Muscle Actions

Question 1

Deltoids

Answer 1

Position. Shoulder
Origin. Clavicle and scapula
Insertion. Humerus
Primary action. Abduction, flexion and extension of shoulder

Question 2

Biceps brachii

Answer 2

Position. Front of upper arm
Origin. Scapula
Insertion. Radius
Primary action. Flexion of elbow, supination of forearm, flexion of shoulder

Question 3

Triceps brachii

Answer 3

Position. Back of upper arm
Origin. Humerus and scapula
Insertion. Ulna
Primary action. Extension of elbow, extension of shoulder

Question 4

Latissimus dorsi

Answer 4

Position. Sides of the back
Origin. Lower thoracic vertebrae, lumbar vertebrae and ilium
Insertion. Humerus
Primary action. Adduction and extension of shoulder

Question 5

Trapezius

Answer 5

Position. Upper back
Origin. Base of skull, cervical and thoracic vertebrae
Insertion. Clavicle and scapula
Primary action. Elevation, retraction and depression of shoulder girdle

Question 6

Rhomboid

Answer 6

Position. Beneath trapezius
Origin. Upper thoracic vertebrae
Insertion. Scapula
Primary action. Retraction of shoulder girdle

Question 7

Pectoralis major

Answer 7

Position. Chest
Origin. Clavicle and sternum
Insertion. Humerus
Primary action. Horizontal flexion and adduction

Question 8

Erector spinae

Answer 8

Position. Either side of spine
Origin. Sacrum, ilium, ribs , vertebrae
Insertion. Ribs, vertebrae, occipital bone
Primary action. Extension and lateral flexion of spine

Question 9

Rictus abdominis

Answer 9

Position. Along the centre of the abdomen
Origin. Pubis
Insertion. Sternum
Primary action. Flexion of spine and lateral flexion of spine

Question 10

Internal obliques

Answer 10

Position. Sides of abdomen
Origin. Ribs. Ilium
Insertion. Ilium pubis and ribs. Linea. Alba
Primary action. Rotation and lateral flexion of spine

Question 11

External obliques

Answer 11

Position. Sides of abdomen
Origin. Ribs
Insertion. Ilium and pubis
Primary action. Rotation and lateral flexion of spine

Question 12

Transversus abdominis

Answer 12

Position. Abdomen
Origin. Iliac crest and lumbar fascia
Insertion. Pubis and Linia alba
Primary action. Support of internal organs, forced expiration

Question 13

Diaphragm

Answer 13

Position. Beneath. Rib cage
Origin. Sternum, costal cartilages and lumbar vertebrae
Insertion. Central tendon of diaphragm
Primary action. Depresses and aids in expiration

Question 14

Intercostals

Answer 14

Position. Between ribs
Origin. Ribs and costal cartilages
Insertion. Superior border of next rib below
Primary action. Elevated ribs and aids in expiration

Question 15

Hip flexors

Answer 15

Position. Through the pelvis onto front of the thigh
Origin. Ilium, lumbar vertebrae
Insertion. Femur
Primary action. Flexion of hip

Question 16

Gluteus maximus

Answer 16

Position. Bottom
Origin. Ilium
Insertion. Femur
Primary action. Extension and external rotation of the hip

Question 17

Abductors

Answer 17

Position. Outside of upper thigh
Origin. Ilium
Insertion. Femur. Tibia
Primary action. Abduction of hip, flexion of hip

Question 18

Adductors

Answer 18

Position. Inner thigh
Origin. Pubis, ischium
Insertion. Femur
Primary action. Adduction of hip

Question 19

Quadriceps

Answer 19

Position. Front of thigh
Origin. Ilium, femur
Insertion. Tibia
Primary action. Extension of knee and flexion of hip

Question 20

Hamstrings

Answer 20

Position. Back of thigh
Origin. Ischium, femur
Insertion. Tibia, fibula
Primary action. Extension of hip and flexion of knee

Question 21

Gastrocnemius

Answer 21

Position. Calf
Origin. Femur
Insertion. Calcaneus. Heel bone
Primary action. Plantar flexion of ankle and flexion of knee

Question 22

Soleus

Answer 22

Position. Calf beneath gastrocnemius
Origin. Tibia
Insertion. Calcaneus
Primary action. Plantar flexion of ankle

Question 23

Tibialis anterior

Answer 23

Position. Front of lower limb
Origin. Tibia
Insertion. Metatarsal and tarsal
Primary action. Dorsiflexion and inversion of ankle