Muscle Anatomy: Origins, Insertions, and Actions

These flashcards cover the origins, insertions, and actions of various muscles as presented in the lecture.

External oblique

Origin: lumbodorsal fascia; Insertion: linea alba and on pubis; Action: constricts the abdomen.

Internal oblique

Origin: lumbodorsal fascia; Insertion: linea alba; Action: compresses the abdomen.

Transverse abdominis

Origin: lumbodorsal fascia; Insertion: linea alba; Action: compresses the abdomen.

Rectus abdominis

Origin: pubic symphysis; Insertion: sternum and costal cartilages; Action: retracts ribs and sternum; compresses abdomen.

Pectoantibrachialis

Origin: manubrium; Insertion: fascia of the forearm; Action: draws arm toward the chest.

Pectoralis major

Origin: sternum and median ventral raphe; Insertion: humerus; Action: draws arm toward the chest.

Pectoralis minor

Origin: sternum; Insertion: humerus; Action: draws arm toward the chest.

Xiphihumeralis

Origin: xiphoid process; Insertion: humerus; Action: draws the arm toward the chest.

Sternomastoid

Origin: median raphe and manubrium; Insertion: on the skull from the lambdoidal ridge to the mastoid process; Action: turns and lowers the head.

Cleidomastoid

Origin: clavicle; Insertion: mastoid process; Action: pulls clavicle toward the neck or turns the head on neck.

Clavobrachialis/clavodeltoid

Origin: clavicle and clavotrapezius; Insertion: ulna; Action: flexes the forearm.

Masseter

Origin: zygomatic arch; Insertion: posterior half of the lateral surface of the mandible; Action: elevates the lower jaw.

Temporalis

Origin: superior nuchal line to the zygomatic process; Insertion: coronoid process of the mandible; Action: elevates the lower jaw.

Digastric

Origin: jugular and mastoid process; Insertion: mandible; Action: lowers the lower jaw.

Mylohyoid

Origin: cricoid cartilage of larynx; Insertion: hyoid bone; Action: raises floor of mouth; pulls hyoid forward.

Geniohyoid

Origin: medial surface of the mandible near the symphysis; Insertion: body of hyoid bone; Action: pulls the hyoid forward.

Sternothyroid

Origin: sternum; Insertion: thyroid cartilage; Action: pulls larynx posteriorly.

Thyrohyoid

Origin: thyroid cartilage; Insertion: posterior horn of the hyoid bone; Action: raises the larynx.

Sternohyoid

Origin: sternum; Insertion: anterior horn of the hyoid bone; Action: pulls hyoid posteriorly; raises ribs and sternum.

Stylohyoid

Origin: stylohyal bone of hyoid; Insertion: body of hyoid bone; Action: raises hyoid.

Cricothyroid

Origin: cricoid cartilage; Insertion: thyroid cartilage; Action: tenses vocal cords.

Latissimus dorsi

Origin: spines of thoracic and lumbar vertebrae; Insertion: intertubular groove of humerus; Action: pulls arm dorsally and caudally.

Spinotrapezius

Origin: spines of thoracic vertebrae; Insertion: spines of scapula; Action: pulls scapula dorsally and caudally.

Acromiotrapezius

Origin: spines of cervical and thoracic vertebrae; Insertion: spine and metacromion process of scapula; Action: draws scapula dorsally and holds scapulae together.

Clavotrapezius

Origin: superior nuchal line; Insertion: clavicle; Action: draws the clavicle dorsally and cranially.

Levator scapulae ventralis

Origin: occipital bone and transverse process of atlas; Insertion: metacromion process and clavicle; Action: draws the scapula cranially.

Rhomboideus major

Origin: neural spines of thoracic vertebrae; Insertion: vertebral border of the scapula; Action: draws scapula dorsally and medially.

Rhomboideus minor

Origin: neural spines of thoracic vertebrae; Insertion: vertebral border of the scapula; Action: draws scapula dorsally and medially.

Rhomboideus capitis

Origin: lambdoidal ridge (superior nuchal line); Insertion: vertebral border of the scapula; Action: draws the scapula cranially and rotates it.

Splenius

Origin: neural spines of thoracic vertebrae; Insertion: lambdoidal ridge (superior nuchal line); Action: turns and raises the head.

Supraspinatus

Origin: supraspinous fossa of scapula; Insertion: greater tuberosity of the humerus; Action: extends the humerus.

Acromiodeltoid

Origin: acromion process of scapula; Insertion: deltoid ridge of humerus; Action: flexes and rotates humerus.

Spinodeltoid

Origin: spine of the scapula; Insertion: deltoid ridge of humerus; Action: flexes and rotates humerus.

Infraspinatus

Origin: infraspinous fossa of scapula; Insertion: greater tuberosity of humerus; Action: rotates humerus.

Teres major

Origin: axillary border of scapula; Insertion: medial surface of the humerus in common with latissimus dorsi; Action: flexes, rotates, and lowers the humerus.

Teres minor

Origin: axillary border of scapula; Insertion: greater tuberosity of humerus; Action: assists teres major.

Subscapularis

Origin: subscapular fossa; Insertion: lesser tuberosity of humerus; Action: pulls humerus medially.

Serratus ventralis

Origin: first ten ribs; Insertion: medial surface of scapula; Action: draws scapula cranially and lowers it.

Serratus dorsalis

Origin: median dorsal raphe; Insertion: on each rib; Action: draws ribs cranially.

Scalenes

Origin: transverse processes of cervical vertebrae; Insertion: ribs; Action: raises ribs; flexes neck.

Internal intercostals

Origin: cranial border of one rib; Insertion: caudal border of next rib craniad; Action: draw adjacent ribs together and lower ribs.

External intercostals

Origin: caudal border of one rib; Insertion: cranial border of next rib caudad; Action: raise ribs at inhalation.

Triceps brachii

Insertion: olecranon process of ulna; Action: extensors of the forearm. Long head: Origin: axillary border of the scapula. Lateral head: Origin: deltoid ridge of humerus. Medial head: Origin: dorsal surface of the shaft of humerus.

Anconeus

Origin: distal end of humerus; Insertion: lateral surface of proximal end of ulna; Action: strengthens the elbow and rotates the ulna.

Epitrochlearis or Extensor antibranchii

Origin: latissimus dorsi; Insertion: olecranon process (elbow); Action: extends forearm and rotates the ulna to supinate hand.

Biceps brachii

Origin: coracoid process of the scapula; Insertion: radius; Action: flexes and supinates the forearm.

Brachialis

Origin: lateral surface of humerus; Insertion: proximal end of ulna; Action: flexes forearm.

Extensor carpi ulnaris

Origin: distal end of humerus and lateral border of ulna; Insertion: proximal end of the 5th metacarpal; Action: extends ulnar side of the wrist and 5 digits.

Extensor digitorum lateralis

Origin: lateral surface of humerus; Insertion: digits by joining tendons of extensor digitorum communis; Action: extends digits.

Extensor digitorum communis

Origin: lateral surface of humerus just above extensor digitorum lateralis; Insertion: tendons of 4 digits; Action: extends digits.

Brachioradialis/supinator longus

Origin: middorsal border of humerus; Insertion: distal end of humerus; Action: rotates hand to supine position.

Extensor carpi radialis

Origin: humerus; Insertion: 2nd and 3rd metacarpals; Action: extends hand.

Pronator teres

Origin: distal end of humerus; Insertion: medial border of radius; Action: rotates radius to prone position.

Flexor carpi radialis

Origin: distal end of humerus; Insertion: 2 and 3 metacarpals; Action: flexes wrist.

Palmaris longus

Origin: distal end of humerus; Insertion: tendons on all digits; Action: flexes digits.

Flexor profundus digitorum

Origin: ulna and humerus; Insertion: base of phalanges; Action: flexes digits.

Flexor carpi ulnaris

Origin: distal end of humerus; Insertion: pisiform bone of wrist; Action: flexes digits.

Tensor fascia lata

Origin: ilium and neighboring fascia; Insertion: patella and tendon by fascia lata; Action: extends thigh and aids in abduction and rotation.

Biceps femoris

Origin: ischium; Insertion: patella and lateral border of tibia; Action: abducts thigh and flexes shank.

Caudofemoralis

Origin: transverse processes of the 2nd and 3d caudal vertebrae; Insertion: patella; Action: abducts thigh and flexes shank.

Gluteus maximus

Origin: transverse processes of the last sacral vertebra and the 1st caudal vertebra; Insertion: greater trochanter of femur; Action: abducts thigh.

Gluteus medius

Origin: adjacent fascia; crest of ilium, and lateral surface of ilium; Insertion: greater trochanter of femur; Action: abducts thigh.

Sartorius

Origin: ventral border of ilium; Insertion: patella and proximal end of tibia; Action: adducts and rotates thigh, extends tibia.

Quadriceps femoris

Insertion: patella and adjacent ligaments; Action: extends lower leg. Vastus lateralis: Origin: greater trochanter and surface of femur. Rectus femoris: Origin: ventral border of ilium near acetabulum. Vastus medialis: Origin: femur. Vastus intermedius: Origin: surface of femur.

Gracilis

Origin: border between ischium and pubis; Insertion: proximal end of tibia; Action: adducts thigh.

Adductor longus

Origin: cranial border of pubis; Insertion: femur; Action: adducts thigh.

Adductor femoris

Origin: pubis; Insertion: femur; Action: adducts thigh.

Semimembranosus

Origin: ischium; Insertion: medial surface and shaft of femur; Action: extends thigh.

Semitendinosus

Origin: ischial tuberosity; Insertion: proximal end of tibia; Action: flexes shank.

Tenuissimus

Origin: transverse process of the 2nd caudal vertebra; Insertion: inserting fascia of biceps femoris; Action: Abductor of thigh in common with biceps femoris.

Tibialis anterior

Origin: proximal ends of tibia and fibula; Insertion: tendon to 1st metacarpal; Action: flexes foot.

Extensor digitorum longus

Origin: distal end of femur; Insertion: tendons to all phalanges; Action: extends toes/digits.

Peroneus

Origin: proximal of fibula; Insertion: bases of metatarsals; Action: extends toes.

Gastrocnemius

Origin: knee fascia and distal end of femur; Insertion: calcaneus by Achilles tendon; Action: extends foot.

Soleus

Origin: proximal end of fibula; Insertion: calcaneus; Action: extends foot.

Plantaris

Origin: patella and femur; Insertion: by a thick tendon into the ventral surface of calcaneus; Action: flexes toes/digits.

Flexor digitorum longus

Origin: tibia, fibula and adjacent fascia; Insertion: tendons on all digits; Action: flexes digits.

Tibialis posterior

Origin: tibia, fibula, and fascia; Insertion: scaphoid and medial cuneiform of ankle; Action: extends foot.