Muscle - Function, Origin, Insertion Flashcards
deltoid function
abduct arm up to 90 degree perpindicular to body
anterior fibers: flexion, medial rotation
middle fibers: abduction
posterior fibers: extension & lateral rotation of humerus
deltoid origin
anterior fibers: lateral third of clavicle
middle fibers: acromion process
posterior fibers: spine of scapula
deltoid insertion
all 3 fibers converge to insert on deltoid tuberosity (Vshape on lateral humeral shaft)
Rotator cuff muscles
Supraspinatus, Infraspinatus, Teres minor, Subscapularis
SITS
supraspinatus function
abduction initiator of humeral abduction
Very vulnerable to tear/impingement
supraspinatus origin
supraspinatus fossa of scapula
supraspinatus insertion
superior facet of greater tuberosity of humerus (medial)
infraspinatus function
external/lateral rotation of shoulder, assist in shoulder extension and adduction
infraspinatus origin
infraspinous fossa of scapula
infraspinatus insertion
middle facet of greater tuberosity of humerus
teres minor function
externally/laterally rotate humerus and additional stability (similar to infraspinatus)
teres minor origin
lateral border of scapula
teres minor insertion
interior facet of greater tuberosity of humerus
teres major function
adduction, medial rotator of humerus
assist in extension of arm in abduction
teres major origin
lateral border of inferior angle of scapula
teres major insertion
medial lip of intertubercular groove of humerus
(adjacent to latissimus dorsi)
subscapularis function
internal rotation of humerus, assist in adduction of arm
helps stabilize glenohumeral joint in anterior displacement
only anterior rotator cuff muscle
subscapularis origin
subscapular fossa (anterior surface of scapula)
subscapularis insertion
lesser tuberosity of humerus (most medial of all rotator cuff insertions)
abduction of 0-10 degrees
supraspinatus muscle via suprascapular nerve
abduction of 15-110 degrees
abduction to horizontal position is due to deltoid muscle via axilllary nerve
abduction 110-180 degeres
raise above horizontal uses scapular rotation by trapezius muscle (via spinal accessory nerve) and serratus anterior (via long thoracic nerve)
Jobe/Empty can test
pain or weakness = positive
suggest supraspinatus tendiopathy/tear
anterior relations of shoulder joint
subscapularis muscle ccovers anterior aspect, then coracobrachilais and short bicep head
posterior relations of shoulder joint
infraspinatus and teres minor muscles cover posterior aspect of joint, long head of triceps runs inferiorly
superior relations of shoulder joint
supraspinatus msucle, coracoacromial arch and deltoid muscle lie superior to joint
inferior relations of shoulder joint
axillary nerve and posterior circumflex humeral vessels course around surgical neck of humerus, inferiro to joint capsule
rotator cuff tears
from repeat overhead motion or acute trauma, include pain, weakness, limited ROM especially overhead
shoulder impingement syndrome
compress rotator cuff tendons between humeral head and acromion
leads to inflamation, pain, decrease shoulder function specially overhead
frozen shoulder
progressive stiffness and loss of shoulder motion
Moves through freezing, frozen and thawing stages with varying degrees of pain and limitations
glenohumeral instability
excessive humeral head movement in fossa leads to subluxation or dislocation
from truama, stress, congenital laxity
function of pectoralis major
adduction of humerus, medial rotation of humerus, flexion of humerus, extension of flexed humerus, depression of shoulder girdle
pectoralis major heads
clavicular & sternocostal head
origin of pectoralis major (clavicular head)
anterior surface of medial half of clavicle
origin of pectoralis major (sternocostal head)
anterior surface of sternum, superior six costal cartilages, aponeurosis of external oblique
insertion of pectoralis major
lateral lip of intertubercular grooce of humerus
Fibers twist @ junction, creating superior fibers attach inferiorly and inferior attach superiorly
What muscles insert in the intertubercular groove?
latissimus dorsi, pectoralis major, and teres major
superficial fascia of pectoral region
vary amount fat and mammary gland, continuous with superficial fascia of neck, abdomen, upper limb
pectoral fascia deep
covers pec major, attach to clavicle and continuous with fascia of deltoid & serratus anterior muscles
clavipectoral fascia
this is pierced by cephalic vein, thoracoacromial artery, lateral pectoral nerve and lymphatics (CALL)
area inferior to pec minor has suspensory ligament of axilla and creates armpit
pectoralis minor function
accessory to respiration (elevate ribs when scapula fixed)
stabilize scapula (inferiorly and anteriorly agains thoracic wall)
assist protraction & downward rotation of scapula
pectoralis minor origin
outer surfaces & upper borders of 3-5th ribs costal cartilage
pectoralis minor insertion
medial border and superior surface of coracoid process of scapula
subclavius function
stabilize sternoclavicular joint in shoulder movement
depresses & draw clavicle anteriorly
origin of subclavius
junction of first rib and costal cartilage (costochondral junction)
insertion of subclavius
groove on inferior surface of middle third clavicle
serratus anterior function
protract scapula
hold scapula against thoracic wall
rotate scapula up during arm abduction
assist in forced inspiration when shoulders fixed
serratus anterior origin
external surface of upper 8-9 ribs at side of chest well
serratus anterior insertion
entire anterior length of medial border of scapula, wrap around inferior angle
biceps brachii function
chief supinator
biceps brachii insertion
tuberosity of radiuis
biceps brachii origin
short head: coracoid process
long head: supraglenoid tubercle
corachobrachialis function
felx/adduct arm
corachobrachialis origin
coracoid processc
corachobrachialis insert
medial humerus
brachialis function
chief flexor
brachialis origin
anteriot humerus
brachialis insert
coronoid process & tuberossity of ulna
triceps brachii function
chief extensor
triceps brachii oroigin
long: infraglenoid tubercle
lateral: posterior humerus
medial: posterior humerus
triceps brachii insertion
proximal end of olecranon
aconeus function
extending forarm
aconeus origin
lateral epicondyle
aconeous insert
lateral olecranon, sup/post ulna
