L8 Flashcards
What is the nerve supply of the posterior forearm?
Posterior interosseus nerve, from deep branch of the radial nerve
Deep branch of radial nerve - posterior interosseous nerve
Winds around the neck of radius pierces the 2 heads of supinator to become the (P) interosseus nerve.
Where is the blood supply for the posterior compartment of forearm from?
Posterior interosseus artery
What is the posterior interosseus artery? (from)
A branch of the common interosseous from the ulnar artery
What is the posterior compartment blood supply reinforced by?
Perforating branches of anterior interroseus artery
What are the muscles on the radial/lateral side of the posterior forearm?
- Brachioradialis
- Ext. Carpi Radialis Longus
- Brevis
What are the muscles on the middle and ulna side of the posterior forearm?
- Ext. Digitorum,
- Ext. Digiti Minimi
- Ext. Carpi Ulnaris
What tendons of thumb muscles form the anatomical snuffbox?
- Abductor Policis Longus
- Extensor Policis Brevis
- Extensor Policis Longus
What is the insertion of brachioradialis?
Base of styloid process of radius
What is the origin of brachioradialis?
Upper 2/3 of (L) supracondylar ridge of humerus
What muscle forms the lateral border of the cubital fossa?
Brachioradialis
Give the clinical for brachioradialis
Can be transplanted into flexor pollicis longus to produce flexion of the thumb in median nerve palsy
Test for damage to brachioradialis?
Place forearm in midprone position and flex against resistance while palpating the muscle belly.
What is the nerve supply for brachioradialis?
Branch of Radial nerve (C5,C6) arising above elbow
What is the action of brachioradialis?
Pulls on radial styloid process flexing at forearm. Ulna follows passively falling into the midprone position weak pronating
What is the course of the brachioradialis?
- Forms (L) border of the cubital fossa - along preaxial border of the forearm - overlies radial nerve & artery as they lie on: Supinator / Pronator Teres tendon / FDS & FPL
What is the lower part of the tendon of brachioradialis overlaid by?
- Abductor policis longus
- Extensor policis brevis
What are the actions of the extensor carpi radialis longus?
Extensor & radial abductor of the wrist - important as a synergist enabling finger flexors to produce a grip.
Test of carpi radialis longus
Pronate forearm & extend the wrist then abduct against resistance palpate muscle belly (L) side of elbow & tendon proximal to anatomical snuffbox.
What is the origin of extensor carpi radialis longus?
Lower 2/3 lateral supracondylar ridge of humerus
What is the insertion of extensor carpi radialis longus?
base of 2nd metacarpophalangeal
What is the action of extensor carpi radialis longus?
Extensor & radial abductor of the wrist - important as a synergist enabling finger flexors to produce a grip.
What is the course of extensor carpi radialis longus?
Behind brachioradialis - beneath deep outcropping thumb muscles - across floor of anatomical snuffbox
What is the nerve supply of extensor carpi radialis longus?
Branch of radial nerve (C6,C7) arising above the elbow.
What is the common extensor origin?
Anterior aspect of lateral epicondyle
What muscles fuse with the common extensor tendon?
- Extensor carpi radialis brevis
- Extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris
Clinical of common extensor tendon
Chronic mechanical degradation of the tendon due to overuse injury results in common extensor tendonosis more commonly known as Tennis elbow
What is the origin of extensor carpi radialis brevis?
Common extensor origin
Insertion of extensor carpi radialis brevis
Base of the 3rd metacarpophalangeal
What is the innervation of extensor carpi radialis brevis?
Deep branch of radial nerve (C6,C7)
Actions of extensor carpi radialis brevis
Indispensable as a synergist in forming a strong grip.
What muscle has a symmetrical insertion to flexor carpi radialis?
Extensor carpi radialis brevis
Course of common extensor origin
Deep to extensor carpi radialis longus - tendon
crossed deep outcropping thumb muscles - floor of anatomical snuffbox
What is the origin of extensor digitorum?
Common extensor tendon
What is the insertion of extensor digitorum?
Extensor expansions of 2nd - 5th digits.
What is the nerve supply of the extensor digitorum?
Posterior interosseous branch of the radial nerve (C7,C8)
What are the actions of extensor digitorum?
Extends the digits and assists with wrist extension
What is the test of extensor digitorum?
Pronate forearm and extend fingers at MCP joints push proximal phalanges into flexion
What are the relations of extensor digitorum?
Rounded belly by mid-forearm - diverges from 3 muscles on radial side - separated from them by deep thumb muscles - 4 tendons pass under extensor retinaculum - tendons are crowded together and overlie EI tendon - over the dorsum of
the hand the tendons are joined together to a variable degree by tendinous bands - tendons insert into the extensor expansion
What is the origin of extensor digit minimi?
Common extensor tendon
What is the insertion of the extensor digiti minimi?
Extensor expansion on dorsum of 5th MCP joint.
Innervation of extensor digiti minimi
Interosseous nerve C7,C8
What is the test for extensor digiti minimi?
Pronate forearm and extend fingers at MCP joints push proximal phalanges into flexion
What are the actions of extensor digiti minimi?
Assists extensor digitorum with extension of the little finger and wrist joint
What are the relations of extensor digiti minimi?
Muscle belly separates from common origin - becomes tendinous - tendon passes beneath extensor retinaculum - lies on dorsum of distal radio-ulnar joint - tendon splits into 2 slips which lie together on 5th MCP - tendon of ED joins them as a band near the MCP joint.
What is the origin of extensor carpi ulnaris?
- Common extensor tendon
- Aponeurosis from subcutaneous border of ulna
What is the insertion of extensor carpi ulnaris?
Base of 5th MCP
What are the relations of extensor carpi ulnaris?
Aponeurotic origin is in common with FCU - tendon lies in groove beside the ulnar styloid process symmetrical to insertion of FCU on the palmar aspect of 5th MCP.
Nerve supply of extensor carpi ulnaris
Posterior interosseous nerve in the forearm (C6, C7).