Arm and Elbow Flashcards
describe the role and structure of the axilla
provides gateway to upper limb, area of transition between neck and arm
formed by clavicle, scapula, upper thoracic wall, humerus and related muscles
pyramidal shape with four sides with an inlet and a floor
describe the shape and structure of the axillary inlet
triangular in shape and formed by the lateral border of rib 1, posterior surface of the clavicle and superior border o the scapula up to the caracoid process
what forms the anterior wall of the axilla
lateral part of the Pec Maj, pec minor, subclavian and underlying fascia
what forms the medial wall of the axilla
upper thoracic wall and serrates anterior
what forms the lateral wall of the axilla
narrow, formed by inter tubercular sulcus of humerus
the lateral wall is formed by the inter tubercular sulcus of the humerus but what muscles attach to this site
floor - lats
medial - teres major
lateral - pec major
which muscles make up the posterior wall of the axilla
subscap
distal parts of lat dorsi and teres major
proximal part of long head of triceps brachii
what forms the floor of the axilla
clavipectoral fascia and skin
anterior fold is superior to the posterior fold
what are the key major nerves and vessels that pass through the axilla
axillary artery
axillary vein
brachial plexus
running through the axilla space are two muscles what are they
biceps brachii
coracobrachialis
what lymphatics can be found in the axilla
all lymphatics of upper arm and large portion of adjacent trunk drain into axilla lymphatics: humeral nodes (lateral) pectoral nodes (anterior) subscapular nodes (posterior) central nodes apical nodes
what is the brachial plexus formed by
ventral rami of C5 and C8 and most of T1
describe the route of the brachial plexus and where it originates
originates in the neck and passes laterally and inferiorly over rib 1 and enters the axilla
what are the three trunks of the brachial plexus
superior - formed by the union of C5 and C6 roots
middle - continuation of C7
inferior - union of C8 and T1
from the origin of the sup, middle and inf branches of the brachial plexus what happens to them next
they divide into a posterior and anterior division
what are the three cords of the brachial plexus after the trunk origins
the lateral cord is the merger of the anterior division of the superior and middle trunks
the posterior cord is formed by the merger of all posterior divisions of the trunks
the medial cord is an extension of the anterior division of the inferior trunk
there are 5 major terminal branches of the brachial plexus which come from the lateral, posterior and medial cords, what are they
musculocutaneous nerve from C5/6/7
axillary nerve from C5/6
Median Nerve from C5-T1
radial nerve from C5-T1
ulnar nerve from C8-T1
what is the role of the musculocutaenous nerve
innervates the brachialis, biceps brachiaii and coracobrachialis
provides sensation to the lateral half of the anterior forearm and a smaller portion of the posterior forearm
what is the role of the axillary nerve
innervates teres minor and deltoid
provides sensation to the inferior region of the deltoid
what is the role of the median nerve
innervates most of the flexor muscles of the forearm, thenar muscles and the two lateral lumbircals associated with the index finger and middle finger
provides sensation to the lateral part of the palm and the lateral three and a half fingers on the palmar surface of the hand
what is the role of the radial nerve
innervates the triceps brachii and the muscles in the posterior compartment of the forearm
provides sensation to the posterior aspect of the arm and the forearm - and posterolateral aspect of the hand
what is the role of the ulnar nerve
innervates the muscle of the hand (apart from thenar and two lateral lumbricals) flexor carpi ulnaris and medial half of flexor digitorum profundus
provides sensation to the anterior and posterior surfaces of the medial one and a half fingers and associated palm area
what is the distinctive M shape formed by in the gross axilla
Musculocutaneous, median and ulnar nerves
where does the axillary artery come from and what does it split into / supply
from subclavian, supplies the walls of the axilla and related regions - it becomes the brachial artery which has 6 branches
what are the 6 branches of the axillary artery which stems from the subclavian
superior thoracic artery
thoracic-acromial artery and lateral thoracic artery
subscapular artery, anterior and posterior humeral circumflex artery
what does the superior thoracic artery supply (first part)
supplies upper region of the medial and anterior axillary walls
what happens to the thoracic-acromial artery and lateral thoracic artery (from the second part)
TA artery immediately splits into pectoral, deltoid, clavicular and acromial branches
LT artery supplies the serrates anterior and the anterior walls of the axilla
what happens to the subscapular, anterior and posterior circumflex arteries
subscap supplies most of he posterior wall of the axilla
anterior supplies the glenohumoral joint and head of humerus
posterior supplies sculls surrounding the neck of the humerus before anastomosis with the anterior
what are the size differences between the third part of the axillary artery ie subscap, anterior and posterior circumflex
subscap is the largest
anterior is smaller than the posterior
describe the path of the axillary vein
continuation of the basilic vein - passes through axilla medial and anterior axiallary inlet and becomes the subclavian vein which crosses the border of rib 1
describe the path of the brachial artery
continuation of the axillary artery found in anterior part of arm
starts at the lower border of the teres major and terminates just distal to the elbow joint where it divides into the radial and ulnar arteries
it starts lateral proximally but then moves medially in the distal arm between the lateral epicondyle and medial epicondyle of the humerus
what are the branches of the brachial artery
two ulnar collateral vessels which surround the elbow
profunda brachial artery (passes into the posterior compartment)
nutrient arteries to the humerus which enter humerus anteriomedially
describe the path of the paired brachial veins
medial and lateral sides of the brachial artery (deep veins of arm)
what are the two superficial veins of the arm
large subcutaneous basilic and cephalic
describe the path of the basilic vein
passes vertically in distal part of arm then penetrates deep fascia to assume position medial to the brachial artery and becomes axillary vein at lower border of teres major
describe the path of the cephalic vein
superiorly on the anterior-lateral aspect of arm through anterior wall of axilla to reach axillary vein
where do the cephalic and basilic vein anastomose
anterior elbow joint via the median cubital fossa
what is the difference in role of the two compartments of the arm
anterior predominantly flex the elbow joint
posterior extend the joint
which muscles are found in the anterior compartment
coracobrachilais
brachiallis
biceps brachii
what innervates the anterior muscles of the arm
musculocutaneous (flexors)
describe the path off the coracobrachialis
tip of coracoid process to medial side of the midshaft of the humerus
passes through axilla
describe the path of the biceps brachii
two heads
short head - originates from the coracoid process with the coracobracialis
long head oprginiates as a tendon from the supraglenoid tubercle of the scapula
describe the long head of the biceps brachii
long head (tendon) passes through glenohumeral joint superior to the head of the humerus and through the inter tubercular sulcus from the supraglenoid tubercle
where does the biceps brachii insert
radial tuberosity
where does the brachialis originate and insert and travel path
distal half of anterior aspect of humerus
it is deep to the biceps brachii
connects as a tendon to the ulnar tuberosity
what is the only muscle of the posterior compartment of the arm
triceps brachii
describe the structure of the triceps brachii
long head originates from infraglenoid tubercle of scapula
medial head originates from the shaft of the humerus inferior to the radial groove
the lateral head originates from a roughening above the radial groove
where to the 3 heads of the triceps converge and insert
converge onto olecranon of the ulna
what innervates the tricep muscle
branches of the radial nerve
why do we test the reflexes of the biceps and triceps
to check damages to the brachial plexus
what does poor reflex of the triceps vs biceps indicate
poor biceps = damage to musculocutaneous nerve
poor triceps = damage to radial nerve
poor in both = damage to superior trunk or roots C5/6
what are the borders of the quadrilateral space
superior = teres minor lateral = surgical neck of humerus inferior = teres major medial = long head of the triceps
what important structures pass through the quadrilateral space
axillary nerve and posterior circumflex humeral artery
how can you identify the posterior aspect of the humerus
linear diagonal roughing which marks the attachment of the triceps brachii
starts at the surgical neck and finishes diagonally down at the deltoid tuberosity
where is the radial groove situated
posterior surface of the humerus running along side the diagonal roughening
what lies in the radial groove
radial nerve and profunda brachii artery
what does the bone of the humerus distally turn into
lateral supraepicondylar ridge
medial supraepicondylar ridge
describe the structure of the distal end of the humerus
condyle - made up of the capitulum (lateral, articulates with the radius) and trochlea (medial, articulates with the ulna)
epicondyles lateral (attach muscles in posterior forearm) and medial (attach muscles in the anterior)
three fossae:
radial - anterior surface immediately superior to capitulum
coronoid fossa - superior to trochlea
olecranon - largest, posterior surface superior to trochlea
which part of the condyle of the humerus is visible on the posterior aspect
trochlea
describe the route of the ulnar nerve in the arm to forearm
around the posterior surface of the medial epicondyle and can be palpated against the bone
what are the three main features of the proximal radius
head, neck and radial tuberosity
describe the articulation of the radius to the humerus and the ulna
proximal radius is horizontal disc shaped which articulates with the capitulum of the humerus
the medial aspect of the radius articulates with the radial notch on the ulna
what is found on the neck of the radius
radial tuberosity - roughened for the attachment of the biceps brachii
describe the structure of the proximal ulna
larger than proximal head of ulna
consists of the: olecranon, coronoid process, trochlear notch, radial notch, tuberosity of the ulna
what is the olecranon of the ulna
large projection of bone
has an articular anterolateral surface for the trochlear notch which articulates with the trochlear of the humerus
what is found at the very superior point of the olecranon of the ulna
roughened surface for articulation with the triceps brachii
describe the role and structure of the coronoid process of the ulna
aids in forming the trochlear notch
the lateral surface is marked by the radial notch for articulation with the head of the radius
what are the three joints of the elbow
Elbow joint: (flexion and extension of forearm)
humero-ulnar
humero-radial
superior radioulnar joint (pronation and supination of the forearm)
describe the surrounding structure of the elbow joint
articulating surfaces covering in hyaline cartilage covered in synovial membrane as well as areas of pads of fat
all enclosed in a fibrous membrane
