humerus components
head body trochlea capitulum coronoid fossa olecranon fossa supracondylar ridges - medial and lateral
humeral head
- articulates with
- components
articulares with glenoid cavity of the scapula components -greater tubercle -lesser tubercle -intertubercular groove (sulcus)
humeral head
-anatomic vs. surgical neck
anatomical -lies between head and the tubercles surgical -more likely region of breakage -lies at beginning of body or shaft, distal to tubercles
humeral body
- location
- components and description of each
ends distally at expansions (medial and lateral epicondyles)
deltoid tuberosity
-anterolateral “bump” indicating insertion of deltoid muscle
radial groove (spiral groove)
-posterior aspect; position of radial nerve
trochlea of humerus
- function
- medial to trochlea…
articulates with ulna
medial to trochlea is a deep groove, sulcus for ulnar nerve - “funny bone”
capitulum
-function
articulates with radius
elbow articulations
humeroulnar
humeroradial
proximal radioulnar
elbow ligaments
radial collateral ligament ulnar collalteral ligament -anterior head -posterior head -oblique head annular ligament of radius -proximal radioulnar joint
muscles of the arm
-confined to
confined to anterior and posterior compartments
anterior and posterior compartments of arm -formed by…
-separating structures attached at…
medial and lateral intermuscular septa from fascia encircling arm
attached at
-medial and lateral supracondylar ridges of humerus
anconeus
- located primarily _____ due to…
- functions…
in forearm
due to insertion on ulna
functions along with medial head of triceps brachii
-anatomically is not always distinguishable
what must occur at the ulna during pronation?
- why
- what happens if this does not occur?
- what does this mean for the humeroulnar joint?
ulna must abduct
maintains position of hand (as in turning a screw driver)
pronation without abduction results in change in placement of hand during pronation
humero-ulnar joint is necessarily loose-packed
muscles of the cubital region
- primarily located where?
- where do they act
primarily located in forearm
action
-move forearm at elbow joint
-do not act on the hand or wrist
arm blood supply
- entirity comes from…
- majority of arteries have…
entirity comes from brachial artery (axillary artery after passing teres major)
majority of arteries have a matching paired set of veins
which veins are not matched to an artery?
cephalic
median cubital
median vein of forearm
basilic
brachial veins (paired to artery) do what?
anastomose with each other and the superficial veins
veins of the arm through the subclavian vein
- where are valves located
- number compared to LE
- size of vein compared to corresponding artery
- why this size?
valves located at the distal and proximal ends
not as many as LE
smaller than corresponding artery
-majority of venous return being handled by superficial venous plexus
muscular branches of artery
- for anterior compartment where do they come from
- for posterior compartment where do they come from
anterior
-brachial artery
posterior
-deep brachial artery
deep brachial artery
- splits into…
- what does it do around the lateral epicondyle
splits into anterior and posterior descending branches surrounding the lateral epicondyle of humerus to anastomose with collaterals from the brachial artery
profunda brachii (deep brachial artery)
- relation to brachial
- location
first and largest branch
branches and follows the radial nerve posteriorly around the radial groove to the posterior surface of the humerus
radial and ulnar arteries
- location
- formed from
found at the level of the cubital fossa
result of the brachial artery branching
recurrent branches
-created by…
radial artery
-one recurrent branch
ulnar artery
-anterior and posterior recurrent branches
anastomosis around the elbow
-formed from
anterior and posterior branches of deep brachial artery
radial recurrent artery
superior and inferior ulnar collaterals
anterior and posterior ulnar recurrent arteries
superior and inferior ulnar collateral arteries
- arise from
- superior follows…
arise from brachial artery proximal to division within cubital fossa
superior follows ulnar nerve
muscles of arm innervated by…
radial
musculocutaneous
median and ulnar nerves
- formed in…
- location
- function
formed in axilla
descend along brachial artery through arm to reach forearm
innervate muscles and skin of forearm
radial nerve
- size compared to other branches of posterior cord
- location
- function
largest location -curves posteriorly around the humerus in the radial groove (with deep brachial artery) innervates -triceps -anconeus -supinator -brachioradialis continues into forearm to innervate extensors of the wrist
musculocutaneous nerve
- formed from
- function
- continues into forearm as…
small branch of lateral cord
innervates
-muscles of the anterior compartment of the arm
continues into forearm as lateral cutaneous nerve of forearm
median and ulnar nerves
-location
travel down lateral and medial side of brachial artery, respectively
median nerve protected in cubital fossa by…
lying deep to bicipital tendon
ulnar nerve
- begins…
- where does it go?
begins in anterior muscular compartment
pierces the medial intermuscular septum to continue distally along the medial head of the triceps
cubital fossa
-borders
superior -line crossing from medial to lateral epicondyles of humerus medial -pronator teres lateral -brachioradialis floor -brachialis -supinator roof -deep fascia -includes bicipital aponeurosis (covered by superficial fascia, loose CT, and skin)
cubital fossa
-contains
bicipital tendon brachial artery -its terminal radial and ulnar brahcnes brachial veins parts of median and radial nerves
median cubital vein in relation to cubital fossa
runs in loose CT superficial to deep fascia covering cubital fossa
radial nerve
-pressure may result in…
may result in temporary to long term paralysis or weakness of the extensors muscles of the wrist in the forearm
-called wrist drop
musculocutaneous nerve damage in the axilla
-results in…
weakened flexion and supination of forearm
anesthesia of lateral forearm also possible
damage to median nerve
-results in…
loss of sensation to lateral portion of palm loss of -pronation -flexion of wrist and digits -complex thumb movements
damage to ulnar nerve
- results in…
- effect on forearm flexors compared to median nerve damage
weakened
- flexion and adduction of wrist
vs. median nerve - innervates less
- flexion less severely affected
sharp blow on medial side of elbow can result in…
tingling or anesthesia of the medial two digits if ulnar nerve is affected (in ulnar groove)
this is the funny bone
brachial/axillary artery damage
- can result in
- may lead to…
can result in loss of blood supply to forearm
-results in paralysis of deep flexors of wrist
permanent damage may occur
-produces a permanent flexion contracture due to atrophy and shortening of deep flexor muscles
anastomotic circulations and injury
- work best when…
- what will anastomotic circulations do if lack of perfusion is sudden and lasting
work best when
-“rerouting” of blood takes place over time
will allow minimal survival if lack of perfusion is sudden and lasting
