Human Muscular System



1. Muscles of Mastication


Temporalis

Superior muscle of mastication

Closes jaw

O: Temporal bone. I: Coronoid process of mandible.


Masseter

Inferior, superficial muscle of mastication

Closes jaw

O: Maxilla & zygomatic arch of temporal bone I: Mandible


Pterygoid (Lateral & Medial)

Deep muscles of mastication

Elevate, protrude & move mandible from side to side (as in grinding food)

O: Sphenoid bone & maxilla I: Mandible



2. Muscles of Facial Expression


Frontalis

Forehead muscle

Raises eyebrows, wrinkles forehead skin

O: Galea aponeurotica I: Skin of eyebrows

Also called frontal belly of occipitofrontalis (epicranius)


Occipitalis

Muscle at the back of the head


Pulls scalp posteriorly

O: Occipital & temporal bones I: Galea aponeurotica

Also called occipital belly of occipitofrontalis (epicranius)


Orbicularis oculi

Blinking muscle

Blinks, winks, & closes eye

O: Frontal bone and maxilla I: Tissue around eyes


Orbicularis oris

Kissing muscle

Closes mouth, purses and protrudes lips

O: Mandible and maxilla I: Skin & muscle around mouth


Zygomaticus (Major & Minor)

Smiling muscle; raises corner of mouth

O: Zygomatic bone I: Skin & muscle at corner of lips


Buccinator

Cheek muscle

Compress cheek, as in sucking and whistling

O: Maxilla and mandible near molars I: Orbicularis oris



3. Muscles of the Neck


Platysma

Anterior, flat neck muscle

Depress jaw, lowers corner of mouth, tenses skin of neck

O: Fascia of the cervical region I: Mandible & tissue around mouth


Sternocleidomastoid

Paired, anterior neck muscles

One rotates head laterally; both flex neck

O: Sternum and clavicle I: Mastoid process of temporal bone


Splenius capitis & cervicus

Posterior neck muscles

One rotates head laterally, both extend head

O: Vertebrae C7-T6 I: Occipital bone & mastoid process of temporal bone



4. Suprahyoid Muscles


Digastric

V-shaped throat muscle

Opens mouth; depress mandible; elevate hyoid bone during swallowing

O: Mandible & mastoid process of temporal bone I: Hyoid bone


Mylohyoid

Flat, triangular throat muscle

Elevate hyoid bone and elevate floor of mouth during swallowing

O: Mandible I: Hyoid bone



5. Muscles of Respiration


Diaphragm

Major muscle of inspiration


External intercostals

Superficial muscles between ribs

Elevate rib cage, expand thorax and aid in inspiration

O: Ribs I: Ribs


Internal intercostals

Deep muscles between ribs

Depress rib cage, compress thorax and aid in forced expiration

O: Ribs I: Ribs



6. Muscles of the Abdominal Wall


External oblique

Superficial, lateral trunk muscle; strongest of the trunk muscles

One laterally flex & rotate spine; both flex vertebral column

O: Ribs 5-12 I: Iliac crest and linea alba


Internal oblique

Deep, lateral trunk muscle

One laterally flex & rotate spine; both flex vertebral column

O: Iliac crest I: Ribs 9-12 and linea alba


Transversus abdominis

Deepest of the lateral trunk muscles

Compress abdomen

O: Iliac crest and ribs 7-12 I: Pubis and linea alba


Rectus abdominis

Sit-up muscle; medial trunk muscle from the pubis to rib cage

Gives abdomen a washer-board appearance (8-pack)

Flex vertebral column, compress abdomen

O: Pubis I: Sternum and ribs 5-7



7. Muscles of the Vertebral Column


Quadratus lumborum

Flat muscle of posterior abdominal wall, from iliac crest to rib 12

One laterally flex spine, both extend vertebral column

O: Iliac crest I: Vertebrae L1-L4 and rib 12


Erector spinae (Iliocostalis, Longissimus & Spinalis muscles)

 Major muscle group of the vertebral column

Laterally flex spine & extend vertebral column

O: Iliac crest, vertebrae and ribs I: Vertebrae and ribs



8. Muscles of the Pectoral Girdle

Serratus anterior

Boxers muscle; superficial, lateral chest muscle

Abduct & rotate scapula; aid horizontal arm movements (as in punching)

O: Ribs 1-9 I: Scapula


Trapezius

Large, superficial, kite-shaped, upper back muscle

Adduct & elevate scapula (as in shrugging shoulders); hyperextend head

O: Occipital bone and thoracic vertebrae I: Clavicle and scapula



9. Muscles that Move the Humerus


Pectoralis major

Large, fan-shaped, chest muscle

Flex, rotate & adduct arm

O: Sternum, clavicle and ribs 1-6 I: Proximal humerus


Latissimus dorsi

Swimmer's muscle on lower back

Extend, rotate & adduct arm

O: Lower spine and iliac crest I: Proximal humerus


Deltoid

Triangular shoulder muscle

Abduct & rotate arm

O: Clavicle and scapula I: Deltoid tuberosity of humerus


Supraspinatus, Infraspinatus, Subscapularis & Teres minor

Rotator cuff muscles of scapula; tendons reinforce the shoulder rotator cuff

Stabilize shoulder joint and rotate arm

O: Scapula I: Greater and lesser tubercles of humerus


Teres major

Muscle of inferior scapula

Extends arm at shoulder, adducts & rotates arm

O: Scapula I: Intertubercular sulcus of humerus



10. Muscles that Move the Forearm


Biceps brachii

Superficial, anterior arm muscle

Flex & supinate forearm

O: Scapula I: Proximal radius


Brachialis

Deep, anterior arm muscle

Flex forearm

O: Distal humerus I: Proximal ulna


Triceps brachii

Posterior arm muscle

Extend forearm

O: Scapula and proximal humerus I: Olecranon process of ulna


Brachioradialis

Superficial, lateral forearm muscle

Synergist in forearm flexion; stabilizes elbow

O: Distal humerus I: Radius

Forearm flexors are anterior to the Brachioradialis

Forearm extensors are posterior to the Brachioradialis



11. Forearm Muscles that Move the Wrist and Fingers


Flexor carpi radialis

Anterior, center of forearm

Flex wrist & abduct hand

O: Distal humerus I: Metacarpals 2-3


Flexor carpi ulnaris

Anterior, medial forearm

Flex wrist & adduct hand

O: Distal humerus and proximal ulna I: Carpals & metacarpal 5


Extensor carpi radialis longus

Posterior, lateral forearm

Extend wrist & abduct hand

O: Distal humerus I: Metacarpal 2


Extensor digitorum

Posterior, center of forearm

Extend wrist & extend fingers

O: Distal humerus I: Phalanges of fingers 2-5


Extensor carpi ulnaris

Posterior, medial forearm

Extend wrist & adduct hand

O: Distal humerus and proximal ulna I: Metacarpal 5



12. Muscles that Move the Thigh


Iliopsoas (Iliacus & Psoas major)

Anterior hip muscles

Flex thigh & trunk

O: Ilium, sacrum and lumbar vertebrae I: Lesser trochanter of femur


Gluteus maximus

Large, superficial buttock muscle

Extend & laterally rotate thigh

O: Sacrum and iliac crest I: Gluteal tuberosity of femur


Gluteus medius

Deep buttock muscle

Abduct & medially rotate thigh

O: Ilium I: Greater trochanter of femur


Tensor fascia latae

Lateral hip muscle

Flex & abduct thigh

O: Iliac crest I: Tibia


Gracilis

Superficial muscle on medial thigh

Adduct thigh, flex leg

O: Pubis I: Tibia


Pectineus

Anterior muscle on middle of proximal thigh

Flex & adduct thigh

O: Pubis I: Femur


Adductor longus & magnus

Anterior, medial thigh muscles

Adduct, flex & rotate thigh

O: Pubis I: Femur



13. Thigh Muscles that Move the Leg


Sartorius

Tailor's muscle; longest muscle in the body

Runs obliquely across anterior thigh, from hip to knee

Flex, abduct & rotate thigh

O: Ilium I: Proximal tibia


Quadriceps femoris group (Rectus femoris, Vastus lateralis, Vastus medialis & Vastus intermedius)

Football Kicker's Muscle on anterior thigh

Extend leg at knee, flex thigh at hip

O: Femur and ileum I: Tibial tuberosity


Hamstring group (Biceps femoris, Semimembranosus & Semitendinosus)

Posterior thigh muscle; antagonist to Quadriceps

Flex leg at knee, extend thigh at hip

O: Ischial tuberosity I: Proximal tibia and fibula



14. Muscles of the Leg that Move the Ankle, Foot and Toes


Tibialis anterior

Large, anterior leg muscle

Dorsiflex & invert foot

O: Proximal tibia I: Tarsal & metatarsal 1


Extensor digitorum longus

Anterior, lateral leg muscle

Dorsiflex foot & extend toes

O: Proximal tibia & fibula I: Phalanges of toes 2-5


Fibularis longus & brevis

Superficial, lateral leg muscle

Plantar flex & evert foot

O: Proximal fibula I: Tarsals & metatarsals

Also called Peroneus longus & brevis


Triceps surae 

The two calf muscles (gastrocnemius and soleus) considered as one group inserting via the calcaneal tendon into the calcaneal tuberosity


Gastrocnemius

Superficial calf muscle

Flex leg & plantar flex foot

O: Distal femur I: Calcaneus


Soleus

Deep calf muscle

Plantar flex foot

O: Proximal tibia and fibula I: Calcaneus



References:

(1) Marieb, Elaine and Hoehn, K., 2010, Human Anatomy and Physiology, 8th Edition, Benjamin Cummings.

(2) Tortora, Gerard and Derrickson, B., 2009, Principles of Anatomy and Physiology, 12th Edition, Wiley.

(3) Stedman’s Medical Dictionary, 28th Edition, 2007, Lippincott, Williams & Wilkins.

(4) Dorland's Illustrated Medical Dictionary, 31st Edition, 2007, Elsevier Inc.

(5) William C. Brown Publishers, 1992, Human Skeletal Musculature, Video.