Bio Exam Flashcards
Origin: Epicranial Aponeurosis
Insertion: Skin over supraorbital margin (eyebrow skin)
Action: Moves scalp, eyebrows, wrinkles skin of forehead
Frontal Belly of Occipitofrontalis
(front=forehead)
Origin: Medial wall or margin of orbit
Insertion: Skin surrounding eyelids
Action: Closes eye; produces wrinkling, blinking, squinting (“blink” muscle)
Orbicularis oculi
(orb=circular, ocul=eye)
Origin: Body of mandible
Insertion: Skin at inferior corner (angle) of mouth
Action: Draws corners of mouth inferiority and laterally (“frown” muscle)
Depressor anguli oris
(depressor=depresses, angul=angle, or=mouth)
Origin: Zygomatic bone
Insertion: Skin at superolateral edge of mouth
Action: Elevates corner of the mouth (“smile” muscle)
Zygomaticus major
(zygomatic=cheekbone, major=greater)
Origin: Zygomatic arch
Insertion: Ramus (lateral surface) and angle of mandible
Action: Elevates and protracts mandible; prime mover of jaw closure
Masseter
(maseter=chewer)
Origin: Manubrium and sternal end of clavicle
Insertion: Mastoid process
Action: Unilateral action: Lateral flexion, rotation of head to opposite side. Bilateral action: Flexes neck
Sternocleidomastoid
(sterno=sternum, cleido=clavicle, masto=mastoid process)
Origin: Ligamentum nuchae and spinous process of C7-T3
Insertion: Occipital bone and mastoid process of temporal bone
Action: Unilateral action: Turns head to same side. Bilateral action: Extends head/neck
Splenius Capitis
(splenion=bandage)
Action: Contraction causes flattening of diaphragm (moves inferiorly), and thus expansion of thoracic cavity; increases pressure in abdominopelvic cavity
Diaphragm
(dia=across, phragm=partition)
Origin: External and inferior borders of the inferior 8 ribs
Insertion: Linea alba by a broad aponeurosis; some to iliac crest
Action: Unilateral action: Lateral flexion of vertebral column; rotation of vertebral column to the opposite side. Bilateral action: Flexes vertebral column and compress abdominal wall; used in forced exhalation
External oblique
Origin: Superior surface of pubis near symphysis
Insertion: Xiphoid process of sternum; inferior surfaces of ribs 5-7
Action: Flexes vertebral column; compresses abdominal wall; used in forced exhalation
Rectus abdominis
Origin: Occipital bone (superior nuchal line); ligamentum nuchae; spinous processes of C7-T12
Insertion: Clavicle; acromion process and spine of scapula
Action: Superior fibers: Elevate and superiorly rotate scapula. Middle fibers: Retract scapula. Inferior fibers: Depress scapula
Trapezius
(trapezion=irregular four-sided figure)
Origin: Spinous processes of T7-T12; ribs 8-12; iliac crest; thoracolumbar fascia
Insertion: Intertubercular sulcus of humerus
Action: Agonist of arm extension; also adducts and medially rotates arm (“swimmers muscle”)
Latissimus dorsi
(latissimus=widest, dorsi=back)
Origin: Acromial end of clavicle; acromion and spine of scapula
Insertion: Deltoid tuberosity of humerus
Action: Anterior fibers: Flex and medially rotate arm. Middle fibers: Agonist of arm abduction. Posterior fibers: Extend and laterally rotate arm
Deltoid
(delta=triangular)
Origin: Medial clavicle; costal cartilages of ribs 2-6; body of sternum
Insertion: Lateral part of intertubercular sulcus of humerus
Action: Agonist of arm flexion; also adducts and medially rotates arm. Also horizontal adduction of arm
Pectoralis major
Origin: Long head: Supraglenoid tubercle of scapula. Short head: Coracoid process of scapula
Insertion: Radial tuberosity and bicipital aponeurosis
Action: Flexes forearm, powerful supinator of forearm. Long head flexes arm
Biceps brachii
(biceps=two heads, long head & short head)
