Upper Limb Anatomical Areas Flashcards
What are the borders of the axilla region?
Apex: lateral border of the first rib, superior border of scapula, and the posterior border of the clavicle.
Lateral wall: intertubecular groove of the humerus.
Medial wall: serratus anterior and the thoracic wall.
Anterior wall: contains the pectoralis major and the underlying pectoralis minor and the subclavius muscles.
Posterior wall: subscapularis, teres minor and latissimus dorsi.
How does the size of the axilla vary with arm movement?
Decreases in size most markedly with arm fully abducted.
When are the contents of the axilla most at risk?
When the arm is fully abducted.
What are the three main routes by which structures leave the axilla?
Into the upper limb - inferiorly and laterally, majority of contents.
Via the quadrangular space - gap in the posterior wall of the axilla
Clavipectoral triangle - opening in the anterior wall of the axilla.
What structures pass out of the axilla via the quadrangular space?
Axillary nerve, posterior circumflex humeral artery.
What is the clavipectoral triangle bounded by?
The pectoralis major, deltoid, and clavicle.
Which structures enter and leave the clavipectoral triangle?
Enters - cephalic vein.
Leaves - medial and lateral pectoral nerves.
What are the key contents of the axilla region?
Axillary artery, axillary vein, brachial plexus, biceps brachii, coracobrachialis and axillary lymph nodes.
What are the three parts of the axillary artery?
One medial to the pectoralis major, one posterior to pectoralis major and one lateral to the pectoralis major.
What are the key two tributaries of the axillary vein?
Cephalic and basilic.
Where do the biceps brachia and coracobracialis attach?
To the coracoid process of the scapula.
What is thoracic outlet syndrome?
Where the vessels and nerves in the apex of the axilla get compressed between bones.
What are some causes of thoracic outlet syndrome?
Trauma (e..g fractures clavicle), repetitive lifting of arms.
What is the clinical presentation of thoracic outlet syndrome?
Pain in the affected limb, tingling, muscle weakness and discolouration.
What is axillary clearance and when is it used?
It is removal of the axillary nodes used with patients with confirmed breast cancer to prevent spread through the lymphatics.
What could be damaged in axillary clearance? And what would this lead to?
Long thoracic nerve damage, leading to winged scapula.
Where is the cubital fossa located?
In the depression on the anterior surface of the elbow joint.
What are the border of the cubital fossa?
Lateral border: medial border of the brachioradialis muscle.
Medial border: lateral border of the pronator teres muscle.
Superior border: an imaginary line between epicondyles of the humerus.
What forms the floor of the cubital fossa?
Proximally the brachial, distally the supinator muscle.
What forms the roof of the cubital fossa?
The skin and fascia, reinforced by the bicipital aponeurosis.
What vein runs within the roof of the cubital fossa?
The median cubital vein.
What is the contents of the cubital fossa?
Radial nerve, biceps tendon, brachial artery, median nerve.
Where does the radial nerve divide into its deep and superficial branches?
As it passes underneath the brachioradialis muscle.
Where does the biceps tendon attach?
To the radial tuberosity, distal to the neck of the radius.
Where does the brachial artery bifurcate?
At the apex of the cubital fossa, into the radial and ulnar arteries.
Where does the median nerve leave the cubital fossa?
Between the two heads of the pronator teres.
Where can the brachial pulse be felt?
By palpating immediately medial to the biceps tendon in the cubital fossa.
Why is the cubital fossa a common site for venepuncture?
Because the median cubital vein is located superficially within the roof of the cubital fossa. It connects the basilica and cephalic veins and can be easily accessed.
How do supracondylar fractures occur?
By falling on a flexed elbow.
What type of fracture is a supracondylar fracture?
A transverse fracture, spanning the two epicondyles.
How can supracondylar fractures affect the structures in the cubital fossa?
Swelling or direct damage can disturb blood supply of forearm from brachial artery. Can lead to ischaemia and Volkmanns ischaemic contracture. Damage to median or radial nerves.
How does Volkmanns ischaemic contracture present?
Uncontrolled flexion of the hand. Flexor muscles become fibrotic and short.
What is the carpal tunnel?
A narrow passageway on the anterior portion of the wrist that is an entrance to the palm for tendons and the median nerve.
What are the layers of the carpal tunnel?
The deep carpal arch and a superficial flexor retinaculum.
What forms the carpal arch of the carpal tunnel?
Laterally formed by the scaphoid and trapezium tubercles. Medially formed by the hook of the hamate and the pisiform.
What forms the flexor retinculum of the carpal tunnel?
Thick connective tissue. Becomes carpal arch into carpal tunnel by bridging space between the medial and lateral parts of the arch. Originates on the lateral side and inserts on the medial side of the carpal arch.
What are the contents of the carpal tunnel?
9 tendons surrounded by synovial sheaths and the median nerve.
Flexor pollicus longus tendon, 4 tendons of the flexor digitorum profundus and 4 tendons of the flexor digitorum superficialis.
What is the pathway of the median nerve as it passes through the carpal tunnel?
It divides into two branched: recurrent branch and palmar digital nerves as it passes through the carpal tunnel. Palmar digital nerve gives sensory innervation to palmar skin and dorsal nail beds of lateral three and a half digits. Motor innervation to lateral two lumbricals. Recurrent branch supplies the theatre muscle group.
What is the cause of carpal tunnel syndrome?
Compression of the median nerve from thickened ligaments and tendon sheaths. Idiopathic aetiology though.
What can untreated carpal tunnel syndrome lead to?
Weakness and atrophy of the thinner muscles.
How does carpal tunnel syndrome present?
Numbness, tingling and pain in the distribution of the median nerve. Sometimes pain radiates to forearm. Pain worse in the morning and can wake the patient at night.
How can carpal tunnel syndrome be tested for?
Tapping the nerve in the carpal tunnel to elicit pain in media nerve distribution, Tinel’s sign.
Holding wrist in flexion for 60 seconds to elicit numbness or pain in median nerve distribution, Phalen’s manoeuvre.
How can carpal tunnel syndrome be treated?
Using a splint overnight holding the wrist in dorsiflexion. Corticosteroids injected into carpal tunnel if splint is ineffective. Surgical decompression of the carpal tunnel can be used in severe cases.
What is the anatomical snuffbox?
A triangular depression on the lateral aspect of the dorsum of the hand at the level of the carpal bones.
How can the anatomical snuffbox been shown more clearly
By abducting the thumb.
What are the borders of the anatomical snuffbox?
Ulnar border: tendon of the extensor pollicis longus.
Radial border: tendons of the abductor pollicis longus and exensor pollicis brevis.
Proximal border: styloid process of the radius.
Floor: carpal bones; scaphoid and trapezium.
Roof: skin.
What are the contents of the anatomical snuffbox?
Radial artery - crosses the floor of the anatomical snuffbox in an oblique manner. Runs deep to the extensor tendons.
A branch of the radial nerve - subcutaneously runs across roof of anatomical snuffbox.
Cephalic vein.
Where can the radial pulse be palpated in some individuals in the anatomical snuffbox region?
By placing two fingers on the proximal portion of the anatomical snuffbox.
How can the scaphoid be fractured?
By a blow to the wrist, like falling on an outstrecthed hand.
What is unique about the blood supply to the scaphoid?
It runs distal to proximal.
Why is a scaphoid fracture an emergency?
It can damage blood supply to the proximal part of the bone which could cause avascular necrosis and future arthritis for the patient.
