MSK 4 - Upper Limbs 4 Flashcards
What are the 3 functional groups that the muscles of the posterior forearm can be organised into?
1) Muscles that extend and abduct or adduct the hand at the wrist joint
2) Muscles that extend the medial four digits
3) Muscles that extend or abduct the thumb
What is A?
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Olecranon
What is B?
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Anconeus
What is C?
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Flexor carpi ularnis
What is D?
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Extensor carpi ulnaris
What is E?
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Extensor digiti minimi
What is F?
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Extensor pollicis longus
What is G?
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Anatomical snuff box
What is H?
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Extensor pollicis brevis
What is I?
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Abductor pollicis longus
What is J?
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Extensor digitorum
What is K?
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Extensor carpi radialis brevis
What is L?
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Extensor carpi radialis longus
What is M?
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Lateral epicondyle
What is N
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Brachioradialis
What is the action of extensor carpi radialis longus and brevis on the wrist joint?
They both extend and abduct the wrist joint.
Other than extension and abduction of the wrist, what other actions are the extensor carpi radialis longus and brevis involved in with the help of the flexor carpi radialis?
They cause radial deviation of the wrist
What are the muscles that extend the medial 4 digits?
- Extensor digitorum
- Extensor indicis
- Extensor digiti minimi
What is the origin of the extensor digitorum?
Lateral epicondyle of humerus
How many tendons does the extensor digitorum have?
As its fleshy muscle belly runs distally it ducks under the extensor retinaculum, and divides into 4 tendons for the fingers – very similar to FDS and FDP in Lesson 3.
What is A?
Abductor pollicis longus
What is B?
Extensor pollicis longus
What is C?
Extensor pollicis brevis
Where is the supinator found?
This muscle envelops the neck and the proximal part of the shaft of the radius, covering it completely, except on its medial side.
What is the action of supinator?
Supinates forearm
For extensor digitorum:
- innervation
- main action
- Innervation
- Radial nerve
- Main action
- Extend medial 4 digits at MCP joint
For extensor carpi radialis longus:
- innervation
- main action
- Innervation
- Radial nerve
- Main action
- Extend and abduct wrist
For extensor carpi radialis brevis:
- innervation
- action
- Innervation
- Radial nerve
- Action
- Extend and abduct wrist
For brachioradialis:
- innervation
- action
- Innervation
- Radial nerve
- Action
- Flexion of elbow (weak, maximal when forearm in midpronated position)
For extensor carpi ulnaris:
- innervation
- action
- Innervation
- Radial nerve
- Action
- Extend and adduct wrist
For supinator:
- innervation
- action
- Innervation
- Radial nerve
- Action
- Supinates forearm
For extensor digiti minimi:
- innervation
- action
- Innervation
- Radial nerve
- Action
- Extends 5th finger at MP joint
What supplies all of the innervation to the extensors?
Radial nerve
What branches does the radial nerve give of?
As the radial nerve leaves the cubital fossa it gives off a deep and superficial branch.
What is the deep branch of the radial nerve called?
Posterior interosseus nerve
What is the main motor nerve of the extensors of the forearm?
Posterior interosseus nerve
Through what muscle does the posteiror interosseus nerve run through?
It runs deep to the supinator muscle eventually piercing it to enter the extensor compartment of the forearm.
What fibres are contained in the superficial branch of the radial nerve?
The superficial branch is purely sensory and distributed to skin on the dorsum of the hand. As it branches at the cubital fossa it runs deep to brachioradialis and enters the hand passing over the anatomical snuff box
Where does the superficial branch of radial nerve run?
As it branches at the cubital fossa it runs deep to brachioradialis and enters the hand passing over the anatomical snuff box
What is A?
Superficial branch of radial nerve
What is B?
Posterior branch of radial nerve
Why is the arterial supplie of the posterior forearm complicated?
The arterial supply is complex network of arterial anastomosis including
- The posterior interosseus artery arising from the ulnar artery
- The recurrent interosseous artery – a branch of the above.
What are some arteries of the posterior forearm?
Posterior interosseus artery
Recurrent interosseous artery
What are the following branches of:
- posterior interosseus artery
- recurrent interosseous artery
- Posterior interosseus artery is a branch of radial artery
- Recurrent interosseous artery is a branch of posterior interosseus artery
What exists of the dorsum of the hand to provide stability and a tunnel for the extensor tendons?
Extensor retinaculum
What is A?
Extensor retinaculum
What is a ganglion?
Non-tender cysts can grow on the synovial sheaths found on the back of the hand
These are often more inconvenient than functionally limiting and can be removed surgically
What is a ganglion also called?
Synovial cyst
Which of the cephalic and basilic vein in lateral and medial continuation of dorsal venous arch?
Medial - basilic vein
Lateral - cephalic
What is A?
Extensor retinaculum
What is B?
Radial artery
What is C?
Abductor pollicis longus
What is D?
Extensor pollicis brevis
What is E?
Tendon of extensor pollicis longus
What are the boundaries of anatomical snuff box:
- medial border
- lateral border
- floor
- Medial border
- Tendon of EPL
- Lateral border
- Tendons of APB and EPB
- Floor
- Scaphoid and trapezium
Which artery can you feel pulsating on its floor?
Radial artery
For extensor pollicis longus:
- innervation
- action
- Innervation
- Posterior interosseous nerve
- Action
- Extend wrist
- Extend distal phalanx of thumb
- Extend metacarpophalangeal and carpometacarpal joints
For extensor pollicis brevis:
- innervation
- actions
- Innervation
- Posterior interosseous nerve
- Actions
- Extend wrist
- Extend proximal phalanx of thumb
- Extend carpometacarpal joint
For adductor pollicis longus:
- innervation
- action
- Innervation
- Posterior interosseous nerve
- Action
- Extend wrist
- Abduct thumb
- Extend thumb at carpometacarpal joint
What supplies the innervation to all extensors of thumb?
Posterior interosseous nerve
What are the extensors of the thumb?
- Extensor pollicis longus
- Extensor pollicis brevis
- Adductor pollicis longus
What usually causes a distal forearm fracture?
Mechanical fall such as hand stretched out to cushion impact
How can distal forearm fractures be classified?
- According to x-ray
- Colle’s fracture
- Anterior displacement of shalf of radius on the distal aspect of the bone (dinner fork deformity)
- Caused by falling onto an extended wrist
- Most common
- Smith’s fracture
- Posterior displacement of the radius on the distal aspect of bone
- Caused by falling onto flexed rwist, or by direct blow to forearm
- Colle’s fracture
For scaphoid fracture:
- aetiology
- presentation
- complications
- Aetiology
- Similar mechanism to Colle’s feacture
- But more often occuring in elderly
- Presentation
- Pain felt during palpation of anatomical snuff box
- Complications
- Malunion of bone
- Avascular necrosis
What do the 4 extensor digitrum tendons flatten to form?
Extensor expansions
What is each extensor expansion?
Each extensor expansion is a triangular tendinous aponeurosis that wraps around the dorsum and sides of the head of the metacarpal and base of the proximal phalanx.
What is A?
Middle conjoint tendon
What is B?
Oblique interosseus fibres
What is C?
Extensor digitorum
What is D?
Metacarpal
What is E?
Interosseous muscle
What is F?
Lumbrical muscle
What is G?
Lateral band
What stabilises the extensor expansion?
Once distal to the proximal phalanx, a number of ligaments stabilise the extensor expansion. These include the tendinous fibres of the interossei and lumbrical muscles
What are the main tendons that insert distally to the proximal phalanx?
The main tendons which insert distally are the middle and terminal conjoint tendons. The middle onto the base of the middle phalanx, and terminal onto the base of the distal phalanx respectively
Where do the following insert:
- middle conjoint tendon
- terminal conjoint tendon
- Middle conjoint tendon
- Base of middle phalanx
- Terminal conjoint tendon
- Base of distal phalanx
What 4 muscles attach onto the extensor expansion?
- Lumbricals of hand
- Extensor indicis muscle
- Dorsal interossei of hand
- Palmar interossei of hand