- 3 of the deep muscles:-
1. abductor pollicis longus,
2. extensor pollicis brevis, and
3. extensor pollicis longus-
- Emerge from between tendons of :
extensor digitorum &
extensor carpi radialis brevis
- And pass into the thumb.
All superficial muscles cross the elbow joint
(arising from: Tip of lat. Epicondyle)
Deep muscles (except supinator)
don’t cross the elbow
2 bones of forearm & interosseous membrane
& pass to: thumb and index
o Extensor carpi radialis longus
Post. Interosseous n.
For any muscle
descends in the upper 2/3
under cover of the
In the lower 1/3 of the forearm
it passes posteriorly
deep to tendon of
brachioradialis to reach the
dorsum of the hand .
Superficial terminal branch of radial n.
skin of the lateral 2/3 of the dorsum of the
and the dorsal s. of the lateral 3 ½ fingers as
far as the second phalanges.
Deep terminal branch
Posterior interosseous nerve
One of 2 terminal br. Of
Infront of lat.
● winds backwards passing between
superficial and deep fibers of the
supinator (piercing it) to reach the
back of the forearm.
● In the back
descends between the superficial
and deep m.
1) the post. interosseous a. in the upper
2)terminal part of ant. interosseous a. in
the lower 1/3 of the forearm