Posterior forearm Flashcards
What nerve supplies the posterior forearm?
-Radial
Name the muscles of the posterior forearm
- 3 to the wrist -> ECRL, ECRB. and ECU
- 3 to the fingers -> ED, EDM, EI
- 3 to the thumb -> EPL, EPB, ABPL
- 3 misc -> brachioradialis, Anconeous, Supinator
What is the function of the muscles in the posterior forearm?
-Extension at the wrist and fingers
What is the function of brachioradialis?
-Flexion of elbow (especially in half pronated position)
How can brachioradialis act as a landmark to find radial artery and nerve?
-They are sandwiched between brachioradialis and deep flexor muscles in distal forearm
What are the functions of extensor carpi radialis longus and brevis?
-ABdution and extension of the wrist
How can you tell the difference between ECRL and ECRB?
-ECRL is superficial and slimmer to ECRB
What is the function of extensor digitorum?
-Main extensor of the fingers at MCP and both IP joints
How do you test the function of ED?
- Forearm pronated
- Extend fingers against resistance
Where does ED insert?
-Into the extensor hood of each finger
Where does Extensor digiti minimi lay in relation to ED?
-Medially
What is the function of extensor digiti minimi?
- Extends the 5th digit
- Contributes to wrist extension
What is the function of extensor carpi ulnaris?
- Extension of the wrist
- ADduction
What does anconeous blend with?
-Fibres of triceps brachii
What is the function of anconeous?
- Moves ulna during pronation
- extension of the elbow joint
-What is Lateral epicondylitis?
- Tennis elbow
- Inflammation of the periosteum of the lateral epicondyle
- Onset usually 40-50 years
- Caused by repetitive strain of suprficial extensors
What are the superficial extensor muscles?
-ECRL, ECRB, ECU, ED, EDM, Brachioradialis, Anconeous
What is the function of supinator?
-Supination
What nerve passes between the two heads of supinator?
-Deep branch of radial nerve
Where is ABductor pollicis longus situated in relation to supinator?
-Immediately distally
What is the function of ABductor pollicis longus?
-ABducts the thumb
Why is the Abductor pollicis longus tendon important?
-Makes the lateral border of the anatomical snuff box
Where is extensor pollicis brevis situated in relation to ABductor pollicis longus?
-Deep and medial
What is the function of Extensor pollicis brevis?
-Extends the carpometacaral and metacarpopalangeal joints of the thumb
Why is the tendon of extensor pollicis brevis important?
-Makes the lateral border of the anatomical snuff box
How can you tell the difference between EPB and EPL?
-EPL has a larger muscle belly
What is the function of EPL?
-Extends all the joints of the thumb
Why is the tendon of extensor pollicis longus important?
-Makes the medial border of the anatomical snuff box
What is the function of extensor indices?
-Extends the index finger
What is wrist drop?
-Unopposed flexion of the wrist caused by radial nerve injury that has occured proximal to the elbow
Where and how are common sites of damage to the radial nerve?
- Axilla -> humeral dislocation or proximal fracture
- Radial groove -> humeral shaft fracture
