upper limb anatomy Flashcards
Demonstrate dermatomes of upper limb on yourself
C4-T2
Describe the cutaneous innervation of the hand?
median nerve
- thumb, Index finger, middle finger, ring finger (1/2), thenar side
ulnar nerve
- little finger, 1/2 ring finger, hypothenar side and dorsal
radial
- thumb, dorsal hand
Describe the lymphatics of the superficial limb?
- -superficial lymphatics originate from lymphatic plexus in the hand
- -ascend with superficial veins (cephalic or basilic) and terminate in the apical axillary LNs
either -
- cephalic vein - lymph nodes enter the apical axillary LNs - but some enter deltopectoral LNs
- or basilic vein - lymph nodes enter the cubital LNs - humeral axillary LNs - central axillary LNs - apical axillary LNs
Describe the drainage of the deep lymphatics of the upper limb?
Ascend with the major deep veins(radial and ulnar vein) in the upper limb and terminate in the humeral (lateral) axillary lymph nodes - drain central axillary LNs - apical axiallary LNs - supraclavicular LNs - R+L subclavian lymphatic trunks
How does the right and left subclavian lymphatic trunks drain?
right subclavian lymphatic trunk
joined by right jugular trunk = right lymphatic duct - joins the right venous angle to enter the right subclavian vein
left subclavian trunk
joins the thoracic duct and enters the left brachiocephalic vein
Describe the course of the median nerve in the forearm?
- emerges from cubital fossa - lateral crosses medial to brachial artery
- passes between 2 heads of pronator teres
- descends deep to flexor digitorum superficialis
- continues distally between flexor digitorum superficialis and flexor digitorum profundus
- more distally runs deep to palmaris longus
- passes deep to flexor retinaculum
- gives off palmar cutaneous branch before passing deep to flexor retinaculum
What structures are supplied by the median nerve?
no branches in the arm
articular branches to the elbow joint
branches to proximal radioulnar joint
-muscular branches to forearm muscles: pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis
-anterior interosseous nerve: pronator quadratus, flexor pollicus longus, flexor digitorum profundus (digits 2, 3) branches to inferior radioulnar joint, wrist and carpal joints
-palmar cutaneous branch:
sensory innervation of lateral palm
-recurrent branch to thumb muscles:
opponens pollicis,
abductor pollicis brevis,
flexor pollicis brevis
-palmar digital branch to: divides into 2 (medial and lateral branch) (medial branch divides into 2)
= lumbricals 1, 2
= palmar surface
= fingertips of lateral 3.5 digits (thumb to half the ring finger)
= nail beds lateral 3.5 digits
what are the branches of the median nerve distal to the flexor retinaculum and what do they supply?
1- recurrent branch to thumb muscles
- opponens pollicis
- abductor pollicis brevis
- flexor pollicis brevis
- palmar digital branch
then gives off
= medial branch - divides again into 2
- supplies the palm skin
the cleft and adjacent sides of the ring and middle fingers and the middle and index fingers
- supplies the second lumbrical
= lateral branch
supplies the palmer skin, radial side of index and the whole of thumb and its web on the palmer surface and the distal part of the dorsal surface
the branch of the index finger supples the first lumbrical
they both supply the nail beds and distal dorsal skin of the digits
Identify the boundaries and contents of the cubital fossa?
boundaries -
superior = line connecting medial to lateral epicondyles medially = pronator teres (lateral border)
laterally = brachioradialis (medial border)
base = brachialis and supinator muscles
roof = skin, SC tissue, fascia - reinforced by bicipital aponeurosis, median cubital vein
-contents:
lateral to medial =
radial nerve, biceps tendon, brachial artery, median nerve
Describe the course of the radial nerve in the upper limb?
- C5-C7 branch of posterior cord
- exits axilla
- passes through triangular interval (lower triangular space)
- crosses humerus obliquely over radial groove with profunda brachii artery
- pierces the intermuscular septum
- passes between brachialis and brachioradialis,
- then anterior to lateral epicondyle then divides into branches:
1) deep branch pierces supinator, supplies it, emerges in posterior compartment as posterior interosseous nerve
2) superficial (sensory) branch runs between pronator teres and brachioradialis to the anatomical snuffbox
Major branches of the radial nerve?
main branch of radial nerve: triceps, anconeus, brachioradialis, extensor carpi radialis longus
elbow joint
runs between the brachilais and brachioradialis = then
splits into deep branch and the superficial branch
1) deep branch of radial nerve: gives off the supinator and extensor carpi radialis brevis (becomes the posterior interosseous branch after it gives off the supinator) extensor carpi ulnaris extensor digiti minimi extensor digitorum
= posterior interosseous branch of radial nerve:
- abductor pollicis longus,
- extensor pollicis brevis
- extensor pollicis longus,
- extensor indicis
2) superficial sensory branch of radial nerve runs between pronator teres and brachioradialis to the anatomical snuffbox
Functional deficits from radial nerve injury in mid arm?
- -elbow extension would be preserved due to action of long head and lateral head of triceps
- -wrist drop would be present - inability to extend wrist and MCP joints of fingers and thumb
- interphalangeal joints maintained due to lumbericals and interossei
- -sensory loss over radial 2/3 dorsum of hand
Describe the course of the ulnar nerve at the elbow?
passes posterior to the medial epicondyle of the humerus and medial to the olecranon. It lies in the grooved surface of the posterior band of the ulnar collateral ligament at the elbow.
What clinical findings would be present if the ulnar nerve is injured at the elbow?
- sensory loss
1. of medial half of palmar aspect of hand (palmer cutaneous branch)
2. medial half of dorsal aspect hand and medial 1.5 fingers (dorsal cutaneous branch)
3. medial 1.5 fingers on palmer surface (superficial branch)
-motor loss
1. flexor carpi ulnaris = flex and adduct
2. medial 2 FDP (III and IV) = flex interphalangeal joints 4th and 5th digits
3. hypothenar muscles (Abductor digiti minimi, opponens digiti minimi, flexor digiti minimi) = flex and abducts 5th MCPJ
4. adductor pollicis + 1/2 flexor pollicis brevis = adducts thumb
5. interosseous, 3/4 lumbrical = abducts and adducts 3rd and 4th fingers
paralysis of almost all intrinsic hand muscles apart from 2 radial lumbricals and thenar compartment = causes claw hand
How would you differentiate an ulnar nerve lesion at the elbow from one at the wrist?
more pronounced claw hand if lesion is more distal as flexor digitorum profundus and flexor carpi ulnaris are preserved
Demonstrate where sensation changes may occur if the ulnar nerve is injured in the forearm?
- sensory loss
1. of medial half of palmar aspect of hand (palmer cutaneous branch)
2. medial half of dorsal aspect hand and medial 1.5 fingers (dorsal cutaneous branch)
3. medial 1.5 fingers on palmer surface (superficial branch)
4. ulnar aspect of the wrist
Describe the superficial drainage of the upper limb?
-dorsal and palmar networks drain to
cephalic (anterolateral)
AND
basilic (posteromedial) veins
palm drains dorsally
- connected in cubital fossa by median cubital vein
- basilic vein goes deep (drains middle and distal 1/3 arm) and joins brachial vein to form axillary vein
- cephalic begins in roof of anatomic snuff box and pierces clavipectoral fascia (runs in deltopectoral groove) to join axillary vein, runs inferior to the clavicle
Can you describe the venous drainage of the upper limb?
superficial + deep
superficial - -dorsal and palmar networks drain to cephalic (anterolateral) AND basilic (posteromedial) veins
palm drains dorsally
- connected in cubital fossa by median cubital vein
- basilic vein goes deep (drains middle and distal 1/3 arm) and joins brachial vein to form axillary vein
- cephalic begins in roof of anatomic snuff box and pierces clavipectoral fascia (runs in deltopectoral groove) to join axillary vein, runs inferior to the clavicle
deep -
palmar venous arch
radial and ulnar veins corresponds to the arteries
starts at the venous comitantes - join to form the brachial vein that joins with the basilic vein to form the axillary vein
What are the boundaries of the axilla?
- base = level of 4th rib, forms the armpit
- apex = first rib, clavicle, superior scapula
- anterior wall = pectoralis minor and major, clavipectoral fascia
-posterior wall =
scapula, subscapularis, (on surface)
teres major, latissimus dorsi (inferior)
- lateral wall = intertubercular sulcus of humerus
- medial wall = 1-4th rib and serratus anterior
Contents of the axilla?
- axillary sheath (axillary artery, axillary vein(formed from basilic and brachiel veins + becomes the subclavian vein lateral border of the first rib, brachial plexus)
- axillary LNs - pectoral, subscapular, humeral, central, apical
- fat
what is it and describe it - Brachial plexus formation/ relations?
It is a major nerve network supplying the upper limb extends from the neck to the axilla which results in the formation of multisegmental peripheral nerves
- union of anterior rami (root) of C5-T1
- roots: between anterior/middle scalene
- trunks: roots unit to form 3 trunks - form in lower part of posterior triangle - 1st part axillary artery = superior, middle, inferior
- divisions: form behind the clavicle = each trunk divides into anterior and posterior divisions
-cords: embrace the 2nd part of the axillary artery posterior to pectoralis minor - outer border of first rib
= form 3 cords - lateral, posterior, medial
posterior divisions of all 3 trunks forms posterior cord
-terminal branches: surround the 3rd part of the axillary artery inferior to pectoralis minor
major peripheral nerves supplying the upper limb form from these cords:
lateral cord C5-7 formed from super and middle trunks 1. lateral pectoral nerve 2. musculocutaneous nerve 3. lateral root - median nerve
posterior cord C5-T1 formed from the superior, middle and inferior trunks 1. upper and lower subscapularis 2. thoracodorsal nerve 3. axillary nerve 4. radial nerve
medial cord C8-T1 formed from inferior trunk 1. medial pectoral nerve 2. medial cutaneous nerve of arm 3. medial cutaneous nerve of forearm 4. medial root of median nerve 5. ulnar nerve
Terminal branches of the medial cord?
- ulnar nerve
- medial pectoral nerve
- medial cutaneous nerve of arm
- medial cutaneous nerve of forearm
- medial root of median nerve
What are the nerve roots of the posterior cord?
C5, C6, C7, C8, T1
What are the terminal branches of the posterior cord?
lateral cord: C5, C7
posterior cord: C5, C6, C7, C8, T1
medial cord: C8, T1
-Axillary nerve: (C5-6)
joint - glenohumeral (shoulder)
muscles - deltoid and teres minor
sensation - to skin over inferior aspect of deltoid
-Radial nerve: (C5 - T1)
muscles - all muscle of posterior compartment of arm and forearm
sensation - to posterior/inferolateral arm, posterior forearm, dorsum of hand lateral to ring finger
other branches - -upper subscapular: C5 muscle - to subscapularis -lower subscapular : C6 muscle - inferior part of the subscapularis and teres major -Thoracodorsal: C6,7,8 muscles - to lat dorsi
Nerve most likely to be injured in brachial plexus?
radial nerve
Apart from wrist extensor weakness, what other functions may be lost with a radial nerve lesion in the axilla?
finger extension
sensory loss over radial 2/3 dorsum. of hand
