Superficial Back Flashcards
What STRUCTURES make up the shoulder girdle?
scapula, clavicle, and proximal humerus
What JOINTS make up the shoulder girdle?
ST, SC, AC, GH
scapulothoracic, sternoclavicular, acromioclavicular, and glenohumeral
what is the only bony articulation that holds the upper extremities to the axial skeleton?
the SC joint - sternoclavicular
what is one of the biggest reasons for shoulder pain?
because the scapula is held against the thoracic cage purely by muscle, weakness in muscle may contribute to pain in shoulder
what type of joint is the GH joint?
ball and socket
triplanar
what is the shoulder girdle built for?
mobility and stability for the upper extremities
why might the shoulder girdle not be the most stable in itself?
it depends on the strength of the musculature supporting it
is the shoulder built for weightbearing?
no
do the four joints of the shoulder girdle move independently or dependently to one another?
dependently, they move together as a unit
what is the benefit of the shape of the clavicle?
it improves the strength to the bone and transmits force from the upper extremities to the axial skeleton
what does the disc at the medial end of the clavicle do?
provides a little bit of a cushion
because the SC joint is so shallow, the disc gives it more congruency and shock absorption
where are clavicular fractures the most common?
where the medial 2/3 meets the lateral 1/3
how do clavicular fractures happen?
falling directly onto the shoulder or on outstretched hand
what is a major risk when it comes to clavicle fractures?
it the jagged end of the broken clavicle drops down too much, it could nick the subclavian artery and lead to a bleed out
where are shoulder separations most common?
the AC joint - acromioclavicular
where are shoulder dislocations most common?
the GH joint - glenohumeral
what type of bone is the scapula?
flat bone
is the ANTERIOR surface of the scapula convex or concave?
concave
is the POSTERIOR surface of the scapula convex or concave?
convex
which rib does the superior angle of the scapula lie on top of?
the second rib
which rib does the inferior angle of the scapula lie on top of?
the seventh rib
what runs down the bicipital groove of the humerus?
the biceps brachii tendon
why is there a surgical neck of the humerus?
because the area that the surgical neck is the area in which fractures are most common
what is the axilla?
the region between the pectoral muscles, the scapula, the arm, and the thoracic wall
your armpit
what is the apex of the axillary wall?
the convergence of the clavicle, scapula, and rib 1
what is the base of the axillary wall?
fascia and skin of the armpit
what makes up the anterior wall of the axillary wall?
pectoral muscles
pectoralis major forms the anterior axillary fold
what makes up the posterior wall of the axillary wall?
scapula and subscapularis muscles
latissimus dorsi and teres major form the posterior axillary fold
what creates the lateral wall of the axillary wall?
the humerus
what creates the medial wall of the axillary wall?
rib cage
what are the abbreviations to remember the arteries / veins of the UE?
BC SC A ST TA LT SS A/PHC
brachiocephalic, subclavian, superior thoracic, thoraco-acromial, lateral thoracic, subscapular, ant/post humeral circumflex
what is different about the brachiocephalic vein?
there is only one of these and it’s only on the right side
the left side comes directly off the aorta
the axillary lymph nodes become enlarged when?
when there are infections in the hand or UE
what might the axillary lymph nodes be involved in?
breast cancer
what happens if the axillary lymph nodes are removed due to breast cancer?
lymphedema
what joint is the most important out of the four joints of the shoulder girdle?
the ST joint - scapulothoracic
is the ST joint a real anatomic joint?
no
the ST joint movements are linked to what other joints?
SC and AC
how does the ST joint help the GH joint?
helps facilitate movement at the GH joint
what is the reference point of the scapula?
the glenoid of the scapula
what do the muscles of the ST joint do?
keeps the scapula following the contour of the thorax as it moves
why does the scapula need to move at all?
to keep the glenoid fossa and head of the humerus aligned - which provides movement and stability of the arm
what is the normal range of the ST joint?
60 degrees
what is the normal range of the GH joint?
120 degrees
what is scapulohumeral rhythm?
coordinated movement of the GH and ST joint
180 degrees of movement
what ratio does the scapulohumeral rhythm occur in?
1:2 ratio
for every 3 degrees of movement, 1 degree is generated by the ST joint and 2 degrees is generated by the GH joint
what is upward tilt / tipping of the scapula?
movement of the inferior angle of the scapula away from the thorax
what is lateral tilt / winging of the scapula?
movement of the vertebral border of the scapula away from the thorax
what type of joint is the SC joint?
plane synovial w/ 3 degrees of freedom
what movements occur at the SC joint?
elevation/depression
protraction/retraction
rotation
what movements are at the ST joint?
elevation/depression
abduction/adduction (protraction/retraction)
upward/downward rotation
what are the four ligaments at the SC joint?
anterior/posterior sternoclavicular ligament
costoclavicular ligament
interclavicular ligament
what does the posterior sternoclavicular ligament do?
checks the a/p movement of the head of the clavicle
what does the costoclavicular ligament do?
reinforces the joint capsule and limits elevation of the medial end of the clavicle
what does the interclavicular ligament do?
limits depression of clavicle
what type of joint is the AC joint?
plane synovial w/ 3 degrees of freedom
what is a negative thing the AC joint allows?
winging and tipping of scapula
what are the acromioclavicular ligaments?
superior/inferior acromioclavicular ligament
coracoclavicular ligament
coracoacromial ligament
what are the two parts the coracoclavicular ligaments divide into?
the trapezoid (lateral)
the conoid (medial)
what does the conoid ligament do?
prevents superior displacement of the clavicle on the acromion
if you lose one or both of the two aspects of the coracoclavicular ligament, what happens?
the clavicle will shoot up and form a “step deformity”
it is a grade II or III shoulder separation
at the AC joint, upward/downward rotation occurs in what plane?
transverse (horizontal)
at the AC joint, rotation occurs in what plane?
sagittal
what does the glenoid labrum do?
deepens the glenoid fossa and increases the size of the articular surface
at the GH joint, is the capsule taut or slack superiorly?
taut, therefore making it slack inferiorly
at the GH joint, where is it reinforced the most?
on the anterior side
what is the coracohumeral ligament?
connects the coracoid process with the greater tubercle
- supports the humerus against the pull of gravity
where are the two bursa located in the shoulder?
subacromial
subscapular
what does the subacromial bursa do?
separates the supraspinatus tendon and head of humerus from the acromion process
how can an impingement of the supraspinatus muscle occur?
because the tendon is between the head of the humerus and the AC joint, so it can get squashed
what is the “5th joint” of the shoulder girdle?
the coracoacromial arch
what does the coracoacromial arch do?
protects the top of the humeral head, muscles, tendons, and bursae from trauma from above such as heavy purses
