5 anterior forearm.ppt

The anatomy of the anterior compartment of the forearm

1. The anatomy of anterior compartment of forearm By: Dr. Mehrdad A sgari Ph.D of Anatomical Sciences, Department of Anatomy, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran In The Name Of Allah

2. The front of the forearm Skin Superficial fascia Deep fascia

3. Basilic vein Cephalic vein Accessory Cephalic vein Median antebrachial vein Superficial fascia

4. Superficial fascia

5. The front of the forearm Deep fascia The forearm is enclosed in a sheath of deep fascia, which is attached to the posterior border of the ulna . This fascial sheath, together with the interosseous membrane & fibrous intermuscular septa, divides the forearm into several compartments, each having its own muscles, nerves, and blood supply.

6. Anterior ( flexor ) compartment muscles Superficial group (origin at medial epicondyle) Pronator teres (pronates forearm) Flexor carpi radialis (flexes and abducts wrist) Palmaris longus (absent in some individuals; tenses palmar aponeurosis) Flexor carpi ulnaris (flexes and adducts wrist) Flexor digitorum superficialis (flexes PIP joints via four tendons)

7. Superficial Flexors They arise - more or less- from the common flexor origin (front of medial epicondyle ). All are supplied by median nerve except one, flexor carpi ulnaris, FCU (ulnar n.). All cross the wrist joint except one , pronator teres, (PT).

8. Pronator teres Origin: 1. humeral head: from medial epicondyle of the humerus 2. ulnar head: from the medial margin of the coronoid process Insertion: M iddle part of the lateral surface of the shaft of the radius Nerve: median Action: Pronation of the forearm at the radio-ulnar joints help to Flexion of the forearm at the elbow joint . Relations: median nerve passes between the two heads and ulnar artery is deep to both heads

9. Flexor carpi radialis Origin: medial epicondyle of the humerus Insertion: into palmar surface of the bases of the 2 nd & 3 rd metacarpal bones Nerve: median Action: flexion & abduction of the hand at the wrist joint Relations: in the lower part of forearm, radial artery lies between the tendons of the brachioradialis and flexor carpi radialis

10. Palmaris longus Origin: medial epicondyle of the humerus Insertion:  Into the palmar aponeurosis and flexor retinaculum Nerve: median Action: flexion of the hand at the wrist joint makes the palmar aponeurosis tense. Relations: 1. lies over the median nerve 2. passing superficial to flexor retinaculum 3. absent in 10% subjects

11. Flexor carpi ulnaris Origin: 1. humeral head: medial epicondyle of the humerus 2. ulnar head: medial margin of olecranon process posterior border of ulna Insertion: pisiform bone pisohamate lig . pisometacarpal lig . Nerve: ulnar Action: flexion & adduction of the hand at the wrist joint Relations: ulnar nerve passes between the two heads

12. Flexor digitorum superficialis Origin: 1. H umeroulnar head ; medial epicondyle medial border of coronoid process of the ulna 2. Radial head : anterior border of radius( ant. Oblique line) 3. F ibrous arch ulna to radius Insertion: Its tendon divides into 4 tendons which are inserted into the middle phalanges of the medial 4 fingers Nerve: median Action: Flexion of the PIP, MP of the medial 4 fingers Helps of flexion of the hand at the wrist joint Relations: median nerve and ulnar artery pass deep to this arch

13. Deep group Flexor digitorum profundus (flexes at DIP joint) Flexor pollicis longus ( flexes thumb) Pronator quadratus (pronates forearm) Anterior ( flexor ) compartment muscles

14. Flexor digitorum profundus Origin: 1. upper ¾ of the ant. & med. Surface of ulna 2. upper ¾ of the post. Border of ulna 3. med. Surface of olecranon & coronoid process 4. adjoining part of ant. Surface of the interosseus membrane Insertion: The muscle divides into 4 tendons which pierce the tendons of the flexor digitorum superficialis and are inserted into the bases of the distal phalanges of the medial 4 fingers . Nerve: Its lateral half: from the anterior interosseus nerve ( median nerve ). Its medial half: from the ulnar nerve Action: Flexion of DIP of the medial 4 fingers Helps in flexion of the PIP, MP of the medial 4 fingers Helps of flexion of the hand at the wrist joint is the chief gripping

15. Relations: ant. Interosseus nerve and vessels descend on the anterior surface of the interosseus membran between Flexor digitorum profundu s and Flexor pollicis longus

16. Flexor pollicis longus Origin: 1. upper ¾ of the ant. Surface of radius 2. adjoining part of ant. Surface of the interosseus membrane Insertion: The base of the distal phalanx of the thumb Nerve: median (anterior Interosseus branch) Action: flexion of the thumb Relations: Simillar to previously

17. Pronator quadratus Origin: on the lower ¼ of ant. Surface of ulna Insertion: into the lower ¼ of ant. Surface of radius Nerve: Median nerve (anterior Interosseus branch) Action: pronator of forearm at the radio-ulnar joints.

18. Supination and pronation It occurs in the superior and inferior radioulnar joints; (pivot synovial joint) Muscles produce supination Biceps brachii. Supinator. Muscles produce pronation Pronator teres. pronator quadratus. NB. Brachioradialis put the forearm in midprone-supine position.

19. Arterial Supply to the Forearm Radial artery It begins in the cubital fossa when the brachial artery divides into the radial and ulna artery. It passes distally, travels under the brachioradialis, resting on the deep flexor muscles. The artery briefly travels on the lateral side of the radius , before travelling over the anterior surface of the radius. The artery then winds around the lateral aspect of the wrist, before entering the palm of the hand to form the deep palmer arch.

20. RADIAL ARTERY Relations: Anterior: Brachioradialis & Skin and fascia. Posterior: Tendon of biceps Supinator Insertion of Pronator teres Flex. Dig.Sup. Flex. Poll. Lon. Pronator Quadratus Radius. Medially: Pronator teres , Flex. Carpi Radialis Laterally: Brachioradialis , Superficial br. Radial N.

21. RADIAL ARTERY 1- Radial Recurrent 2- Muscular 3- Palmar Carpal 4-Dorsal Carpal 5- Superficial Palmar

22. Arterial Supply to the Forearm Ulnar artery Larger than the radial artery. It passes between the arch formed by the radial and ulnar attachment of the flexor digitorum superficialis and descends through the anterior compartment. It enters the palm of the hand in front of the flexor retinaculum , and promptly divides in superficial and deep palmer branches.

23. Relations: Anterior: Pronator teres, Flex.Carp.Rad.,Palmaris Long., Flex. Dig.Sup. , Flex.Carp.Ulnaris, Skin & fascia, Palmar cutaneus br. Ulnar N. Posterior: Flex. Digitorum Profundus Medially: Ulnar N. , Flex. Carpi Ulnaris Laterally: Flex. Digitorum Superficialis

24. ULNAR ARTERY Branches: 1- Ant. Ulnar Recurrent 2- Post. Ulnar Recurrent 3- Common Interosseous * Ant. Interosseous Nutrient branches for radius & ulna Median a. * Post. Interosseous - Recurrent Interosseous 4- Muscular 5- Palmar Carpal 6- Dorsal Carpal

25. 3- Common Interosseous Ant. Interosseous Nutrient branches for radius & ulna Median a. Post. Interosseous Recurrent Interosseous

26. Dorsal Carpal branch

27. https://web.duke.edu/anatomy/lab11/lab12_prelab.html

28. Nerves Pattern of Forearm 3 nerves supply of the forearm and each nerve passes between 2 heads of muscle Nerve supply of the flexor compartment : The median nerve passes between the 2 heads of pronator teres . The ulnar nerve passes between the 2 heads of flexor carpi ulnaris . Nerve supply of the extensor compartment : - passes between the 2 layers of the supinator - The posterior interosseous nerve (a branch from the radial nerve)

29. M edian nerve  In the cubital fossa, it runs on the medial side of the brachial artery. It descends between the 2 head of pronator teres and runs between flexor digitorum superficialis and profundus . It lower part, emerges from the lateral side of the flexor digitorum superficialis and becomes superficial (or covered by palmaris longus tendon). It enters the hand deep to the flexor retinaculum.

30. Median Nerve-Branches 1 . Muscular branches: all the superficial muscles of the anterior compartment except flexor carpi ulnaris 2. Articular branches: to the elbow joint. 3 . Anterior interosseus nerve . Branches- - Muscular branches: all the muscles of deep flexion in the anterior compartment except the medial part of digitorum profundus . - Articular branches: to the wrist joint, the distal radioulnar joint, and the joints of the carpus.

31. Median Nerve-Branches 4. Palmar cutaneous branches: passes superficial to the flexor retinaculum and supplies skin of the lateral 2/3 of the palm. 5. Enters the palm of hand through the carpal tunnel , gives off a muscular branch ( recurrent branch )to the thenar muscles and terminates by dividing into three common palmar digital nerves

32. Ulnar Nerve The ulnar nerve passes behind the medial epicondyl e and enters the forearm between the two heads of flexor carpi ulnaris . It descends between the flexor carpi ulnaris and the flexor digitorum profundus . The ulnar nerve becomes superficial at the wrist, before entering the palm in front of the flexor retinaculum .

33. Ulnar Nerve-Branches Muscular branches: flexor carpi ulnaris medial half of the flexor digitorum profundus . Articular branches: to the elbow joint. Palmar cutaneous branch: passes superficial to the flexor retinaculum supplies skin of the medial 1/3 of the palm. Dorsal cutaneous branch: supplies the skin of the medial 1/3 of the dorsal surface of the hand and the dorsal surface of the medial 1.5 fingers (except nail beds).