ANAPHY MT 100 LEC - Muscular System: Origins, Insertions, and Actions

Frontalis

Origin: Cranial aponeurosis | Insertion: Skin of eyebrows | Primary Action: Raises eyebrows

Orbicularis oculi

Origin: Frontal bone and maxilla | Insertion: Tissue around eyes | Primary Action: Blinks and closes eye

Orbicularis oris

Origin: Mandible and maxilla | Insertion: Skin and muscle around mouth | Primary Action: Closes and protrudes lips

Temporalis

Origin: Temporal bone | Insertion: Mandible | Primary Action: Closes jaw

Masseter

Origin: Zygomatic bone and maxilla | Insertion: Mandible | Primary Action: Closes jaw

Buccinator

Origin: Maxilla and mandible near molars | Insertion: Orbicularis oris | Primary Action: Compresses cheek; holds food between teeth during chewing

Zygomaticus

Origin: Zygomatic bone | Insertion: Skin and muscle at corner of lips | Primary Action: Raises corner of mouth

Sternocleidomastoid

Origin: Sternum and clavicle | Insertion: Temporal bone (mastoid process) | Primary Action: Flexes neck; laterally rotates head

Platysma

Origin: Connective tissue covering of superior chest muscles | Insertion: Tissue around mouth | Primary Action: Tenses skin of neck

Occipitalis

Origin: Occipital and temporal bones | Insertion: Cranial aponeurosis | Primary Action: Fixes aponeurosis and pulls scalp posteriorly

Trapezius

Origin: Occipital bone and all cervical and thoracic vertebrae | Insertion: Scapular spine and clavicle | Primary Action: Raises, retracts, and rotates scapula

Latissimus dorsi

Origin: Lower spine and iliac crest | Insertion: Proximal humerus | Primary Action: Extends and adducts humerus

Erector spinae

Origin: Iliac crests, ribs 3-12, and vertebrae | Insertion: Ribs, thoracic and cervical vertebrae | Primary Action: Extends and laterally flexes spine

Quadratus lumborum

Origin: Iliac crest, lumbar fascia | Insertion: Transverse processes of upper lumbar vertebrae | Primary Action: Flexes spine laterally; extends spine

Deltoid

Origin: Scapular spine and clavicle | Insertion: Humerus (deltoid tuberosity) | Primary Action: Abducts humerus

Pectoralis major

Origin: Sternum, clavicle, and first to sixth ribs | Insertion: Proximal humerus | Primary Action: Adducts and flexes humerus

Rectus abdominis

Origin: Pubis | Insertion: Sternum and fifth to seventh ribs | Primary Action: Flexes vertebral column

External oblique

Origin: Lower eight ribs | Insertion: Iliac crest | Primary Action: Flexes and rotates vertebral column

Biceps brachii

Origin: Scapula of shoulder girdle | Insertion: Proximal radius | Primary Action: Flexes elbow and supinates forearm

Brachialis

Origin: Distal humerus | Insertion: Proximal ulna | Primary Action: Flexes elbow

Triceps brachii

Origin: Shoulder girdle and proximal humerus | Insertion: Olecranon process of ulna | Primary Action: Extends elbow

Flexor carpi radialis

Origin: Distal humerus | Insertion: Second and third metacarpals | Primary Action: Flexes wrist and abducts hand

Flexor carpi ulnaris

Origin: Distal humerus and posterior ulna | Insertion: Carpals of wrist and fifth metacarpal | Primary Action: Flexes wrist and adducts hand

Flexor digitorum superficialis

Origin: Distal humerus, ulna, and radius | Insertion: Middle phalanges of second to fifth fingers | Primary Action: Flexes wrist and fingers

Extensor carpi radialis

Origin: Humerus | Insertion: Base of second and third metacarpals | Primary Action: Extends wrist and abducts hand

Extensor digitorum

Origin: Distal humerus | Insertion: Distal phalanges of second to fifth fingers | Primary Action: Extends fingers

Iliopsoas

Origin: Ilium and lumbar vertebrae | Insertion: Femur (lesser trochanter) | Primary Action: Flexes hip

Adductor muscles

Origin: Pelvis | Insertion: Proximal femur | Primary Action: Adduct and medially rotate thigh

Sartorius

Origin: Ilium | Insertion: Proximal tibia | Primary Action: Flexes thigh on hip

Quadriceps group

Origin: Vasti: femur; Rectus femoris: pelvis | Insertion: Tibial tuberosity via patellar ligament | Primary Action: All extend knee; rectus femoris also flexes hip on thigh

Tibialis anterior

Origin: Proximal tibia and fibula | Insertion: First cuneiform and first metatarsal of foot | Primary Action: Dorsiflexes and inverts foot

Extensor digitorum longus

Origin: Fibula | Insertion: Distal toes 2-5 | Primary Action: Extends toes

Fibularis muscles

Origin: Fibula | Insertion: Metatarsals of foot | Primary Action: Plantar flex and evert foot

Gluteus maximus

Origin: Sacrum and ilium | Insertion: Proximal femur (gluteal tuberosity) | Primary Action: Extends hip

Gluteus medius

Origin: Ilium | Insertion: Proximal femur | Primary Action: Abducts thigh; steadies pelvis during walking

Hamstring muscles

Origin: Ischial tuberosity | Insertion: Proximal tibia (head of fibula for biceps femoris) | Primary Action: Flex knee and extend hip

Gastrocnemius

Origin: Distal femur | Insertion: Calcaneus via calcaneal tendon | Primary Action: Plantar flexes foot and flexes knee

Soleus

Origin: Proximal tibia and fibula | Insertion: Calcaneus | Primary Action: Plantar flexes foot