon.
• Branches include:
• Anterior and posterior ulnar recurrent arteries.
• Common interosseous artery (giving rise to anterior, posterior, and recurrent interosseous arteries).
• Dorsal and palmar carpal branches.
• Deep palmar branch (anastomosing with the deep palmar arch of radial artery).
• Superficial palmar arch (terminal, anastomosing with the superficial palmar branch of the radial artery).

Radial Artery

• (common place for measuring the pulse rate).
• Pulsations can be palpated lateral to the tendon of flexor carpi radialis muscle.
• Branches including radial recurrent, dorsal carpal, palmar carpal, superficial palmar and deep palmar branches -*Superficial palmar branches anastomoses with the superficial palmar arch of the ulnar artery). -*Deep palmar arch is terminal and anastomoses with the deep palmar branch of the ulnar artery

Superficial Palmar Arch

• Continues along the ulnar artery and then branches along the radial artery
• Common palmar digital arteries are branches of this arch with palmar metacarpal arteries from the deep palmar arch
• Each artery listed then branches into a pair of smaller "proper palmar digital arteries"

Deep Palmar Arch

• Continues along the radial artery, completed by the deep palmar branch of the ulnar artery Palmar and Princeps pollicis arteries branch from this arch

Veins of the Upper Limb

• Classified as superficial and deep.
• Deep veins: Comitant veins that follow the path of the arteries, possessing the same name.
• Superficial veins: Basilic and cephalic veins, which collect superficial drainage.
  • Basilic vein continues on as the axillary vein.
  • Deep veins and the cephalic vein drains into the axillary.
  • Basilic vein continues on as the axillary vein.
    • Axillary vein drains into the subclavian.
  • The median cubital vein connects the basilic and cephalic veins.
    • Drainage highly variable
    • The median antebrachial cubital vein lies in the anterior portion of the forearm

Clinical note on veins

• Venipuncture at the cubital fossa is a common practice due to venous prominence and easy access.
  • Used for obtaining blood samples, blood transfusions, or intravenous injections.
  • Median cubital or basilic veins are commonly selected.