Anatomy Practical 3 - Muscles pt. 1: Origin, Insertion, and Action

Masseter

Masseter

A: Raises mandible

Temporalis

A: raises mandible

Sternocleidomastoid

A: pulls head to one side, towards the chest, and raises sternum

Splenius capitus

A: extend, hyperextend, and rotate head

trapezius

A: extends head, raises scapulae

serratus anterior (boxers muscle)

A: abducts and rotates scapula upward, pushes shoulders forward when pushing something

Pectoralis minor

A: abducts and rotates scapulae downward, raises ribs 3-5 for forced inspiration

upper arm flexors

Pectoralis major

upper arm extensors

latissimus dorsi, teres major

deltoid

upper arm abductors

pectoralis major

A: adducts and medially rotates arm

Latissimus Dorsi

A: extends & adducts and medially rotates upper arm

Teres major

A: extends, adducts and medially rotates arm

Deltoid

A: Abducts, extends and laterally rotates arm

Biceps Brachii

A: flexes and supinates forearm, rotates the arm

Brachialis

A: strongest flexor of elbow

Brachioradialis

A: pronates and supinates forearm

Triceps Brachii

A: extend forearm

External Oblique

A: tenses abdominal wall, compresses abdomen

Internal Oblique:

A: tenses abdominal wall, compresses abdomen

Rectus Abdominis

A: compresses abdomen, flexes vertebral column

Transverse Abdominis

A: compresses adbomen

Gluteus maximus

A: extension of leg at hip, straighten leg when walking, raises body from sitting position, laterally rotates thigh

Gluteus Medius:

A: abducts, medially rotates thigh

Tensor Fascial Latae

A: flexes, abducts thigh

Adductor longus

O: pubic bone

I: Posterior surface of femur

Abductor magnus

O: ischial tuberosity

I: femur

Gracilis

O: pubic bone
I: medial surface of tibia

Biceps femoris

O: ischial tuberosity & posterior femur
I: head of fibula & lateral condyle of tibia

Semitendinosus

O: ischial tuberosity
I: medial surface of tibia

Semimembranosus

O: ischial tuberosity
I: medial condyle of tibia

Sartorius

A: flexion, helps cross legs

Rectus femorus

A: extension of leg at knee

Vastus lateralis

O: Greater Trochanter

I: Patella

Vastus medialis

O: Femur

I: Patella

Vastus intermedius

O: Femur
I: Patella

Tibialis anterior

A: Dorsal Flexion

Gastrocnemius

A: Plantar flexion

Soleus

A: plantar flexion

Names of the '“breathing muscles”

Internal intercostals

External intercostals

Diaphram

Action of internal intercostals

depresses ribs

Action of external intercostals

elevates ribs

Quadriceps femoris group

Rectus femorus, Vastus lateralis, Vastus medialis, Vastus intermedius