Muscles: Origin, Insertion, and Action
Rectus Femoris
Origin: Anterior inferior iliac spine & superior acetabulum Insertion: Tibial tuberosity & patella Action: Flexes thigh, extends knee
Sartorius
Origin: Anterior superior iliac spine Insertion: Proximal/medial tibia Action: Flexes and laterally rotates thigh, flexes leg
Brachialis
Origin: Anterior, distal surface of humerus Insertion: coronoid process of ulna Action: Flexes forearm
Pectoralis Major
Origin: Clavicle, sternum, cartilages of ribs 1-7 Insertion: Tendon into sulcus of humerus Action: flexes, adducts, and medially rotates arm
Orbicularis oculi
Origin: Frontal and maxillary bones Insertion: tissue of eyelid Action: Closes eyelid
Vastus Lateralis
Origin: Greater trochanter of femur, linea aspera, and interotrochanteric line Insertion: Tibial tuberosity & patella Action: Extends knee
External intercostal
Origin: Inferior border of a rib above Insertion: Superior border of rib below Action: Elevates ribs (increases volume in thorax)
Infraspinatus
Origin: Infraspinous Fossa Insertion: Greater tubercle of humerus Action: Laterally rotates arm, stabilizes shoulder joint
Internal oblique
Origin: Inguinal ligament, iliac crest, lumbar fascia Insertion: Linea alba, ribs 10-12, pubic crest Action: Compresses abdominal wall, laterally rotates trunk
Semitendinosus
Origin: Ischial Tuberosity Insertion: Proximal/medial tibia Action: Extends thigh, flexes knee
External Urethral Sphincter
Origin: Ischial and pubic rami Insertion: To median raphe at base of penis, inner fibers encircle urethra Action: Males: Closes urethra, compresses prostate and bulbo-urethral gland
Semimembranosus
Origin: Ischial tuberosity Insertion: Medial condyle of tibia & lateral condyle of femur Action: Extends thigh, flexes knee
Biceps Femoris
Origin: Ischial tuberosity, Linea aspera Insertion: Head of fibula, lateral condyle of tibia Action: Extends thigh, flexes leg
Extensor digitorum longus
Origin: Lateral Condyle of tibia, proximal fibula, & interosseus membrane Insertion: Middle of distal phalanges Action: Extends toes, dorsiflexes foot
Teres Minor
Origin: Lateral border of scapula Insertion: Greater tubercle of humerus Action: Laterally rotates and adducts arm, stabilizes shoulder joint
Tibialis anterior
Origin: Lateral condyle tibia & interosseus membrane Insertion: First metatarsal and first cuneiform by tendon Action: Dorsiflexes and inverts foot
Brachioradialis
Origin: Lateral supracondylar ridge of humerus Insertion: styloid process of radius Action: Flexes forearm
Rhomboid minor
Origin: Ligamentum nuchae, Spines C7-T1 Insertion: Vertebral border of scapula at scapular spine Action: Adducts scapula (draws scapulae together)
Vastus medialis
Origin: Linea aspera & interotrochanteric line Insertion: Tibial tuberosity & patella Action: Extends knee
Vastus Intermedius
Origin: Proximal, anterior femur Insertion: Tibial tuberosity by patellar tendon Action: extends knee
Adductor Magnus
Origin: Pubis, ischium Insertion: Gluteal tuberosity, linea aspera, adductor tubercle of distal femur Action: Adducts, flexes, extends and laterally rotates thigh
Serratus Anterior
Origin: Ribs 1-8 Insertion: Vertebral border and inferior angle of scapula Action: Abducts scapula (moves scapula away from spinal column)
External oblique
Origin: Ribs 5-12 Insertion: Linea alba, iliac crest, pubis Action: Compresses abdominal wall, laterally rotates trunk
Rhomboid major
Origin: Spines of T2-5 Insertion: Lower one-third of vertebral border of scapula Action: adducts scapula (draws scapulae together)
Sternocleidomastoid
Origin: Sternum, clavicleMastoid process of temporal bone Insertion: Mastoid process of temporal bone Action: Abducts, rotates, and flexes head
Subscapularis
Origin: Subscapular fossa Insertion: Lesser tubercle of humerus Action: Medially rotates arm, stabilizes shoulder joint
Internal intercostals
Origin: Superior border of a rib below Insertion: Inferior border of rib above Action: Depresses ribs (decreases volume in thorax)
Supraspinatus
Origin: Supraspinatus Fossa Insertion: Greater tubercle of humerus Action: Abducts arm, helps stabilize shoulder joint
Temporalis
Origin: Temporal fossa Insertion: coronoid process of mandible Action: Closes mandible
Masseter
Origin: Zygomatic arch Insertion: Angle and ramus of mandible Action: Closes mandible
Pectoralis minor
Origin: anterior surface of ribs 3-5 Insertion: coracoid process of scapula Action: draws scapula forward and inferiorly
Gluteus Maximus
Origin: dorsal ilium, sacrum, & coccyx Insertion: Gluteal tuberosity of femur, iliotibial tract Action: Extends thigh (powerfully)
Platysma
Origin: fascia over pectoralis major and deltoid Insertion: inferior border of the mandible and skin of lower face Actions: draws the corners of the mouth down; it aids in depression of the mandible
Triceps Brachii
Origin: glenoid cavity of scapula, distal and posterior groove of humerus Insertion: Olecranon process of ulna Action: Extends and adducts arm, extends forearm
Tensor fasciae latae
Origin: iliac crest, anterior iliac surface Insertion: iliotibial band of fasciae latae Action: steadies trunk
Erector Spinae
Origin: iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament Insertion: angles of the ribs, transverse and spinous processes of vertebrae, posterior aspect of the skull Action: extends and laterally bends the trunk, neck and head
Orbicularis oris
Origin: indirect from maxilla and mandible Insertion: Skin of lips Action: Closes lips
Latissimus Dorsi
Origin: indirect to process of lower 6 vertebrae, lumbar verge, iliac crest Insertion: Intertubercular sulcus of humerus Action: Extends, adducts, and medially raises arm; draws shoulder inferiorly.
Diaphragm
Origin: inferior border of ribs and sternum, costal cartilage of last 6 ribs and lumber vertebrae Insertion: central tendon Action: pushes the abdominal viscera inferiorly, increasing the volume of the thoracic cavity (inspiration)
Gracillis
Origin: inferior ramus and body of pubis Insertion: medial tibia Action: Adducts thigh, flexes leg
Transverse abdominus
Origin: inguinal ligament, iliac crest, cartilage of last 5 ribs Insertion: linea alba & pubic crest Action: compresses abdominal contents
Deltoid
Origin: lateral clavicle, acromion process, spine of scapula Insertion: Deltoid tuberosity of humerus Action: Abducts arm; flexes, extends, medially, and laterally rotates arm
Extensor Carpi Ulnaris
Origin: lateral epicondyle of humerus & posterior border of the ulna Insertion: base of metacarpal 5 Action: extends the wrist; adducts the hand
Extensor Carpi Radialis Longus
Origin: lateral supracondylar ridge of the humerus Insertion: base of metacarpal 2 Action: extends the wrist; abducts the hand
Gastrocnemius
Origin: medial & lateral condyles of femur Insertion: Calcaneus by calcaneal tendon Action: Flexes leg, plantar flexes foot
Flexor Carpi Radialis
Origin: medial epicondyle of humerus Insertion: base of metacarpals 2 & 3 Action: flexes the wrist, abducts the hand
Flexor Carpi Ulnaris
Origin: medial epicondyle of humerus, olecranon process, & posterior surface of ulna Insertion: pisiform, hamate, and base metacarpal 5 Action: flexes wrist, adducts hand
Ischiocavernosus
Origin: medial surface of the ischial tuberosity and the ischiopubic ramus Insertion: corpus cavernosum and crus of the penis/clitoris Action: compresses the corpus cavernosum
Trapezius
Origin: occipital bone, spines of C7-T12 vertebrae Insertion: Acromion and spinous process of scapula Action: elevates and adducts scapula
Bulbospongiosus
Origin: perineal body and fascia of the bulb of the vestibule Insertion: perineal membrane and corpus cavernosum of the clitoris Action: compresses the vestibular bulb and compresses the spongy urethra
Levator Ani
Origin: posterior surface of the body of the pubis, fascia of the obturator internus m. (arcus tendineus levator ani), ischial spine Insertion: anococcygeal raphe and coccyx Action: elevates the pelvic floor
Soleus
Origin: proximal tibia and fibula & interosseus membrane Insertion: Calcaneus by calcaneal tendon Action: Plantar flexes foot
Rectus Abdominis
Origin: pubic crest & pubic symphysis Insertion: Cartilages of ribs 5-7, xiphoid process Action: Flexes vertebral column, compresses abdominal wall
Biceps Brachii
Origin: tendon of sulcus, & capsule of shoulder joint. coracoid process of scapula Insertion: Radial Tuberosity Action: Flexes arm, flexes forearm, supinates hand
Levator Scapulae
Origin: transverse processes of C1-C4 vertebrae Insertion: medial border of the scapula from the superior angle to the spine Action: elevates the scapula
Hyoglossus
Origin: upper border of the greater horn of the hyoid and body of the hyoid bone Insertion: spreads out into the intrinsic muscles of the tongue Action: depresses the sides of the tongue; retracts the tongue
Gluteus Medius
Origin: upper lateral ilium Insertion: Greater trochanter of femur Action: Abducts and medially rotates thigh
Zygomaticus
Origin: upper lateral surface of the zygomatic bone Insertion: skin of the angle of the mouth Action: elevates and draws the corner of the mouth laterally