upper limb Flashcards
What ventral rami supply the brachial plexus?
C5,6,7,8 + T1
What roots make up the Superior trunk of the brachial plexus?
C5+C6
What roots make up the middle trunk of the brachial plexus?
C7
What roots make up the Inferior trunk of the brachial plexus?
C8+T1
What happens to each of the trunks of the brachial plexus?
bifurcate into anterior and posterior divisions
What do anterior divions supply?
Flexors/ anterior
What do posterior divions supply?
extensors/ posterior
What do the divisions of the brachial plexus become?
cords
What makes up the Lateral cord of the brachial plexus?
Anterior divisions of superior and middle trunks
what makes up the posterior cord of the brachial plexus?
posterior divisions of superior, middle and inferior trunks
what makes up the medial cord?
Anterior division of inferior trunk
Why are the cords named the way they are?
about relation to axillary artery
What does the lateral cord become?
musculocutaneous nerve and some of the median nerve
what does the posterior cord become?
Radial nerve and axillary nerve
What does the medial cord become?
Ulnar nerve and some of the median nerve
What are other branches off the posterior cord?
upper subscapular, lower subscapular + thoracodorsal nerves
Where does the long thoracic nerve come from?
roots of C5,6,7
What does the brachial plexus supply?
motor and sensory innervation to upper limb
Where does the dorsal scapular nerve arise from?
C5 root
What does the DSN supply?
levator scapulae, Rhomboid major and minor
What does the LTN innervate?
serratus anterior muscle
where does the suprascapular nerve arise from?
superior trunk
What does the suprascapular nerve supply?
supraspinatus and infraspinatus muscles
Where do the roots/trunks of the brachial plexus exit?
from between anterior and middle scalene muscles on top of the subclavian artery
What myotome is C5 root associated with?
Shoulder abduction
what myotome is C6 root associated with?
flexion of elbow
what myotome is C7 root associated with?
extension of elbow
what myotome is C8 root associated with?
finger flexion
What myotome is the T1 root associated with?
Finger abduction
Where does the lateral pectoral nerve arise?
lateral cord of BP
What does the lateral pectoral nerve innervate?
pec major
Where does the medial pectoral nerve arise?
medial cord of BP
What does the medial pectoral nerve innervate?
pec major and minor
What nerve branches are given off by the medial cord of BP?
medial pectoral, medial cutaneous nerve of arm and MCN of forearm
What branches arise from the posterior cord of BP?
upper and lower subscapular nerves, thoracodorsal nerve
What do the upper and lower sub scapular nerves innervate?
subscapularis muscle
what does the thoracodorsal nerve innervate?
latissimus dorsi muscle
What does the axillary nerve innervate?
deltoid, teres minor muscle
also lateral cutaneous nerve of the arm
What does the radial nerve innervate?
triceps and forearm extensor muscles
also superficial cutaneous branch of radial nerve (supplies back of the hand)
What does the musculocutaneous nerve innervate?
biceps, brachialis, coracobrachialis muscles
also lateral cutaneous nerve of forearm
What does the median nerve innervate?
forearm flexors (only radial half of FDP) + thenar muscles + 1st and 2nd lumbricals
also has superficial cutaneous branch supplies lateral palmar 3.5 fingers and dorsal tips of those fingers
What does the ulnar nerve innervate?
ulnar half of FDP, flexor carpi ulnaris, ulnar side intrinsic hand muscles (PADs, DABs)
also sensory branch ulnar half of ring and whole little finger front and back
What are the components of the scapulothoracic joint?
scapula, thoracic ribs
what are the possible actions of the scapulothoracic joint?
elevation/depression, abduction/adduction, upward/downward rotation
What are the attachments of the trapezius muscle?
Superiorly: external occipital protuberance
Medially: nuchal ligament from skull to C7 and spinous processes from C7 to T12
Laterally: superior spine of scapula, acromion, lateral 1/3 of clavicle
What is the innervation of trapezius?
spinal accessory nerve (CNXI)
Where does levator scapulae attach?
superiorly: transverse processes of upper cervical vertebrae
inferiorly: superior angle of scapula
Where does rhomboid minor attach?
Medially: spinous process C7 + T1
Laterally: medial margin of the scapula
Where does rhomboid major attach?
medially: t2-t5 spinous processes
laterally: medial margin of scapula
What nerve innervates levator scapulae, rhomboid major and minor?
Dorsal scapular nerve
Where does the dorsal scapula nerve arise from?
C5 ventral ramus
Where does serrates anterior attach?
Ribs 1-8
attaches to anterior medial margin of scapula
What innervates serratus anterior?
LTN
Where does pectorals minor attach?
Ribs 3-5
inserts on coracoid process
What sort of joint is the glenohumeral joint?
ball and socket synovial joint
(it is the most moveable synovial joint)
What are the bony components of the glenohumeral joint?
Head of humerus
glenoid cavity of the scapula
what structures help to stabilise the glenohumeral joint (6)?
glenoid labrum, joint capsule, coracohumeral lig, coracoacromial lig, coracoclavicular lig, acromioclavicular lig
what is the glenoid labrum?
fibrocartilaginous ring that articulates with glenoid and humerus that increases the depth of the cavity by 50% and also has a “suction effect to keep humeral head adhered
What attaches within the glenoid labrum?
long head of biceps
tendon goes through inter tubercular groove and in
why is there laxity within the glenohumeral joint capsule and why is this a problem?
has an axillary fold inferiorly to allow laxity to allow abduction of shoulder
this permits dislocation especially inferiorly
What 4 muscles make up the rotator cuff?
supraspinatus, infraspinatus, teres minor, subscapularis
Where does supraspinatus attach and run?
sits in supraspinus fossa of scapula
attaches from posterior medial border of scapula, runs deep to AC joint and attaches to greater tubercle of humerus
What does supraspinatus do?
first 15 degrees glenohumeral abduction
Where does infraspinatus attach?
from posterior medial border of scapula inferior to the spine of scapula
Inserts on greater tubercle of humerus
Where does teres minor attach?
lateral margin of the scapula to greater tubercle of humerus just below insertion of infraspinatus
What is the function of infraspinatus and teres minor?
external rotation of the humerus
Where does the subscapularis muscle attach?
from anterior medial border of scapula to the lesser tubercle of the humerus
What is the function of subscapularis?
internal rotation of the humerus
What is the common function of the rotator cuff muscles?
stabilise the GH joint
What innervates Suparspinatus?
Suprascapular nerve
Where does the supra scapular nerve arise?
superior trunk of BP
C5+6
What innervates infraspinatus?
supra scapular nerve
What innervates the subscapularis muscle?
Upper and lower subscapular nerves
Where do the upper and lower subscapulr nerves arise from?
branches off the posterior cord of the BP
What are the attachments of the deltoid muscle?
Lateral 1/3 of clavicle, acromion and round all the way along spine of scapula
Inserts on deltoid tuberosity ~1/2 way along lateral shaft of humerus
How many bellies does the deltoid muscle have and what are they?
3
anterior, middle and posterior
What is the function of anterior deltoid?
GH flexion
What is the function of middle deltoid?
GH abduction
but only after supraspinatus initiates the movement of first 15 degrees
What is the function of posterior deltoid?
GH extension
What is the innervation of deltoid?
axillary nerve
Where does the axillary nerve come from?
posterior cord branch of BP
What is the innervation of teres minor?
Axillary nerve
What are the 3 inter tubercular groove muscles?
pec major
teres major
latissimus dorsi
What are the attachments of pec major?
medial 1/3 of clavicle and border of sternum + costal cartilage
insert on lateral lip of inter tubercular groove
What are the attachments of Teres major?
Inferior margin of the scapula
passes to anterior of humerus
inserts on inter tubercular groove
What are the attachments of latissimus dorsi?
Spinous processes of T7-sacrum
inserts on inter tubercular groove
What is the innervation of latissimus dorsi?
Thoracodorsal nerve
Where does thoracodorsal nerve arise?
Branch from posterior cord of BP
What allows supination and pronation at the elbow?
Radial head sits in radial notch on the ulna proximally
Distal ulna sits in ulna notch in radius distally
What are the anterior and posterior parts of the proximal ulna called?
Posterior - olecranon
anterior - coronoid process
What are the components of the elbow joint?
Distal humerus - trochlea (medial 2/3 of articulating distal humerus) and capitulum (lateral 1/3 of articulating distal humerus)
trochlea notch (ulna)
Radial head
What are the ligaments of the elbow joint?
joint capsule
radial collateral
ulnar collateral
annular ligament
What is the joint capsule a continuation of?
periosteum
Where does annular ligament sit?
ring around radial head
What are the 4 brachial muscles?
biceps brachii, coracobrachialis, brachialis, triceps brachii
What do bicpes brachii, coracobrachialis and brachialis have in common?
All anterior, flex elbow, innervated by musculocutaneous nerve
What is triceps brachii innervated by?
radial nerve
What are the 2 heads of biceps brachii?
Long head and short head
Where does biceps brachii attach?
Long head: glenoid labrum through intertubercular groove
Short head: coracoid process.
Both insert medially on radius on radial tuberosity
Where does coracobrachialis attach?
coracoid process down to medial humerus
What is the role of biceps brachii?
elbow flexion
also principal supinator of the forearm
What innervates coracobrachialis?
MC nerve
It runs through it
Where does brachialis attach?
Anterior humerus to coracoid process of ulna
Where does triceps brachii attach?
infraglenoid tubercle of scapula, proximal (lateral head) and distal (medial head) humerus
common insertion on olecranon process of ulna
What is the course of the radial nerve in the upper arm?
lies deep to triceps and runs in spiral groove of humerus to end up lateral on arm.
What are the 8 forearm flexor muscles?
Superficial: Pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris
intermediate: flexor digitorum superficialis
Deep: Flexor pollicis longus, flexor digitorum profundus, pronator quadratus
What are the attachments of pronator teres?
medial epicondyle of humerus
to lateral radius
What are the attachments of flexor carpi radialis?
medial epicondyle of humerus
to base of 2nd/3rd metacarpals
What are the attachments of palmaris longus?
medial epicondyle of humerus
to palmar apeneurosis (not onto a bone)
What are the attachments of flexor carpi ulnaris?
medial epicondyle of humerus
to pisiform and base of 5th metacarpal
What are PT, FCR + PL muscles of forearm innervated by?
median nerve
Where does Flexor digitorum superficialis attach?
Medial epicondyle and medial radius
4 separate tendons through CT to middle phalanges of 2nd-5th digits. It bifurcates at each proximal phalange to attach on 2 different parts of middle phalange (does not cross DIP)
Where does flexor pollicis longus attach?
medial and distal radius, through CT, and attaches on distal phalange of thumb
What are the attachments of flexor digitorum profundus?
ulna, through CT, inserting on distal phalanges digits 2-5
What is unique about innervation of FDP?
radial half innervated by median nerve, ulna half innervated by ulna nerve
what are the attachments of the pronator quadratus?
distal ulna and radius
What makes the margins of the carpal tunnel?
Carpal bones, flexor retinaculum
What are the contents of the carpal tunnel?
4 tendons from FDS
4 tendons from FDP
FPL tendon
median nerve
What are the 12 muscles in the forearm extensor compartment?
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
extensor digitorum
extensor digiti minimi
extensor indices
brachioradialis
supinator
anconeus
What are the three forearm extensors that act on the carpal bones?
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
what are the three extensor forearm muscles that act on the thumb?
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
What are the three forearm extensor muscles that act on fingers?
extensor digitorum
extensor digiti minimi
extensor indices
What are the attachments of extensor carpi radialis longus?
lateral epicondyle
base of 2nd metacarpal
What are the attachments of extensor carpi radials brevis?
lateral epicondyle
base of 3rd metacarpal
What are the attachments of extensor carpi ulnaris?
lateral epicondyle
base of 5th metacarpal
What is the action of the extensor carpi muscles?
wrist extension
Are the policies extensor muscles deep or superficial?
deep
What are the attachments of abductor pollicis longus?
Proximal radius
base of 1st metacarpal
What are the attachments of extensor pollicis brevis?
Radius/interosseous membrane
Proximal phalanx of thumb
What are the attachments of extensor pollicis longus?
ulna
distal phalanx of thumb
What are the attachments of extensor digitorum communis?
lateral epicondyle
4 tendons to distal phalanx of digits 2-5 (extensor expansion hood)
What is the action of EDC?
extend wrist + MCP joints
What are the main extensors of interphalangeal joints?
lumbrical muscles
What are the attachments of extensor digiti minimi?
lateral epicondyle
distal phalanx of 5th digit
What are the attachments of extensor indices?
Distal ulna
distal phalanx of 2nd digit
What are the attachments of brachioradialis?
lateral supracondylar ridge
courses along front of elbow
inserts distal radius anteriorly
What is the action of brachioradialis?
elbow flexion
What are the attachments of supinator?
proximal radius and ulna
What are the attachments of anconeus?
olecranon process
lateral epicondyle
What is the common innervation of the forearm extensor muscles?
radial nerve
What are the borders of anatomical snuff box?
EPL medially
EPB laterally
scaphoid bone is floor
APL even more lateral
what runs in the anatomical snuff box?
radial artery
superficial radial nerve
What are the 6 intrinsic hand muscle locations?
thenar muscles
hypothenar muscles
lumbrical muscles
adductor pollicis
palmar interossei
dorsal interossei
What are the three thenar muscles?
Abductor pollicis brevis
flexor pollicis brevis
opponens pollicis
What is the innervation of the thenar muscles?
recurrent branch of median nerve
What are the three hypothenar muscles?
abductor digiti minimi
flexor digiti minimi
opponens digiti minimi
What innervates the hypothenar muscles?
ulna nerve
Where do the lumbrical muscles attach?
FDP tendons (palmar surface of hand)
inserts onto extensor expansion hood on back of finger
what is the action of the lumbrical muscles?
Flexes MCP
extend IP joints
What is the innervation of the lumbrical muscles?
1+2 - median nerve
3+4 - ulna nerve
What are the attachments of adductor pollicis?
has a transverse and oblique head
lateral 3rd metacarpal to proximal phalanx of thumb
What is the action of Doral interosseous muscles?
Abduct (DAB)
How many Dorsal interosseous muscles are there?
4
what is the action of palmar interosseous muscles?
adduct (PAD)
How many palmar interosseous muscles are there?
3
What is the innervation of the interosseous muscles?
ulna nerve
What is the course of the median nerve + its branches?
arises from medial and lateral cords of BP
passes through axilla and upper arm with no branches
passes infant of medial supracondylar ridge of humerus
enters the forearm and branches to supply: forearm flexors (PT, FCR, PL, FDS)
Anterior interosseous nerve (runs along interosseous membrane and innervates 1/2 FDP, FPL, PQ)
Palmar cutaneous branch
courses through carpal tunnel
branches after carpal tunnel:
recurrent branch - supplies thenar muscles
innervates 1st and 2nd lumbricals
Digital cutaneous branch supplies palmar surface of thumb to half of 4th finger. also distal dorsal tips of these fingers.
What is the course of the ulna nerve + its branches?
Arises from medial cord of BP
courses through axilla and arm with no branches
passes behind medial epicondyle in the cubital tunnel
Branches in the forearm:
supplies FCU, 1/2 FDP
passes through Guyana’s canal to enter the hand
Branches to supply:
cutaneous innervation to palmar + dorsal lateral 1.5 fingers
supplies hypothenar muscles, lumbricals 3+4, PADs + DABs, Adductor pollicis
What is the course of the radial nerve + its branches?
arises from posterior trunk of BP
runs in radial groove posterior to humerus and innervates triceps in upper arm
crosses elbow anterior to lateral epicondyle
crosses to posterior forearm to supply:
all 11 forearm extensors
cutaneous branch to supply dorsal medial 2.5 fingers except tips
