Upper Limb 3 Flashcards
What do the muscles in the anterior compartment of the forearm do in general compared to the posterior compartment of the forearm?
Anterior compartment = flexion and pronation
Posterior compartment = extension and supination
Name the 3 groups of muscles of the anterior forearm
Superficial
Intermediate
Deep
What are the 4 muscles of the superficial group of the anterior forearm?
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
What is the common flexor origin of the anterior forearm?
How does this compare to the common extensor origin?
Medial epicondyle
Lateral epicondyle
What is the action of pronator teres?
Pronation of the forearm
What is the innervation of the pronator teres?
Median nerve
Pronator teres = pronation
The other 3 muscles of the superficial group of the anterior forearm flex the hand at the wrist joint.
Which muscles in addition to this adduct and abduct at the wrist joint?
Adduct the wrist joint = flexor carpi ulnaris
Abduct the wrist joint = flexor carpi radialis
What two muscles work to abduct the wrist?
Flexor carpi radialis
Extensor carpi radialis (longus and brevis)
What two muscles work to adduct the wrist?
Flexor carpi ulnaris
Extensor carpi ulnaris
What nerves supply the 4 muscles of the superficial group of anterior compartment of forearm?
Median supplies all apart from the flexor carpi ulnaris which is supplied by the ulnar nerve
What is unique about the brachioradialis muscle?
Belongs to the extensor compartment and is supplies by an extensor compartment nerve even though it is a flexor of the elbow joint.
Major exception to the generalisation that the radial nerve supplies only extensor muscles and that all flexors lie in the anterior compartment
Which nerve inervates the brachioradialis muscle?
What is the segmental value?
Radial nerve
c5, C6, c7
What muscle is the only member of the intermediate group of muscles in the anterior compartment of the forearm?
Flexor Digitorum Superficialis (FDS)
How many tendons does the flexor digitorum profundus give rise to?
To which fingers are these tendons attached?
4 tendons
Index finger to pinkie (2-5)
Which phalynx does the tendons of flexor digitorum superficialis insert?
Because of this what joints does this muscle flex?
Middle
Wrist, MCP, and interphalangeal joints
(NOT distal interphalangeal joint)
What nerve supplies the flexor digitorum superficialis?
What is the segmental value? (C7, C8, T1)
Medial nerve
What 3 muscles make up the deep group of the anterior compartment of the forearm?
Flexor digitorum profundus (FDP)
Flexor pollicis longus
Pronator quadratus
What joints does the flexor digitorum profundus act on?
What are its main actions?
Wrist and all joints of the fingers
Flexes wrist and distal interphalangeal
Describe the nerve supply of the flexor digitorum profundus
Dual nerve supply
Ulnar nerve -> Medial part (c8, T1)
Median nerve -> Lateral part (C8, t1)
What is the action and nerve supply of the plexor pollicis longus?
Long flexor of the thumb
Median nerve (C8, t1)
Where is the origin and insertion of the pronator quadrates?
Origin = front of the ulna
Insertion into radius
What is the action of the pronator quadratus?
What is the nerve supply?
Pronates forearm; deep fibres bind radius and ulna together
Anterior interosseous nerve, from median nerve (C8, t1)
What is the relationship of the brachial artery with the medial nerve in the cubital fossa?
The nerve is medial to the brachial artery in the cubital fossa
Which muscle(s) does the median nerve not supply in the forearm?
Flexor carpi ulnaris and medial half of flexor digitorum profundus
Does the median nerve enter the hand by passing below or above the flexor retinaculum?
Below
Describe the path of the ulnar nerve as it enters the 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 ulnas muscle
How does the ulnar nerve lie in relation to the ulnar artery in the distal forearm?
Medial
What are the two terminal branches of brachial artery?
Radial and Ulnar artery
In close relation to which part of radius does the brachial artery divides into 2 terminal branches?
Opposite neck of radius
What makes up the walls of the carpal tunnel?
Roof = flexor retinaculum
Lateral side = scaphoid and trapezium
Medial side = Pisiform and hamate
What is the fibrous retinaculum?
Strong fibrous band which converts the concavity of the palmar surface of the carpus (carpal bones) and convertes it into a channel, the carpal tunnel.
What are the contents of the carpal tunnel?
Median nerve
4 tendons of Flexor digitorum superficialis
4 tendons of flexor digitorum profundus
1 tendon of flexor pollicis longus
What is the most sensitive structure in the carpal tunnel that could be affected in carpal tunnel syndrome?
Median nerve
Carpal tunnel syndrome results from what?
Any lesion that significantly reduces the size of the carpal tunnel
If the median nerve is effected in carpal tunnel syndrome what symptoms may the patient experience?
Tingling
Diminished sensation
Abscence of tactile sensation to the area supplied by the nerve
What muscle of the forearm is continuous with the fascia of the palm called the palmar aponeurosis?
Palmaris longus tendon
The intrinsic muscles of the hand are located in 5 compartments.
Name them
Thenar compartment
Hypothenar compartment
Adductor compartment
Lumbicals and long flexor tendons - central compartment
Interossei compartment
The thenar muscles from the thenar eminence on the lateral part of the palm are responsible mainly for what?
Apposition of the thumb
Name the 3 muscles which make up the thenar eminence
Flexor pollicis brevis
Abductor pollicis brevis
Opponens pollicis
Which nerve innervates all 3 muscles of the thinner eminence?
Recurrent Branch of Median Nerve
The nerve which innervates the thenar muscles is made up of fibres from which segmental levels?
C8 and T1
What 3 muscles make up the hypothenar eminence?
hypothenar muscles
Abductor digiti minimi
Flexor Digiti Minimi
Oppenens digiti minimi
Which nerve innervates all the hypothenar muscles?
Deep branch of the Ulnar Nerve
What is the segmental value of the nerve innervating the hypothenar muscles?
C8, T1
The adductor pollicis is made up of 2 heads
Name them
Transverse head
Oblique head
Which nerve innervates the adductor pollicis?
Deep branch of the ulnar nerve (C8, T1)
What is the action of the adductor pollicis on the thumb?
Adducts the thumb towards the lateral border of the palm
Among the short muscles of the hand, there are 4 earth worm-like muscles forming the central compartment
What are these collectively called?
Lumbricals
From which long flexor tendon do the lumbricals originate?
Tendon of flexor digitorum profundus
What is the action of the lumbrical muscles?
Flex the fingers at the metacarpophalangeal joint and simultaneously extend the interphalangeal joint of 2nd to 5th digits
How are the lumbricals innervated?
Medial two lumbricals innervated by the ulnar nerve and the lateral two are innervated by the median nerve
The interossei are present between what bones?
Metacarpal bones
How many dorsal and hor many palmar interossei are there?
4 dorsal
3 palmar
What are the actions of the dorsal and palmar interossei muscles on the fingers?
DAB
-Dorsal Interossei ABduct fingers
PAD
-Palmar Interossei ADduct the fingers
Which nerve innervates the dorsal and palmar interossei muscles?
Ulnar
What segmental levels provide nerve fibres to the ulnar nerve?
C8, T1
Lesion of which trunk affects these short muscles of the hand?
What is the paralysis called?
Lower trunk
Klumpke paralysis
What are the segmental levels involved in Klumpke paralysis (lower trunk)?
C8, T1
Describe the blood supply to the hand
The ulnar and radial arteries and their branches provide all the blood to the hand.
Both arteries after entering the palm contribute to the formation of arterial arches - superficial and deep palmar arteries
These arterial arches provide collateral circulation in the hand
Which artery is the main contributor of the superficial palmar arch?
What about the deep palmar arch?
Ulnar = Superficial
Radial = deep
What muscles do the radial nerve supply?
None
Supplies skin on the dorsal aspect of the hand
The ulnar nerve innervates most of the intrinsic muscles of the hand except what?
Thenar muscles and the first and second lumbrical muscle
The wrist joint is which kind of joint?
Synovial condyloid joint
What structures make up the proximal and distal aspects of the wrist joint?
Proximal:
-Distal end of radius and the articular disc
Distal:
-Proximal row of the carpal bones (except the pisiform)
What is the combined action of extensor and flexor carpi ulnaris on the wrist joint?
They act as adduction or cause ulnar deviation
Which muscles are responsible for the abduction of the wrist joint?
Extensor + flexor carpi radialis
