A&P Lab 10: The Muscular System - Gross Anatomy of Muscles Flashcards
Origin
point of attachment of the muscle tendon to the originating or immoveable bone
Insertion
attachment site of the muscle tendon to the moveable bone
Action
movement of the bone that occurs during muscle contraction
Epicranius
frontalis & occipitalis with aponeurosis in between; raises eyebrows and occipitalis pulls scalp posteriorly
Orbicularis oculi
circular sphincter muscle of eyelids; closes eyes, draws eyelids inferiorly
Orbicularis oris
circular sphincter of the muscle of the mouth; closes mouth, protrudes lips
Levator labii superioris
between orbicularis oris and inferior margin of the eye; elevates upper lip, opens the mouth
Zygomaticus
consists of 2 muscles (major & minor) from corner of mouth to cheek; elevates lateral corners of the mouth to smile
Mentalis
superficial muscle of the chin; protrudes lower lip, wrinkles the chin
Platysma
thin, superficial muscle of the neck; depresses jaw and lower lip to turn the mouth downward
Masseter
covers the lateral aspect of the ramus of the mandible; closes jaw, elevates mandible
Temporalis
fan-shaped muscle on the lateral head; closes jaw, elevates/retracts jaw
Buccinator
main muscle of the cheek deep to the masseter; draws corner of mouth laterally (as in whistling)
Medial pterygoid
elevates jaw, assists in closing jaw
Lateral pterygoid
extends from behind the cheekbone to the upper jaw; protracts jaw to grind teeth
Sternocleidomastoid
large, V-shaped muscle of the lateral and anterior neck with 2 heads of origin on either side; flexion of the neck forward when both heads contract together and rotation to the shoulder of opposite side if independent
Scalenes
on lateral and anterior neck, consists of anterior, middle, and posterior; flexion and slight rotation of neck, elevation of 1st ribs
Digastric
2 bellies (fleshy part of a muscle) united by a tendon to form a V shape beneath the shin; together they elevate hyoid, open mouth, depress jaw
Stylohyoid
narrow muscle below angle of the jaw; elevate and retract hyoid bone
Mylohyoid
deep to the digastric to form the floor of the mouth; depresses the larynx and hyoid bone if mandible is held stationary
Sternohyoid
narrow muscle near the midline of the neck; depresses the larynx and hyoid bone if mandible is held stationary
Sternothyroid
deep and lateral to sternohyoid; depresses the larynx and hyoid bone if mandible is held stationary
Omohyoid
narrow muscle lateral to sternohyoid with 2 bellies, superior and inferior; depresses the larynx and hyoid bone if mandible is held stationary
Thyrohyoid
superior to the sternothyroid; depresses hyoid, elevates larynx if hyoid is stationary
Pectoralis major
large, fan-shaped muscle covering the upper thorax; flexes, adducts, and medially rotates the arm at the shoulder
Deltoid
triangular muscle atop the shoulder; abduction of the arm at the shoulder
Serratus anterior
large, fan-shaped muscle deep to the scapula with serrated margins; protracts the shoulder, upward rotation of the scapula
Levator scapulae
between the shoulder and neck deep to the trapezius; elevates the scapula
Pectoralis minor
small, thin muscle deep to pectoralis major; depresses and protracts the shoulder
Trapezius
large, superior muscle of the back; extends the head, rotates and adducts scapula; elevates or depresses scapula
Latissimus dorsi
broad, flat muscle of the lower back; extends, adducts, and medially rotates the shoulder
Supraspinatus
deep to trapezius within the supraspinous fossa of scapula; a rotator cuff muscle; abduction at the shoulder
Infraspinatus
deep to trapezius within the infraspinous fossa of scapula; a rotator cuff muscle; lateral rotation at the shoulder
Teres minor
small, narrow muscle inferior to infraspinatus; a rotator cuff muscle; lateral rotation at the shoulder
Teres major
inferior to teres minor and scapula; extension, adduction, and medial rotation at shoulder
Rhomboids, major & minor
deep to trapezius and medial to the vertebral border of the scapula; adducts scapula and rotates it downward
Rectus abdominis
medial, segmented superficial muscle of the abdomen; flexes and rotates vertebral column
External oblique
lateral, superficial muscle of the abdomen extending from the pubis to the thoracic cage; flexes and rotates vertebral column
Internal oblique
deep to the external oblique with fibers extending in opposite direction; flexes and rotates vertebral column
Transverse abdominus
deepest muscle of the abdomen with fibers in horizontal direction; compresses the abdomen