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.
What is the fibrous retinaculum?
The fibrous retinaculum is a strong fibrous band which stabilises the concavity of the palmar surface of the carpus (carpal bones), transmitting a number of structures
What is the flexor retinaculum anchored to?
- 4 carpal bones
- Scaphoid and trapezium on lateral side
- Pisiform and hamate bone on medial side
What are the contens of the carpal tunnel?
- 4 tendons of FDS
- 4 tendons of FDP
- 1 tendon of FPL
- Median nerve
What nerve travels through the carpal tunnel?
Median nerve
What is carpal tunnel syndrome?
This is a common clinical condition in which any reduction in the space (secondary to swelling) within the carpal tunnel can result in weakness and tingling in the muscles and skin supplied by the median nerve. If ignored this can result in long-term functional issues
What is the treatment for carpal tunnel syndrome?
The solution?…a simple procedure in which the flexor retinaculum is dissected under local or general anaesthetic and the nerve is freed
Why is the dorsum of the hand looser and more mobile compared to palmar aspect?
The reason for this is that is structure and stability is provided to the palmar aspect of the hand by the palmar fascia. These are fibres which provide a lattice structure, protecting the deep muscles and neurovascular structures.
What is A?
Palmar fascia
What is B?
Flexor retinaculum
Which muscle of the forearm (not found in everyone) is continuous with the fascia of the palm?
Pulmaris longus
What are the 5 compartments of the muscles of the hand from superficial to deep?
- Thenar compartment
- Hypothenar compartment
- Lumbricals and long flexor tendons – central compartment
- Adductor compartment
- Interosseous compartment
What aspect of the hand do the thenar muscles form?
The thenar muscles form the fleshy muscle belly (thenar eminence) on the lateral aspect of the palm.
What are the 3 muscles that forms the thenar muscles?
- Abductor pollicis brevis (APB)
- Flexor pollicis brevis (FPB)
- Opponens pollicis (OP)
How are the thenar muscles layered?
- 2 superficial
- APB and FPB
- 1 intermediately deep to them
- OP
What is A?
Flexor pollicis brevis
What is B?
Abductor pollicis brevis
What is C?
Opponens pollicis
What is the nerve supply for the thenar eminence?
Median nerve
Which nerve segment from the brachial plexus serves to provide the majority of the innervation to the thenar muscles?
C8 and T1
What do the hypothenar muscles form?
The hypothenar muscles form the fleshy muscle belly (hypothenar eminence) on the lateral aspect of the palm.
What are the 3 hypothenar muscles?
- Abductor digiti minimi
- Flexor digiti minimi
- Opponens digiti minimi
Which nerve innervates the hypothenar muscles?
Ulnar nerve
Which nerve root from the brachial plexus serves to provide the majority of the innervation to the hypothenar muscles?
C8 and T1
What is ‘opposition’?
Opposition is the movement of the thumb (pollicis), or little finger (digiti minimi) towards the other fingers.
What lies deep to thenar and hypothenar eminence?
Central compartment and lumbricals
What does the central compartment contain?
This contains the flexors tendons passing distally from the forearm to the digits, with their respective synovial sheathes.
What tendons are found in the central compartment?
- Flexor digitroum superficialis
- Flexor digitorum profundus
- Flexor pollicis longus
How many muscles forms the lumbricals?
4 small muscles
What do the lumbricals arise from?
They arise from the medial and lateral aspects of the FDP tendon, between the 1st to 5th metacarpals
What action do the lumbricals have on:
- fingers at metacarpophalangeal joint
- fingers at interphalangeal joint of 2nd to 5th digits
- Metacarpophalangeal joints
- Flex fingers
- Interphalangeal joints of 2nd to 5th digits
- Extend fingers
What nerve(s) innervates the lumbricals?
- Medial 2 lumbricals
- Ulnar nerve
- Lateral two lumbricals
- Median nerve
How many heads does the adductor pollicis have?
- 2 heads
- Oblique head
- Transverse head
What is A?
Oblique head of adductor pollicis
What is B?
Transverse head of adductor pollicis
Adductor pollicis:
- action
- innervation
- Action
- Adduction of thumb
- Innervation
- Median nerve
What are the deepest muscles of the hand?
Interossei
Where do the interossei lie?
Between the metacarpal bones
How many interossei are they?
- 4 dorsal interossei
- 3 palmar interossei
What is the action of :
- dorsal interossei
- palmar interossei
- Dorsal interossei
- Abduction of fingers
- Palmar interossei
- Adduction of fingers
Remember:
- DAB - Dorsal interossei ABduct fingers
- PAD - Palmar interossei ADduct fingers
Which nerve innervates the dorsal and palmar interossei muscles?
Ulnar nerve
Which spinal segment contributes the most to the innervation of the interossei?
C8 and T1
What is the arterial supply of the hand?
The ulnar and radial arteries provide the blood supply to the hand. Once they reach the palm they form the superficial and deep palmar arch.
How is blood supply in the hand maintained if an artery becomes blocked?
Superficial and deep palmar arches arches anastomose with each other, therefore if one artery becomes blocked the other can maintain blood supply via. its collateral circulation.
Which artery is the main contributor to:
- superficial palmar arch
- deep palmar arch
- Superficial palmar arch
- Ulnar artery
- Deep palmar arch
- Radial artery
What is the venous drainage of hand?
Venous arches associated with respective arterial arches
What is A?
Superficial palmar arch
What is B?
Ulnar nerve
What is C?
Radial artery
What is D?
Median nerve
What is E?
Branches of median nerve
What nerves supplies motor innervation to hand?
The median and ulnar nerves supply the muscles of hand.
What does the median nerve enter the hand through?
Carpal tunnel
What does median nerve supply in the hand?
Majority of the thenar eminence apart from the deep belly of flexor pollicis brevis, and the 1st and 2nd lumbricals
What does the ulnar nerve supply in hand?
Intrinsic muscles that the median nerve does not
What segmental root fibres do the median and ulnar nerves carry to innervate the intrinsic muscles of hand?
C8 and T1
The ulnar nerve is a branch of which cord of the brachial plexus?
Medial cord
How do you test the motor function of following nerves:
- axillary
- musculocutaneous
- radial
- ulnar
- median
- Axillary
- Abduct shoulders (deltoid)
- Musculocutaneous
- Flex elbow (biceps, brachialis)
- Radial
- Extend wrist (posterior compartment of forearm)
- Ulnar
- Spread your fingers (intrinsic muscles of hand)
- Median
- Move your humb towards your nose (abductor pollicis brevis)
How do you test the sensory functiono of the following:
- axillary
- radial
- musculocutaneous
- median
- ulnar
- Axillary
- Outer aspect of shoulder
- Radial
- Posterior arm, forearm and dorsal aspect of lateral 3 and a half fingers
- Musculocutaneous
- Lateral aspect of forearm
- Median
- Palmar aspect of lateral 3 and a half fingers
- Ulnar
- Palmar and dorsal aspect of medial 1 and a half fingers
What is A?
Proximal radio-ulnar joint
What is B?
Tuberosity of radius
What is C?
Styloid process of radias
What is D?
Olecranon of ulna
What is E?
Distal radio-ulnar joint
What is F?
Styloid process of ulna
What is the interosseous membrane?
The interosseous membrane is an incomplete fibrous structure, conforming stability to the forearm structure in addition to the proximal and distal radio-ulnar joints.
It is lax enough to allow supination and pronation at the radio-ulnar joints.
What sits between the ulna and the carpal bones?
Triangular fibrocartilage complex
What scaphoid bones does the radius articulate with?
Scaphoid and lunate bones
What type of fluid is found between the forearm and carpal bones?
Synovial fluid
What is support of the wrist provided by?
Support to the wrist joint is provided by a number of ligaments, these of which you don’t need to know in detail.
Flexion of the wrist joint is caused by contraction of the muscles in what compartment?
Anterior compartment
Extension of the wrist joint is caused by contraction of the muscles in what compartment?
Posterior compartment
The combined action of flexor and extensor carpi ulnaris cause what of the wrist?
Ulnar deviation (or adduction) of wrist
Which muscles are responsible for radial deviation or abduction of the wrist?
flexor and extensor carpi radialis
What bones forms the hands?
- Carpals
- Metacarpals
- 5 of them
- Proximal and distal phalanx in thumb
- Proximal, middle and distal phalanges in fingers 2 to 5
What are the joints called between the phalanges?
Interphalangeal joints
What joint sare between the carpals and metacarpals?
Carpo-meto-carpal (CMC) joints
What joints are between the metacarpals and the phalanges?
Metacarpophalangeal (MP) joints
What are the 7 carpals called?
- Lunate
- Scaphoid
- Trapezium
- Trapezoid
- Capitate
- Hamate
- Trizetrum
What is A?
Ulna
What is B?
Lunate
What is C?
Traqetrium
What is D?
Hamete
What is E?
Capitate
What is F?
Metacarpals (5th left, then 4th, then 3rd…)
What is G?
Trapezium
What is H?
Trapezoid
What is I?
Scaphoid
What is J?
Radius
