Muscles: Origin, Insertion, and Action

Muscle, Origin, Insertion, and Action with models

Epicranius

* Origin: Aponeurosis
* Insertion: eyebrow skin
* Action: elevates eyebrows, wrinkles forehead

Orbicularis Oculi

* Origin: frontal & maxilla bone
* Insertion: eyelid tissue
* Action: blinking

Buccinator

* Origin: maxilla & mandible
* Insertion: orbicularis oris
* Action: compresses cheeks inward (whistling/sucking)

Zygomaticus

* Origin: zygomatic bone
* Insertion: skin/muscle at corner of mouth
* Action: raises corners of mouth (smiling)

Orbicularis Oris

* Origin: maxilla & mandible
* Insertion: skin & muscle around mouth
* Action: closes and puckers the lips

Temporalis

* Origin: temporal bone
* Insertion: mandible
* Action: closes jaw

Masseter

* Origin: zygomatic bone
* Insertion: mandible
* Action: closes jaw

Sternocleidomastoid

* Origin: sternum, clavicle
* Insertion: temporal bone
* Action: rotates head to opposite side (one side only)
* flexes head (both sides)

Trapezius

* Origin: occipital bone, thoracic vertebrae
* Insertion: clavicle, scapula
* Action: elevates/adducts scapula, extends neck

Levator Scapulae

* Origin: vertebrae
* Insertion: superior scapula
* Action: adducts scapula

Rhomboid Major & Rhomboid Minor

* Origin: vertebrae
* Insertion: scapula
* Action: adducts scapula

Pectoralis Minor

* Origin: ribs
* Insertion: scapula
* Action: pulls scapula downward/forward (abducts scapula)

Serratus Anterior

* Origin: ribs
* Insertion: scapula
* Action: pulls scapula against chest wall

Supraspinatus

* Origin: scapula
* Insertion: humerus
* Action: stabilizes shoulder joints

Infraspinatus

* Origin: scapula
* Insertion: humerus
* Action: stabilizes shoulder joints

Teres Minor

* Origin: scapula
* Insertion: humerus
* Action: stabilizes shoulder joints

Subscapularis

* Origin: scapula
* Insertion: humerus
* Action: stabilizes shoulder joints

Pectoralis Major

Origin: clavicle, sternum, ribs

Insertion: humerus

Action: adducts/flexes arm

Deltoid

* Origin: clavicle, scapula
* Insertion: humerus
* Action: abducts/flexes arm

Coracobrachialis

* Origin: scapula
* Insertion: humerus
* Action: adducts/flexes arm

Latissimus Dorsi

* Origin: vertebrae, ribs
* Insertion: humerus
* Action: adducts/extends arm

Teres Major

* Origin: scapula
* Insertion: humerus
* Action: adducts/extends arm

Biceps Brachii

* Origin: scapula
* Insertion: radius
* Action: flexes forearm at elbow

Brachialis

* Origin: humerus
* Insertion: ulna
* Action: flexes forearm at elbow

Brachioradialis

* Origin: humerus
* Insertion: radius
* Action: flexes forearm at elbow

Triceps Brachii

* Origin: scapula
* Insertion: ulna
* Action: extends forearm at elbow

Flexor Carpi

* Action: flex hand at wrist

Flexor Digitorum

* Action: flex the fingers

Extensor Carpi

* Action: extend hand at wrist

Extensor Digitorum

* Action: extends hands & fingers

Rectus Abdominis

* Origin: pubic bone
* Insertion: sternum, ribs
* Action: stabilizes pelvis

Tendinous Intersection

between rectus abdominus muscles (horizontal white line on stomach) → 6 pack

Linea Alba

xiphoid process to pubis (vertical white line on stomach)

External Oblique

* Origin: ribs
* Insertion: linea alba
* Action: flexes & compresses abdomen

Internal Oblique

* Origin: os coxae
* Insertion: linea alba
* Action: flexes & compresses abdomen

Transverse Oblique

* Origin: ribs
* Insertion: linea alba
* Action: compresses abdomen

External Intercostals

* Action: breathing in

Internal Intercostals

* Action: breathing out

Diaphragm

* Action: breathing in

Sartorius

* Origin: os coxae
* Insertion: tibia
* Action: flexes knee

Tensor Fasciae Latae

* Origin: os coxae
* Insertion: iliotibial tract
* Action: flexes thigh

Iliopsoas

* Origin: os coxae
* Insertion: femur
* Action: flexes thigh

Gluteus Maximus

* Origin: os coxae
* Insertion: femur
* Action: extends thigh

Gluteus Medius

* Origin: os coxae
* Insertion: femur
* Action: abducts thigh

Gluteus Minimus

* Origin: os coxae
* Insertion: femur
* Action: abducts thigh

Adductor Longus

* Origin: os coxae
* Insertion: femur
* Action: adducts/flexes thigh

Adductor Magnus

* Origin: os coxae


* Insertion: femur
* Action: adducts/flexes thigh

Pectineus

* Origin: os coxae
* Insertion: femur
* Action: adducts/flexes thigh

Gracilis

* Origin: os coxae
* Insertion: tibia
* Action: adducts/flexes thigh

Rectus Femoris

* Origin: os coxae
* Insertion: patella/tibia
* Action: extends leg at knee

Vastus Lateralis

* Origin: femur
* Insertion: patella/tibia
* Action: extends leg at knee

Vastus Medialis

* Origin: femur
* Insertion: patella/tibia
* Action: extends leg at knee

Vastus Intermedius

* Origin: femur
* Insertion: patella/tibia
* Action: extends leg at knee

Biceps Femoris

* Origin: os coxae
* Insertion: tibia
* Action: extends thigh

Semitendinosus

* Origin: os coxae
* Insertion: tibia
* Action: extends thigh

Semimembranosus

* Origin: os coxae
* Insertion: tibia
* Action: extends thigh

Tibialis Anterior

* Action: dorsiflexes foot at ankle

Extensor Digitorum Longus

* Action: dorsiflexes foot at ankle

Fibularis Longus

* Action: plantar flexes foot at ankle

Gastrocnemius

* Origin: femur
* Insertion: calcaneus via calcaneal tendon
* Action: plantar flexes foot at ankle

Soleus

* Action: plantar flexes foot at ankle

Flexor Digitorum Longus

* Action: plantar flexes foot at ankle