MSK 3 - Upper Limbs 3 Flashcards
What action do muscles of the anterior compartment of the forearm have?
- Flexors of the wrist and digits
- Facilitates pronation of forearm at radio-ulnar joint
How are the muscles of anterior compartment of forearm arranged?
- Superficial
- Intermediate
- Deep
What is A?
Pronator teres
What is B?
Brachioradialis
What is C?
Flexor carpi radialis
What is D?
Palmaris longus
What is E?
Flexor carpi ulnaris
What is the common flexor origin for the superficial and intermediate flexors?
Medial epicondyle of humerus
What is a muscle that is absent in 20% of people?
Palmaris longus
If this diagram represents the superficial flexors of forarm, what is each line?
A - flexor carpi ulnaris
B - palmaris longus
C - flexor carpi radialis
D - pronator teres
What are the superficial flexors of the forearm?
- Flexor carpi ulnaris
- Palmaris longus
- Flexor carpi radialis
- Pronator teres
What is the action of pronator teres?
Pronates and flexes forearm
Apart from flexing the wrist, which superficial muscle is involved in adduction (ulnar deviation) of the wrist joint?
Flexor carpi ulnaris
Apart from flexing the wrist, which superficial muscle is involved in abduction (radial deviation) of the wrist joint?
Flexor carpi radialis
Which of the following are involved in adduction of wrist and abduction of wrist:
- flexor carpi ulnaris
- flexor carpi radialis
- Flexor carpi ulnaris
- Adduction
- Flexor carpi radialis
- Abduction
What is adduction and abduction of wrist also called?
Adduction - ulnar deivation
Abduction - radial deviation
What is the innervation of the superficial flexors?
Three superficial muscles are supplied by median nerve with the ulnar nerve suppling the flexor carpi ulnaris muscle
What musles(s) are in intermediate group of flexors?
Only flexor digitorum superficialis (FDS)
How many tendons does the flexor digitorum superficialis insert as?
4
Why is the distal tendon of the FDS interesting?
When approaching its insertion point it splits into two loops passing around the back of the phalanx. This provides a tunnel in which the flexor digitorum profundus tendon can pass through attaching onto the distal phalanx.
To which digits (fingers) are the 4 tendons of FDS attached?
Middle phalenges of medial four digits
On which phalanx are the tendons of the FDS attached?
Middle
Flexor digitorum superficialis:
- origin
- insertion
- action
- innervation
- Origin
- Extensive origin in forearm
- Insertion
- Middle phalanges of medial 4 digits
- Action
- Flexion of wrist, metacarpophalangeal and proximal interphalangeal joints
- Innervation
- Median nerve (C7, C8, T1)
What posterior muscle acts with the anterior muscles on the elbow?
Brachioradialis
Brachioradialis:
- action
- innervation
- Action
- Flexes elbow
- Innervation
- Radial nerve
What is the exception to the rule that all flexors lie in anterior comparment and that only radial nerve innervates them?
Brachioradialis
What are the 3 deep muscles of the anterior forearm?
- Flexor digitorum profundus (FDP)
- Flexor pollicis longus
- Pronator quadratus
What is A?
Flexor digitorum profundus
What is B?
Flexor pollicis longus
What is C?
Pronator quadratus
What is its main action of FDP on the wrist and finger joints?
Flexes wrist, flexes distal interphalangeal joints of medial 4 digits
What is the nerve supply of flexor digitorum profundus?
- Ulnar nerve
- Medial part (to digits 4 and 5)
- Median nerve
- Lateral part (to digits 2 and 3)
Flexor pollicis longus:
- action
- innervation
- Action
- Flexion of thumb
- Innervation
- Median nerve (anterior interosseous nerve from median nerve)
Pronator quadratus:
- origin
- insertion
- action
- innervation
- Origin
- Front of ulna
- Insertion
- Radius
- Action
- Synergy with pronator teres muscle to form powerful pair of pronators at both proximal and distal radioulnar joints
- Innervation
- Median nerve (anterior interosseous nerve from median nerve)
What is A?
Brachial artery
What is B?
Ulnar nerve
What is C?
Ulnar artery
What is D?
Radial artery
What is E?
Radial nerve
Median nerve:
- course
- innervates
- Course
- The median nerve enters the forearm medial to the brachial artery. It then heads under the pronator teres muscle and passes down the forearm between the FDS and FDP.
- It enters the carpal tunnel traverse the flexor retinaculum
- Innervates
- All muscles of anterior forearm apart from flexor carpi ulnaris and medial half of flexor digitorum profundus
How does the median nerve travel relatrive to brachial artery?
Medial to it
Describe the course of ulnar nerve in forearm?
- After passing posterior to the medial epicondyle of the humerus the ulnar nerve enters the forearm by passing between the heads of flexor carpi ulnaris muscle.
- Both the ulnar nerve and ulnar artery descend close to each other down the medial aspect of the forearm
Does the ulnar nerve pass the medial or lateral epicondyle of humerus?
Medial
What muscles does the median nerve pass between in the forearm?
FDS and FDP
What muscle does the ulnar nerve enter the forearm by passing between the heads of?
Flexor carpi ulnaris muscle
What does ulnar nerve descent down forearm close to?
Both the ulnar nerve and ulnar artery descend close to each other down the medial aspect of the forearm
Where does the ulnar nerve lie relative to the ulner artery at the level of the wrist?
The ulnar nerve lies medial to the ulnar artery at the level of the wrist
Where does the brachial artery divide into the radial and ulnar arteries?
Neck of radius
What does the ulnar artery run next to in forearm?
In the forearm ulnar artery runs distal with the ulnar nerve, between flexor carpi ulnaris and flexor digitorum profundus.
What muscles does the ulnar artery travel between in the forearm?
Between flexor carpi ulnaris and flexor digitorum profundus.
What does the ulnar artery form after running through the wirst?
Superficial palmar arch
Describe the course of the radial artery in forearm?
The radial artery initially starts under brachioradialis and runs over the pronator teres and flexor pollicis longus lying on the distal radius
It then enters the hand forming the deep palmar arch.
What does the radial artery form when it enters the hand?
Deep palmar arch
Which of the radial and ulnar arteries forms:
- superficial palmar arch
- deep palmar arch
- Ulnar artery
- Superficial palmar arch
- Radial artery
- Deep palmar arch
Which arterial pulse you can feel at the distal third of the forearm medial to the tendon of flexor carpi radialis muscle?
Radial pulse
What test can be used to determine patency of arteries in distal forearm prior to sampling of arterial blood or insertion of arterial lines?
Allen’s test
Why is Allen’s test done?
Some people have unilateral circulation in distal forearm, so canulation can cause ischaemia to the hand
What is the carpal tunnel?
The carpal tunnel is the passageway from the forearm to the hand passing deep to the flexor retinaculum.