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Forearm
The document summarizes the anatomy of the forearm, including its bony framework, fascia, compartments, muscles, nerves and blood vessels. The forearm has two compartments - anterior and posterior. The anterior compartment contains flexor muscles innervated by the median and ulnar nerves and supplied by the ulnar and radial arteries. The posterior compartment contains extensor muscles innervated by the radial nerve's deep branch and posterior interosseous nerve. Common injuries include fractures of the distal forearm bones like the scaphoid.
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Forearm
- 1. UL: Forearm Lecture 5 MarynaKornieieva, PhD, MD Asst. of Clinical Anatomy
- 2. Learning objective 1. Bonesand joints of forearm 2. Forearm as a region 3. Compartments of forearm 4. Contents of anterior compartment 5. Contents of posterior compartment 6. Topographic structures of wrist7. Distal Forearm Fractures
- 3. Bony Framework ofForearm Supination Pronation Axis of rotation Anular ligament
- 4. The Forearm: Borders,Superficial Structures Medial cutaneous n. of forearm Lateral cutaneous n. of forearm Lateral cutaneous n. of forearm Posterior cutaneous n. of forearm Elbow Wrist Forearm Hand
- 5. Deep Fascia ofForearm Attachment of deep fascia to the ulna Intermuscular septae Volkmann’s ischemic contractureCompartment Syndrome of the Forearm Fasciotomy for forearm compartment syndrome. Supracondylar fracture When the wrist is flexed to a right angle it is possible to extend the fingers.
- 6. Anterior Compartment ofForearm Nerve s.: Median + UlnarBlood supply: Ulnar and Radial arteries Palmaris longus Flexor carpi ulnaris Flexor carpi radialis Pronator teres 4 superficial 1 intermediate 3 deep muscles Flexor digitorum superficialis Flexor digitorum profundus Flexor policis longus Pronator tquadratus Medial epicondyle Common flexor tendon, CFT “Golfer’s elbow” (Medial epicondylitis)
- 7. Pronators Origin: Humeral head:CFT; Ulnar head. Insertion: Lateral aspect of shaft of radius Pronator Teres Pronator quadratus Origin: Anterior surface of shaft of ulna. Innervation: PT - median nerve; PQ - anterior interosseous branch of median nerve. Insertion: Anterior surface of shaft of radius. Pronator syndrome • pain and tenderness in the proximal aspect of the anterior forearm; • hypesthesia (decreased sensation) of palmar aspects of the radial three and half digits and adjacent palm.
- 8. Flexors of Fingers Flexordigitorum profundus Origin: Anteromed ial surface of shaft of ulna. Insertion: Distal phalanges of medial four fingers. Innervation: Ulnar (medial half) and Median (lateral half) nerves. Function: Flexes distal phalanx of fingers Flexor digitorum superficialis Origin: 1. Humeroulnar head 2. Radial head Insertion: Middle phalanx of medial four fingers. Innervation: median nerve
- 9. Long Flexor ofThumb Insertion: Distal phalanx of thumb. Function: Flexes distal phalanx of thumb Origin: Anterior surface of shaft of radius. Flexor pollicis longus Carpal Tunnel Flexor Retinaculum FPL FDS + FDP Innervation: Anterior interosseous n.
- 10. Flexors of Wrist Origin:CFO Insertion: Bases of second and third metacarpal bones Flexor carpi radialis Nerve s.: Ulnar nerve Origin: 1) humeral head CFO 2) ulnar head Insertion: Pisiform bone, hook of the hamate, base at fifth metacarpal bone Flexor carpi ulnaris Palmaris Longus Insertion: palmar aponeurosis “Cubital tunnel syndrome” Ulnar n. Nerve s.: Median nerve LRadial a. L L Median n. Ulnar a +n
- 11. Radial and Ulnaraa. Radial artery 5 4 6 7 Branches of ulnar a.: 4. Common interosseous artery; 5. Anterior and posterior ulnar recurrent arteries; 6. Muscular arteries; 7. Dorsal carpal branch and Palmar carpal branch. Ulnar Artery Common interosseous a.(4) Anterior i/o (9) Wrist AC PC 4 8 9 Branches of radial a.: 1. Radial recurrent a. 2. Muscular aa. 3. Superficial palmar a. Recurrent i/o (10) Anterior ulnar recurrent (5) Posterior ulnar recurrent (5) Posterior i/o (8) Superficial palmar archDeep palmar arch Ulnar artery 1 2 3
- 12. Median Nerve inForearm Course: • Enters the forearm passing between two heads of the pronator teres (★); • Descends to the wrist laying b/w flexors digitorun superficialis and profundus; • Enters the hand via the carpal tunel. Carpal tunel syndrome Common places of injury: At the wrist Upper forearm FDP FDS Supracondylar fracture of the humerus At the elbow Pronator teres syndrome + Lunate dislocation
- 13. • at thewrist (superficial to flexor retinaculum) • at the elbow (posterior to medial epicondyle) Common places of injury: Guyon's canal syndrome Cubital tunnel syndrome Course: Ulnar Nerve Flexor Carpi Ulnaris Flexor digitorum profundus Guyon’s canal Palmar cutaneous branch Dorsal cutaneous branch
- 14. Posterior Compartment ofForearm Blood supply: Posterior and anterior interosseous arteries The superficial group Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Anconeus Nerve supply to the muscles: Deep branch of the radial nerve Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis The deep group Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Lateral epicondyle Common extensor tendon, CET Extensor retinaculum “Tenis elbow”
- 15. Supinator of Forearm Origin:Lateral epicondyle of humerus, anular ligament of proximal radioulnar joint, and ulna. Insertion: Neck and shaft of radius Innervation: Deep branch of radial nerve – posterior interosseous nerve Arcade of Frohse (supinator arch) “Radial tunnel syndrome” / “Posterior interosseous nerve syndrome”/ “Supinator syndrome” Sensory loss will not present because PIN is purely motor.
- 16. Radial Nerve inForearm Common places of injury: 1) Radial (spiral) groove of the humerus 2) Entering the posterior compartment of forearm b/w 2 heads of supunator Radial tunnel syndrome 2 1 Course Deep branch of radial n. Brachioradialis (faded) Extensor Carpi Radialis Longus Superficial branch of radial n.
- 17. Extensors of Fingers Origin:Posterior surface of shaft of ulna Origin: CEO Extensor digitorum Insertion: Extensor expansion of 2nd -5th fingers Extensor digiti minimi Extensor indicis
- 18. Extensors of Wrist Origin:Insertion: Extensor carpi radialis longus (2) Extensor carpi radialis brevis (3) Extensor carpi ulnaris (1) Brachioradialis Insertion: Styloid process of radius Origin: Lateral supracondylar ridge Action: Flexes forearm at elbow joint; rotates forearm to the midprone position. 1 2 3
- 19. Thumb Muscles Extensor Pollicis Brevis Abductor PollicisLongus Extensors Pollicis Origin: Posterior surface of shafts of radius/ulna/interosseous membrane Insertion: Base of first metacarpal bone Insertion: Base of proximal phalanx Insertion: Base of distal phalanx
- 20. “Anatomical snuffbox” the lateralborder: - abductor pollicis longus; - extensor pollicis brevis; the medial border - extensor pollicis longus; the floor - scaphoid and trapezium. Borders: Palpable structures: • Radial artery; • Scaphoid and trapezium in the floor; • Radial styloid process proximally; • Base of the first metacarpal distally.
- 21. Distal Forearm Fractures Scaphoidfracture Scaphoid fracture in two weeks:
- 22. Summary Posterior compartment Anteriorcompartment Radial n: • Brachioradialis • Extensor carpi radialis longus Posterior interosseous n: • all the rest muscles Anterior interosseous n: • all the deep muscles (exception: medial half of FDP) Median n: • all muscles of the superficial and intermediate groups Ulnar n: 1 and ½ – flexor carpi ulnaris + medial half of FDP
- 23. Thank you foryour attention!!!