Elbow + Forearm Flashcards
What is at risk of damage with a humeral mid-shaft fracture?
Can damage radial nerve and profunda brachii artery if fracture is through the spiral groove (located at posterior aspect of humerus)
Which nerve passes posteriorly to the medial epicondyle of the humerus?
Ulnar nerve
What can cause a fracture of the olecranon?
Direct trauma
Avulsion caused by a strong triceps contraction (e.g. in a fall)
Which nerve may be affected by a fractured neck of radius?
Posterior interosseous nerve (branch of radial nerve)
What movement does the LCL of the elbow resist?
Adduction/ varus movement of forearm
What movement does the MCL of the elbow resist?
Abduction/ valgus movement of forearm
What are the markers of the anconeus triangle?
Radial head, lateral epicondyle of humerus and olecranon of ulna
What is the Anconeus triangle used for?
Region for elbow injection or aspiration
What movements does the radioulnar joint permit?
Pronation
Supination
What muscles are involved in supination of the forearm?
Biceps Brachii (innervated by musculocutaneous C5+C6) Supinator (Layer 2 of posterior forearm; innervated by posterior interosseous, branch of radial C5+C6)
What muscles are involved in pronation of the forearm?
Pronator Teres (Layer 1 of anterior forearm - innervated by median C6+C7) Pronator Quadratus (Layer 3 of anterior forearm - innervated by anterior interosseous, branch of median)
What forms the proximal (or superior) radioulnar joint?
Radius, Ulna and Annular ligament
What type of joint are the radioulnar joints?
Synovial pivot joints
What does the articular disc of the wrist do?
Separates ulna from proximal carpal bones of wrist joint (radiocarpal joint)
What actions do the anterior compartment of the forearm muscles do?
Wrist flexion
Digit flexion
Pronation
What actions do the posterior compartment of the forearm muscles do?
Wrist extension
Digit extension
Supination
Thumb abduction
Which muscles are involved in flexion of the wrist?
Anterior compartment of forearm:
Flexor Carpi Ulnaris (ulnar nerve)
Flexor Carpi Radialis (median nerve)
Palmaris Longus (median nerve)
What muscle abducts the wrist?
Flexor Carpi Radialis (median nerve)
What muscle adducts the wrist?
Flexor Carpi Ulnaris (ulnar nerve)
What are the attachment points for anterior compartment muscles?
Tendons of layers 1 + 2 attach to medial epicondyle of humerus
What is Golfer’s Elbow?
Medial epicondylitis
What is Tennis Elbow?
Lateral epicondylitis
What forms the roof of the carpal tunnel?
Transverse carpal ligament
What muscles flex the fingers?
Layer 2 anterior compartment: Flexor Digitorum Superficialis (up to proximal interphalangeal joints)
Layer 3 anterior compartment: Flexor Digitorum Profundus (to the distal interphalangeal joints)
What nerves cause finger flexion?
Flexor Digitorum Superficialis (to digits 2-5) + Flexor Digitorum Profundus (to digits 2+3) innervated by the median nerve
Flexor Digitorum Profundus (to digits 4+5) innervated by the ulnar nerve
[Nb. Need to test finger flexion at DIP of 2/3 and 4/5 to test for median and ulnar nerve function]
What muscle flexes the thumb?
Flexor Pollicis Longus (Layer 3 of anterior forearm - innervated by median nerve)
What is the golden rule of innervation to the anterior forearm?
Everything median EXCEPT flexor carpi ulnaris and flexor digitorum profundus to digits 4 and 5 which are innervated by the ulnar nerve
What muscles extend the wrist?
Extensor Carpi Radialis Longus + Brevis (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)
Extensor Carpi Ulnaris (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)
Where is the origin of the muscles of layer 1 of posterior forearm?
Lateral epicondyle of humerus (except ECRL and Anconeus)
ECRL = supracondylar ridge
What muscles abduct the wrist?
Extensor Carpi Radialis Longus + Brevis (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)
What muscle adducts the wrist?
Extensor Carpi Ulnaris (Layer 1 of posterior forearm - innervated by deep branch of radial nerve)
What muscles extend the fingers?
Extensor Digitorum (Layer 1 of posterior forearm - innervated by deep branch of radial nerve) Extensor Digitorum Minimi (Layer 1 of posterior forearm - innervated by deep branch of radial nerve) - to 5th digit only Extensor Indicis (Layer 2 of posterior forearm - innervated by posterior interosseous, branch of radial nerve) - to PIP of index finger only
What muscles extend the thumb?
Extensor Pollicis Brevis (Layer 2 of posterior forearm - innervated by posterior interosseus branch of radial nerve) - to MCP only
Extensor Pollicis Longus (Layer 2 of posterior forearm - innervated by posterior interosseus branch of radial nerve) - to all joints
What muscles abducts the thumb?
Abductor Pollicis Longus (Layer 2 of posterior forearm - innervated by posterior interosseous branch of radial nerve)
What is affected in De Quervains Tenosynovitis?
Compartment 1 of wrist (containing abductor pollicis longus and extensor pollicis brevis)
What can be affected in Compartment 3 of the wrist?
Extensor Pollicis Longus - can wear on the dorsal radial tubercle and rupture
What can be affected in Compartment 6 of the wrist?
Extensor Carpi Ulnaris - can wear on the ulnar styloid process and rupture
What is the contents of Compartment 2 of the wrist?
Extensor Carpi Radialis Longus + Brevis
What is the contents of Compartment 4 of the wrist?
Extensor Digitorum
Extensor Indicis
What is the contents of Compartment 5 of the wrist?
Extensor Digitorum Minimi
What are the actions of the brachioradialis muscle?
Elbow flexion
Moves forearm to mid pronation/ supination
What forms the borders of the cubital fossa?
Lateral = brachioradialis Medial = pronator teres Superior = inter-epicondylar line Roof = aponeurosis of biceps
