Download SO_cyprus_Posterior Aspect of Forearm_2014

POSTERIOR (EXTENSOR)
ASPECT OF FOREARM
Prof. Dr. Selda Önderoğlu
Structures from superficial to deep
• Skin
• Superficial fascia- superficial vessels and
nerves
Skin innervation-mainly by the posterior
cut. n. of forearm( radial nerve)
. Deep fascia ( extensor retinaculum)
. Muscles
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
Muscles-SUPERFICIAL GROUP
1-Brachioradialis m.
2-Extensor carpi radialis longus
3-Extensor carpi radialis brevis
4-Extensor carpi ulnaris
5-Extensor digitorum
6-Extensor digiti minimi
7-Anconeus (?)
Muscles-DEEP GROUP
1-Supinator ( pierced by radial n.)
2-Abductor pollicis longus
3-Extensor pollicis longus
4-Extensor pollicis brevis
5-Extensor indicis (/ext.indicis proprius)
BRACHIORADIALIS MUSCLE
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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
or: supracondylar ridge
ins:second metacarpal
bone
N: radial nerve ( itself!)
F:extention of forearm
and hand
COMMON EXTENSOR TENDON
• Lateral epicondyle of humerus
The extensor mm. Also orginate from:
• 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.
muscles Attaching to
the dorsal digital expansion
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Extensor digitorum m.,(superf.m.of forearm)
Extensor digiti minimi m. (superf.m.of forearm)
Extensor indicis proprius m. (deep m. Of 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
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Supinator ( pierced by radial n.)
Abductor pollicis longus
Extensor pollicis longus
Extensor pollicis brevis
Extensor indicis proprius
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)
• I:
abd.poll.longus:1st metacarpal bone
ext.poll.brevis:prox. Phalanx of thumb
Ext. indicis: dors.digital expansion
functions: ??
Deep branch of radial n.
(post.interooseus nerve)
Pierces the supinator m.
Posterior interooseus artery
Gives the blood supply to the
extensor aspect of forearm
Courses together with the
post.inteross. N.
ANATOMICAL SNUFF BOX
When the thumb is extended.
Bounded
-laterally: abductor pollicis longus tendon
Extensor pollicis brevis tendon
- medialy: Extensor pollicis longus tendon.
within:
Radial a.
Scaphoid bone