Muscles (LAB) Top 10

Question 1

latissimus dorsi

Answer 1

ORIGIN:
- spinous process-vertebrae T6-L5
- thoracolumbar fascia
- iliac crest
- inferior 3-4 ribs
- inferior angle of scapula
INSERTION:
- intertubercular groove of the humerus
INNERVATION:
- thoracodorsal nerve
ACTION:
- adduction
- extends & internally rotates arm
- powerful rotator of trunk

Question 2

biceps brachii

Answer 2

ORIGIN:
- short head: coracoid process of the scapula
- long head: supraglenoid tubercle
INSERTION:
- radial tuberosity
- bicipital aponeurosis
INNERVATION:
- musculocutaneous nerve
ACTION:
- flexes elbow
- flexes and abducts shoulder
- supinates radioulnar joint in forearm

Question 3

triceps brachii

Answer 3

ORIGIN:
- long head: infra glenoid tubercle of the scapula
- lateral head: above the radial groove
- medial head: below the radial groove
INSERTION:
- olecranon process of ulna
INNERVATION:
- radial nerve
ACTION:
- extends forearm
- adducts arm
- extends shoulder

Question 4

deltoid

Answer 4

ORIGIN:
- lateral third of the clavicle
- acromion
- the spine of the scapula
INSERTION:
- deltoid tuberosity of humerus
INNERVATION:
- axillary nerve
ACTION:
- shoulder abduction
- flexion
- extension

Question 5

sternocleidomastoid

Answer 5

ORIGIN:
- manubrium
- medial portion of the clavicle
INSERTION:
- the mastoid process of the temporal bone
INNERVATION:
- spinal accessory nerve
ACTION:
- unilaterally: contra/ipsilateral cervical rotation and flexion
- bilaterally:
- cervical flexion
- elevation of sternum
- assists in forced inhalation

Question 6

pectoralis major

Answer 6

ORIGIN:
- clavicular head;
medial half of the clavicle
- sternocostal head:
- sternum
- superior six costal cartilages
- aponeurosis external oblique muscle
INSERTION:
- bicipital groove of the humerus
INNERVATION:
- pectoral nerve
ACTION:
- adducts and medially rotates the humerus
- draws scapula anteriorly & inferiorly

Question 7

biceps femoris

Answer 7

ORIGIN:
- tuberosity of the ischium
- linea aspera of the femur
INSERTION:
- head of the fibula - articulates with the back of the lateral tibial condyle
INNERVATION:
- long head: tibial nerve
- short head: fibular nerve
ACTION:
- flexes knee joint
- laterally rotates knee joint (flexed knee)
- extends hip joint (long head)

Question 8

gluteus maximus

Answer 8

ORIGIN:
- the gluteal surface of ilium
- lumbar fascia
- sacrum
- sacrotuberous ligament
INSERTION:
- gluteal tuberosity of the femur
- iliotibial tract
INNERVATION:
- gluteal nerve
ACTION:
- external rotation and extension of the hip joint
- support for extended knee through the iliotibial tract
- chief antigravity muscle
- abduction of hip

Question 9

gastrocnemius

Answer 9

ORIGIN:
- lateral condyle
- medial condyle
INSERTION:
- Achilles tendon/calcaneal tendon
INNERVATION:
- tibial nerve
ACTION:
- plantar flexes foot
- flexes knee

Question 10

rectus femoris

Answer 10

ORIGIN:
- inferior iliac spine
- groove on the iliac portion of the acetabulum
INSERTION:
- patellar tendon
INNERVATION:
- femoral nerve
ACTION:
- knee extension
- hip flexion