Muscles

Question 1

Masseter

Answer 1

Origin: zygomatic arch

Insertion: lateral surface and angle of mandibular ramus

Action: elevatation, adduction, and protrusion of the mandible

Question 2

Sternocleidomastoid

Answer 2

Origin: clavicular head and sternal head

Insertion: mastoid process

Action: (together) flex neck; (alone) bends neck toward shoulder and turns face to opposite side

Question 3

Pectoralis major

Answer 3

Origin: cartilage of ribs 2-6, body of sternum, and inferior, medial portion of clavicle

Insertion: crest of greater tubercle and lateral lip of intertubercle sulcus of humerus

Action: flexion, adduction, and medial rotation of shoulder

Question 4

Rectus femoris

Answer 4

Origin: anterior inferior iliac spine and superior acetaelar rim of ilium

Insertion: tibial tuberiosity; patella

Action: extension at knee; flexion at hip

Question 5

Adductor longus

Answer 5

Origin: inferior ramus of pubis

Insertion: linea aspera of femur

Action: Adducts and flexes thigh at hip

Question 6

Trapezius

Origin/Action/Insertion/Innervation/Blood Supply

Answer 6

Origin: 1. inion (external occipital protuberance) 2. superion nuchal line 3. Spines of cervical and thoracic vertebrae

Insertion: 1. Spine of scapula 2. Acromion 3. lateral 1/3 of clavicle

Action: elevation, adductin, depression, rotation

Innervation: motor function: accesory nerve (CN XI); sensation: ventral rami of C3 and C4 cervical nerves

Arterial supply: Transverse cervical artery

Question 7

Deltoid

Answer 7

Origin: clavicle and acromion process and spine of the scapula

Insertion: deltoid tuberosity of the humerus

Action: whole muscle: abduction of shoulder. anterior: flexion and medial rotation of humerus. posterior: extension and lateral roation humerus

Question 8

Rhomboid major

Answer 8

Origin: spinous process of T2-T5 vertebrae

Insertion: vertebral border of scapula from spine to inferior angle

Action: adducts and performs downward roation of the scapula

Question 9

Supraspinatus

Answer 9

Origin: supraspinous fossa of scapula

Insertion: greater tubercle of humerus

Action: abduction of shoulder

Question 10

Triceps brachii

Answer 10

Origin: scapula

Insertion: posterior olecranon process of ulna

Action: extension at elbow

Question 11

Gluteus maximus

Answer 11

Origin: iliac crest, posterior gluteal line, and lateral surfae of ilium, sacrum, coccyx, and thoracolumbar fascia

Insertion: iliotibial tract and gluteal tuberosity of femur

Action: extension and lateral rotation at hip; helps stabilize the extended knee; abduction at the hip (superior fibers only)

Question 12

Tensor fascia latae

Answer 12

Origin: Iliac crest

Insertion: Tibial

Action: Abducts and flexes thigh at hip

Question 13

Semitendinosus

Answer 13

Origin: ischial tuberosity

Insertion: proximal, medial surface of tibia near insertion of gracilis

Action: flexion at knee; extension and medial rotation at hip

Question 14

Semimembranosus

Answer 14

Origin: iscial tuberosity

Insertion: posterior surface of medial condyle of tibia

Action: flexion at knee; extension and medial rotation at hip

Question 15

Gastrocnemius

Answer 15

Origin: femoral condyles

Insertion: calcaneus via calcaneal tendon

Action: plantar flexion at ankle; flexion at knee

Question 16

rectus abdominis

Answer 16

Origin: superior surface of pubis around symphysis

Insertion: inferior surfaces of cartilages (ribs 5-7) and xiphoid process of sternum

Action: Depresses ribs, flexes vertebral column and compresses abdomen

Question 17

latissimus dorsi

Answer 17

Origin: 1) spines of lumbar, sacral, and lower 6 thoracic vertebrae 2) iliac crest 3) lower 4 ribs 4) inferior angle of scapula

Insertion: medial lip and floor of intertubercular groove

Action: 1) extend 2) hyperextend 3) medial rotation (at shoulder joint)