Upper Limb Anatomy Flashcards
What shape is the axilla?
Pyramidal shape
What are the borders of the axilla?
Has a
Base
Apex
4 walls
What makes up the anterior wall of the axilla?
Pectoralis major
Pectoralis minor
Under which joint does the axilla lie under?
Shoulder joint/ glenohumeral joint
What makes up the posterior border of the axilla?
Subscapularis
Teres minor
Latissimus dorsi
What makes up the medial wall of the axilla?
Serratus anterior
and
Thoracic wall
What makes up the lateral border of the axilla?
Intertubercular groove of humerus
What are the contents of the axilla?
Axillary artery Axillary vein Brachial plexus Biceps brachii and coracobrachialis Axillary lymph nodes
The axillary artery is a continuation of which artery?
Subclavian artery
At which anatomical point does the axillary artery begin?
Lateral edge of 1st rib
At which anatomical point does the axillary artery become the brachial artery?
Lower border of teres major muscle
The axillary artery continues as?
Brachial artery
What does the brachial artery bifurcate into?
Radial artery
Ulnar artery
Where does the brachial artery bifurcate?
As it crosses the cubital fossa
Which plexus innervates the upper limb?
Brachial plexus
Which nerve roots form the brachial plexus?
Ventral rami of C5,6,7,8 and T1
Which nerve roots form the upper/superior trunk?
C5/6
Which nerve roots form the middle trunk?
C7
Which roots form the lower/inferior trunk?
C8 and T1
What is Erb’s Palsy?
Injury to upper trunk (C5/6)
Which palsy is associated with waiter tip
Erbs palsy
Describe waiters tip
Medially rotates upper limb with wrist flexed
How does Erb’s palsy commonly occur?
Birth trauma
Dystocia
Which segmental roots of the brachial plexus contribute to the lower trunk of the brachial plexus
C8 and T1
What is Klumpke’s Palsy
Injury to the lower trunk
How are the cords of the brachial plexus named
Named for their position in relation to the axillary artery
What are the 3 cords of the brachial plexus
Lateral
Medial
Posterior cords
What are the major nerve branches of the brachial plexus
Musculocutaneous nerve Axillary nerve Median Nerve Radial nerve Ulnar nerve
Name the major arteries of the upper limb
Subclavian artery Axillary artery Brachial artery Radial artery Ulnar artery
What are the 2 palmar arches of the hand?
Superficial palmar arch
Deep palmar arch
What are the main superficial veins of the upper limb?
Cephalic vein
Basilic vein
Median Cubital vein
Which vein arises at the lateral end of the dorsal venous arch
Cephalic vein
Which vein arises from the medial end of the dorsal venous arch
Basilic vein
Why do superficial veins assume important in medical practice?
Because they are commonly used for intravenous injections for transfusions and for withdrawing bloods
From which vein to which vein does the median cubital vein shunt blood?
From cephalic to basilic vein
What is a dermatome?
Are of skin supplied by one spinal segment
Which dermatome lies over the nipples?
T4
Which dermatome lies over the umbilicus
T10
Which dermatome supplies the thumb?
C6
Which dermatome supplies the index and middle finger?
C7
Which dermatome supplies the ring and little finger?
C8
Where do lymphatic vessels from the upper limb drain into?
Axillary lymph nodes
What are the 4-5 distinct groups of the axillary lymph nodes/
Apical group Central group Lateral group Anterior/pectoral group Posterior/subscapular group
When is enlargement of the axillary lymph nodes common
During malignancy
Which group of LN would drain the lateral part of the breast?
Axillary lymph nodes
Which group of LN would drain the medial breast close to sternum?
Internal mammary/thoracic LN
Infection around the umbilicus can spread to both superficial inguinal and axillary LN why?
Above it drained by axillary
Below it drains to superficial inguinal LN
What is the pectoral girdle?
Set of bones which connect the upper limb to the axial skeleton on both sides
What are the 2 ends of the clavicle called?
Sternal end
Acromial end
Which end of the clavicle is medial?
Sternal end
Which end of the clavicle is lateral
Acromial end
Which part of the clavicle is the weakest?
Middle 1/3
What type of joint is the acromioclaviclar joint?
Synovial plane
What type of joint is the sternoclavicular joint?
Synovial saddle
What does the acromioclaviclar joint connect?
Lateral clavicle (acromial end)
And
Acromion of scapula
What does the sternoclavicular joint connect?
Sternal/medial clavicle
Manubrium of sternum
Which muscles cause elevation of the scapula?
Upper trapezius
Levator scapulae
Rhomboids
Which muscles cause depression of the scapular
Lower Trapezius
Serratus anterior
Pectoralis minor
Which muscles cause protraction of the scapula?
Serratus anterior
Which muscle causes retraction of the scapula?
Middle trapezius fibres
Rhomboid muscles
Which muscle causes lateral (upward rotation) of the scapula
Upper and middle trapezius fibres
Which muscles cause medial (downward) rotation of the scapula?
Rhomboids
Pectoralis minor
Levator scapulae
With help from gravity
What type of joint is the glenohumeral joint?
Ball and socket
Is the rhomboid major muscle superior or inferior to rhomboid minor muscle
Inferior
Which is the most superficial back muscle?
Trapezius
Innervation of trapezius
Accessory nerve
Cranial nerve 11
How do you test the trapezius muscle
Ask the patient to shrug their shoulders
What do upper trapezius fibres do to the scapula
Elevate it
What do middle fibres of the trapezius do to the scapula?
Retract it
What do lower fibres of the trapezius muscle do to the scapula?
Pull it inferiorly
What is the ball of the glenohumeral joint?
Head of the humerus
What forms the socket of the glenohumeral joint?
The glenoid cavity
The rim of cartilage surrounding the glenohumeral socket is the
Glenoid labrum
What is the function of the glenoid labrum?
To deepen the socket
What nerve is injured in winging of the scapula?
Long thoracic nerve
During which procedure is the long thoracic nerve commonly injured
Axillary nerve clearance in breast surgery
Which aspect of the glenohumeral joint does the glenohumeral ligaments strengthen?
Anterior aspect
What does the coraco-acromial ligament prevent
Superior displacement
What does the coracohumeral ligament strengthen?
Superior aspect of joint capsule
Which part of the shoulder joint capsule is weakest as is not protected by muscles or ligaments
Anterior
Inferior
Name the 4 rotator cuff muscles
Subscapularis
Supraspinatus
Infraspinatus
Teres minor
Where do the 4 rotator cuff muscles extend from to?
Scapula to humerus
What is the most important role of the 4 rotator cuff muscles?
To pull the humeral head into the glenoid fossa
Which 2 intrinsic shoulder muscles extend from the scapula and trunk to the humerus
Deltoid
Teres major
What is the action of anterior fibres of the deltoid muscle?
Flexion and medial rotation of arm
What is the action of middle fibres of the deltoid muscle?
Abduction of arm
Which muscles does the middle deltoid take over from in abduction of the arm
Takes over from supraspinatus which abducts first 15 degrees
What is the action of the posterior deltoid fibres?
Extension and lateral rotation of arm
What is the nerve supply to the deltoid muscle
Axillary nerve
In what common injury is the axillary nerve commonly trapped
Shoulder dislocation
Fracture of surgical neck of humerus
Where would you test for sensation loss in axillary nerve injury?
Regimental badge area
Where do the fibres of the pectoralis major originate from
Medical third of clavicle
Sternum
Ribs
What is the action of the pectoralis major on the shoulder
Flexion
Adduction
Which vein below the clavicle is used for placement of central lines
Subclavian vein
What is the action of the serratus anterior on the scapulae
Protraction
What is the nerve supple of the serratus anterior?
Long thoracic nerve
What are the actions of the teres major on the shoulder joint
Adduction
Medial rotation
What are the actions of the actions of the latissimus dorsi on the shoulder?
Extension
Medial rotation
Adduction
Which muscle causes flexion of the shoulder joint
Pectoralis major
Anterior deltoid
Coracobrachialis
Biceps Brachii
Which muscles cause extension of the shoulder joint?
Posterior deltoid
Teres major
Latissius dorsi
Which muscles cause adduction of the shoulder joint?
Pectoralis major
Latissimus dorsi
Theres major
Coracobrachialis
Which muscles cause abduction of the shoulder joint?
0-15 degrees supraspinatus
15-90 degrees- middle deltoid fibres
Past 90 degrees the scapula needs rotated
Which muscles cause internal/medial rotation of the shoulder
Subscapularis Lattisimus dorsi Pectoralis major Teres major Anterior deltoid
Which muscles cause lateral or external rotation of the shoulder joint?
Teres minor
Infraspinatus
What are the 3 main muscles in the anterior compartment of the arm
Biceps brachii
Coracobrachialis
Brachialis
How many heads does the bicep muscle have?
2
Which is the most anterior muscle of the anterior arm
Biceps brachii
Where does the biceps brachii insert into distally?
Tuberosity of the radius
What are the 2 heads of the biceps brachii muscles?
Long head
Short head
Which head of the biceps brachiii arises from the coracoid process?
Short head
Which other muscle arises at the coracoid process?
Coracobrachialis
Which head of the biceps brachii arises from the supraglenoid tubercle?
Long head
What is the action of the biceps brachii on the shoulder and elbow joint?
Flexion at both joint
What is the action of the biceps on the superior radio ulnar joint
Powerful supinator
What is the nerve supply to the biceps?
Musculocutaneous nerve
Which segmental fibres mainly innervate the biceps brachii muscle
C5,6,7
From which cord of the brachial plexus does the musculocutaneous nerve arise from?
Lateral cord
What is the action of the coracobrachialis on the shoulder joint?
Flexion arm at shoulder
Weak adduction
What is the nerve supply of the coracobrachialis?
Musculocutaneous nerve
What are the BBC muscles?
Biceps Brachii
Brachialis
Coracobrachialis
What is the innervation of the BBC muscles?
Musculocutaneous nerve
Where does the brachialis muscle insert?
To the coronoid process of the ulna
What is the main action of the brachialis on the elbow joint?
Flexion at elbow
Which nerve supplies the brachialis?
Musculocutaneous nerve
What is the main nerve of the anterior compartment of the arm?
Musculocutaneous nerve
Which muscle does the musculocutaneous nerve pierce?
The coracobrachialis
What does the musculocutaneous nerve continue as?
Lateral cutaneous nerve of forearm
Why is the musculocutaneous nerve called the musculocutaneous nerve
Cause it supplies muscle
And also has cutaneous sensation functions
From which part of the forearm does the musculocutaneous nerve carry cutaneous sensations?
Lateral aspect of the forearm
What is the brachial artery a continuation of?
The axillary artery
Where does the brachial artery end?
At the cubital fossa
What does the brachial artery bifurcate into?
The radial and ulnar artery
What is the profunda brachii artery a branch of?
Brachial artery
Which artery is commonly auscultated to measure blood pressure?
Brachial artery
From which cords does the median nerve arise from?
Lateral cord
AND
Medial Cord
Does the median nerve give any branches in the axillary or upper arm?
No
What are the roots of the median nerve
C6-T1
How does the median nerve travel in relation to the brachial artery?
Initially along the lateral side of brachial artery
Crossing to the medial side of the brachial a. and entering the cubital fossa
From which cord does the ulnar nerve arise?
Lateral cord
What are the root values of the ulnar nerve
C8 and T1
Where does the ulnar nerve pass posterior to?
Medial epicodyle
In the forearm what does the ulnar nerve run alongside?
The ulnar bone
How does the ulnar nerve descend initially
Medial side of brachial artery then entering the posterior compartment
Which fracture of the humerus could damage the ulnar nerve?
Medial epidoncyle
Which fracture of the humerus could damage the axillary nerve?
Fracture of the surgical neck of the humerus
Which fracture of the humerus could damage the radial nerve
Fracture of the radial groove
Where is the cubital fossa located?
Front of the elbow
What shape is the cubital fossa
Triangular
Which artery is contained in the cubital fossa?
Brachial
Which bifurcates at the apex into radial and ulnar
Which artery pulsation can be felt medial to the tendon of biceps brachii in the cubital fossa?
Brachial artery
What is the base of the cubital fossa and imaginary line between?
An imaginary line drawn between the two epicondyles of the humerus
What is the medial border of the cubital fossa formed by?
Lateral border pronator teres
What is the lateral border of the cubital fossa formed by?
Medial border brachioradialis m.
What are the contents of the cubital fossa?
Biceps tendon Brachial artery (which bifurcates) Median nerve
Which vein is the usual choice for IV injections?
Median cubital vein
Which muscle occupies the entire posterior compartment of the arm?
Triceps
How many heads does the tricep have?
3
What are the 3 heads of the triceps?
Long head
Medial head
Lateral head
Where does the long head of the triceps originate from
Scapula
Where do the lateral and medial heads of the triceps originate from?
Humerus
Lateral- superior radial groove
Medial - inferior radial groove
Where does the common tendon of the triceps insert into?
Olecranon process of the ulna
Olecranon process and coronoid process are parts of which forearm bone?
Ulna
Which head of the triceps has its proximal attachment on the infraglenoid tubercle of the scapula?
Long head
What is the main action of the triceps on the elbow joint?
Extension of arm at elbow joint
What type of joint is the elbow joint?
Synovial hinge
What type of joint is the glenohumeral (shoulder) joint?
Ball and socket
What is the nerve supply to the triceps and aconeus muscle?
Radial nerve (remember posterior compartment)
What is the action of the aconeus on the elbow joint?
Extension at the elbow
Which cord from th brachial plexus does the radial nerve originate from
Posterior cord
What are the nerve root values of the radial nerve?
C5-T1
What is the characteristic sign of radial nerve injury?
Wrist drop
Which branch of the brachial artery accompanies the radial nerve in the radial groove?
Profunda Brachii
In which groove does the radial artery travel?
Radial groove
In what humerus fracture may the radial nerve be damaged?
In the radial groove in midshaft humeral fractures
What type of joint is the elbow joint?
Synovial hinge joint
What are the 2 ligaments of the elbow?
Medial (ulnar) collateral ligament
Lateral (radial) collateral ligament
Which ligament of the elbow holds the head of the radius?
Radial (lateral) collateral ligament
What are the movements of the elbow joint
Flexion
Extension
What are the 3 flexors of the elbow joint?
Biceps Brachii
Brachialis
Brachioradialis
What are the 2 extensors of the elbow joint?
Triceps Brachii
Aconeus
What type of joint is the proximal radio-ulnar joint?
Synovial pivot
What type of joint is the distal radio-ulnar joint?
Synovial pivot
What movements occur at the radio ulnar joint?
Supination
Pronation
Where is the proximal radio-ulnar joint located?
Immediately distal to elbow joint
Which 2 muscles cause pronation of the radio-ulnar joint?
Pronator teres
Pronator Quadratus
Which 2 muscles allow supination of the radioulnar joint?
Supinator
Biceps Brachii
Which ligament holds the head of the radius at the radio-ulnar joint?
Annular ligament
Where is the distal radio-ulnar joint located?
Immediately proximal to the wrist joint
Which articulation forms the distal radio-ulnar joint?
Ulnar notch of radius
and
Head of Ulnar bone
Which articulation forms the proximal radio-ulnar joint?
Radial notch of ulnar
And
Head of Radius bone
Which muscle is the most powerful supinator of the forearm?
Biceps Brachii
Are muscles of the anterior forearm flexors or extensors?
Flexors of wrist and digits
Also pronators of forearm
What layers are the muscles of the anterior forearm divided into?
Superficial
Intermediate
Deep
What are the 4 muscles of the superficial anterior forearm
Pronator teres
Flexor carpi radialis
Flexor Carpi ulnaris
Palmaris longus
What is the action of the pronator teres?
Pronation of forearm
What is the action of the pronator teres?
Pronation of forearm
What is the innervation of the pronator teres muscle?
Median Nerve
What is the common origin of the superficial anterior forearm muscles?
Medial epicondyle of humerus
Apart from flexing the wrist which superficial anterior forearm muscle is involved in adduction of the wrist?
Flexor carpi ulnaris
What are the actions of the flexor carpi ulnaris?
Flexion at wrist
Adduction at wrist
Apart from flexing the wrist which superficial anterior forearm muscle is involved in abducting the wrist?
Flexor carpi radialis
What are the actions of the flexor carpi radialis?
Flexion at wrist
Abduction at wrist
Which superficial anterior forearm muscle is innervated by the ulnar nerve?
Flexor carpi ulnaris
Apart from the flexor carpi ulnaris which nerve innervates the other 3 superficial anterior forearm muscles
Median nerve
In which compartment of the forearm is the brachioradialis located?
Posterior/Extensor Compartment
On which joint does the brachioradialis act on?
Elbow joint
What is the innervation of the brachioradialis?
Radial nerve
What is the main action of the brachioradialis
Flexion at the elbow joint
Which muscles are contained in the intermediate group of the anterior forearm?
Flexor Digitorum Superficialis
Why is the flexor digitorum superficialis called this?
Because it is superficial to the flexor digitorum profundus
How many tendons does the flexor digitorum superficialis give rise to?
4
To which digits are the 4 tendons of the flexor digitorum superficialis attached to?
Metacarpal 2,3,4,5
On to which phalanx are the tendons of the flexor digitorum superficialis
Middle Phalanx
What is the action of the flexor digitorum superficialis
Flexion wrist
Flexion metacarpophlangeal joints (2,3,4,50
Flexion interphalangeal joints (2,3,4,5)
What is the innervation
of the flexor digitorum superficialis
Median Nerve
Name the muscles of the deep group of the anterior forearm
Flexor digitorum Profundus
Flexor pollicis longus
Pronator quadratus
What is the action of the flexor digitorum profundus?
Flexes distal interphalangeal joints (2,3,4,5)
Flexes metacarpophalangeal joints (2,3,4,5)
Flexes wrist
What is the main action of the FDP on the the wrist and finger joints?
Flexion
What is the innervation of the FDP? (flexor digitorum profundus?)
Medial half by ulnar nerve
Lateral half by median nerve
Why is the flexor digitorum profundus (FDP) said to have dual nerve supply?
Because half is innervated by the median nerve and half is innervated by the ulnar nerve
2 nerves supply this muscle
Onto which phalanx does the FDP tendons attach?
Distal phalanx
What is the action of the flexor pollicis longus?
Long flexor of the thumb
What shape is the pronator quadratus muscle?
Square shaped
What is the action of the pronator quadratus muscles?
Pronation of the forearm
What is the innervation of the pronator quadratus muscle?
Median nerve
Which nerve is the main nerve of the anterior compartment of the forearm?
Median nerve
Which muscles does the median nerve not supply in the forearm?
Flexor carpi ulnaris
Medial half of flexor digitorum profundus
Does the median nerve enter the hand by passing below or above the flexor retinaculum?
Below
How does the ulnar head enter the forearm
By passing between the heads of the flexor carpi ulnaris muscle
Which bone does the ulnar artery descend close to?
Ulnar bone
The ulnar nerve is …. to the ulnar artery
Medial
What are the 2 terminal branches of the brachial artery
Radial artery
Ulnar artery
Which arterial pulse can you feel at the distal third of the forearm medial to the tendon of flexor carpi radialis muscle?
Radial pulse
Is the carpal tunnel superficial or deep to the flexor retinaculum?
Deep
What are the contents of the carpal tunnel
Median nerve
4 tendons of the Flexor Carpi Superficialis
4 tendons of the Flexor carpi Profundus
1 tendon of flexor pollicis longus
Which is the most sensitive structure in the carpal tunnel that could be affected in carpal tunnel syndrome?
Median nerve
Which muscle of the forearm is continuous with the fascia of the palm shown above?
Palmaris longus
What are the 5 muscle compartments of the hand?
Thenar compartment Hypothenar compartment Adductor compartmnt Lumbricals and long flexor tendon (central compartment) Interosseous compartment
Which nerve innervates all thenar muscles?
Median nerve
Name the 3 thenar muscles
Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis
What is the action of the abductor pollicis brevis?
Abducts thumb
What is the action of the flexor pollicis brevis
Flexes MCP joint thumb
What is the action of the Opponens pollicis
Opposes thumb to little finger
Which muscles produce the hypothenar eminence on the medial palm?
Hypothenar muscles
Name the hypothenar muscles
Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi
Which nerve innervates all the hypothenar muscles?
Ulnar nerve
What do the muscle bellies of the thenar muscles produce?
The thenar eminence
What is the action of the abductor digiti minimi
Abducts little finger
What is the action of the flexor digiti minimi?
Flexes MCP of little finger
What is the action of the opponens digit minimi?
Rotates metacarpal of little finger towards palm
What are the 2 heads of the adductor pollicis?
Transverse head
Oblique head
Which nerve innervates the adductor pollicis muscle?
Ulnar nerve
What is the action of the adductor pollicis on the thumb?
Adducts the thumb
Which are the earthworm like muscles?
Lumbricals
From which long flexor tendon do these lumbricals originate?
Flexor digitorum profundus
What is the action of the lumbrical muscle?
Flex the fingers are the metacarpal joints
Simultaneously
Extend the interphalangeal joint 2nd to 5th digits
The medial 2 lumbricals are innervated by
Ulnar nerve
The lateral 2 lumbricals are innervated by the
Median nerve
Describe DAB and PAD
Dorsal interossei abduct the fingers
Palmar interossei adduct the fingers
What is the action of the dorsal interossei
Abduct the fingers
What is the action of the palmar interossei
Adduct the fingers
Which nerve innervates the dorsal and palmar interossei
Ulnar nerve
Which 2 arteries provide all the blood to the hand?
Ulnar and radial artery
What are the 2 palmar arches?
Superficial palmar arch
Deep palmar arch
Which artery is the main contributor of the superficial palmar arch?
Ulnar artery
Which artery is the main contributor of the deep palmar arch?
Radial artery
Which 2 nerves supply the muscles of the hand
Median nerve
Ulnar nerve
The median nerve enters the hand through
Carpal tunnel
The ulnar nerve is a branch of which cord of the brachial plexus?
Medial cord
What type of joint is the wrist joint
Synovial condyloid
Or
Synovial Ellipsoid
What movements can occur at the wrist joint
Flexion Extension Circumduction Adduction (ulnar deviation) Abduction (radial deviation)
Which carpal bones form the proximal row of the wrist joint?
Scaphoid
Lunate
Triquentral
Pisiform
Which bones forms the distal articular part?
Trapezium
Trapeziod
Capitate
Hamate
What is the action of the anterior muscles of the forearm on the wrist joint
Flexion
What is the action of the posterior muscles of the forearm on the wrist joint
Extension
Is the ulna part of the wrist joint?
No
Distally what forms the wrist joint
Proximal row of carpal bones
Proximally what forms the wrist joint
Distal end of radius
Articular disk
Which muscles are responsible for the abduction of wrist joint?
Abductor pollicis longus,
Flexor carpi radialis, Extensor carpi radialis longus
Extensor carpi radialis brevis
Which muscles are responsible for adduction of the wrist joint?
Extensor carpi ulnaris
Flexor carpi ulnaris
What is the action of the extensor carpi radialis longus and extensor carpi radialis brevis on the wrist joint?
Extension
Abduction wrist
What is the action of the extensor digitorum
Extensor of the fingers and wrist
What is the common extensor origin of the posterior forearm
Lateral epicondyle
What are the 7 superficial muscles of the posterior forearm?
Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digit minimi Extensor Carpi ulnaris Aconeus
Name the 3 muscles that extend or abduct the thumb in the deep posterior compartment
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
What is the innervation of the extensor digitorum
Radial nerve
What is the innervation of the extensor carpi radialis longus and brevis
Radial nerve
What is the innervation of the extensor carpi ulnaris
Radial nerve
What is the innervation of the brachioradialis
Radial nerve
What is the innervation of the supinator muscle
Radial nerve
What is the innervation of the extensor digit minimi?
Radial nerve
What is the main action of the extensor digitorum
Extends medial 4 digits at MCP joints
What is the main action of the extensor carpi radialis longus
Extension and abduction of the wrist
What is the main action of the extensorecarpi radialis brevis?
Extension and abduction of the wrist
What is the main action of the brachioradialis
Flexion at the wrist
Why is the brachioradialis muscle an exception to the rules?
Posterior compartment and innervated by radial nerve
Yet it is a flexor of the wrist not an extensor
What is the main action of the extensor carpi ulnaris?
Extension and adduction at the wrist
What is the main action of the supinator muscle
Supinates the forearm
What is the main action of the extensor digiti minimi
Extends the little finger
What is the innervation of the supinator muscle?
Radial nerve
What do the deep muscles of the posterior forearm:
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus act on?
Thumb
Which nerve innervates the
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus muscles of the thumb?
Posterior interosseous branch of radial nerve
What is the main action of the extensor pollicis longus
Extension at MCP and IP (interphalangeal) joint of thumb
What is the main action of the extensor pollicis brevis?
Extension of the thumb at the MCP joint
What is the difference between the extensor pollicis longus and brevis of the thumb?
Longus extends thumb at all joints
Brevis extends thumb at MCP joints only
What is the main action of the Abducuctor pollicis longus?
Abduction of the thumb
Where does the radial nerve divide into the superficial and deep branches?
Cubital fossa
What is the deep branch of the radial nerve called?
Posterior interosseous nerve
Which 2 carpal bones can you feel in the anatomical snuffbox?
Scaphoid
Trapezium
Which artery lies on the floor of the anatomical snuffbox
Radial artery
What makes up the medial (ulnar) border of the anatomical snuffbox?
Tendon of extensor pollicis longus
What makes up the lateral (radial) border of the anatomical snuffbox?
Tendon of the extensor pollicis brevis and abductor pollicis longus
