the shoulder and proximal upper extremity Flashcards
what are the muscles that compose the anterior part of the shoulder?
- Pectoralis Major
- Deltoid
- Subscapularis
- subclavius
- pectoralis minor
- serratus anterior
Pectoralis Major
origin
insertion
action?
origin: medial clavicule and sternal head
insertion: lateral lip of the intertubercular groove of the humerus
action: GH flexion, Adduction and internal rotation
Deltoid
origin
insertion
action?
origin: lateral third of the clavicle, acromion and spine of the scapula
insertion: deltoid tuberosity of the humerus
action:
1) anterior fibers: GH flexion and medial rotation
2) middle fibers: GH abduction
3) posterior fibers: GH extension and lateral rotation
Subscapularis
origin
insertion
action?
origin: subscapular fossa
insertion: lesser tubercule of the humerus
action: internal rotation of the GH joint
subclavius
origin
insertion
action?
origin: costal cartilage of rib I
insertion: inferior surface of clavicle
action: depression of the clavicle
pectoralis minor
origin
insertion
action?
origin: ribs 3-5
insertion: coracoid process of the scapula
action: depression of the scapula
serratus anterior
origin
insertion
action?
origin: Lateral border of ribs I-VIII
insertion: anteromedial border of the scapula
action: protraction (abduction) and depression of the scapula
what anterior shoulder muscles act on the GH joint?
- deltoid
- pectoralis major
- subscapularis
what anterior shoulder muscles act on the “scapulothoracic joint”?
- pectoralis minor
- subclavius
- serratus anterior
what muscles make up the rotator cuff? do they belong to the anterior or posterior side of the shoulder?
- subscapularis (anterior)
- supraspinatus (posterior)
- infraspinatus (posterior)
- teres minor (posterior)
what is the acronym to recall the rotator cuff muscles?
SItS muscles
what is the common function shared by the muscles of the rotator cuff?
they create a cuff around the GH joint and stabilize it.
what are some joint components found around the subscapularis muscle?
we have 2 different bursaes to relieve frictions
- subtendinous bursa of subscapularis
- subcoracoid bursa to reduce friction between the muscle and the coracoid process which sits rights above
Supraspinatis
origin
insertion
action?
origin: supraspinous fossa of the scapula
insertion: greater tubercule of the humerus (superior facet)
action: initiates arm abduction at the GH joint for the first 30 degrees of motion
what is the name of the bursa found next to the supraspinatus muscle? why?
-the subacromial bursa prevents the belly of the muscle from being caught in the acromion
there is also lateral to it the subdeltoid bursa.
Infraspinatus
origin
insertion
action?
origin: Infraspinous fossa of the spine of the scapula
insertion: greater tubercules of the humerus (middle facet)
action: external rotation of the arm
teres minor
origin
insertion
action?
origin: Lateral superior border of the scapula
insertion: greater tubercule of the humerus (inferior facet)
action: external rotation of the arm
where is the subacromial bursa located?
right above the tendon of the supraspinatus and below the acromion on the posterior side of the shoulder
where is the subcoracoid bursa located?
above the subscapularis muscles and beneath the coracoid process on the anterior side of the shoulder
where is the subtendinous burda of subscapularis located?
on the anterior inferior side of the shoulder between the subscapularis muscle and the tendon of the bicep brachii
what are the posterior muscles of the shoulder excluding those of the rotator cuffs?
- Teres Major
- levator scapulae
- Rhomboid minor and major
- trapezius
- latissimus dorsi
Teres Major
origin
insertion
action?
origin: lateral (inferior) border of the scapula
insertion: medial lip of the interbercular groove on the humerus
action: extension, addiction and internal rotation of the GH joint
the greater tubercule is a common insertion to what?
3 of the 4 muscles of the rotator cuff
SIt
what is the triangular space bordered by? what does this space contain?
- teres minor
- tricep brachii long head
- teres major
this space contains the curcymflex scapular artery
what is the quadrangular space bordered by? what does this space contain?
- teres minor
- proximal humerus
- Teres major
- triceps brachii long head
contains: auxillary nerve and posterior circumflex humeral artery
Levator Scapulae
origin
insertion
action
origin: TPS CI-CIV
insertion: superomedial boarder of the scapula
action: elevation and downwards rotation of the scapula
Rhomboid minor and major
origin
insertion
action?
origin: SP’s CVII-TV
insertion: medial boarder of the scapula
action: retraction (Adduction) of the scapula
slight contibution to the elevation and downwards rotation of the scapula
what type of back muscles are the levator scapulae and the rhomboid minor and major?
they are part of the second superficial layer of the back’s extrinsic muscles
Trapezius origin insertion action innervation blood supply
origin: external occipital protuberance, ligamentum of nuchae, SPs CVII-TXII
insertion: spine of the scapula, acromion and clavicle
action:
upper fibers –> elevate the scapula
middle fibers –> retraction (adduction) and upward rotation of the scapula
lower fibers –> upwards rotation of the scapula during adduction of the arm during depression of the scapula
innervation: spinal accessory nerve C11
blood supply: transverse cervical artery
Latissimus Dosi
origin
insertion
action
origin: SPs of TVI-LV,
sacrum, illiac crest, throacolumbar apneurosis
insertion: floor of the interbercular groove of the humerus
action: extension, adduction and internal rotation of the arm at the GH joint.
the intertubercular groove is a common insertion for which muscles?
- Pectoralis Major
- Latissimus Dorsi
- Teres Major
what acronym(s) can you use to recall the insertions on the intertubercular groove?
-PLT
or
-A miss between 2 majors
what is the trianglular interval bordered by? what does this space contain?
- Teres Major
- long head of the tricep muscle
- lateral head of the tricep muscle
conains: the deep brachial artery and the radial nerve
