ANAT: Upper Limb (Upper Arm) Flashcards
label all parts of this image
- A = axilla
- B = arm
- C = cubital fossa
- D = forearm
- E = hand
- F = digits
where are the flexor and extensor muscles of the upper limb housed (distal to the axilla)?
- flexor muscles: anterior
- extensor muscles: posterior
how many nerves innervate the anterior and posterior compartments of the upper limb (distal to the axilla)?
- anterior: 3
- posterior: 1
anatomically, where does the brachial plexus sit?
- roots: begin at the intervertebral foramina and sit between the middle and anterior scalene muscles
- trunks: between middle and anterior scalenes
- divisions: deep to the clavicle
- cords: deep to pectoralis minor
- terminal branches: emerge at the lateral border of pec minor
do posterior or anterior rami form nerve plexus?
- only anterior because limbs originate from the front of the body, not the back
label all components
- A = intervertebral foramen (hole)
- B = ventral root of spinal nerve
- C = dorsal root ganglion
- D = mixed spinal nerve
- E = posterior ramus
- F = anterior ramus
label A, B, C, D, E
- A = roots
- B = trunks
- C = divisions
- D = cords
- E = terminal branches
- Real Tradies Drink Cold Beer
label F, G, H, I, J
- F = superior trunk
- G = middle trunk
- H = inferior trunk
- I = anterior divisions
- J = posterior divisions
label K, L, M
- K = lateral cord
- L = posterior cord
- M = medial cord
label N, O, P, Q, R
- N = musculocutaneous nerve
- O = axillary nerve
- P = radial nerve
- Q = median nerve
- R = ulnar nerve
musculocutaneous nerve:
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- C5, C6, C7
- motor: anterior flexor muscles of arm (biceps brachii, brachialis, coracobrachialis)
- sensory: anterolateral forearm
- starts as most lateral nerve from lateral cord, pierces coracobrachialis, runs between brachialis and biceps brachii, then continues as lateral cutaneous nerve down forearm
axillary nerve:
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- when is it at risk of damage
- C5, C6
- motor: deltoid + teres minor
- sensory: regimental badge area (kind of over the deltoid)
- starts from posterior cord (superior to radial nerve and posterior to axillary a.) and ends @ deltoid and teres minor
- risk of damage during shoulder dislocation as it supplies glenohumeral joint
radial nerve
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- when is it likely to be injured
- all 5 roots (C5, C6, C7, C8, T1)
- motor: posterior upper arm (triceps brachii), posterior forearm - EXTENSORS
- sensory: posterior arm and forearm, dorsal surface of lateral 1.5 digits
- RUNS ABOVE TERES MAJOR, very close to humerus, between triceps heads. superficial sensory branch wraps around dorsal surface of thumb and deep motor branch turns into interosseous branches
- injury: midshaft humeral fracture (wrist drop)
median nerve:
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- when is it at risk of injury
- all 5 roots (C5, C6, C7, C8, T1)
- motor: anterior forearm EXCEPT flexor carpi ulnaris and medial half of flexor digitorum profundus (ulnar nerve), thenar eminence, lateral 2 lumbricals (II and III phalanges)
- sensory: lateral 3 digits + on dorsal surface and lateral 3.5 digits on palmar surface
- runs medially down upper arm, passes thru cubital fossa and between 2 heads of pronator teres, goes thru carpal tunnel to supply lateral hand muscles
- at risk: distal humeral fractures, compression in the carpal tunnel
ulnar nerve
- what roots is it made up of
- motor innervation
- sensory innervation
- where does it run anatomically
- when is it at risk?
- C8, T1
- motor: flexor carpi ulnaris, medial half of flexor digitorum profundus, all intrinsic hand muscles except thenar eminence and lateral 2 lumbricals (these are median nerve)
- sensory = medial 1.5 digits on palmar and dorsal surfaces
- runs very medial all the way down the arm, posterior to medial epicondyle
- at risk in distal humerus (medial epicondyle) and wrist compression
what is A and what is its function?
- dorsal scapular nerve
- innervates levator scapulae (A), rhomboids major (C), and rhomboids minor (B)
what is B and what is its function?
- long thoracic nerve
- innervates serratus anterior
what is C and what is its function?
- suprascapular nerve
- innervates supraspinatus (A) and infraspinatus (B)
what is D and what is its function?
- nerve to subclavius
- innervates subclavius
what is E and what is its function?
- E = lateral pectoral nerve - innervates upper pectoralis major
what are I, J and K and what is K’s function?
- I = medial cutaneous nerve of the forearm
- J = medial cutaneous nerve of the arm
- K = medial pectoral nerve - innervates lower pectoralis major and pectoralis minor
what are F, G and H and what do they innervate?
- F = lower subscapular nerve - innervates lower subscapularis and teres major
- G = middle subscapular/thoracodorsal nerve - innervates latissimus dorsi and teres major
- H = upper subscapular nerve - innervates upper subscapularis
label all dermatomes
- A = C3
- B = C4
- C = C5
- D = C6
- E = C7
- F = C8
- G = T1
upper limb myotomes
- C5 arms out wide: shoulder abduction
- C6 smell your wrist: elbow flexion and wrist extension
- C7 no zombies in heaven: elbow extension and wrist flexion
- C8 you’re doing great: thumb extension and ulnar deviation
- T1 one and done: finger abduction
describe the arterial supply of the entire arm
- subclavian artery (under clavicle)
- turns into axillary artery after clavicle)
- axillary branches into anterior and posterior circumflex humeral arteries
- axillary continues to become brachial artery @ inferior border of teres major
- brachial branches into profunda brachii and then continues, branching off into radial and ulnar arteries
- radial and ulnar arteries join together to create the superficial and deep palmar arches
- superficial palmar arch becomes common digital arteries
what do the axillary and brachial arteries supply?
- axillary: axilla, pectoral region, shoulder joint
- brachial: all upper arm muscles (anterior and posterior)
how does the axillary artery relate to the cords of the brachial plexus?
- the cords are named relative to the axillary artery (medial, lateral, posterior)
describe the 3 parts of the axillary artery
- 1st part: medial to pecs minor
- 2nd part: deep to pecs minor
- 3rd part: lateral to pecs minor
what do the radial and ulnar arteries supply?
- radial: posterolateral component of forearm inc. thumb and index finger
- ulnar: anteromedial component of forearm
label all components
- A = axillary artery
- B = posterior humeral circumflex artery
- C = anterior humeral circumflex artery
- D = subscapular artery
- E = brachial artery
describe the superficial veins of the whole arm and which is the most common for venepuncture?
- cephalic vein (lateral) and basilic vein (medial): both drain into axillary vein
- median cubital vein: connects cephalic and basilic veins in cubital fossa
- median antebrachial vein: diff anatomical variations for where it drains into
- ANY of these veins are used for venepuncture h/w median cubital vein is the most common
describe the deep veins of the whole arm
- basically same as arteries
describe the axillary lymph nodes
- apical nodes (@ the apex)
- central nodes
- subscapular nodes (posterior)
- pectoral nodes (anterior)
- humeral nodes (lateral) - furthest from breast
contents of axilla
- axillary v. and a.
- lymph nodes for upper limb
- brachial plexus (cords and terminal branches)
- short head of biceps + coracobrachialis
describe the base of the axilla
- armpit skin
- subcutaneous tissue
- deep axillary fascia
describe the anterior wall of the axilla
- pecs major and minor
- subclavius
- clavipectoral fascia
describe the apex of the axilla
- 1st rib
- lateral 1/3 of the clavicle
- coracoid process
describe the posterior wall of the axilla
- subscapularis
- teres major
- latissimus dorsi tendon
describe the medial wall of the axilla
- serratus anterior
describe the lateral wall of the axilla
- bicipital groove of humerus
- coracobrachialis
- short head of biceps
label A, B, C, D
- A = medial border
- B = superior angle
- C = superior border
- D = acromion
label E, F, G, H
- E = acromial angle
- F = lateral angle
- G = lateral border
- H = inferior angle
anatomical vs surgical neck of humerus
- surgical = where the shaft starts
- anatomical = more superior, where the epiphyseal plate is
3 types of humeral fractures and what structures are at risk?
- proximal (surgical neck = most common) - damage axillary nerve and posterior circumflex artery (FOOSH)
- midshaft - damage radial nerve + profunda brachii
- supracondylar (distal) - most likely to damage ulnar nerve due but also radial and median nerve
glenoid labrum
- extra fibrocartilage around the glenoid fossa which increases the SA of the point of articulation
- prevents dislocation
what are A, B, C and D?
- A = acromion (superior and posterior to coracoid)
- B = coracoid process
- C = head of humerus
- D = glenoid fossa
what are E, F, G and H?
- E = greater tubercle (posterolateral)
- F = lesser tubercle (anteromedial)
- G = subscapular fossa
- H = supraspinous fossa
what are I, J, K and L?
- I = infraspinous fossa
- J = spine of scapula
- K = deltoid tubercle
- L = suprascapular notch
what are A, B and C?
- A = coracoacromial ligament
- B = coracohumeral ligament
- C = glenohumeral ligament
what are A and B?
- A = subacromial bursa: bursitis causes pain in 70-120 degrees of abduction
- B = subscapular bursa
what are A, B, C, D and E?
- A = periosteum
- B = joint capsule
- C = articular cartilage
- D = synovial membrane
- E = synovial/joint cavity containing synovial fluid
3 ligaments which support the AC joint
- acromioclavicular
- coracoclavicular (formed by conoid and trapezoid ligaments)
what are A, B, C and D and what are their functions?
- A = supraspinatus (abduction)
- B = infraspinatus (external rotation)
- C = teres minor (external rotation)
- D = subscapularis (internal rotation)
what are A and B and what are their functions?
- A = deltoid (abduction 15-90˚)
- B = teres major (adduction)
what are A, B, C and D?
- A = trapezius (scapular rotation)
- B = levator scapulae
- C = rhomboids minor
- D = rhomboids major
what are A, B, C and D?
- A = pectoralis major
- B = pectoralis minor (deep to pec major)
- C = subclavius
- D = serratus anterior (scapular protraction and upward rotation)
why is the rotator cuff so stable?
- all multipennate muscles which means they create little movement when they contract
- work together to keep head of humerus against glenoid fossa during movement
which muscles attach to the greater and lesser tubercle of the humerus?
- greater: supraspinatus, infraspinatus, teres minor (posterior, from medial to lateral - SIT)
- lesser: subscapularis (anterior)
which position is the most susceptible to shoulder dislocation
- abduction and external rotation b/c least stability (no muscles in the anterior/inferior position)
what are A, B, C and D? (biceps brachii)
- what movements can the biceps do?
- describe its vasculature
- A = long head (lateral): travels thru intertubercular groove and attaches onto supraglenoid tubercle (right above glenoid labrum)
- B = short head (medial): originates at coracoid process
- C = biceps tendon which attaches to radial tubercle
- D = bicipital aponeurosis (fanning out of tendon to disperse force), attaches to forearm fascia
biceps brachii:
- describe its origin and insertion
- describe its innervation
- describe its arterial supply
- what movements is it responsible for?
- origin: short head originates @ coracoid process, long head originates @ bicipital groove
- insertion: radial tuberosity and bicipital aponeurosis
- innervation: musculocutaneous n.
- arterial: brachial and anterior circumflex humeral a.
- flexion and supination
what is A?
- describe its origin and insertion
- describe its innervation
- describe its arterial supply
- what movement is it responsible for?
- brachialis
- origin: distal humerus and intermuscular septum
- insertion: proximal ulna
- innervation: musculocutaneous (medial) and radial nerve (lateral)
- arterial: brachial a.
- movement: elbow flexion
what muscle is B?
- describe its origin and insertion
- describe its innervation
- describe its arterial supply
- what movements is it responsible for
- coracobrachialis
- origin: coracoid process
- insertion: middle of humerus
- innervation: musculocutaneous n.
- arterial: brachial + anterior circumflex arteries
- movements: shoulder flexion and adduction
isotonic and isometric movements
- isotonic: muscle length changes
> concentric: contraction during shortening
> eccentric: contraction during lengthening - isometric: length of muscle doesn’t change
what are A, B and C? (triceps brachii)
- where does each head originate?
- what is the insertion?
- A = long head (originates @ scapula)
- B = lateral head (originates @ posterior humerus)
- C = medial head (over the top of the long and lateral head, originates @ intermuscular septum)
- all 3 heads join and insert @ ulna
triceps brachii:
- describe its innervation
- describe its arterial supply
- what movements is it responsible for?
- innervation: radial nerve
- arterial: deep brachial artery
- movement: extension
triple test approach re: breast lesion
- clinical examination
- breast imaging (usually mammography and U/S, +/- MRI)
- biopsy/tissue pathology
what are A, B, C and D?
- A = nipple/areolar complex
- B = adipose tissue
- C = pec major
- D = fibroglandular tissue
what is the innervation of: pecs major and minor, serratus anterior
- pecs major: medial and lateral pectoral nerve
- pecs minor: medial pectoral nerve
- serratus anterior: long thoracic nerve
what is the innervation of: latissimus dorsi, deltoid, teres major
- lats: thoracodorsal n.
- deltoid: axillary n.
- teres major: lower subscapular n.
describe the innervation of the rotator cuff
- subscapularis: upper and lower subscapular n.
- infraspinatus and supraspinatus: suprascapular n.
- teres minor: axillary n.
describe the innervation of the anterior upper arm muscles
- biceps brachii: musculocutaneous n.
- coracobrachialis: musculocutaneous n.
- brachialis: musculocutaneous and radial n.
describe the innervation of: trapezius, levator scapulae, rhomboids
- trapezius: accessory spinal nerve
- levator scapulae: dorsal scapular nerve
- rhomboids: dorsal scapular nerve
innervation of subclavius
- subclavian nerve
list some bones commonly fractured during a FOOSH
- clavicle (change in curvature)
- humerus (surgical neck or supracondylar)
- distal radius head or neck
- scaphoid (esp. @ its waist)
deltoid function
- anterior deltoid: shoulder flexion
- middle deltoid: abduction past 15 degrees (first 15 degrees are supraspinatus)
- posterior deltoid: shoulder extension
describe the mechanism of shoulder abduction to 180˚
- 0-15˚: supraspinatus (glenohumeral)
- 15-90˚: deltoid (glenohumeral)
- 90-150˚: scapulothoracic joint (formed by medial border of scapula and ribs) rotates scapula upwards, facilitated by trapezius and serratus anterior. sternoclavicular joint elevates clavicle
- 150-180˚: AC joint
- NB pain @ 65 degrees = impingement
clavicle fracture:
- where is it most common to occur?
- causes
- what can this damage
- most common where it changes curvature
- causes: FOOSH
- may damage divisions of brachial plexus
rotator cuff tendinopathy
- usually affects supraspinatus b/c tendon runs thru subacromial space
- usually caused by overuse e.g. swimming
- can lead to bursitis + impingement
what is thoracic outlet syndrome
- thoracic outlet = space b/n clavicle and 1st rib containing brachial plexus, subclavian a. and v.
- can be compressed due to having an extra rib, physical trauma, pregnant or pancoast tumour (tumour of lung apex)
- pancoast tumour can compress inferior trunk of brachial plexus = ulnar nerve
boundaries of quadrangular space + triangular space + triangular interval (posterior shoulder)
which muscle is responsible for preventing winging of the scapula?
- serratus anterior
if the AC joint is disolocated, which way will the shoulder joint drop?
- anteriorly and inferiorly
Saturday night palsy
- compression of radial nerve in axilla
- leads to wrist drop
- i.e. due to sleeping weirdly after getting drunk
erb’s palsy
- damage to upper trunk
- arm rests in waiter’s tip position with elbow extended and pronated and wrist flexed
- often caused by childbirth
klumpke’s palsy
- damage to lower trunk (C8,T1)
- arm rests in claw hand position with elbow flexed and supinated and fingers flexed
- caused by childbirth (poor bubbas can’t catch a break) or grabbing something to break your fall
