1. Muscles of the Forearm
Dr.Nivin Sharaf MD

2. Objectives
-Describe the function of the muscles in the anterior and posterior compartment of the forearm.
-Name and identify the muscles in the anterior (flexor/pronator) and posterior (extensor/supinator) compartments of the forearm, noting their relations.
-Name and identify the neurovascular structures in the anterior) and posterior compartments of the forearm, noting their relations.

3. Functional organization of Anterior and posterior forearm.

4. Names of the Muscles of forearm
Many of them
Long names: good guide to location and function
Location: ie. superficial / deep
radial / ulnar
(which side is the thumb on??)
Function: ie. flexor / extensor
adductor / abductor
Does it act on the thumb (pollux) or the fingers (digits)?

5. Functional Organization
Anterior compartment – flexor / pronator
Posterior Compartment – extensor / supinator
Flex the wrist ………[flexor]
Extend the wrist ……..[extensor]
Pronate the forearm ……..[pronator]
Acting on wrist (carpus) only ……[carpi]
Acting on fingers ……..[digiti / digitorum]
Acting on thumb (pollux) ……[pollicus]

6. Flexion / Extension at the wrist joint.

7. Adduction / abduction at the wrist joint.

8. X X Movements of fingers. MCP (condyloid jts): flexion / extension
abduction / adduction
IP (hinge jts): flexion / extension X X

9. Movements of the thumb – a specialized digit, occur at
right angles to the fingers. Mainly at the CMC (saddle) jt.
MCP – condyloid; IP – hinge (like fingers).

10. Muscles of Forearm

11. Flexor / pronator Compartment.
Anterior forearm:
Flexor / pronator Compartment.
Protonator teres
Superficial:
common flexor origin
pronator teres
flexor carpi radialis
palmaris longus
flexor digitorum
superficialis,
flexor carpi ulnaris
Brachioradialis
flexor carpi radialis
palmaris longus
flexor digitorum superficialis
flexor carpi ulnaris

12. Functional organization: Only flex at the wrist. Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
Flexor Carpi Radialis
Palmaris Longus
Flexor Carpi ulnaris

13. Muscles of the Forearm

14. Anterior Fore Arm
Pass
Fail

15. Ant Fore arm Wrist Flexors FCU+FCR FDS FDP PL Nerve Supply Wrist Add
Wrist Abd
FCR
Nerve Supply

16. Post. Forearm Superficial disection
Nerve Supply
Radial Nerve
Anatomical snuff box

17. Post. Forearm A: Extensor Digitorum B: Extensor Carpi Ulnaris C:
Brachio Radialis D:
Biceps Brachii E:
Triceps F:
Extensor Retinaculum

18. Muscles of the Forearm Post View
Origin :Lateral epicondyle of humerus Insertion Lateral surface of olecranon and superior part of posterior surface of ulna Action Assists triceps in extending forearm; stabilizes elbow joint; abducts ulna during pronation Innervation Radial nerve (C7, C8 and T1)
Anconeus
Origin :Lateral epicondyle of humerus Insertion Lateral surface of olecranon and superior part of posterior surface of ulna Action Assists triceps in extending forearm; stabilizes elbow joint; abducts ulna during pronation Innervation Radial nerve (C7, C8 and T1) Arterial Supply Middle collateral branch of deep brachial artery Recurrent interosseous artery
Radial nerve innervates the BEST.
 Brachioradialis  Extensors  Supinator  Triceps

19. Deep posterior compartment. - abductor pollicis longus
- extensor pollicis brevis
- extensor pollicis longus
- extensor indicis
- supinator
Functional organization:
extend hand at wrist
extend / abduct thumb
extend index finger
supinate
abductor pollucis longus
extensor pollicis brevis
extensor pollicis longus
extensor indicis

20. Deep Dissection Forearm
Post
Ant

21. Quiz 12. Pronator Teres 13. Flexor carpi radialis:
14. Flexor Digitorum:
15. Extensor carpi ulnaris:
16. Extensor digitorum:
17. Extensor carpi radialis:

22. Rotators of the Radius
Pronators
Supinator
Biceps Brachii

23. Pronation / Supination:
Occurs at radio-ulnar jts.
Proximal:
Head of radius
articulates with radial notch of ulna (pivot jt). It is held in place by the annular ligament.
Distal – Radius pivots around the fixed distal end of ulna (pivot jt).
Radio-ulnar articulation is stabilized by interosseus membrane.

24. Common Extensor Origin

25. Course of radial and ulnar arteries in forearm
Axillary vein:
continuation of basilic vein

26. Neurovasculature (deep). Lateral: radial artery radial nerve Midline:
median nerve
anterior interosseus a.
anterior interosseus n.
(deep branch of median)
Medial:
ulnar artery
(gives off common interosseus artery divides into anterior and posterior branches)
ulner nerve
radial n
ulnar a
radial a.
ulnar n
median n
anterior interosseus a + n

27. Radial nerve and its branches supply
Neurovasculature.
Radial nerve and its branches supply
all muscles in posterior compartment, including brachioradialis (!).
- superficial radial nerve
- deep radial nerve
- posterior interosseus nerve.
Posterior interosseus artery runs between superficial and deep muscles
Brachioradialis
Deep branch
posterior interosseus branch
Superficial branch

28. Lateral: radial artery radial nerve Midline: median nerve
Neurovasculature.
Lateral: radial artery
radial nerve
Midline: median nerve
[supplies all muscles except
flexor carpi ulnaris and
medial half of flexor
digitorum profundous]
Medial: ulnar artery
ulnar nerve
radial n.
Brachioradialis
radial a
ulnar n.
ulnar a.
median n.

29. Ulnar Nerve Medial ½ of FDP FCU
All hand muscles except 11/2 muscle groups(lateral 2 lumbricals and thenar muscles )

30. References Grey’s Anatomy Netter Keith Moore www.maestro.uottawa.ca
Recommended reading:
Clinically Oriented Anatomy,6th edition Keith Moore
Pages:

31. Thank you!