Muscle Functions for Lab Practical

Masseter

closes jaw by elevating mandible, chewing

Temporalis

closes jaw by elevating mandible, chewing

Mentalis

raises and protrudes lower lip

Orbicularis Oris

closes lips, protrudes lips, shapes lips during speech

Orbicularis Oculi

closes eyes, squinting, blinking

Sternocleidomastoid (SCM)

rotates head toward opposite side, neck flexion when both SCMs activated

Pectoralis Major

adduction of shoulder, horizontal adduction of shoulder, and internal rotation of shoulder

Pectoralis Minor

moves scapula anteriorly, elevates ribs during breathing

Rectus Abdominis

flexes trunk

External Obliques

rotates trunk, flexes trunk

Deltoid

abducts the shoulder, also flexes, extends, internally rotates, and externally rotates shoulder

Biceps Brachii

flexes the elbow, supinates forearm, flexes shoulder

Triceps Brachii

extends elbow, extends shoulder

Subscapularis

internally rotates shoulder (RTC)

Supraspinatus

abducts shoulder (works along with shoulder ERs) (RTC)

Infraspinatus

externally rotates shoulder (RTC)

Teres Minor

externally rotates shoulder (RTC)

Teres Major

internally rotates shoulder, extends shoulder

Levator Scapulae

elevates scapula (pectoral girdle)

Brachioradialis

flexes elbow

Extensor Digitorum

extends fingers

Trapezius

extends neck, elevates, depresses, rotates, adducts, and stabilizes scapula

Latissimus dorsi

extends humerus, adducts humerus, internal rotates shoulder

Erector Spinae

extends trunk

Gluteus Maximus

extends hip

Gluteus Medius

abducts hip, stabilizes pelvis during stance phase of gait

Gluteus Minimis

internal rotation of hip, trunk extension

Tensor Fascia Latae (TFL)

abducts hip, flexes hip

Psoas Major

flexes hip

Iliacus

flexes hip

Rectus Femoris

flexes hip, extends knee

Vastus Lateralis

extends knee

Vastus Medius

extends knee

Adductor Group

adducts hip

Gracilis

adducts hip, flexes knee

Sartorius

flexes hip, flexes knee, externally rotates hip

Biceps Femoris

extends hip, flexes knee

Semimembranosus

extends hip, flexes knee

Semitendinosus

extends hip, flexes knee

Gastrocnemius

plantarflexes ankle

Tibialis Anterior

dorsiflexes ankle, inverts ankle

Extensor Hallucis Longus (EHL)

extends great toe

RTC

Rotator Cuff muscle group