Posterior Aspect of Forearm PDF

POSTERIOR (EXTENSOR) ASPECT OF FOREARM Prof. Dr. Selda Önderoğlu NEU Faculty of Medicine Department of Anatomy [email protected]  Structures from superficial to deep Skin Superficial fascia- superficial vessels and nerves Skin innervation-mainly by the posterior cut. n....

POSTERIOR (EXTENSOR) ASPECT OF FOREARM Prof. Dr. Selda Önderoğlu NEU Faculty of Medicine Department of Anatomy [email protected]  Structures from superficial to deep Skin Superficial fascia- superficial vessels and nerves Skin innervation-mainly by the posterior cut. n. of forearm( br.of radial nerve). Deep fascia ( at wrist:extensor retinaculum). Muscles& deep avn. SKIN INNERVATION Superficial veins: Beginning of the Cephalic and basilic veins Deep fascia mm. On the post.aspect of forearm Two groups: A- Superficial B- deep  SUPERFICIAL DEEP GROUP GROUP 1-Brachioradialis m. 2-Extensor carpi radialis 1-Supinator ( pierced by radial n.) longus 2-Abductor pollicis longus 3-Extensor carpi radialis 3-Extensor pollicis longus brevis 4-Extensor pollicis brevis 4-Extensor carpi ulnaris 5-Extensor indicis (/ext.indicis 5-Extensor digitorum proprius) 6-Extensor digiti minimi 7-Anconeus (?) SUPERFICIAL GROUP DEEP GROUP 1-Brachioradialis m. 2-Extensor carpi radialis longus 1-Supinator ( pierced by 3-Extensor carpi radialis radial n.) brevis 2-Abductor pollicis 4-Extensor carpi ulnaris longus 5-Extensor digitorum 6-Extensor digiti minimi 3-Extensor pollicis longus 7-Anconeus (?) 4-Extensor pollicis brevis 5-Extensor indicis (/ext.indicis proprius) BRACHIORADIALIS MUSCLE The most superficial muscle.Forms the lateral border of the cubital fossa. Or:supracondylar ridge+lat.intermuscular septum Ins:lateral side of radius (above styloid process) n.: radial nerve (itself!) F.: flexor of forearm(flexes better when forearm is pronated)  EXTENSOR CARPI RADIALIS LONGUS MUSCLE or: supracondylar ridge ins:second metacarpal bone N: radial nerve ( itself!) F:extention of forearm and hand  COMMON EXTENSOR TENDON Lateral epicondyle of humerus is the common extensor tendon for the extensor (posterior) mm of forearm The extensor mm. Also orginate from: the Radial collateral lig. Of elbow joint +intermuscular septa. N: all the muscles except the brachioradialis and ext. carpi rad. Longus are innervated by the deep branch of the radial nerve ( posterior interosseus nerve) Muscles originating from the common extensor tendon Extensor carpi radialis brevis m. ins: 3rd metacarpal bone Extensor digitorum m. ins:dorsal digital expansion Extensor digiti minimi m.( ext. Quinti proprius m.) ins:dorsal digital expansion Extensor carpi ulnaris m. ins: 5th metacarpal bone Anconeus m. At the back of elbow joint Helps the extension of forearm  DORSAL DIGITAL EXPANSION (EXTENSOR EXPANSION) Small aponeurosis which covers the dorsum of the phalanges except the thumb. Triangular in shape. Base: covers the dorsal aspect of the metacarpophalangeal joint. then divides into 3 slips: Intermediate slip: attach to the base of second phalanx 2 lateral slips: unite and attach to the base of the distal phalanx.(apex)  muscles Attaching to the dorsal digital expansion Extensor digitorum m.,(superf.m.of ext.forearm) Extensor digiti minimi m. (superf.m.of ext.forearm) Extensor indicis proprius m. (deep m. Of ext. forearm) interossei mm.( hand ) Lumbrical mm.(hand)  INSERTIONS! Base of first metacarpal bone: abductor pollicis longus m. Base of second metacarpal bone: extensor carpi radialis longus m. Base of third metacarpal bone: extensor carpi radialis brevis m. Base of fifth metacarpal bone :extensor carpi ulnaris m.  Muscles-DEEP GROUP Supinator ( pierced by radial n.) Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis proprius Ext. Mm.-deep group Supinator m. Or: lat.epicondyle and supinator crest of ulna ins: ant,lat,and post aspect of radius n.: deep br. Of radial n F:supination of forearm and hand  Deep group of extensors O: from radius,ulna and interosseus membrane according to its position (medial or lateral) Insertions: - abd.poll.longus:1st metacarpal bone -ext.poll.brevis: proximal Phalanx of thumb - Ext. indicis: dorsal digital expansion The motor n. of the posterior aspect of forearm is the Deep branch of radial n. (post.interooseus nerve) Pierces the supinator m.! Posterior interosseus artery: Gives the blood supply to the extensor aspect of forearm Courses together with the post.inteross. N.  ANATOMICAL SNUFF BOX (radial fossa) When the thumb is extended. Bounded -laterally: abductor pollicis longus tendon Extensor pollicis brevis tendon - medialy: Extensor pollicis longus tendon. within the fossa located: - Radial a. - Scaphoid bone Arterial network around the elbow joint  Video links https://www.youtube.com/watch?v=7F4dHDwwvhQ https://www.youtube.com/watch?v=PxDDJYAsMZY https://www.youtube.com/watch?v=8J_yLwAehKE https://www.youtube.com/watch?v=joKzYrctekw extensors-dissected https://www.youtube.com/watch?v=IZvdgl8M1qo wrist region-dissected Acknowledgement: I thank you to all the scientists who for their efforts of providing and sharing the information/knowledge used in this ppt.