Important Muscles

Question 1

Trapezius=
inserts:
innervation:
action:

Answer 1

inserts: lateral third of clavicle, medial aspect of the acromion and spine of scapula
innervation: spinal part of CN XI (spinal accessory-motor) and branches of C3 & C4 (proprioception)
action: shrugs the shoulder, retracts and rotates the scapula

Question 2

Latissimus dorsi=
inserts:
innervation:
action:

Answer 2

inserts: floor of the bicipital groove
innervation: thoracodorsal nerve (C6, 7, 8)
action: adducts, extends, and medially rotates the arm

Question 3

Levator Scapulae=
insertion:
innervation:
action:

Answer 3

insertion: from the superior angle to the root of the spine of the scapula
innervation: dorsal scapular nerve (C5)
action: elevates the scapula

Question 4

Scalenus anterior=
inserts:
innervation:
action:

Answer 4

inserts: scalene tubercle on the superior aspect of the first rib
innervation: anterior rami of C4, 5 & 6
action: ipsilateral lateral flexion of the neck; accessory muscle of respiration

Question 5

Scalenus Medius=
insertion:
innervation:
action:

Answer 5

insertion: upper aspect of the 1st rib between groove for subclavian artery and the scalene tubercle
innervation: rami of C3 to C7

Question 6

Serratus Anterior=
inserts:
innervation:
action:

Answer 6

inserts: along the medial aspect of the inferior surface of the scapula
innervation: Long thoracic nerve (C5, 6 & 7)

Question 7

Deltoid=
inserts:
innervation:
action:

Answer 7

inserts: deltoid tubercle of the humerus
innervation: axillary nerve (C5 & 6)
action: abducts the arm (15-90degrees), anterior fibers flex & medially rotates the arm, posterior fibers extend and laterally rotate the arm

Question 8

Pectoralis Major=
inserts:
innervation:
action:

Answer 8

inserts: lateral lip of the bicipital groove
innervation: medial and lateral pectoral nerves (C8 & T1 & C5, 6, 7 respectively)
action: adducts, flex and medially rotates the arm; it also extends the flexed arm

Question 9

Supraspinatus=
inserts:
innervation:
action:

Answer 9

inserts: superior facet of the greater tuberosity of the humerus
innervation: suprascapular nerve (C5 & 6)
action: initiates abduction (0-15degrees) of the arm; this is one of the 4 rotator cuff muscles

Question 10

Infraspinatus=
inserts:
innervation:
action:

Answer 10

inserts: middle facet of greater tuberosity of the humerus (just below supraspinatus insertion)
innervation: suprascapular nerve (C5 & 6)
action: externally rotates the humerus: this is one of the 4 rotator cuff muscles

Question 11

Teres Major=
inserts:
innervation:
action:

Answer 11

inserts: medial lip of the bicipital groove
innervation: lower subscapular nerve (C5 & 6)
action: extends, adducts and medially rotates the arm

Question 12

Teres Minor=
inserts:
innervation:
action:

Answer 12

inserts: inferior facet of greater tuberosity of humerus (just below infraspinatus insertion)
innervation: axillary nerve (C5 & 6)
action: externally rotates the arm; this is one of the 4 rotator cuff muscles

Question 13

Subscapularis=
inserts:
innervation:
action:

Answer 13

inserts: lesser tuberosity of the humerus
innervation: upper and lower subscapular nerves (C5 and 6)
action: internally rotates and adducts the arm; this is the last of the 4 rotator cuff muscles

Question 14

Sternocleidomastoid=
Inserts:
innervates:
action:

Answer 14

inserts: manubrium of sternum and medial third of clavicle
innervation: spinal part of CN XI (spinal accessory-motor) and ventral rami of C2, C3 (proprioception)
action: tilts the head towards the shoulder on the same side and rotates the head to the opposite side.

Question 15

Biceps Brachii=
inserts:
innervates:
action:

Answer 15

inserts: posterior border of the radial tuberosity of the radius
innervation: : musculocutaneous nerve (C5, 6, 7)
action: flexes and supinates the elbow

Question 16

Triceps=
inserts:
innervates:
action:

Answer 16

inserts: olecranon of the ulna
innervation: radial nerve (C7 and C8)
action: extends the forearm and adducts the arm

Question 17

Brachioradialis=
inserts:
innervates:
action:

Answer 17

inserts: base of the styloid process of the radius
innervation: radial nerve (C6 and C7)
action: flexes the forearm

Question 18

Pronator Teres=
inserts:
innervates:
action:

Answer 18

inserts: medial epicondyle of the humerus and medial border of the coronoid process of ulna
innervation: median nerve (C6 and 7) which passes between the humeral and ulnar heads
action: pronates the forearm and flexes the elbow

Question 19

Psoas Major=
inserts:
innervates:
action:

Answer 19

inserts: lesser trochanter of the femur
innervation: L2, 3 and 4 from the lumbar plexus
action: flexes the thigh and trunk

Question 20

Gluteus Maximus=
inserts:
innervates:
action:

Answer 20

inserts: gluteal tuberosity of the femur (25%) and iliotibial band (75%)
innervation: inferior gluteal nerve (L5, S1 and S2)
action: extends and externally rotates the thigh

Question 21

Piriformis=
inserts:
innervates:
action:

Answer 21

inserts: medial aspect of the superior border of the greater trochanter of the femur
innervation: S1 and S2 from the lumbosacral plexus
action: externally rotates the thigh

Question 22

Tensor Fasciae latae=
inserts:
innervates:
action:

Answer 22

inserts: iliotibial tract
innervation: superior gluteal nerve (L4, 5 and S1)
action: maintains knee extension and abducts the thigh

Question 23

Quadriceps femoris=
inserts:
innervates:
action:

Answer 23

inserts: tibial tuberosity via the patellar tendon which encloses the patella
innervation: femoral nerve (posterior divisions of L2, 3 and 4)
action: extends the knee, stabilizes the patella and flexes the thigh (through the action of rectus femoris)

Question 24

Tibialis anterior=
inserts:
innervates:
action:

Answer 24

inserts: inferomedial aspect of the medial cuneiform and base of 1st metatarsal bone
innervation: deep peroneal nerve (L4 and L5)
action: dorsiflexes and inverts the foot

Question 25

Extensor Hallucis Longus= inserts: innervates: action:

Answer 25

inserts: base of the dorsal aspect of the distal phalanx of the 1st toe innervation: deep peroneal nerve (L5 and S1) action: extends the big toe and dorsiflexes the ankle

Question 26

Peroneus Longus= inserts: innervates: action:

Answer 26

inserts: inferolateral aspect of the medial cuneiform and base of 1st metatarsal bone innervation: superficial peroneal nerve (L5 and S1) action: plantar flexes and everts the foot

Question 27

Gastrocnemius= inserts: innervates: action:

Answer 27

inserts: posterior aspect of the calcaneus via the calcaneal tendon (achilles) innervation: tibial nerve (S1 and S2) action: plantar flexes the ankle

Question 28

Soleus= inserts: innervates: action:

Answer 28

inserts: calcaneal tendon to the posterior surface of the calcaneus innervation: tibial nerve (S1 and 2) action: plantar flexes the ankle and aids in the venous return from the leg

Question 29

Tibialis Posterior= inserts: innervates: action:

Answer 29

inserts: navicular, the three cuneiform bones and the bases of the 2nd to 4th metatarsal bones innervation: tibial nerve (L5 and S1) action: plantar flexes and inverts the foot; supports the medial longitudinal arch of the foot.