upper arm (not incl elbow) Flashcards
what is the axilla
area which lies underneath glenohumeral joint, at junction of upper limb and thorax
it is a pyramidal space that provides passageway for vessels and nerves going to and from upper limb
border of axilla: apex (aka axillary inlet)
lateral border of first rib, superior border of scapula and posterior border clavicle
border of axila: lateral wall
intertubercular groove of humerus
border of axilla: medial wall
serratus anterior and thoracic wall (ribs + intercostal muscles)
border of axilla: anterior wall
pectoralis major + minor, and subclavious muscles
border of axilla: posterior wall
subscapularis, teres major and latissimus dorsi
contents of axilla
axillary artery axillary vein (+ tributaries) brachial plexus axillary lymph nodes biceps brachii (short head) corachobrachialis
when does subclavian artery become axillary artery
as it crosses lateral border of first rib
when does axillary artery become brachial artery
after passing lower margin of teres major
3 parts of axillary artery
one medial to pectoralis minor
one posterior to pectoralis minor
one lateral to pectoralis minor
what parts of axillary artery travel in axilla
medial + posterior
how is brachial plexus divided into 5 parts
roots, trunks, divisions, cords and branches
read that damn cadaver book
brachial plexus: roots
anterior rami of spinal nerves C5-T1
brachial plexus: trunks
superior: C5 + C6
middle: C7
inferior: C8 + T1
the trunks travel laterally, crossing the posterior triangle of the neck
brachial plexus: divisions
each trunk divides into 2 branches within the posterior triangle of the neck
one division moves anterior and other posterior –> anterior and posterior divisions
we now have 3 anterior and 3 posterior nerve fibres which leave posterior triangle and pass into axilla
they recombine into the cords
brachial plexus: cords
lateral cord: anterior division superior trunk + anterior division middle trunk
posterior cord: posterior divisions of superior, middle and inferior trunks
medial cord: anterior division of inferior trunk
major branches of brachial plexus
musculocutaneous nerve axillary nerve median nerve radial nerve ulnar nerve
from which spinal nerves and cord does musculocutaneous nerve originate
lateral cord
C5, 6, 7
from which spinal nerves and cord does axillary nerve originate
posterior cord
C5, 6
from which spinal nerves and cord does median nerve originate
lateral and medial cords
C6-T1
from which spinal nerves and cord does radial nerve originate
posterior cord
C5-T1
from which spinal nerves and cord does ulnar nerve originate
medial cord
C8 + T1
what are the 5 main arteries of upper limb
subclavian a axillary a brachial a radial a ulnar a
where do radial and ulnar arteries originate
bifurcation of the brachial artery within the cubital fossa
median cubital vein
communicating vein which shunts blood from cephalic vein to basilic vein
most common site for venepuncture - fixed position in ante-cubital fossa
basilic vein
originates from medial end dorsal arch and ascends the medial aspect of upper limb
how is axillary vein formed
basilic vein, at border of teres major, moves deep into arm and combines with brachial veins from deep venous system to form axillary vein
cephalic vein
arises from lateral end dorsal venous arch
ascends antero-lateral aspect of upper limb passing antriorly at elbow
drains into axillary vein
where do all lymphatic vessels from upper limb drain into
axillary nodes
axillary nodes are divided into distinct groups…
anterior (or pectoral group) posterior (or subscapular group) apical group central group lateral (or brachial) group
bones and joints of pectoral girdle
scapula and clavicle
acromioclavicular joint
sternoclavicular joint
what is pectoral girdle
set of bones which connects upper limb into the axial skeleton
features which can help ‘side’ a clavicle
the lateral aspect of clavicle is flatter than medial aspect
superior surface is smoother than inferior surface
the conoid tubercle (attachment for conoid ligament) on inferior aspect of lateral portion clavicle
what type of joint is acromioclavicular joint
plane synovial joint (between acromion of scapula and clavicle)
what type of joint is sternoclavicular joint
saddle synovial joint
2 stages of abduction of arm
first 30° - caused by muscles acting on glenohumeral (shoulder) joint
beyond 30° - scapula being pulled upwards (elevated) and laterally rotating on the chest wall (scapula-thoracic movement)
muscles involved in scapular movement: elevation
trapezius (upper fibres)
levator scapulae
muscles involved in scapular movement: depression
trapezius (lower fibres)
muscles involved in scapular movement: protraction (forward movement)
serratus anterior
pectoralis minor + major
muscles involved in scapular movement: retraction (backward movement)
trapezius (middle fibres)
rhomboids
muscles involved in scapular movement: medial (downward) rotation - depressing glenoid cavity
gravity
levator-scapulae
rhomoid major + minor
pectoralis minor
what type of joint is gleno-humeral joint (shoulder joint)
synovial ball and socket joint
ball = head of humerus socket = glenoid cavity
what is glenoid labrum
rim of cartilage that surrounds glenoid cavity (socket of shoulder joint)
it deepens glenoid fossa to reduce disproportion in surfaces
what aspect of glenohumeral joint does coracohumeral ligament strengthen
anterior-superior aspect joint capsule
what is coraco-acromial arch
made of acromion, coracoid process of scapula and caracoacromial ligament
prevents superior displacement of humeral head
what aspect of glenohumeral joint do glenohumeral ligaments strengthen
anterior aspect joint aspect
what does transverse humeral ligament form
roof of bicipital groove
what is weakest aspect of shoulder joint capsule
inferior-anterior part
not protected by muscles or ligaments
which bursa communicates with the glenohumeral joint capsule
subscapular bursa
subacromial bursa
reduces friction beneath deltoid, promoting free motion of rotator cuff tendons
sits between infra/supra-spinatus muscles and deltoids, extending superiorly to lie below acromion and coracoacromial ligaments
attachments of subcapularis muscle
proximal: medial 2/3 of costal aspect scapula
distal: lesser tubercle humerus
subscapularis muscle movement of shoulder joint
medially rotates arm
nerve supply subscapularis muscle
upper + lower subscapular nerves
attachments of supraspinatus muscle
supraspinous fossa of scapula
greater tuberosity of humerus
supraspinatous muscle movement at shoulder joint
abduction of arm
supraspinatus muscel nerve suppluy
suprascapular nerve
attachments of infraspinatous muscle
infraspinous fossa of scapula
greater tubercle of humerus
infraspinatus muscle movement of shoulder joint
laterally rotates arm
nerve supply of infraspinatus muscle
suprascapuar nerve
attachments of teres minor muscle
posterior surface of scapula, adjacent to its lateral border
lesser tuberosity of humerus
teres minor muscle movement of shoulder joint
laterally rotates arm
nerve supply teres minor muscle
axillary nerve
although rotator cuss muscles have a role in movement of glenohumeral joint, there primary function is to…
pull the humeral head into glenoid fossa: additional stability
what are the rotator cuff muscles
subscapularis
supraspinatus
infraspinatus
teres minor
what are the shoulder joint muscles
deltoid pectoralis major teres major trapezius latissimus dorsi levator scapulae rhomboids
what nerve supplies deltoid muscle
axillary n
anterior fibres deltoid muscle
flexion and medial rotation at shoulder joint
middle fibres deltoid muscle
abduct the arm at shoulder joint
posterior fibres deltoid muscle
extension and lateral rotation at shoulder joint
nerve supply to pectoralis major muscle
lateral and medial pectoral nerves
action of pectoralis major
adduct shoulder
medially rotate humerus at glenohumeral joint
pectoralis minor nerve supply
medial pectoral nerve
teres major actions
adducts and extends at shoulder and medially rotates arm
nerve supply trapezius muscle
accessory nerve
what muscles cause flexion of shoulder (sagittal plane)
pectoralis major
anterior deltoid
coracobrachialis
what muscles cause extension of shoulder (sagittal plane)
posterior deltoid
latissismus dorsi
teres major
what muscles cause abduction of shoulder
0-90 degrees: supraspinatous, middle fibres deltoid
90-180degrees: trapezius, serratus anterior
what muscles cause adduction shoulder
pectoralis major
latissimus dorsi
teres major
what muscles cause medial or internal rotation of shoulder
subscapularis
lastissimus dorsi
pectoralis major
teres major
what muscles cause lateral or external rotation shoulder
infraspinatous
teres minor
muscles of anterior compartment arm
biceps brachii
coracobrachialis
brachialis
biceps brachii attachments
short head: originates from coracoid process of scapula
long head: originates from supraglenoid tubercle of scapula
both heads unite at dital 3rd upper arm forming short tendon which inserts onto radial tuberosity
functions of biceps brachii
supination of forearm (at superior radio-ulnar joint)
flexes both shoulder and elbow joint
nerve supply of biceps brachii
musculocutaneous nerve (biceps tendon reflex tests C6)
action of brachialis muscle
flexion of elbow jiont
attachments of brachialis muscle
anterior surface of distal shaft humerus to coronoid process of ulna
nerve supply brachialis muscle
musculocutaneous nerve (with contributions from radial nerve)
attachments corachobrachialis muscle
tip of coracoid process of scapula to medial aspect mid-shaft humerus
action corachobrachialis muscle
flexes arm at shoulder joint
nerve supply corachobrachialis muscle
musculocutaneous nerve
pathway of musculocutaneous nerve
enters arm by perforating corachobrachialis, descends distally between biceps brachii and brachialis muscles. after crossing elbow joint it gives off terminal branch to supply skin as lateral cutaneous nerve forearm
what is main branch brachial artery
profunda brachii
pathway median nerve upper arm
descends along lateral side axillary artery, crosses to lateral aspect brachial artery and enters cubital fossa
gives off no branches in axilla or upper arm
pathway ulnar nerve upper arm
descends along medial side brachial artery and enters anterior compartment arm through medial intermuscular septum
runs along medial head of triceps and to lie behind medial epicondyle at elbow
what compartment of arm is triceps muscle in
posterior compartment upper arm
attachments triceps muscle
long head arises from scapula and, lateral and medial heads arise from humerus. Common tendon of triceps is inserted into olecranon process of ulna
function triceps muscle
extension of arm at elbow
nerve supply triceps muscle
radial nerve
what does radial nerve innervate
triceps muscle and extensor muscles in forearm
pathway of radial nerve
arises in axilla region where it’s situated posteriorly to axillary a. runs down with main branch axillary a. (profunda brachii)
descends down around midshaft region of humerus in radial groove
teres major nerve supply
lower subscapular nerve
nerve supply latissimus dorsi
thoracodorsal nerve
nerve supply levator scapulae
dorsal scapula nerve
nerve supply rhomboids
dorsal scapular nerve
serratus anterior innervation
long thoracic nerve
