Upper Extremity

Dermatomes

upper extremity: C4 through T2

nipples innervated by T4

umbilicus by T10

Groin by L1

What if there is a total transection of the spinal cord at the C5 level? could probably shrug

Posterior forearm and hand

Superficial Layer

most originate from lateral epicondyle

brachioradialis m: radial side closer to elbow

Anconeus m: tiny muscle more toward midline of forearm

extensor carpi ulnaris m: runs down ulna to wrist

Extensor carpi radialis brevis m: runs down radius but more midline of forearm

extensor carpi radialis longus m: runs down radius but more lateral

extensor digitorum m: runs down between radius and ulna, splits into 4 tendons for the 4 fingers

extensor digiti minimi m: runs medially next to ED to pinky finger

Deep Layer

Supinator m: most proximal m in this layer, short muscle

abductor pollicis longus m: under the supinator, runs lateral to thumb/wrist

extensor policis brevis m: small m between APL and EPL, runs to thumb

extensor pollicis longus m: attaches below APL and run down midline then over to thumb

extensor indicis m: attaches below EPL and runs to index finger

Hand

4 dorsal interosseous mm: abduct digits 2-4 (move away from middle finger)

Additional Info

posterior interosseous n: emerges from supinator m, from deep branch of radial n, the artery and vein run with this

anatomical snuff box: little depression near wrist that is in between the EPB and EPL tendons

Anterior Forearm

Nerves

median n: supplies most of the anterior forearm and some hand, runs between the FDS and FDP

Ulnar n: supplies most of the hand and some of anterior forearm

Superficial layer

all attach at medial epicondyle

pronator teres m: shortest muscle here, most proximal

flexor carpi radialis m: runs from medial epicondyle to end of first digit

palmaris longus: middle muscle, runs to palm, can be missing in ~15% of people

Flexor digitorum superficialis m: can kind of see between PL and FCU

flexor carpi ulnaris m: runs right along medial side down to pinky

Intermediate layer

flexor digitorum superficialis m: runs down midline of forearm, tendons insert on middle phalanges of digits 2-5

Deep Layer

Flexor pollicis longus m: runs down the radial side and into thumb

flexor digitorum profundus m: big muscle that runs down the ulna and branches into digits 2-5

Deepest layer

pronator quadratus m: square shaped muscle that covers the wrist area, very obviously deep layer

Arm and Hand

misc. info

Blood supply: as vessel gets smaller less tissue types are involved

clinical anatomy: def= study of the structure of the human body and its application to healthcare practice for Dx and Tx

blood pressure: measurement of force applied to artery walls, relates to heart fxn, blood volume, and vessel wall resistance

when taking BP the brachial a gets closed off

capillary refill: measures how heart is functioning, should refill quickly

bed sore is when the body is pushing down and blood moves out of the capillary bed

Vessels

brachial artery: splits into superior and inferior collateral arteries, eventually becomes radial and ulnar

Radial a. gives rise to the Radial Recurrent a

Ulnar a. gives rise to the Anterior and Posterior Ulnar Recurrent aa and… the Common Interosseous a. which splits into the Anterior and Posterior Interosseous aa

Nerves

musculocutaneous n: between biceps and brachialis, supplies all muscles of the arm

radial n: down radius (lateral), supplies posterior arm and forearm and brachioradialis m

median n: runs between radius and ulna, supplies most of the anterior forearm and some hand (goes through carpal tunnel)

ulnar n: runs down ulna (medial), supplies some forearm and most of the hand, outside of the carpal tunnel

Hand

palmar aponeurosis: c.t on palm, connects with PL

superficial palmar arch: formed by the Ulnar a, supplies the hand

common palmar digital aa: arteries that run within palm

proper palmar digital aa: runs within the fingers

deep palmar arch: formed by the radial a

lumbricals: 4 mm in the palm on the thumb (lateral) side

FDS: tendon inserts on middle phalanx of each digit

FDP: inserts into distal phalanx of each digit

Thenar eminence: group of muscles as base of thumb, flexor pollicis brevis (closest to middle of hand), abductor pollicis brevis (closest to outside of hand), and opponens pollicis (deep to the other muscles)

Hypothenar eminence: group of muscles under pinky finger, flexor digiti minimi (closest to middle of hand), abductor digiti minimi (closest to outside of hand), and opponens digiti minimi (deep to the other muscles)

palmar interosseous mm: 3 muscles (in the palm) that adduct the fingers (move toward the middle finger)

Arm

biceps m: main muscle of arm

brachialis m: deep to biceps and close to elbow

coracobrachialis m: deep to biceps and close to axilla

Axilla

misc. info

xiphoid process: the pointed end of the sternum

deltopectoral groove: meeting of deltoid and pectoralis major, where the cephalic vein is

lymphatic system: houses immune system, includes lymph nodes and thoracic duct

definition of the axilla: pyramid-shaped space between proximal portion of arm and lateral wall of chest

axillary a is the central structure of the axilla

medial wall of axilla: serratus anterior m, innervated by long thoracic n

lateral wall of axilla: humerus

posterior wall of axilla: subscapular m, teres major m, and latissimus dorsi

anterior wall of axilla: pectoralis major and minor mm

7 cervical vertebrae but 8 cervical nerves, so C1-C7 nerves are above their corresponding vertebrae, with C8 below C7 vertebrae

Axillary A

begins at lateral border of 1st rib (from subclavian)

ends at inferior border of teres major (then becomes brachial a)

latissimus dorsi is probably a better border for AA

1st division is proximal to pec. minor m

2nd division is posterior to pec minor m

3rd division is distal to pec minor m

Superior thoracic a: only branch from part 1 of AA

Thoracoacromial trunk: 1 of 2 branches from 2nd part of AA, has 4 branches off it (Clavicular, Acromial, Pectoral, and Deltoid)

lateral thoracic a: 2nd of 2 branches from 2nd part of AA, runs on lateral border of pec minor

Posterior and anterior humeral circumflex aa: 2 of 3 branches off 3rd part of AA, wrap arounf humerus

Subscapular a: 3rd of 3 branches off 3rd part of AA, has 2 branches off of it, thoracodorsal artery (goes down thorax), and circumflex scapular a (goes arounf scapula

Brachial Plexus

supplies UE with sensory innervation from skin to deep structures, motor innervation to skeletal muscles, and postganglionic sympathetic fivers to smooth muscles of muscle of blood vessels, sweat glands, arrector pili mm

4 parts: roots, trunks, divisions, cords (named for their relation to the AA (and branches)

common injuries: hanging by 1 arm or baby shoulder caught on mothers pubic symphysis during birth

Roots: C5-T1 and includes branches phrenic n, nerve to deep neck mm, dorsal scapular, and long thoracic

Trunks: 5 roots into 3 trunks, superior (2 branches: nerve to subclavius and suprascapular n), middle, and inferior

Divisions: 3 divisions with anterior and posterior splits

Cords: lateral, medial, and posterior cords

Branches:

lateral cord (3): lateral pectoral n, musculocutaneous n, lateral root of median n
Medial cord (5): medial pectoral n, medial cutaneous n of arm, medial cutaneous n of forearm, medial root of median n, ulnar n
posterior cord (5): upper subscapular n, thoracodorsal n, lower subscapular n, axillary n, radial n

Shoulder

17 muscles attached to scapular, but 4 make up rotator cuff

Rotator cuff

holds humerus in close proximity to Glenoid fossa

Subscapularis: inserts on lesser tubercle, for internal rotation and adduction of humerus
supraspinatus: inserts on the top of the greater tubercle, for abduction of humerus, supplied by suprascapular n
infraspinatus: inserts on the posterior aspect of greater tubercle, for external rotation and adduction of humerus, supplied by suprascapular n
teres minor: inserts on the posterior aspect of greater tubercle, for external rotation and adduction of humerus, supplied by axillary n