MSK 3 - Upper Limbs Flashcards
anterior compartment of the forearm:
These muscles are _______ of the wrist and digits and facilitate _________ of the forearm at the radio-ulnar joint
They are arranged into a …………
flexors
pronation
superficial, intermediate and deep group
a
Pronator teres
b
Brachioradialis
c
Flexor carpi radialis
d
Flexor digitorum superficialis
e
Flexor carpi ulnaris
The _______ epicodyle of the humerus acts as the common flexor origin for the superficial and intermediate flexors. A common ______ arises from here, providing the proximal insertion point for these 4 muscles
Any overuse injury (such as ______ elbow) is reflected by pain here
medial
tendon
golfers
what is a muscle that everyone may not have?
The palmaris longus (not shown above) is a muscle which is absent in about 20% of people! It is a long thin muscle and is one of the most superficial structures found at the wrist joint – see if you have one by flexing the wrist joint
Simply put, the superficial flexors of the forearm can be drawn as below, with the 4 muscles fanning out from the common flexor origin
what are each of the muscles?
PT – Pronator Teres
FCR – Flexor Carpi Radialis
PL – Palmaris Longus
FCU – Flexor Carpi Ulnaris
What is the action of pronator teres?
Pronation of the forearm and weak elbow flextion
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 carip radialis
Three superficial muscles are supplied by ______ nerve with the ulnar nerve suppling the _____________ muscle
median
flexor carpi ulnaris
what and where is the Flexor Digitorum Superficialis (FDS)?
Lies immediately deep to the superficial group of flexors in the forearm and is seen as the only muscle on the intermediate group of the forearm
The flashy mass of muscle has an extensive origin in the forearm, and passes distally down the arm giving rise to 4 tendons.
where and how does the FDS attach?
The distal tendon of FDS is interesting, as 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?
2-5 - index, long, ring, pinky
On which phalanx are they inserted?
middle
what is the FDS function?
The FDS flexes the wrist, metacarpophalangeal and proximal interphalangeal joints
Can this muscle act on the distal interphalangeal joint? (FDS)
no
What nerve innervates FDS?
Median nevre (C7, C8 and T1)
Brachioradialis:
Although seen as a muscle that lies in the posterior (extensor) compartment of the forearm the brachioradialis acts on the elbow joint with the other anterior muscles.
What is the main action of this muscle?
Flexes elbow when the forearm is in neutral and acts to stabilize the elbow during rapid flexion or extension
which nerve innervates the brachioradialis?
Radial nerve
what rule is the brachioradialis an exception of?
Brachioradialis is the exception to the rule that all flexors lie in the anterior compartment, and that the radial nerve only innervates extensor muscles
whata re the deep groups of msucles related to?
The deep group of muscles are in contact with the bones and interosseous membrane.
The flexor digitorum profundus (FDP) is in relation to the ulna, the flexor pollicis longus in in relation to the radius, and the pronator quadratus which is closely related to the distal parts of both bones.
a
Flexor pollicis longus
b
Flexor digitorum profundus
c
Pronator quadratus
where is the Flexor Digitorum Profundus (FDP)?
FDP is a long, thick muscle that lies deeply in the front of the forearm. It also lies more superficially on the medial border and back of the forearm
What is its main action of FDP on the wrist and finger joints?
flexion
The FDP has a dual nerve supply
Which part of the FDP is supplied by ulnar nerve?
Which part of the FDP is supplied by median nerve?
Ulnar half/Medial half
Radial half/Lateral half
Pollicis – _______
Brevis – ______
Profundus – _____
Quadratus – __________
Thumb
Short (If there’s a brevis muscle, then they’ll likely be a longus!)
Deep (if there’s a profundus, then they’ll likely be a superficialis!)
Square/Rectangular
FPL Is the long flexor of the thumb – which nerve innervates this muscle?
Anterior interosseous branch of the median nerve
where is the Pronator Quadratus?
Lies deeply in the distal part of the forearm, taking origin from the front of the ulna, and passing across to be inserted into the radius
What is the innervation of this muscle? (pronator quadratus)
Anterior interosseous branch of the median nerve
Pronator Quadratus works in synergy with the pronator _____ muscle and form a powerful pair of _______ at both the proximal and distal radioulnar joints
teres
pronators
a
Radial nerve
b
Radial artery
c
Brachial artery
d
Ulnar nerve
e
Ulnar artery
The median nerve enters the forearm _____ to the brachial artery. It then heads under the _______ ___ muscle and passes down the forearm between the FDS and FDP.
It enters the carpal tunnel ____ to the flexor retinaculum
medial
pronator teres
deep
Which muscle(s) does the median nerve not supply in the anterior forearm?
Flexor carpi ulnaris and medial half of flexor digitorum profundus
what is the course/location of the ulnar nevre in the forearm?
After passing posterior to the median 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
The ulnar nerve lies ulnarly/medial to the ulnar artery at the level of the wrist
The brachial artery exits the ante-cubital fossa, and divides into the _____ and _____ arteries at the ____ of the radius
radial
ulnar
head
In the forearm ulnar artery runs distal with the ulnar nerve, between what?
flexor carpi ulnaris and flexor digitorum profundus
what does the ulnar artery form?
It then forms the superficial palmar arch after running through the wrist
what is the route of the radial artery?
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
Which arterial pulse you can feel at the distal third of the forearm medial to the tendon of flexor carpi radialis muscle?
Radial pulse
Clinical: Allen’s Test
what is allens test?
To determine the patency of the arteries in the distal forearm (prior to sampling of arterial blood, or insertion of arterial lines), Allen’s test is used.
The reason that this is performed is because in some individuals a unilateral circulation exists in the distal forearm. Therefore, if any cannulation is performed there is a risk of causing ischaemia (due to reduced blood flow) to the hand
what is carpal tunnel?
The carpal tunnel is the passageway from the forearm to the hand passing deep to the flexor 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
The flexor retinaculum is anchored to 4 of the carpal bones below these are what?
The scaphoid and the trapezium on the lateral side
The pisiform and hamate bone on the medial side
what is the contents of the carpal tunnel?
4 tendons of flexor digitorum superficialis
4 tendons of flexor digitorum profundus
1 tendon of flexor pollicis longus
Median Nerve
Clinical – Carpal Tunnel Syndrome
what is it?
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
The solution?…a simple procedure in which the flexor retinaculum is dissected under local or general anaesthetic and the nerve is freed
what si the fascia of the palm?
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
Which muscle of the forearm (not found in everyone) is continuous with the fascia of the palm?
palmaris longus
The small, intrinsic muscles of the hand allow for fine movements of the fingers, often working in combination with each other.
Working from superficial to deep there are 5 compartments, what are they?
- Thenar compartment
- Hypothenar compartment
- Lumbricals and long flexor tendons – central compartment
- Adductor compartment
- Interosseous compartment
whata re the thenar muscles?
The thenar muscles form the fleshy muscle belly (thenar eminence) on the lateral aspect of the palm.
They are composed of 3 muscles, 2 lying superficial, and 1 immediately deep to these.
Identify these muscles on the next slide
- Abductor pollicis brevis (APB)
- Flexor pollicis brevis (FPB)
- Opponens pollicis (OP)
a
Flexor pollicis brevis (FPB)
b
Opponens pollicis (OP)
c
Abductor pollicis brevis (APB)
The nerve supply for the thenar eminence is mainly derived from the _______ nerve, however the exception to this is the deep belly of FPB, which is supplied by the _____ nerve
median
ulnar
Which nerve segment from the brachial plexus serves to provide the majority of the innervation to the thenar muscles?
C8 or T1 (more so T1) – most supplied by the median nerve, T1 mainly gives rise to the inner muscles of the hand (interossi, thenar and hypothenar
what are the hypothenar msucles?
The hypothenar muscles form the fleshy muscle belly (hypothenar eminence) on the lateral aspect of the palm
- 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
Opponens = what?
Digiti Minimi = what?
Indices = what?
Opponens – Related to the function of the muscle – contraction causes opposition
Digiti Minimi – Muscle works on the little finger (mini-digit!)
Indices – Muscle works on the index finger
You’ll have noticed a couple of the muscles of the hand named ‘opponens’ - this describes their function
what is it?
Opposition is the movement of the thumb (pollicis), or little finger (digiti minimi) towards the other fingers.
Think of opposition of the thumb as the movement it makes to form the ‘OK Sign’ in divers sign language
Lying deep to the thenar and hypothenar eminence is the central compartment
This contains the flexors tendons passing distally from the forearm to the digits, with their respective synovial sheathes
These are what?
- flexor digitorum superficialis
- flexor digitorum profundus
- Flexor pollicis longus
central compartment - Additionally, 4 small muscles of the hand originate here the _________
lumbricals
They arise from the medial and lateral aspects of the FDP tendon, between the 1st to 5th metacarpals
The lumbricals ____ the fingers at the metacarpophalangeal joints and ______ the interphalangeal joint of 2nd to 5th digits.
The medial two lumbricals are innervated by ______ nerve and the lateral two are innervated by _____ nerve
The lumbricals flex the fingers at the metacarpophalangeal joints and extend the interphalangeal joint of 2nd to 5th digits.
The medial two lumbricals are innervated by median nerve and the lateral two are innervated by ulnar nerve
what is A and B?
A = Adductor pollicis: oblique head
B = Adductor pollicis: transverse head
Adductor Pollicis (deeper than thenar muscles)
Lying deep in the hand below the neurovascular structures, this muscle has 2 heads
what si the function and action of the adductor pollicis?
Contraction of this muscle adducts the thumb
Which nerve innervates adductor pollicis?
Deep branch of the ulnar nerve (root value C8, T1)
what are the interossi, where are they and how many is there?
hese muscles are deepest in the hand and lie between the metacarpal bones (hence interossei); there are 4 dorsal and 3 palmar interossei
what is the function of the interossi?
A mnemonic is used to remember the action of dorsal and palmar interossei muscles on the fingers
DAB – Dorsal Interossei ABduct the Fingers
PAD – Palmar Interossei ADduct the Fingers
Which nerve innervates the dorsal and palmar interossei muscles?
Deep branch of the ulnar nerve (C8 and T1)
Which spinal segment contributes the most to the innervation of the interossei?
C8 and T1
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.
These 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 of superficial palmar arch?
Which artery is the main contributor of the deep palmar arch?
superficial = Ulnar artery
deep = Redial artery
Venous arches are associated with the respective arterial arches
a
Superficial palmar arch
b
Ulnar nerve
c
Median nerve
d
Median nerve
e
Superficial branch of the radial nerve
motor supply to the hand:
what supplies the muscles of the hand?
The median and ulnar nerves supply the muscles of hand
what muscles does the median nerve supply in the hand?
The median nerve enters the hand through the carpel tunnel and proceeds to supply the majority of the thenar eminence apart from the deep belly of flexor pollicis brevis, and the 1st and 2nd lumbricals
what muscles does the ulnar nerve supply in the hand?
Ulnar nerve innervates the rest of the intrinsic muscles of the hand
The median and ulnar nerves carry the segmental fibres of C _ and T _ to innervate the respective intrinsic muscles of the hand.
C5
T1
The ulnar nerve is a branch of which cord of the brachial plexus?
medial
The first and second lumbricals (the most radial two) are innervated by the ______ nerve. The third and fourth lumbricals (most ulnar two) are innervated by the ______ nerve. This is the usual innervation of the lumbricals (occurring in 60% of individuals)
median
ulnar
Clinical – Specific Nerve Testing (Try this Yourself)
Assessment of the upper limb nerves is something you will do time and time again to assess neurological problems
An understanding of the nerve distribution is vital to diagnose which nerve is affected and at which point of its course it is affected.
Motor Testing (Actions) - what is done for each nerve?
Axillary – Abduct the Shoulders (Deltoid)
Musculocutaneous – Flex the Elbow (Biceps, Brachialis)
Radial – Extend your Wrist (Post. Compartment of Forearm)
Ulnar – Spread Your Fingers (Intrinsic Muscles of the Hand)
Median – Move Your Thumb towards Your Nose (Abductor Pollicis Brevis)
Clinical:
Sensory Testing - what is done for each nerve?
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
Bones of Forearm, Wrist and Hand
Radius and Ulna
a
Proximal radio-ulnar joint
Bones of Forearm, Wrist and Hand
Radius and Ulna
b
Radial tuberosity
Bones of Forearm, Wrist and Hand
Radius and Ulna
c
Radial styloid process
Bones of Forearm, Wrist and Hand
Radius and Ulna
d
Radial styloid process
Bones of Forearm, Wrist and Hand
Radius and Ulna
e
Distal radio-ulnar joint
Bones of Forearm, Wrist and Hand
Radius and Ulna
f
Styloid process (ulna)
what is the interosseous membrane and its function?
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?
Articular disc and synovial fluid – triangular fibrocartilage complex (TFC)
The radius articulates with the _______ and ______ (carpal bones)
scaphoid
lunate
What type of fluid is found between the forearm and carpal bones?
Synovial fluid
Flexion of the wrist joint is caused by contraction of the muscles in the _______ compartment
anterior
Extension of the wrist joint is caused by contraction of the muscles in the ________ compartment
posterior
The combined action of flexor and extensor carpi ulnaris cause ____ deviation or ______ of the wrist
ulnar
adduction
Which muscles are responsible for radial deviation or abduction of the wrist?
extensor and flexor carpi radialis
what is circumduction of the wrist joint?
Circumduction of the joint is the rotation of the wrist using a combination of all the movements listed above
what are the metacarpals?
The metacarpals are the bones sitting between the carpal bones and the phalanges.
There are 5 in total and articulate proximally at the carpo-meto-carpal (CMC) joints, and distally at the metacarpophalangeal (MP) joints
The _________ are the distal bones in the hand
phalanges
what phalanxs do you have and what are the joints called between them?
There is a proximal and distal phalanx in the thumb
There are proximal, middle and distal phalanges in fingers 2 to 5.
The interphalangeal joints are the names of the joints between these bones
