The Upper Limb Flashcards
Where is the radial nerve susceptible to injury?
- In the axilla
- In the radial groove
What might you seen if a patient has a radial nerve palsy?
Wrist drop due to unopposed flexion of the wrist as the extensor muscles are innervated by the radial nerve
How would a radial nerve injury occur in the axilla and what clinical picture would you see?
Could happen with dislocation of the shoulder of a proximal humeral fracture, or from excessive pressure
- Wrist drop
- Loss of sensation over all parts of the arm that the radial nerve supplies - lateral and posterior upper arm, posterior forearm and dorsal surface of lateral three digits of the hand
How would a radial nerve injury occur in the axilla and what clinical picture would you see?
Could happen with dislocation of the shoulder of a proximal humeral fracture, or from excessive pressure
- Wrist drop
- Loss of sensation over all parts of the arm that the radial nerve supplies - lateral and posterior upper arm, posterior forearm and dorsal surface of lateral three digits of the hand
How might damage to the radial nerve occur in the radial groove and what clinical picture would you see?
- Fracture of the shaft of the humerus
- Wrist drop
- Loss of sensation to the dorsal surface of the lateral three digits
How could the deep branch of the radial nerve be damaged and what would the clinical picture be?
- Fracture of the radial head or posterior dislocation of the radius at the elbow joint
- No wrist drop but loss of innervation to the posterior compartment of the forearm except supinator and extensor carpi radialis longus
How could the deep branch of the radial nerve be damaged and what would the clinical picture be?
- Fracture of the radial head or posterior dislocation of the radius at the elbow joint
- No wrist drop but loss of innervation to the posterior compartment of the forearm except supinator and extensor carpi radialis longus
- No sensory loss as it is a motor nerve
What could affect the superficial branch of the radial nerve and what would the clinical picture be?
- Laceration the forearm
- No loss of motor function as it is a sensory nerve
- Sensory loss to the dorsal surface of the lateral three digits
What is the sensory function of the axillary nerve?
The regimental badge area/lower deltoid
What is the motor function of the axillary nerve?
- Teres minor
- Deltoid
- Shoulder abductors
From which cord of the brachial plexus does the axillary nerve come from?
Posterior
What are the spinal roots of the axillary nerve?
C5 and C6
How might an injury to the axillary nerve occur and what would you see clinically?
- Trauma to the shoulder
- Paralysis of teres minor and deltoid, therefore unable to abduct the limb
- Loss of sensation over the regimental badge area
What motor function does the musculocutaneous nerve have?
-BBC
Biceps brachii, brachialis and coracobrachialis
What is the sensory function of the musculocutaneous nerve?
Innervation of the lateral surface of the forearm
How might you sustain an injury to the musculocutaneous nerve and what might be seen clinically?
- Stabbing the in the axilla as the nerve is very well protected
- Weakened flexion of the shoulder and the elbow and weakened supination
- Loss of sensation over the lateral side of the forearm
What is the motor function of the median nerve?
Flexor muscles of the anterior compartment of the forearm, thenar muscles and the lateral two lumbricals of the hand
What is the sensory function of the median nerve?
Lateral three and a half digits on the palmar surface of the hand
Which nerve is compressed in carpal tunnel syndrome
Median nerve
What can happen if carpal tunnel syndrome is untreated?
Atrophy and weakness of the thenar muscles
What two tests can you perform to test for carpal tunnel syndrome
- Tinels sign - Tapping the nerve in the carpal tunnel to elicit pain
- Phalens manoever - Holding the wrist in flexion for 60secs to elicit pain/numbness of the median nerve distribution
What might you see if the median nerve is damaged at the elbow and how might this have occurred?
-Supracondylar fracture of the humerus
-Paralysed flexors and pronators therefore the forearm is always supinated and flexion is weak. No flexion of the thumb
Characteristic sign is the Hand of Benediction
-Loss of sensation over the areas that the median nerve innervates
What might you see if the median nerve is damaged at the wrist and how might this occur?
-Lacerations proximal to the flexor retinaculum
-Paralysis of the thenar muscles and the lumbricals that the median nerve innervates
-Loss of sensation in the areas of the hand that the median nerve innervates
Hand of Benediction
What might you see if the median nerve is damaged at the wrist and how might this occur?
-Lacerations proximal to the flexor retinaculum
-Paralysis of the thenar muscles and the lumbricals that the median nerve innervates
-Loss of sensation in the areas of the hand that the median nerve innervates
Hand of Benediction
What is the motor function of the ulnar nerve?
- Muscles of the hand (except thenar muscles and the lateral two lumbricals)
- Flexor carpi ulnaris
- Medial half of flexor digitorum profundus
What is the sensory function of the ulnar nerve?
Anterior and posterior surface of the medial one and a half fingers
How might the ulnar nerve become damaged at the elbow and what would the clinical picture be?
- Fracture of the medial epicondyle
- Patient can’t grip paper placed between fingers as there is loss of motor function of the interossi. There is loss of motor function of flexor carpi ulnaris medial half of the flexor digitorum profundus
How might the ulnar nerve become damaged at the wrist and what would the clinical picture be?
- Laceration to the wrist
- The interossi muscles are paralysed and there is reduction in movement of the medial two fingers due to loss of innervation of the medial lumbricals
- Sensory loss over the palmar side of the medial one and a half fingers
- Gives characteristic ulnar claw
What are the articulating surfaces of the elbow?
- Trochlear notch of the ulnar and the trochlea of the humerus
- Head of the radius and the capitulum of the humerus
What type of joint is the elbow?
Synovial hinge
What movements can the elbow produce and what muscles do this?
- Flexion = Brachialis, Biceps brachii, brachioradialis
- Extension = Anconeus, triceps brachii
What movements can the elbow produce and what muscles do this?
- Flexion = Brachialis, Biceps brachii, brachioradialis
- Extension = Anconeus, triceps brachii
In which directions can the elbow joint be considered weak
-Anteriorly and posteriorly
Which ligaments act to strengthen the elbow joint?
-Medial and lateral collateral ligaments
Where do you find the radial collateral ligament?
Lateral side of the joint extending from the lateral epicondyle and blending with the anular ligament of the radius
Describe the anular ligament of the radius
Acts as a ligamentous collar, attach to the ulnar anterior and posterior to the radial notch
Describe the ulnar collateral ligament
Has 3 bands:
- Anterior = strongest
- Posterior
- Oblique = deepens the socket for the trochlea
Describe the ulnar collateral ligament
Has 3 bands:
-Anterior = strongest
-Posterior
-Oblique = deepens the socket for the trochlea
Originates on the medial epicondyle and attaches to the coronoid process and the olecranon of the ulna
Which are the important bursae of the elbow joint?
- Intratendinosus = formed within the tendon of the triceps brachia
- Subtendinosus = found between the olecranon and the tendon of the triceps
- Subcutaneous = Between olecranon and the overlying connective tissue
What is the course of the radial nerve at the elbow?
Anterior to the lateral epicondyle
What is the course of the ulnar nerve at the elbow?
Posterior to the medial epicondyle
What arteries form an anastomoses around the elbow?
- Collateral arteries
- Recurrent branches of the radial, the ulnar arteries and the interosseus arteries
Who are elbow dislocations more common in and why?
-Children as the anular ligament hasn’t adopted its funnel shape and the tendons in children tend to be more stretchy
Classic history is when traction is applied to the forearm (swinging between parents)
What is the difference between a subluxation and a dislocation?
Dislocation = complete loss of contact of the joint surfaces Subluxation = partial dislocation of a joint so the bone ends are misaligned but are still in contact
Why does tennis elbow (epicondylitis) occur?
Due to overuse. Inflammation of the common tendinous origin of the flexor or extensor muscles.
Medial epicondyle for golfers
Lateral epicondyle for tennis players
What might cause a Volkmanns ischaemic contracture?
Supraepicondylar fracture due to interference of the blood supply in the forearm via the brachial artery
What is the interosseous membrane?
Connective tissue sheet that joins the radius and the ulna together between the radioulnar joints
Name 3 functions of the interosseous membrane?
- Holds the radius and the ulna together during pronation and supination
- Acts as a site of attachment for muscles in the anterior and posterior compartments of the forearm
- Transfers forces from the radius to the ulna
What forms the proximal radioulnar joint?
Head of the radius and the radial notch of the ulna
What forms the distal radioulnar joint?
Ulnar notch of the radius and the head of the ulna
What type of joints are the radioulnar joints?
Pivot joints
What is the function of the articular disc of the distal radioulnar joint?
- Binds the radius and the ulna together during movement at the joint
- Separates the distal radioulnar joint from the wrist joint
In which way are the radius and the ulna not crossed over
Supination
What are the sacciform recesess
Extensions of the synovial membrane on the neck of the radius and at the distal radius and ulna
What is the wrist joint also known as?
The radiocarpal joint
What are the articulating surfaces?
- Distal - the proximal row of carpal bones (not pisiform)
- Proximal - distal end of the radius and the articular disc
Which ligaments maintain the stability of the wrist joint?
- Palmar radiocarpal - ensures the hand follows the radius is supination
- Dorsal radiocarpal - ensures the hand follows the forearm on pronation
- Ulnar collateral - from ulnar styloid process to triquetrum and pisiform - prevents excessive lateral joint displacement
- Radial collateral - radial styloid process to scaphoid and trapezium also prevents excessive lateral joint displacement
How might a fracture of scaphoid occur and what would you see clinically?
- Fall on outstretched hand
- Tenderness over the anatomical snuffbox
- Can be an emergency if the blood flow is disrupted –> avascular necrosis
What is a colles fracture?
Most common pathology of the wrist. Can occur due to an outstretched hand.
Gives a dinner fork deformity. Radius is fractured and the distal fragment is displaced posteriorly. Ulnar styloid process can also become damaged and is avulsed in the majority of cases.
What is the action of the pectoralis major muscle?
- Adducts and medially rotates the humerus
- Draws the scapula anteriorly and inferiorly
- Flexes the humerus
- Extends humerus from flexed position
What is the innervation of the pectoralis major muscle
- Medial and lateral pectoral nerves
What is the action of pectoralis minor muscle
- Depresses the tip of shoulder, protracts the scapula
- Draws scapula inferiorly and anteriorly against thoracic wall
What is the innervation of pectoralis minor
Medial pectoral nerve
What is the action of subclavius
- Depresses the shoulder
What is the innervation of subclavius
- Nerve to subclavius
What is the action of serratus anterior
- Protracts the scapula and hold its against thoracic wall
- Rotates the scapula
What is the innervation of serratus anterior
Long thoracic nerve
What are the boarders of the carpal tunnel?
- Deep: Carpal arch - scaphoid and trapezium tubercules, hook of hamate and pisiform
- Superficial: flexor retinaculum
What tendons pass through the carpal tunnel?
- 1 Flexor pollicis longus
- 4 Flexor digitorum profundus
- 4 Flexor digitorum superficialis
What are the boarders of the anatomical snuffbox?
Ulnar (medial) = Tendon of extensor pollicis longus
Radial (lateral) = Tendons of abductor pollicis longus and extensor pollicis brevis
Proximal = styloid process of the radius
What are the muscles of the posterior compartment of the forearm that have an action on the wrist?
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor carpi ulnaris
What are the muscles of the posterior compartment of the forearm that have an action on the fingers
- Extensor indicis
- Extensor digiti minimi
- Extensor digitorum
What are the muscles of the posterior compartment of the forearm that have an action on the thumb
- Abductor pollicis longus
- Flexor pollicis longus
- Flexor pollicis brevis
What are the muscles of the posterior compartment of the forearm that don’t really fit into a category?
- Anconeus
- Brachioradialis
- Supinator
What are the boarders of the axilla?
Apex - 1st rib, clavicle and scapula
Anterior wall - Pectoralis major and minor
Medial Wall - ribs 1-4 and intercostals, serratus anterior
Base - skin, subcutaneous tissue, axillary fascia
Lateral wall - Humerus
Posterior wall - Scapula, subscapularis, trees major, latissimus dorsi
What are the 5 groups of axillary lymph nodes?
- Pectoral
- Subscapular
- Humeral
- Central
- Apical
What are the boarders of the cubital fossa?
Superior - Line between the medial and lateral epicondyles of the humerus
Medial - Pronator teres
Lateral - Brachioradialis
What runs through the cubital fossa?
Tendon of biceps brachia Brachial artery (then branches to radial and ulnar arteries at the bicipital aponeurosis) Median Nerve
Where in the cubital fossa is blood usually taken from
Median cubital vein which lies anterior to the brachial artery and is separated from it by the aponeurosis of the biceps brachii tendon
