L3 - Anatomy of the shoulder Flashcards
SKELETAL COMPONENTS
i) name the three bones that make up the pectoral girdle
ii) what are the two joints in the shoulder? which one of these is a synovial plane joint? what does this make it susceptible to?
iii) label the diagram
i) pec girdle = clavicle, scapula, humerus
ii) glenohumeral and acromiocalvicular
- AC is a synovial plane joint > easily dislocated
iii) A - acromium, B - coracoid C - greater tubercle of hum,
D - intertub sulucus/bicipital groove, E - lesser tubercle of hum
LIGAMENTS OF SHOULDER REGION
i) what do they do? how strong are they?
ii) how many ligaments does the glenohumeral lig consist of? name them? where do they insert into?
iii) name the three other ligaments in the shoulder
i) stabilise and support the shoulder
ii) GH lig = three small ligaments (sup, mid, inf)
- insert to anatomical neck of humerus
iii) coracoclavic, acromioclavic, coracoacrom
CORACOCLAVICULAR AND CORACOACROMIAL LIGS
i) which is the major stabilising ligament?
ii) which forms an arch, provides support for head of humerus?
iii) what type of dislocation does coracoacromial prevent?
iv) the tendon if which muscle runs under CA ligament?
v) label diagram
i) coracoclavic is major stabiliser
ii) CA forms arch and support for humerus
iii) CA prevents superior dislocation
iv) tendon of supraspinatus runs under
v) A- coracoacromial, B- coracoclavicular
GLENOHUMERAL JOINT
i) what type of joint is it?
ii) give three pairs of movement it allows? what extra movement can it do?
iii) what is it an articulation between?
i) highly mobile ball and socket joint
ii) flex/exten, ab/adduc, lat/med rot and circumduction
iii) artic bet head of humerus and glenoid fossa
ABDUCTION OF THE ARM - DELTOID
i) where does it orig (3 - SAC) and insert
ii) which nerve supplies it? what cord of the BP is this a branch of?
iii) which fibres allow extension and lateral rotation of the arm?
iv) which fibres allow flexion and medial rot of the arm?
i) orig spine of scap, acromium and clavicle
- inserts to deltoid tuberosity of humerus
ii) supplied by axillary nerve - branch of post cord of BP
iii) exten and lat rot by posterior fibres
flexion and med rot by anterior fibres
ADDUCTION OF THE ARM
i) which two muscles allow it?
lat dorsi and pec major
FLEXION OF THE ARM
i) name two muscles that allow it? which fibres of deltoid also contribute?
ii) which muscle flexes the forearm?
iii) label diagram
i) biceps and coracobrachialis plus anterior fibres of deltoid
ii) brachialis flexes the forearm
A - biceps short head, B - biceps long head, C - coracobrachialis, D - brachialis
EXTENSION OF ARM
i) which head of triceps is the only head to extend the arm? which two heads extend the forearm?
ii) which fibres of deltoid and which other muscle also extend the arm?
iii) where do the three heads of triceps insert?
iv) label diagram
i) long head triceps extends the arm
- lat and medial head extend the forearm
ii) post fibres of deltoid and lat dorsi extend the arm
iii) three heads of biceps inster to olecranon of the ulna
iv) A - long head triceps, B - lat head C - med head triceps
D - olecranon of ulna
GLENOHUMERAL JOINT STABILITY
i) what aspect of the humeral head and glenoid fossa makes it unstable? what does this allow for?
ii) what type of dislocation is common? what action can do this?
iii) name four factors increasing stability
i) large humeral head and shallow glenoid fossa makes it unstable
- allows for lots of movement
ii) anterior dislocation is common - him jead descends inferior and ends up anterior - done by throwing
iii) coracoacromial arch, GH ligaments, deepening of GF by glenoid labrum, long heads of biceps and triceps, tendons of rotator cuff muscles
CORACOACROMIAL ARCH/GH LIGAMENTS
i) what is CA arch it formed by? what does it prevent?
ii) what does the GH ligaments support?
iii) label diagram
i) CA arch formed by CA ligament and prevents superior disloc of humerus
ii) GH ligaments support the anterior joint to stop disloc
iii) A - GH ligaments, B - CA ligament, C - Ca arch
LONG HEAD OF BICEPS AND TRICEPS
i) what do they do to the GH joint?
ii) which passes through the joint capsule?
i) splint the joint above and below and hold the humerus against the glenoid fossa
ii) long head biceps passes through the joint capsule
ROTATOR CUFF MUSCLES
i) name the four muscles it comprises of? where do they insert?
ii) what do the tendons fuse with? what do the tendons form around the joint?
iii) which side is the only side the RC muscles dont surround the joint?
iv) label diagram
i) supraspinatus, infraspinatus, teres minor and subscapularis
ii) tendons fuse with joint capsule and form a cuff around the joint
iii) only side RC dont surround the joint is inferior
iv) A - supraspinatus, B - infraspinatus, C - teres minor, D - subscapularis
ROTATOR CUFF MUSCLES - ORIGIN/INSERT
i) label the diagram
ii) where does each originate from?
iii) which structure do they insert to? which order? where does subscapularis insert?
i) A - supraspinatus, B - infraspinatus, C - teres minor
D - axillary nerve
ii) supraspin from supraspinous gfossa
infraspin from infraspinous fossa
teres minor from lateral/inferior scapula
iii) insert to greater tubercle of the humerus (SIT)
subscapularis inserts to lesser tubercle of humerus
ROTATOR CUFF FUNCTION
i) what do they do together?
ii) which muscle initiates abduction?
iii) which two muscles do lateral rotation?
iv) which muscle does medial rotation?
i) together they stabilise th humeral head on the glenoid fossa
ii) suprapspinatus initiates abduction
iii) infraspin and teres minor do lateral rotation
iv) subscapularis does medial rotation
TERES MAJOR
i) what action does it perform? what action does it stabilise the humerus during?
ii) which muscle does it contract with?
iii) where does it origin and insert from?
i) does medial rotation (same as subscapularis)
- stabilises the humerus during abduction
ii) contracts w deltoid
iii) origin from inferior angle of scapula and inserts to medial lip of bicpital groove on humerus
ROTATOR CUFF INJURY
i) which muscle is commonly impinged/injured? why is this?
ii) what can impingement be due to? who is it common in?
iii) label diagram
i) supraspinatus commonly injured due to limited space for tendon under coracoacromial arch
ii) due to repetitive overhead activity (Atheletes)
iii) 1 - deltoid, 2 - supraspinatus, 3 - acromium
SCAPULA ANATOMOSIS
i) name one branch from the axillary? name two branches from the subclavian?
ii) which two part of the subclavian does it come from?
iii) which part of the axillary does it come from?
iv) label diagram
i) axillary = subscapular artery (3rd part)
subclavian = suprascapular from thryocervical trunk (1st part) and dorsal scapula from 3rd part
iv) A - subscap artery, B - dorsal scap artery, C - suprascap
POSTERIOR CORD
i) which two nerves come off it? what muscles do they supply?
ii) what are the three branches of nerves that come of it?
iii) label diagram
i) axillary > deltoid and teres minor
radial > triceps
ii) upper/lower subscap nerves - subscap and teres major
thoracodorsal nerve - lat dorsi
iii) A - axillary B - radial
QUADRANGULAR SPACE
i) which artery and nerve pass through it?
ii) what forms the roof/floor/walls
iii) what does muscles does the nerve that passes through supply? what area of skin does it supply?
iv) a fracture to which area can damage the vesels that run through?
v) label diagram
i) axillary nerve and posterior circumflex humeral artery
ii) roof - teres minor, floor - teres major, walls - humerus and long head of triceps
iii) axillary artery > deltoid and teres minor and badge area of skin
iv) fracture of surgical neck of humerus
v) A - teres minor, B - deltoid, D - teres major, E - long head of triceps F/g - axillary nerve and post circumflex humeral artery
