Muscular System Labs 12 & 13 Vocabulary

Vocabulary flashcards covering origins, insertions, and primary actions of the muscles studied in Labs 12 & 13.

Epicranius (frontal & occipital bellies)

Raises the eyebrows and pulls the scalp posteriorly; frontal belly originates on the epicranial aponeurosis, occipital belly on occipital & temporal bones.

Orbicularis oculi

Circular muscle that closes the eyelids; surrounds orbit and inserts into skin of eyelid.

Orbicularis oris

Encircles the mouth to close and purse the lips; the "kissing" muscle.

Zygomaticus (major & minor)

Elevates the corners of the mouth upward to smile; runs from zygomatic bone to mouth corners.

Risorius

Draws the lips laterally (grimacing); pulls mouth angle toward fascia of masseter.

Buccinator

Compresses cheek (whistling, sucking); deep to masseter, from maxilla/mandible to orbicularis oris.

Masseter

Prime mover of jaw closure; zygomatic arch → angle & ramus of mandible.

Temporalis

Elevates and retracts mandible; temporal fossa → coronoid process of mandible.

Platysma

Superficial neck muscle that tenses skin of the neck; fascia of chest → mandible & mouth skin.

Sternocleidomastoid

Flexes neck and rotates head; manubrium & clavicle → mastoid process of temporal bone.

Sternohyoid

Depresses larynx and hyoid bone during swallowing; posterior manubrium → hyoid.

Pectoralis major

Flexes, adducts, and medially rotates arm; clavicle/sternum/ribs → intertubercular sulcus of humerus.

Deltoid

Prime abductor of the arm; clavicle, acromion, spine of scapula → deltoid tuberosity.

Pectoralis minor

Draws scapula forward and inferiorly; ribs 3-5 → coracoid process of scapula.

Serratus anterior

Protracts scapula, holds it against chest wall, rotates scapula; lateral ribs → vertebral border of scapula.

External intercostals

Elevate ribs during inspiration; inferior border of rib above → superior border of rib below.

Internal intercostals

Depress ribs during forced expiration; superior border of rib below → inferior border of rib above.

Diaphragm

Prime mover of inspiration; flattens to enlarge thoracic cavity; origins on rib cage & vertebrae → central tendon.

Rectus abdominis

Flexes and rotates vertebral column; pubic crest/symphysis → xiphoid process & costal cartilages.

External oblique

Flexes and rotates trunk; compresses abdominal wall; ribs 5-12 → linea alba & iliac crest.

Internal oblique

Synergist to external oblique; lumbar fascia & iliac crest → linea alba & pubic crest.

Transversus abdominis

Compresses abdominal contents; deepest abdominal muscle; lumbar fascia/iliac crest → linea alba & pubis.

Trapezius

Raises, retracts, rotates, and stabilizes scapula; occipital bone & thoracic spines → clavicle, acromion, scapular spine.

Latissimus dorsi

Extends, adducts, and medially rotates arm; thoracolumbar fascia & iliac crest → intertubercular sulcus.

Infraspinatus

Laterally rotates humerus; infraspinous fossa → greater tubercle of humerus.

Teres minor

Lateral rotation of humerus; lateral border of scapula → greater tubercle.

Teres major

Extends, medially rotates, and adducts humerus; posterior scapula → intertubercular sulcus.

Supraspinatus

Initiates abduction of humerus; supraspinous fossa → greater tubercle.

Rhomboids (major & minor)

Stabilize and retract scapula; thoracic spinous processes → medial border of scapula.

Biceps brachii

Flexes elbow and supinates forearm; scapula → radial tuberosity.

Brachioradialis

Flexes forearm at elbow; lateral distal humerus → radial styloid process.

Brachialis

Major forearm flexor; distal anterior humerus → coronoid process of ulna.

Flexor carpi radialis

Flexes wrist and abducts hand; medial epicondyle → bases of metacarpals II & III.

Palmaris longus

Weak wrist flexor; medial epicondyle → palmar aponeurosis.

Flexor carpi ulnaris

Flexes wrist and adducts hand; medial epicondyle → pisiform & base of metacarpal V.

Pronator teres

Pronates forearm; medial epicondyle & coronoid process → mid-shaft of radius.

Flexor digitorum superficialis

Flexes wrist & middle phalanges of fingers 2-5; medial epicondyle → middle phalanges.

Flexor pollicis longus

Flexes the thumb; anterior radius → distal phalanx of thumb.

Flexor digitorum profundus

Flexes distal phalanges of fingers 2-5; ulna & interosseous membrane → distal phalanges.

Triceps brachii

Prime extensor of forearm; scapula & posterior humerus → olecranon process.

Extensor carpi radialis longus

Extends and abducts wrist; lateral supracondylar ridge → base of metacarpal II.

Extensor digitorum

Extends fingers and wrist; lateral epicondyle → distal phalanges 2-5.

Extensor carpi ulnaris

Extends and adducts wrist; lateral epicondyle → base of metacarpal V.

Supinator

Supinates forearm; lateral epicondyle & proximal ulna → proximal radius.

Erector spinae (iliocostalis, longissimus, spinalis)

Prime movers of back extension; also bend trunk laterally; ileum/ribs/vertebrae → ribs & vertebrae above.

Splenius (capitis/cervicis)

Extends or hyperextends head; ligamentum nuchae & spinous processes → mastoid process & occipital bone.

Iliopsoas (psoas major & iliacus)

Major hip flexor; iliac fossa & lumbar vertebrae → lesser trochanter of femur.

Sartorius

Flexes, abducts, laterally rotates thigh; flexes leg; ASIS → medial tibia.

Adductor group (magnus, longus, brevis)

Adduct, flex, and medially rotate thigh; pubis/ischium → linea aspera.

Gracilis

Weak adductor; medially rotates thigh and flexes leg; pubis → medial tibia.

Quadriceps femoris (rectus femoris & vasti)

Extends leg; rectus femoris also flexes thigh; femur & AIIS → tibial tuberosity via patella.

Tibialis anterior

Dorsiflexes and inverts foot; lateral tibia → medial cuneiform & metatarsal I.

Extensor digitorum longus

Extends toes; dorsiflexes foot; lateral tibia & fibula → phalanges of toes 2-5.

Fibularis longus (peroneus longus)

Plantar-flexes and everts foot; head of fibula → tarsal & metatarsal I.

Gluteus maximus

Powerful thigh extensor; ilium/sacrum/coccyx → gluteal tuberosity & IT band.

Gluteus medius

Abducts and medially rotates thigh; stabilizes pelvis; lateral ilium → greater trochanter.

Gluteus minimus

Assists medius in thigh abduction & stabilization; ilium → greater trochanter.

Biceps femoris

Extends thigh and flexes leg; ischial tuberosity & linea aspera → head of fibula & lateral tibia.

Semitendinosus

Extends thigh and flexes leg; ischial tuberosity → medial tibia.

Semimembranosus

Extends thigh and flexes leg; ischial tuberosity → medial condyle of tibia.

Gastrocnemius

Plantar-flexes foot; flexes knee when foot is dorsiflexed; femoral condyles → calcaneus via Achilles tendon.

Soleus

Synergist of gastrocnemius for plantar flexion; proximal tibia/fibula → calcaneus via Achilles tendon.