Shoulder/upper arm (+muscles) Flashcards
olecranon fossa is at the back of humerus what fossa(s) is at the front
coronoid and radius
what articulates with the ulnar and radius on the humerus
ulnar - trochlear
capitulum - radius
3 ligaments between clavicle and sternum
anterior sternoclavicular
costoclavicular
interclavicular
ligaments between clavicle and scapula
acromioclavicular ligament
coracoclavicular ligament:
-trapezoid ligament
-conoid ligament
(the 2 strongest ligaments providing support and attachment for upper limb)
what is glenoid labrum
fibrocartilaginous structure that forms a ring around glenoid fossa to deepen the socket - increasing the stability/congruity of the glenohumeral joint
what is subacromial bursa
sack of synovial fluid within subacromial space between supraspinatus muscle and coracoacromial ligament, it prevents friction and ensures smooth movement of supraspinatus muscle
transverse humeral ligament
between the greater and lesser tubercles of humerus
creates a intertubucular canal that the long head of biceps brachii goes through (keeps it in place)
What movements normally occur at the acromioclavicular and sternoclavicular joints?
Acromioclavicular:
anterior/posterior gliding of acromion during pronation/retraction of scapula
Rotation of clavicle - occurs during abduction and adduction of shoulder
Sternoclavicular:
anterior, posterior & vertical movement of clavicle, limited rotation
Which part of the fibrous capsule of glenohumeral joint is most loose?
Inferior part
Increases risk of inferior dislocation
What are the roles of the acromion and coracoacromial ligament in maintaining gleno- humeral stability?
Limit superior movement of the humeral head and abduction of arm
in which direction is humeral dislocation most common
downward
(Anterior dislocation of the glenohumeral joint is usually caused by excessive extension and lateral rotation of the humerus. It occurs most often in young particularly athletes.)
glenohumeral joint is a ball and socket, what kind of joint is the elbow
hinge (synovial)
annular ligament
around head of radius
stabilising radio-ulnar joint
What movements occur at the humeroradial, humeroulnar, and proximal radioulnar joints?
Humeroradial:
flexion + extension
Humeroulnar:
flexion + extension
Proximal radioulnar:
supination + pronation
What is the anatomical relationship between the epicondyles and olecranon process in elbow extension and flexion
extension - between the epicondyles
flexion - olecranon inferior the epicondyles
lateral and medial epicondylitis
lateral = tennis elbow
- radial nerve injury risk
- pain posterior forearm
- repetitive forceful flexion/extension of wrist /lateral epicondyle
medial = golfer’s elbow
- ulnar nerve injury risk
- anterior forearm pain
- repetitive gripping/flexing/swinging
Subluxation and Dislocation of the Radial Head
sublimation = incomplete dislocation
usually in young children
tear of annular ligament –> radial head move distally out
proximal part of torn ligament may get trapped between radial head and capitulum of humerus
treatment = supination of forearm during elbow flexion
brachial plexus
C5-T1
Roots, Trunks(superior, middle, inferior), Divisions(Anterior, posterior), Cords(lateral, posterior, medial), Branches
what do the branches of the brachial plexus supply and what are their roots
musculocutenaous (C5,6,7)
-biceps brachii
Axillary (C5,6)
- delotoid
- teres minor
median(C6,7,8,T1)
- forearm flexors
- thenar muscles
- 2 lateral finger flexors
radial(all)
- posterior extensor muscles
- triceps brachii
ulnar (C8, T1)
- forearm extensors
- medial finger flexors
winged scapula is a consequence of which nerve damage
long thoracic (C5,6,7)
supplying the serratus anterior
consequence of damaging axillary nerve
can’t abduct arm between 15-90 degrees
up to 15 = supraspinatous
what causes superior and inferior brachial plexus injuries
superior is more common
- increased angle between neck and shoulder
- eg. accident where neck and shoulder seperate
inferior
-upper limb is suddenly pulled superiorly (eg. grabbing onto something as you fall)
when does subclavian become axillary and then brachial artery
becomes axillary at 1st rib
brachial after lower margin of teres major
what muscle divides the axillary into 3 parts
pectoralis minor
1st- above
2nd - behind
3rd - below
branches of axillary artery
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- superior thoracic
- thoracoacromial
- lateral thoracic
- subscapular
- anterior humeral circumflex
- posterior humeral circumflex
muscles that make up rotator cuff
SITS
origin
- supraspinatous (supraspinous fossa)
- infraspinatous (infraspinous fossa)
- teres MINOR (posterior lateral border of scapula)
- subscapularis (subscapula fossa)
all supplied by sub scapular nerve (C5,6) except teres minor (axillary nerve C4-6)
all insert to greater tubercle of humerus except subscapularis (lesser)
supraspinatus tendon is the most commonly torn part of the rotator cuff, likely because it is relatively avascular.
testing for supraspinatous and infraspinatous muscle problems
both are responsible for abducting arm
test for resisting abduction of 20degrees = supraspinatous(/infra)
infraspinatous = externally rotates humerus
problem with externally rotating humerus = infraspinatous
what muscles form the borders of axillary fold
+their origin/insertion
anterior =
pectoralis major
-medial clavicle, sternum, first 6 costal cartilages, aponeurosis of external abdominal obliques
-inserts in greater tubercle crest of humerus
posterior =
latissimus dorsi
-spinous process of T7-12, iliac crest, 9-12th ribs
-intertubucular crest of humerus
teres major
-posterior inferior angle of scapula to lesser humeral tubercle crest
muscles for arm abduction
deltoid (15-90)
supraspinatous (up to 15)
trapezius
muscles for arm adduction
pectoralis major
pectoralis minor
latissimus dorsi
teres major
muscles for arm flexion
Pectoralis Major
Coracobrachialis
Biceps Brachii
Deltoid (Anterior fibres)
muscles for arm extension
Latissimus Dorsi
Teres Major
Long head of triceps
Posterior fibres of deltoid
muscles for internal arm rotation
Subscapularis Latissimus Dorsi Teres Major Pectoralise Major Deltoid (Anterior Fibres)
muscles for lateral arm rotation
Infraspinatus
Teres Minor
Deltoid
deltoid
origin
- lateral 1/3rd clavicle
- acromion
- spine of scapula
insertion
-deltoid tuberosity of humerus
axillary nerve (C5,6)
pectoralis minor
origin
-anterior ribs 3-5
insert
-coracoid process of scapula
action
- protraction
- downward rotation of pectoral
insertion/action difference of trees major and minor
major - lower crest of lesser tubercle
(adduction/internal rotation/extension)
minor - greater tubercle
(lateral rotation)
biceps brachii
musculocuteanous nerve (C5,6)
flexion and supination
long head
-supraglenoid tubercle of scapula
short head
-coracoid process of scapula
both heads converge to biceps brachii tendon —inserts–> radial tuberosity
triceps brachii
lateral head
-posterior humerus superior to radial groove
medial head
-infraglenoid tubercle of scapula
converge to triceps brachii tendon —–inserts—> olecranon of ulna
radial nerve
coracobrachialis
origin: coracoid process
insertion: middle of medial humerus
action: (adduction/) flexion
musculocuteanous nerve (C5-7)
trapezius
origin
- occipital bone
- spinous process C7-T12
insertion
- posterior, lateral 3rd clavicle
- acromion
- spine of scapula
action
- elevates
- depresses
- retracts
- upwardly rotates pectoral
- extends and laterally flexes head/neck
acessory nerve
serratus anterior
origin
-external surfaces of first 9 ribs
insertion
-medial border of scapula (inside/anterior side)
action
-protracts and upwardly rotates pectoral girdle
long thoracic
SCM
origin
- sternal head (Manubrium)
- medial third of clavicle
insertion
-mastoid process
action
- flexing head laterally (ipsilateral)
- rotating head (contralateral side)
accessory nerve (CN XI)
rhomboids
minor
-spinous process C7-T1
major
-spinous process T2-T5
both inserts into medial border of scapula (minor adjacent and major inferior to the scapula spine level)
action
- retraction
- downwardly rotate pectoral girdle
dorsal scapular nerve C4-5
levator scapulae
origin
-transverse process C1-4
insertion
- superior angle of scapula
- medial border of scapula superior to spine of scapula level
action
- elevate and downwardly rotate pectoral girdle
- extend and laterally flex neck at cervical vertebral joints
