Muscles Flashcards
The pivot point of a lever (in many cases a joint)
Fulcrum
1st Class (Definition)
Muscle effort and resistive force (load) act on opposite sides of fulcrum
1st Class (Order)
Effort, fulcrum, load
1st class (example);
Triceps Extension- Effort (triceps), fulcrum (elbow joint), load (weight in hands)
2nd class (definition)
Load is in the middle between the fulcrum and the effort
2nd class (order)
Fulcrum, load, effort (Least common)
2nd class (example)
Calf raise- Fulcrum (ball of foot), load (weight of body), effort (gastrocnemius)
3rd class (definition)
Effort is in the middle between fulcrum and load
3rd class (order)
Fulcrum, effort, load (Most Common)
3rd class (example)
-Bicep Curl- Fulcrum (elbow joint), effort (biceps), load (weight in hand)
-In this case, we are referencing the distal attachment (insertion) of the bicep
Occipotofrontalis (epicranius)
Action= draw of the scalp posteriorly
-raises eyebrows and wrinkled the forehead (horizontally)
Action = draw the eyebrows downward and medially
-Makes angry eyebrows and wrinkles the forehead (vertically)
Corrugator Supercilii
Action = elevate and retract the eyelids
-Keeps the eyes open
Levator Palpebrae Superiorisi
Close eyelids
Orbiularis Oculi
Orbicularis Oris (Superficial)
closes lips, protrudes lips
presses lips against teeth, important for speech production
Orbicularis Oris (Deep)
raises upper lip and moves it forwards (shows upper teeth)
Levator Labii Superioris
Depressor Labii Inferioris
draws lower lip inferiorioly and laterally (shows lower teeth)
Levator Anguli Oris
Raises the angle of the mouth
Depressor Anguli Oris
draws angle of the mouth downwards and laterally
Buccinator
Compresses checks during the chewing process
Risorius
Retracts the angle of the mouth
Depresses the lower jaw
Platysma
adducts, elevates, and internally rotates the eyes
Superior Rectus
depresses and adducts the eyeball
Inferior Rectus
Adducts and moves the eye medially
Medial Rectus
Abducts and moves the eye laterally
Lateral Rectus
medially rotates the eye (intorsion)
Superior Oblique
Laterally rotates the eye (extortion)
Inferior Oblique
Draws head toward shoulder of same side, rotates head to opposite side, flexes cervical spine assists in elevated the thorax
Sternocleidomastoid (R/L)
Scalenes (R/L)
Elevates 1st and 2nd ribs tilt then neck to the same side
Longissimus (Dorsi)
Extends & laterally flexes spine, aids in rib compression
Longissimus (Cervicis)
Extends & laterally flexes spine
Spinalis (Thoracis)
Extends spine
Spinalis (Cervicis)
Extends Head
Quadratus Lumborum
Depresses 12th rib, unilaterally raises pelvis, aids in lumbar spine lateral flexion, major stabilizer of lumbar spine
Flexes vertebral column, tenses abdominal wall, compressed abdominal viscera
Rectus Abdominis
External Oblique (Bilaterally)
Compresses abdomen and flexes the spine
Internal Oblique (Bilaterally)
Compresses abdominal viscera and flexes the spine
Internal Oblique (Unilaterally)
Laterally flexes and rotates spine to same side
Stabilizes spine
Transversospinialis
