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