upper limb anatomy Flashcards
What muscles are supplied by anterior interosseous nerve?
Deep flexors of forearm:
-FDP radial half
-FPL
-pronator quadratus
What muscles are supplied by anterior interosseous nerve?
Deep flexors of forearm:
-FDP radial half
-FPL
-pronator quadratus
What are the branches of the median nerve? Where are they given off? What do they supply?
2 branches in forearm:
–> AIN: supplies deep muscles in anterior forearm
–>Palmar cutaneous: supplies skin of lateral palm
2 branches in hand:
–> recurrent motor branch (supplies thenar muscles)
–> Palmar digital branch: palmar aspect lateral 3.5 fingers
What muscles are supplied directly by the median nerve?
Superficial flexors in forearm:
-Flexor carpi radialis longus
-Flexor digitorum superficialis
-palmaris longus
-Pronator teres
Course of median nerve
-Formed in axilla by union lateral root from lateral cord and medial root from medial cord (C5-T1)
-Crosses from lateral to medial brachial artery middle of arm
-enters cubital fossa, lies deep to bicipital aponeurosis and median cubital vein and medial to brachial artery
-Supplies articular branches to elbow joint
-Enters forearm between 2 heads pronator teres: gives off ain
-Runs in forearm deep to FDS until just before wrist when it becomes superficial
-Palmar cutaneous branch arises 5cm proximal to wrist crease–> supplies sensation to thenar eminence
-Passes through wrist in carpal tunnel, gives off recurrent motor branch just distal to flexor retinaculum.
Which structures of flexor compartment forearm are not supplied by median nerve?
Flexor carpi ulnaris
ulnar half flexor digitorum profundus
How would you test anterior interosseous nerve?
OK sign: flexion IP joint of thumb, DIPJ index finger are impaired
Pinch test: weakness flexion distal phalanx thumb and index
Where does anterior interosseous nerve originate?
Arises between two heads pronator teres
What is origin of recurrent motor branch median nerve? What is its function? why is it clinically significant?
-In or just distal to carpal tunnel
-Hooks back to supply thenar muscles
-Can exit through or superficial to flexor retinaculum, can be injured in carpal tunnel
What is sensation of hand?
Volar:
-Radial 3.5 digits median
-Ulnar 1.5 digits ulnar
Dorsal
-Radial 3.5 supplied by radial nerve to PIPJ
-Distal two phalanx median
-Ulnar 1.5 digits ulnar nerve
Describe term ‘ulnar clawing’
-Lumbricals flex mcpj and extend IPJ
-Intrinsic muscles of hand denervated in distal ulnar nerve injuries
-Loss of ulnar two lumbricals results in hyperextension at MCPJ and flexion at ipj
Describe term ulnar paradox
-Clawing is more marked in distal injuries as the fdp tendons are still functional so the fingers can be flexed
-In more proximal injuries the FDP is denervated so the clawing is less marked
What muscles does ulnar innervate in forearm
Ulnar half FDP
Flexor carpi ulnaris
What does superficial branch ulnar nerve innervate in hand?
Palmaris brevis
Sensation to ulnar 1.5 digits
What is innervation to muscles in hand?
All ulnar except: one half LOAF
-Lateral two lumbricals
-Opponens pollicis
-Abductor pollicis brevis
-flexor pollicis brevis (superficial head)
Abductor pollicis longus innervation
Radial nerve
Flexor pollicis brevis deep head innervation:
Ulnar nerve
What muscles do the deep branch of the ulnar nerve innervate in the hand?
-Hypothenar muscles: Abductor digiti minimi, opponens digiti minimi, flexor digiti minimi brevis
-4x dorsal interossei, 4x palmar interossei
-Ulnar two lumbricals
-Adductor pollicis
-Deep head FPB
What muscles are supplied by Deep branch radial nerve
-Supinator
-Extensor carpi radialis brevis
What muscles are supplied by muscular branches radial nerve
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis longus
What muscles are supplied by posterior interosseous nerve?
-Extensor digiti minimi
-Extensor carpi ulnaris
-Extensor digitorum communis
-Extensor indicis
-Extensor pollicis longus + brevis
-Abductor pollicis longus
What are the branches of the radial nerve?
Muscular branches to triceps
Cutaneous branch
Posterior interosseous branch
What is sensory supply of radial nerve?
-most of the skin of the posterior forearm
-lateral aspect of the dorsum of the hand
-dorsal surface of the lateral three and a half digits
How would you test ulnar function in hand
-Abduct and adduct fingers
-Froment’s test: adduct thumb against index finger (positive if flexion of ipj instead of normal adduction-i.e. compensating for denervated adductor pollicis with FPL)
Nerves that supply thumb muscles
Ulnar:
-Adductor pollicis
-Flexor pollicis brevis (deep head)
Median
-Abductor pollicis brevis
-Opponens pollicis
-Flexor pollicis brevis (superficial head)
Radial nerve
-APL
-EPL
-EPB
What are the muscles supplied by the radial nerve and its branches?
Muscular branches from radial nerve:
Triceps
Anconeus
Brachioradialis
Extensor carpi radialis longus
Sensation over posterior arm and dorsum of forearm via posterior cutaneous branch
Deep branch
-Supinator
-Extensor carpi radialis brevis
Posterior interosseous
-Extensor digiti minimi
-Extensor carpi ulnaris
-Extensor digitorum communis
-Extensor indicis
-Extensor pollicis longus + brevis
-Abductor pollicis longus
Describe course of radial nerve
-Continuation posterior cord brachial plexus, nerve roots C5-T1
-Enters posterior compartement of arm via triangular interval with profunda brachii
-Gives off branches to long and lateral heads of triceps then lies in spiral groove
-Wraps around humerus laterally and gives off branch to medial head triceps
-Travels anterior to lateral epicondyle of humerus to enter cubital fossa
-Passes between two heads supinator
-Gives of PIN and continues as sensory nerve
Name muscles originating from common extensor origin
Tendon that attaches to lateral epicondyle of humerus
–> extensor carpi radialis brevis
–> extensor digitorum communis
–> extensor carpi ulnaris
–> extensor digiti minimi
Extensors originating from lateral epicondyle of humerus
Anconeus
Supinator
Name muscles attaching to lateral supracondylar ridge of humerus
Brachioradialis
Extensor carpi radialis longus
What attaches to Radius, ulna and interosseus membrane
Extensor indicis
EPL
EPB
APL
Describe origins of extensors
Lateral supracondylar ridge humerus (Brachioradialis, ECRL)
Lateral epicondyle of humerus: anconeus, supinator
Common extensor origin:
–> extensor carpi radialis brevis
–> extensor digitorum communis
–> extensor carpi ulnaris
–> extensor digiti minimi
Radius, ulna, interosseous membrane: EI, EPL, EPB, APL
Name branches of axillary artery
Semen tastes like sweet apple pie
Divided into 3 parts, according to relation to pec minor
1st part: superior to pec minor
-Superior thoracic
2nd part: Posterior to pec minor
-Thoracoacromial
-Lateral thoracic
3rd: inferior to pec minor
-Subscapular
-Anterior circumflex humeral
-Posterior circumflex humeral
5 Terminal branches of brachial plexus and root values
Musculocutaneous C5-C7
Axillary (C5-C6)
Radial C5-T1
Median C5-T1
Ulnar C8-T1
Boundaries antecubital fossa
Superior: line connecting medial and lateral epicondyles of humerus
Medial: lateral border pronator teres
Lateral: medial border brachioradialis
Floor: Brachialis medially, supinator laterally
Roof: skin/subcut tissue, reinforced by bicipital aponeurosis
Structures in and on antecubital fossa
Lateral to medial: Really need beer to be at my nicest
-Radial nerve
-Biceps tendon
-Brachial artery
-Median nerve
Structures on surface of cubital fossa: 2 laterl, 3 medial
-Cephalic vein
-Lateral cutaneous nerve of forearm
-Medial cutaneous nerve of forearm
-Median cubital vein
-Basilic vein
Branches from medial cord brachial plexus, muscles they innervate
Medial pectoral nerve: Pec minor, part of pec major (lateral = less, medial = more)
Medial cutaneous nerve of arm
Medial cutaneous nerve of forearm
Medial root median nerve
Ulnar nerve
Name boundaries of carpal tunnel
Superior: flexor retinaculum
Inferior: carpal bones
How many structures pass through carpal tunnel?
10
Name structures which pass through carpal tunnel (under flexor retinaculum)
4x FDS
4x FDP
Median nerve
FPL tendon
What is the relation of recurrent branch MN to carpal tunnel?
arises in or distal to carpal tunnel, then hooks back to supply thenar muscles
What are the attachments of flexor retinaculum?
Hook of hamate and pisiform on ulnar side
Tubercle of scaphoid and ridge of trapezium on radial side
Structures which pass over flexor retinaculum
something from each nerve
Palmaris longus
Palmar cutaneous branch median nerve
ulnar nerve and artery (enter hand through guyon’s canal
What are the borders of the triangular interval? What passes through it?
Medial: long head triceps
Lateral: humerus
Superior: teres major
Structures passing through:
–> radial nerve
–> profunda brachii artery
How is Superficial palmar arch formed? where is it anatomically?
-Formed predominantly by superficial branch ulnar artery, anastomoses with superficial palmar branch radial artery
-Lies just distal to kaplan’s cardinal line (interdigital fold to hook of hamate)
How is deep palmar arch formed?
-Formed predominantly by terminal branch radial artery, anastamoses with deep branch ulnar artery
Where do lumbricals originate and insert?
-Arise from radial aspect fdp tendons in palm
-Insert into extensor expansions on dorsum of digits near MCPJ
-Therefore Flex MCPJs, extend IPs
Where do lumbricals originate and insert? What are their actions?
-Arise from radial aspect fdp tendons in palm
-Insert into extensor expansions on dorsum of digits near MCPJ
-Therefore Flex MCPJs, extend IPJs
Which nerves are susceptible to injury following fracture of the humerus?
-Humeral neck: axillary
-Humeral shaft: Radial (travels in spiral groove)
-Supracondylar: median nerve
-Ulnar nerve: medial epicondyle
Describe course of ulnar nerve
Arises in axillla from medial cord brachial plexus, nerve root C8-T1
Runs medial to brachial artery
Passes posterior to medial epicondyle and through cubital tunnel to enter forearm
Passes between two heads flexor carpi ulnaris to enter flexor compartment
Runs on ulnar border forearm deep to flexor carpi ulnaris
Passes superficial to flexor retinaculum in Guyon’s canal, divides into superficial sensory branch and deep motor branch
Which muscles are responsible for abduction at shoulder
First 30 degrees: Supraspinatus
30-100: lateral fibres deltoid
>100: rotation of scapula on thoracic wall aided by serratus anterior, levator scapulae, trapezius
Name muscles that attach to medial and lateral lips intertubercular groove of humerus
Lateral lip: pec major
Middle: lat dorsi
Medial: teres major
Describe how injury to PIN presents clinically
-Inability to exend MCP joints
-Incomplete wrist drop: ECRL still intact (radial deviation) as this receives innervation direct from radial nerve
Describe how injury to radial nerve below level of spiral groove presents clinically
Complete wrist drop
Inability to extend MCP joints
Preservation of elbow extension as branches to triceps proximal to this level
Name muscles that arise from common flexor origin and describe location of common flexor origin
(medial epicondyle of humerus)
Superficial forearm flexors
Pronator teres
flexor carpi radialis longus
palmaris longus
flexor carpi ulnaris
flexor digitorum superficialis
Name branches arising from lateral cord, muscles they innervate
Lateral cord brachial plexus branches
-Lateral pectoral nerve (part of pec major)
-Lateral root median nerve
-Musculocutaneous nerve (BBC)
Name branches arising from posterior cord, and muscles they supply
ULTRA
Upper subscapular nerve (upper part subscapularis)
Lower subscapular nerve (lower part subscapularis, teres major)
Thoracodorsal nerve (to lat dorsi)
Radial nerve
Axillary nerve (deltoid, teres minor)
Boundaries quadrangular space
Superior: teres minor
Lateral: humerus
Medial: long head triceps
Inferior: Teres major
Structures passing through quadrangular space
Axillary nerve
Posterior circumflex humeral
Structures passing through clavipectoral fascia
Cephalic vein
thoracoAcromial artery
Lymphatics
Lateral pectoral nerve
Levels of axillary lymph nodes
- Below pec minor
- Behind pec minor
- Above (and medial to) pec minor
Structures that can be damaged during axillary node clearance
Axillary vein
Intercostobrachial nerve (cutaneous nerve to axilla and lateral chest wall)
Thoracodorsal nerve (lat dorsi)
Long thoracic nerve
Origin and insertion of biceps brachii
O:
-Long head: supraglenoid tubercle
-Short head: coracoid process
I:
-Radial tuberosity
-Bicipital aponeurosis into fascia of forearm
Origin and insertion coracobrachialis
Origin: coracoid process
Insertion: Humeral shaft
Brachioradialis origin and insertion
Origin: lateral supracondylar ridge of humerus
Insertion: styloid process of radius
ECRL origin and insertion
O: lateral epicondyle and lateral supracondylar ridge of the humerus
I: dorsal surface of the second metacarpal
Boundaries of anatomical snuff box
Radial: APL, EPB
Ulnar: EPL
Proximal: Radial styloid process
Floor: scaphoid and trapezium
Contents of anatomical snuffbox
Contents: (superficial to deep)
-Cephalic vein
-Superficial teraminal branches radial nerve
-ECRL + brevis tendon, lie on ulnar side of snuffbox
-Radial artery
-Bones (radial styloid, scaphoid, trapezium, base 1st metacarpal
Muscles attaching to coracoid process
Coracobrachialis
shorthead biceps brachii
Pec minor (insertion)
Nerves arising from nerve roots in brachial plexus
-C5: dorsal scapular
-C5-C6: nerve to subclavius
-C5-7: long thoracic nerve
Nerves arising from trunks in brachial plexus
-Suprascapular nerve (c5-C6): upper trunk
Muscles that make up rotator cuff and their innervation
Supraspinatus: suprascapular nerve (C5-C6)
Infraspinatus: suprascapular nerve (Upper trunk brachial plexus, C5-C6)
Subscapularis–> upper and lower subscapular nerven –> posterior cord brachial plexus
Teres minor–>axillary nerve, C5, C6 –> posterior cord brachial plexus
Which nerve supplies latissumus dorsi? Where does it originate from?
Thoracodorsal nerve (from posterior cord brachial plexus)
What nerve supplies teres major?
Lower subscapular nerve (posterior cord brachial plexus)
What nerve supplies rhomboids?
Dorsal scapular nerve (from c5 nerve root)
What nerve supplies trapezius?
Accessory nerve
What is a monteggia fracture?
fracture of the proximal ulna associated with dislocation of the radial head
Describe where radial nerve is most susceptible to injury
Axilla: trauma, ill fitting crutches
At level of spiral groove: humeral shaft fracture
At or below level of elbow: monteggia fracture, elbow dislocation
Arcade of frohse (supinator tunnel): PIN most vulnerable at this level
Which structures in flexor compartment of forearm not supplied by MN?
Flexor carpi ulnaris
Ulnar half FDP
Describe term ulnar paradox
-Ulnar clawing of little and ring fingers is more marked in distal lesions than in proximal lesions
-This is because in proximal lesions, the FDP tendons are denervated, therefore the finger cannot be flexed
Upper limb myotomes
c5: shoulder abduction (biceps)
C6: elbow flexion
C7: Elbow extensors (triceps)
C8: Finger flexors
T1: Finger abductors
