radius
- head location
- articulates with
- other important landmarks
head located proximally in discoid shaped
articulates with capitulum and radial notch of ulna
neck
radial tuberosity
medial facing sharpened edge on body
-attachment of interosseus membrane
anterior and posterior oblique lines
ulnar notch; distal radioulnar joint
styloid process; articulation with carpal bones
dorsal tubercle
ulna
-important landmarks
olecranon coronoid process -lateral side has a radial notch -supinator fossa and supinator crest -tuberosity on anterior surface for insertion of brachialis trochlear notch lateral sharpened interosseus border head (distal) -styloid process -convex articular surface laterally for articulation with radius
functions of pronator quadratus and pronator teres in pronation
quadratus
-prime mover
-responsible for initiation
-can act as only pronator during slow unopposed pronation
teres
-increases strength and speed of pronation
radial and ulnar deviation of the hand and wrist require…
pair of muscles radial deviation -flexor carpi radialis -extensor carpi radialis longus -extensor carpi radialis brevis ulnar deviation -flexor carpi ulnaris -extensor carpi ulnaris
lateral epicondyle relation to muscles
common extensor origin of a large number of superficial muscles of posterior surface of forearm
primary movers of supination
biceps brachii is a strong supinator used in forceful movements
supinator is prime mover in non-forceful situations
interosseus membrane
-function
anchors the radius ulna together
serves as an origin for some of the muscles of the forearm
relative strength of radius and ulna’s articulation with humerus
-why is one stronger?
ulna has stronger articulation -olecranon -coronoid process -trochlear notch -all 3 form a strong hinge-type joint radius -articulation with capitulum is only anchored by annular ring surrounding head of radius
distal articulation of forearm
-formed by
radius articulating with
- scaphoid
- lunate
- maybe triquetral and triquetrum
styloid processes (radius and ulna) length comparison
radius styloid process extends more distally
colles fracture
- what is it?
- most common mechanism of injury (MOI)
- how will it present?
- what else may be damaged
what -fracture of styloid process of radius -displacement of styloid process proximally MOI -falling on outstretched hand (forearm extended) presentation -styloid processes at same level may also damage scaphoid bone
ulnar nerve
- path at the distal humerus
- level of protection
swings around the medial epicondyle of the humerus
relative unprotected
nerves of the forearm
median
ulnar
radial
median nerve
-function
innervates all muscles of the anterior (flexor) compartment except
-brachioradialis
-flexor carpi ulmaris
-medial part of flexor digitorum profundus
carries sensory components to the skin of the forearm, hand, elbow, and wrist joints
brachioradialis
- innervation
- functions
- usually listed as occupying what compartment
- -why?
radial nerve
flexor of forearm at the elbow
usually listed as occupying the posterior compartment of the forearm
-due to origin near the common origin of the extensors of the forearm
flexor carpi ulnaris and medial part of flexor digitorum profundus
-innervation
ulnar nerve
anterior interosseus nerve
- what is it?
- function
what
-named muscular branch of the median nerve
-arises near apex of cubital fossa
-courses along anterior surface of the interosseus membrane
innervates
-other 1/2 of flexor digitorum profundus (digits 2, 3)
-flexor pollicis longus
-pronator quadratus
palmar cutaneous branch of median nerve
articular branches of the wrist
ulnar nerve
-location from elbow to wrist
posterior to medial epicondyle
deep to flexor carpi ulnaris along flexor digitorum profundus
medial to ulnar artery
ulnar nerve function
articular branches to elbow muscular branches to -flexor carpi ulnaris -flexor digitorum profundus palmar cutaneous branch to -medial 1/2 of palmar surface of hand (little and ring finger) dorsal cutaneous branch to -medial 1/2 of dorsal surface of hand (little and ring finger)
radial nerve
- enters forearm…
- branches into…
enters on
-anterior side of lateral epicondyle between brachialis and brachioradialis
branches into superficial and deep branch
radial nerve superficial branch
-function
entirely cutaneous skin of -dorsum of wrist -hand -thumb -dorsum of digits 2,3
radial nerve deep branch
- function
- location
entirely muscular and articular innervates -supinator -extensor carpi radialis brevis sweeps around lateral side of radius to extensor compartment
posterior interosseus nerve of radial nerve
- function
- location
innervates
-muscles of the deep extensor compartment
travels with posterior interosseus artery (branch of ulnar artery)
arteries of the forearm
- names
- derived from
names -radial -ulnar derived from radial and ulnar branches of brachial artery brachial artery divides in cubital fossa
radial artery
- location
- branches
location
-direct line continuation of brachial artery
-extends distally in the anterior compartment to styloid process of radius
-then swings dorsally through anatomical snuff box
branches
-radial recurrent artery
-superficial palmar branch of thenar eminence (thumb)
-carpal branches
radial recurrent artery
-part of…
anastomosis of the elbow (cubital anastomosis)
ulnar artery
- location
- function
location -sweeps medially after branching from brachial artery -lies on FDP, lateral to ulnar nerve supplies -medial muscles of hand and forearm -common flexor synovial sheaths -ulnar nerve
ulnar artery
-branches
anterior and posterior ulnar recurrent arteries (anastomosis of elbow)
common interosseus
superficial and deep palmar arches
common interosseus artery off ulnar artery
-branches into
anterior and posterior interosseus arteries
anterior interosseus artery
-location
passes distally and then pierces interosseus membrane to join carpal arteries
posterior interosseus artery
- location
- branches
passes through interosseus membrane to reach the extensor compartment of forearm
usually located deep to pronator teres muscle belly
branches
-muscular branches
-dorsal and palmar carpal arches
anatomical snuff box
- bounded by
- what passes through it?
boundaries -anterior --abductor pollicis longus tendon --extensor pollicis brevis tendon -posterior --extensor pollicis longus tendon radial artery passes deep in this region as it travels from anterior compartment of the forearm to the posterior compartment
carpal tunnel
-what is it (broad definition)
flexor retinaculum closing over the carpal groove or sulcus
carpal tunnel
-contents
median nerve tendons of -FDS -FDP -FPL
flexor carpi radialis (in relation to carpal tunnel)
-encased in _____ to _____
encased in “Y” shaped attachment of flexor retinaculum to scaphoid and trapezium
does not lie in carpal tunnel
compression of the median nerve and difficulty flexing (painful, weak) the digits and wrist can be a result of what?
space occupying lesions
- swelling
- edema
- inflammation of the synovial sheaths
what is one method of releasing pressure in the carpal tunnel
-consequences
cut the flexor retinaculum
flexor retinaculum scars over with a corresponding release in pressure and increase in size of carpal tunnel
