forearm, ulna & radius Flashcards
what is the forearm?
the part of the arm that extends from the elbow to the wrist
What are important landmarks of the radius?
- head
- neck
- radial tuberosity
- roughening for attachment of pronator teres
- radial styloid process
what are important landmarks on the ulna?
- olecranon
- trochlear notch
- coronoid process
- radial notch
- tuberosity of ulna
- interosseus border
- ulnar styloid process
what is the interosseous membrane of the forearm?
- acts as an extrinsic ligament and links the ulna and radius
- assists the proximal and distal radioulnar joints
describe the proximal radioulnar joint
- synovial pivot joint
- articulation between the radial head and the radial notch of the ulna
- pivot joint - supination (holding a bowl of soup) and pronationof the forearm
where is the proximal radioulnar joint located?
- immediately distal to the elblow joint
- enclosed within the same elbow joint capsule
which important ligament holds the radial head in place?
the annular radial ligament - forms a collar around the joint
describe the distal radioulnar joint
location, articulations, type etc
- the distal radioulnar joint is located just proximal to the wrist joint
- articulation between the head of ulna, ulnar notch of radius and the triangular fibrocartilaginoius disc
what is the function of the triangular fibrocartilaginous disc in the distal radioulnar joint?
*** binds radius and ulna together **
* **separates **the distal radioulnar joint from the wrist joint
what is pronation of the forearm?
- the **rotation of the radius and hand around an immobile ulna **
- the ulna remians almost stationary and the radius rotates around it
what is colles’ fracture?
- complete fracture of the radius bone of the forearm close to the wrist
- results in a posterior displacement of the radius
- can happen due to a fall on an outstretched hand
what is smith’s fracture?
- a fracture of the distal end of the radius caused by a fall on the back of the hand
- results in anterior (volar) displacement of the fractured segment
note you only ever hear volar in relation to hand and wrsit injuries
what 2 nerves innervates the anterior compartment of the forearm?
- median nerve
- ulnar nerve
into what 2 categories are the anterior muscles of the forearm divided into?
- superficial
- feep
what are the superficial anterior muscles of the forearm?
- pronator teres (PT)
- flexor carpi radialis (FCR)
- palmaris longus (PL)
- Flexor digitorum superficialis (FDS)
- flexor carpi ulnaris (FCU)
what are the deep muscles of the anterior compartment of the forearm?
- flexor digitorum profundus (FDP)
- flexor pollicis longus (FPL)
- pronator quadratus (PQ)
what is the common origin for the anterior muscles of the forearm?
- medial humeral epicondyle (the flexor origin)
where does the pronator teres muscle insert onto?
- lateral border of radius (remember the roughening ofnthe bone)
- median nerve
where does the flexor carpi radialis (FCR) insert onto & what nerve innervates this muscle ?
- base of 2nd and 3rd metacarpal
- median nerve
where does the palmaris longus muscle insert onto & what nerve innervates this muscle?
- inserts onto palmar aponeurosis
- innervated by the median nerve
where does the flexor carpi **ulnaris ** insert onto and what nerve innervates this muscle?
- base of the 5th MC
- ulnar nerve
where does the flexor digitorum superficialis ( FDS) muscle insert onto and which nerve innervates this muscle?
- inserts onto the phalanges
- innervated by the median nerve
where does the flexor digitorum profundus (FDP) originate and insert onto?
deep muscles
- O: ulna
- I: distal phalanges of digits
where does the flexor pollucis longus (FPL) muscle originate and insert onto?
- O: anterior radius
- I: distal phalanx pollux (thumb)
where does the pronator quadratus muscle originate and insert onto & what nerve innervates it?
- O: ulna (distal)
- I: radius (distal)
- innervated by median nerve
where is the brachial artery located in the forearm?
medial to biceps tendon
**
what does the radial group of posterior forearm muscles consist of?
- brachioradialis
- extensor carpi radialis longus
- extebsor carpi radialis brevis
what muscles are in the thumb/pollux group of the posterior forearm muscles?
- extensor pollicis longus
- extensor pollicis brevis
- abductor pollicis longus
what does the digital group of the posterior forearm muscles contain?
- extensor digitorum
- extensor digiti minimi
- extensor indicis
where does the brachioradialis originate and insert onto?
- o: lateral supracondylar ridge
- I: radial styloid
where does the extensor carpi radialis longus muscle originate and insert onto?
- O: lateral supracondylar ridge
- I: 2nd metacarpal
where does the extensor carpi radialis brevis originate and insert onto?
- O: common origin (medial humeral epicondyle)
- I: 3rd metacarpal
where does the extensor digitorum originate and insert into?
- O: common origin (medial humeral epicondyle)
- I: extensor expansions
what is the origin and insertion of the extensor digiti minimi muscle?
- O: common origin - medial humeral epicondyle
- I: extensory expansion 5th digit
what is the origin & insertion of the extensor indicis muscle?
- O: distal ulna and IO (interosseus) membrane
- I: extensor expansion 2nd digit
where does the extensor pollucis longus muscle originate and insert onto?
- O: distal ulna and IO membrane
- I: pollux
where does the extensor pollicis brevis originate and insert onto?
- O: distal radius and IO membrane
- I: pollux
where does the abductor pollicis longus muscle originate and insert onto?
- O: radius, ulna and io membrane
- I: 1st metacarpal
what is the anatomical snuff box?
- triangular depression found on the lateral aspect of the dorsum of the hand
what are boundaries of the anatomical snuff box?
- medial border - tendon of the extensor pollicis longus
- lateral border - tendon of the extensor pollicis brevis and abductor pollicus longus
- floor - carpal bones - scaphoid & trapezium
- roof - cephalic vein and raial nerve
where does the anconeus originate and insert onto?
- O: common origin - lateral epicondyle of humerus
- inserts onto the olecranon and ulna
where does the extensor carpi ulnaris originate and insert onto?
‘other’ group
- O: common origin and ulna
- I: 5th metacarpal
where does the supinator muscle originate and insert onto?
note 2 heads
- O: lateral epicondyle of the humerus (superficial head)
- O: ulnar head (deep)
- I: proximal radius
