upper limb anatomy Flashcards
What are the articulating surfaces in the shoulder joint?
● Ball and socket synovial joint
● Rounded head of humerus and glenoid cavity of the scapula, deepened by the
labrum.
What anatomical features contribute to the stability of the shoulder joint?
● Joint capsule with fusion of tendons of rotator cuff muscles
● Deepening of glenoid cavity by the glenoid labrum
● Coracoacromial arch superiorly created by the coracoacromial ligament
● Ligaments - anterior glenohumeral ligaments, coracohumeral nd transverse
humeral.
● Rotator cuff muscles - supraspinatus, infraspinatus, teres minor and
subscapularis.
● Tendons of biceps and triceps
What muscles are responsible for abduction and adduction of the shoulder
● Abduction - supraspinatus for the first 15 degrees, deltoid the rest
● Adduction - pec major and lat dorsi acting together, also terms major and long
head of triceps as synergists.
Identify the main features of the scapula
● Glenoid cavity
● Spine
● Supraspinous fossa
● Infraspinous fossa
● Costal surface - Subscapular fossa
● Acromion
● Coracoid process
● Suprascapular notch
● Medial and lateral borders
Where do the scapulohumeral muscles attach?
● Deltoid - acromion and spine of scapula
● Supraspinatus - supraspinous fossa
● Infraspinatus - infraspinous fossa
● Teres minor- middle part of the lateral border
● Teres major - posterior surface of the inferior angle
● Subscapularis - in the subscapular fossa
Describe the bony features of the proximal half of the humerus
● Head, anatomical neck, surgical neck, greater and lesser tubercles,
intertubercular groove, deltoid tuberosity, radial groove
What are the common sites of fracture of the proximal humerus and what nerves
are at risk with these fractures?
● Neck - axillary nerve and brachial plexus
● Midshaft - radial nerve
What are the rotator cuff muscles and describe their actions
● Subscapularis - medial rotation of the humerus
● Supraspinatus initiates abduction - for the first 15 degrees
● Infraspinatus and teres minor do lateral rotation of the humerus
● All 4 muscles together help stabilise the shoulder joint
What is the nerve supply to the rotator cuff muscles?
● Supraspinatus- suprascapular nerve
● Infraspinatus - suprascapular nerve
● Subscapularis - Upper and lower subscapular nerves supply
● Teres minor - posterior branch of the axillary nerve
1 for 2 and 2 for 1 . i.e Suprascapular nerve does both supra and infraspinatus. Then 2 nerves
supply the subscapularis
Please describe the boundaries of the axilla
● Base: axillary skin and fascia
● Apex: Cervicoaxillary canal
● Anterior wall: Pec major and minor, clavipectoral fascia
● Posterior wall: Scapula and subscapularis on its surface, inferiorly latissimus
dorsi and teres major
● Medial wall: thoracic wall, serratus anterior
● Lateral wall: intertubercular groove of the humerus
What are the contents of the axilla?
● Axillary artery in three parts as divided by the pec minor
● Axillary vein formed by the brachial and basilic veins, becomes the subclavian
vein at the lateral border of the 1st rib,
● Brachial plexus
● Axillary lymph nodes - pectoral, subscapular, humeral, central, apical.
● Fat
Please describe the boundaries of the cubital fossa
● Superiorly - a line between humeral epicondyles
● Medially - the lateral border of pronator teres
● Laterally - medial border of brachioradialis
● Floor - brachialis ( & supinator)
● Roof - deep fascia reinforced by the bicipital aponeurosis, subcutaneous tissues
and skin
What are the contents of the cubital fossa?
● Radial nerve
● biceps tendon
● brachial artery dividing into radial and ulnar arteries
● median nerve
● brachialis
Please describe the main features of the proximal ulna
● Olecranon process
● Coronoid process
● Trochlear notch
● Radial notch
● Supinator crest
● ulna tuberosity and the interosseous border
How does the ulna articulate with other bones of the elbow?
● Olecranon and the coronoid process form walls of the trochlear notch which
articulates with the trochlear of the humerus, allowing for flexion and extension.
● On lateral side of the coronoid process is the radial notch which articulates with
the radial head
What are the muscles of the flexor compartment of the forearm?
● Superficial: Pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum
superficialis, flexor carpi ulnaris
● Deep: Flexor digitorum profundus, flexor policis longus, pronator quadratus