Upper Limb Flashcards
What is the medial wall of the axilla?
The thoracic wall
What is the anterior wall of the axilla?
Pectoralis major and Pectoralis minor
What is the posterior wall of the axilla?
The anterior surface of the scapula and latissimus Doris and teres major (inferiorly)
What forms the base of the axilla?
Subcutaneous tissue and axillary fascia
What forms the posterior axillary fold of the axilla?
Latissimus Doris and Teres major
What forms the anterior axillary fold of the axilla?
Pec major
What forms the apex of the axilla?
The cervicoaxillary canal
What are the contents of the axilla?
Axillary artery Axillary vein Cords of the brachial plexus Biceps brachial and coracobrachialis tendons Axillary lymph nodes
What are the 3 parts of the axillary artery?
1st part = medial to pec minor
2nd part = posterior to pec minor
3rd part = lateral to pec minor
What is axillary clearance and what damage can it cause?
The removal of axillary lymph nodes, used as a treatment in breast cancer.
Possible damage to the long thoracic nerve
What is the medial border of the cubital fossa?
Pronator teres
What is the lateral border of the cubital fossa?
Brachioradialis
What is the superior border of the cubital fossa?
An imaginary line between the two epicondyles
What forms the floor of the cubital fossa?
The brachialis muscle and supinator muscle
What forms the roof of the cubital fossa?
Brachial and antebrachial fascia, subcutaneous tissue and skin
What are the contents of the cubital fossa (lateral to medial)?
Radial nerve
Biceps brachii tendon
Brachial artery
Median nerve
Where can the brachial pulse be felt?
By palpating it immediately medial to the biceps brachii tendon in the cubital fossa?
What is thoracic outlet syndrome?
Compression of the vessels and nerves between the bones at the apex of the axilla.
Occurs in trauma (eg fractured clavicle) and in repetition.
Presents with pain, tingling, muscle weakness, discolouration
Why is the glenohumeral joint the most mobile but least stable joint?
The glenoid cavity is very shallow
The articulating surfaces have disproportionate surface area (humeral head much larger)
It allows multiplanar movements
It has a lax capsule
What ligaments stabilise the shoulder joint?
Intra-capsular: 3 Glenohumeral ligaments (superior, middle and inferior)
Extra-capsular: coracoacromial, coracohumeral, transverse humeral (holds tendon of long head of biceps in place) coracoclavicular
What is the Coracoacromial Arch?
The arch made by the coracoid process, the coracoacromial ligament and the acromion.
Stabilises the shoulder joint superiorly and prevents upper displacement of the humerus.
What stabilises the shoulder joint?
Tendons of the rotator cuff muscles Coracoacromial Arch Capsule Ligaments Glenoid labrum The splinting effect of the long head of the biceps and triceps
Name 2 bursa in the shoulder joint and explain their location and why they are important
Subscapular bursa between the subscapularis tendon and the scapular. Reduces wear and tear on the tendon during movement at the shoulder joint.
Subacromial bursa inferior to the deltoid and acromion, superior to the supraspinatus tendon and joint capsule. Facilitates movement of the supraspinatus tendon under the CAA & deltoid.
What is the blood supply to the shoulder joint?
Anterior and posterior circumflex humeral arteries and the suprascapular artery
What structures are vulnerable to injury during an intramuscular injection in the deltoid?
The axillary nerve
The posterior circumflex artery
How and in which direction does dislocation of the shoulder joint usually occur? What structure could it damage?
Usually caused by trauma on an abducted arm.
Occurs in an inferior direction, humeral head locates anteriorly (below the coracoid process) due to the pull of powerful abductors.
Capsule and rotator cuff muscles may tear.
Possible axillary nerve damage
How is axillary nerve damage indicated?
Paralysis of the deltoid - loss of abduction over 15 degrees
Loss of sensation in the regimental badge area.
What is the lateral wall of the axilla?
The intertubercular sinus of the humerus
What is painful arc syndrome?
The supraspinatus tendon rubbing under the CAA, causes irritation and inflammation of the tendon and subacromial bursa (bursitis). Causes pain during 50-130 degrees of abduction due to impingement of tendon & bursa between acromion and head of humerus.
Caused by repetitive overuse, age, avascularity of the tendon.
Why does the shoulder dislocate inferiorly?
It it the least supported. No tendons etc.
Supported superiorly by the CAA
What type of joint is the acromioclavicular joint?
Plane joint
What ligaments strengthen the acromioclavicular joint?
Acromioclavicular ligament Coracoclavicular ligament (conoid and trapezoid parts)
How may damage to the musculocutaneous nerve occur and how is it detected?
Can occur because of compression due to muscle hypertrophy/entrapment between the biceps aponeurosis and brachialis fascia.
Causes weakness of flexion at the elbow and shoulder, and of supination of the forearm
How may damage to the radial nerve occur and how is it detected?
Can during a mid-shaft fracture of the humerus, sleeping with arm in awkward position, pressure from leaning arm over the back of a chair, using crutches.
Causes loss of extension of the wrist and fingers “wrist drop”, weakness of supination, weakness in hand grip
How can damage to the axillary nerve occur?
Fracture at surgical neck of humerus
Dislocation of shoulder
Trauma
Over-aggressive stretching
Where are likely sites of fracture of the humerus?
Mis-shaft
Fracture of the greater tubercles
Surgical neck
Anatomical neck
What is the anatomical snuff box?
The triangular deepening on the radial, dorsal aspect of the hand at the level of the carpal bones.
What is the posterior (medial) border of the anatomical snuff box?
The tendon of extensor pollicis longus
What is the anterior (lateral) border of the anatomical snuff box?
Tendons of extensor pollicis brevis and abductor pollicis longus
What is the proximal border of the anatomical snuff box?
The styloid process of the radius
What forms the floor of the anatomical snuff box?
The scaphoid
What are the contents of the anatomical snuff box?
The radial artery, radial nerve, cephalic vein
What muscles of the forearm are innervated by the median nerve?
Innervates all the anterior muscles apart from flexor carpi ulnaris and the medial half of flexor digitorium profundus
What muscles of the forearm are innervated by the ulnar nerve?
Flexor carpi ulnaris and the medial half of flexor digitorium profundus
What muscles of the forearm are innervated by the radial nerve?
All muscles of the posterior forearm
What ligaments strengthen the elbow joint?
Radial collateral ligament
Ulnar collateral ligament (anterior = strongest & cord-like, posterior=weakest & fanlike, oblique deepens the socket for the trochlea)
Name 2 bursa in the elbow and describe their location
Subcutaneous olecranon bursa, located in the subcutaneous connective tissue over the olecranon, just deep to the skin.
Subtendinous olecranon bursa, between the olecranon and triceps tendon, proximal to its attachment to the olecranon.
What is the blood supply to the elbow joint?
Supplied by an arterial anastomoses (network of vessels formed by collateral arteries and recurrent branches of the ulnar, radial and interosseous arteries)
What is the annular ligament?
A ligament at the proximal radioulnar joint attached to the ulna anteriorly and posteriorly.
Supports the head of the radius and allows it to pivot.
What is pulled elbow?
When the head of the radius subluxates from the annular ligament.
Common in children as the ligaments are not fully developed so are weaker and radial head is still rounded and cartilaginous, meaning it can slip out of annular ligament when pulled.
What articulates at the proximal radioulnar joint?
The head of the radius articulates with the radial notch if the ulna
What articulates at the distal radioulnar joint?
The rounded head of the ulna articulates with the ulnar notch on the medial side of the radius
What movements do the radioulnar joint allow?
Supination and pronation
What ligaments stabilise the wrist (radiocarpal) joint?
Palmar radiocarpal ligaments from the radius to the carpal bones ensure that the hand follows the radius in supination.
Dorsal radiocarpal ligaments from the radius to the carpal bones on the posterior side ensure the hand follows the radius in pronation.
Ulnar collateral ligament from the ulnar styloid process to the triquetrium
Radial collateral ligament from the radial styloid process to the scaphoid.
What is a colles fracture?
A fracture of the distal radius resulting in a fall on an outstretched hand.
Distal fragment displaces posteriorly.
How can a scaphoid fracture occur and what can it result in?
Occurs in a fall on the palm when the hand is abducted.
Results in tenderness over the anatomical snuffbox.
Avascular necrosis of the proximal part may occur because the blood supply to the scaphoid is distal to proximal
What is lateral epicondylitis (tennis elbow)?
Inflammation of the tendons joining the forearm muscles to the lateral epicondyle.
Causes elbow pain, tenderness over the lateral epicondyle, pain in wrist extension and gripping of fingers.
Caused by overuse of tendons/ failed healing of tendons/ direct blow to the epicondyle.
What is a medial epicondyle fracture caused by?
A fall on an outstretched hand with the elbow in full extension.
Typically seen in children and adolescents
Describe the sensory nervous supply in the hand
Median nerve supplies lateral 3.5 digits on palm, tips of dorsal side and proximal lateral palm.
Ulnar nerve supplies the medial 1.5 digits on palmar and dorsal sides and the proximal medial hand.
Radial nerve supplies the anatomical snuffbox and the dorsal lateral hand.
Describe the motor supply to the hand
Median nerve supplies the lateral 2 lumbricals, opponens pollicis, abductor pollicis brevis and flexor pollicis brevis (MEAT LOAF).
Ulnar nerve supplies adductor pollicis, hypothenar eminence, medial 2 lumbricals and the dorsal and palmar interosseous
What structures are in the carpal tunnel?
The 4 tendons of flexor digitorium superficialis
The 4 tendons of flexor digitorium profundus
The tendon of flexor pollicis longus
The Median nerve
What structures lie in Guyons Canal?
Ulnar nerve
Ulnar artery
Palmar is longus tendon
What tendon lies in the flexor retinaculum?
Flexor Capri radialis tendon
What is carpal tunnel syndrome?
Compression of the median nerve and inflammation of the tendons in the carpal tunnel.
Causes numbness and tingling which can radiate distally or proximally.
Positive Phalens sign ie. Full flexion of the wrist for 60 seconds causes pain.
What can cause carpal tunnel syndrome?
= MEDIAN TRAP: Myxoedema (hypothyroidism) Edema (oedema) Diabetes incipidus Idiopathic Acromegaly Neoplasm Trauma Rheumatoid arthritis Amyloidosis Pregnancy
What is a boxers fracture?
A fracture of the 4th and/or 5th metacarpals.
Caused by punching an object with a closed fist.
Causes pain and swelling at the base of the finger
What can cause upper brachial plexus injury?
Shoulder dystocia in neonates.
Clavicular fracture
Trauma
What nerves and muscles are affected by an upper brachial plexus injury?
Suprascapular, musculocutaneous, axillary
Deltoid, biceps brachial, brachialis, coracobrachialis, supraspinatus, infraspinatus
How does an upper brachial plexus injury present clinically?
With Waiters Tip: arm is adducted, medially rotated, forearm is pronated, hand and wrist is flexed.
Cannot abduct arm, rotate laterally or flex elbow
What is Erbs Palsy?
Paralysis of the arm due to an upper brachial plexus injury.
Usually caused by shoulder dystocia in a difficult birth
What can cause injury to the lower brachial plexus?
Shoulder dystocia
Clavicular fracture
Trauma (traction on an abducted arm)
What nerves and muscles are affected by a lower brachial plexus injury?
Median nerve, ulnar nerve
Flexors in the forearm (flexor carpi ulnaris and flexor digitorium profundus in particular), thenar eminence, hypothenar eminence, interosseous muscles of hand
How does injury to the lower brachial plexus present clinically?
With Claw hand: forearm in supinate do, wrist and fingers are flexed.
Harners syndrome may be present (constriction of pupils and drooping eyelids)
What is Klumpkes Palsy?
Paralysis of muscles of the forearm and hand due to a lower brachial plexus injury. Common cause is shoulder dystocia
What can cause injury to the ulnar nerve at the wrist?
Aneurysm of the ulnar artery
Thrombosis
Synovial inflammation
Repeated trauma
What muscles does injury to the ulnar nerve at the wrist affect?
Adductor pollicis
Hypothenar muscles
Interosseous muscles
Medial 2 lumbricals
How does injury to the median nerve at the wrist present clinically?
Ulnar Claw: hyperextension at the MCP joints and flexion at both IP joints in the 4th and 5th digits.
Positive Phalens test and Tinels sign
What can cause injury to the ulnar nerve at the elbow?
Dislocation or fracture of the elbow
Medial epicondylitis
Cubital tunnel syndrome
What muscles are affected by injury to the ulnar nerve at the elbow?
Medial half of flexor digitorium profundus Flexor carpi ulnaris Medial 2 lumbricals Adductor pollicis Hypothenar muscles Interosseous muscles
How does injury to the ulnar nerve at the elbow present clinically?
Ulnar claw: hyperextension of the MCP joints and flexion at the proximal (but NOT distal) IP joints of the 4th and 5th digit
What is the ulnar paradox?
If lesion of the ulnar nerve is more proximal then the claw-like appearance is weakened because of denervation of the FDP which flexes the distal interphalangeal joints.
Therefore a more debilitating injury produces a less pronounced deformity.
What can cause median nerve injury at the wrist?
Carpal tunnel syndrome (causes = median trap)
Laceration of the wrist
What muscles are affected by median nerve injury at the wrist?
Thenar muscles (opponens pollicis, abductor pollicis brevis, flexor pollicis brevis) Lateral 2 lumbricals
How does injury to the median nerve at the wrist present clinically?
Hand of Benediction: patient cannot form a fist when asked as the 2nd and 3rd digits cannot flex
Ape hand: hyperextension of index finger, adducted thumb, cannot oppose thumb
What can cause median nerve injury at the elbow?
Intercondylar fracture of the humerus
Pronator Teres syndrome (entrapment between the 2 heads of pronator Teres)
What muscles are affected by injury to the median nerve at the elbow?
Flexor muscles in the anterior forearm
Lateral 2 lumbricals
Thenar muscles
How does injury to the median nerve at the elbow present clinically?
Weakened pronation
Hand of benediction: patient is unable to form fist, they cannot flex 2nd and 3rd digits (requires lateral half of FDP and lumbricals)
Ape hand: hyperextension of index finger, unable to oppose thumb
