Skeletal Muscles (L)

Question 1

gluteus medius

Answer 1

• origin: ilium
• insertion: femur
• action: hip abductor, medial rotator

Question 2

deltoid

Answer 2

1) spinal head
- origin: spine scapula
- insertion: humerus
- action: arm extension and abduction at shoulder

2) acromial head
- origin: acromion
- insertion: humerus
- action: arm abduction at shoulder

3) clavicular head
- origin: clavicle
- insertion: humerus
- action: arm flexion and abduction at shoulder, medial rotation of humerus

Question 3

brachialis

Answer 3

• origin: humerus
• insertion: ulna
• action: elbow flexion

Question 4

pectoralis major

Answer 4

• origin: clavicle, costal cartilage ribs 1-6
• insertion: humerus
• action: arm flexion at shoulder, extension of flexed arm, medial rotation and adduction of humerus

Question 5

vastus intermedius

Answer 5

• origin: femur
• insertion: patella
• action: knee extension

Question 6

vastus lateralis

Answer 6

• origin: femur
• insertion: patella
• action: knee extension

Question 7

gluteus maximus

Answer 7

• origin: sacrum, ilium
• insertion: femur, iliotibial band
• action: hip extension, lateral rotation

Question 8

latissimus dorsi

Answer 8

• origin: sacrum, lumbar vertebrae, lower thoracic vertebrae
• insertion: humerus
• action: arm extension at shoulder, humerus medial rotation and adduction

Question 9

vastus medialis

Answer 9

• origin: femur
• insertion: patella
• action: knee extension

Question 10

triceps brachii

Answer 10

1) lateral head
- origin: humerus
- insertion: ulna
- action: elbow extension

2) long head
- origin: scapula
- insertion: ulna
- action: arm extension at shoulder

3) medial head not mentioned

Question 11

trapezius

Answer 11

• origin: occipital bone, ligamentum nuchae, spines of thoracic vertebrae
• insertion: clavicle, acromion process, spine of scapula
• action: elevate & adduct scapula (shrug)

Question 12

rectus femoris

Answer 12

• origin: iliac spine
• insertion: patella
• action: flex hip, extend knee

Question 13

supraspinatus

Answer 13

• origin: scapula
• insertion: humerus
• action: arm abduction

Question 14

biceps femoris

Answer 14

1) short head
- origin: femur
- insertion: fibula
- action: knee flexion

2) long head
- origin: ischium
- insertion: fibula
- action: hip extension, knee flexion

Question 15

biceps brachii

Answer 15

1) short head
- origin: scapula
- insertion: radius
- action: arm flexion at shoulder, elbow flexion, forearm supination

2) long head
- origin: scapula
- insertion: radius
- action: arm flexion at shoulder, elbow flexion, forearm supination

Question 16

infraspinatus

Answer 16

• origin: scapula
• insertion: humerus
• action: strengthen posterior shoulder, lateral rotation at shoulder