Muscles of the Forearm

1. Muscles of the Forearm Dr.NivinSharaf 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. Extension Flexion

7. Adduction / abduction at the wrist joint. Ad-duction Ab-duction

8. Movements of fingers. MCP (condyloidjts): 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. Anterior forearm: Flexor / pronator Compartment. Protonator teres • Superficial: • common flexor origin • pronator teres • flexor carpi radialis • palmarislongus • 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 Pass Fail

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

16. Post. ForearmSuperficial disection Nerve Supply Radial Nerve Anatomical snuff box

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

18. Muscles of the Forearm Post View Origin :Lateral epicondyle of humerusInsertion Lateral surface of olecranon andsuperior part of posterior surface of ulna Action Assists triceps in extending forearm;stabilizes elbow joint; abducts ulna during pronationInnervation Radial nerve (C7, C8 and T1) Anconeus Radial nerve innervates the BEST. BrachioradialisExtensorsSupinatorTriceps

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 carpiradialis: 14. Flexor Digitorum: 15. Extensor carpiulnaris: 16. Extensor digitorum: 17. Extensor carpiradialis:

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 • 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 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. 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:744-771

31. Thank you!