Muscle system pt 3

Question 1

Intrinsic muscles of hand

Answer 1

small weak muscles
- thenar eminence (ball of thumb): produce opposition, move thumb toward little finger
- hypothenar eminence (ball of the little finger): each of above groups has flexor, abductor, and opponens muscle
- midpalmar muscles: lumbricals and interossei: abduct + adduct fingers

lie entirely within palm

Question 2

Crossing hip + knee joint muscles

Answer 2

• movements at hip: flexion, extension, abduction, adduction, circumduction, rotation
• most anterior muscles flex femur at hip and extend leg at knee (swing of walking)
• most posterior muscles extend thigh, flex leg (backswing of walking)
• medial muscles all adduct thigh
• lateral muscles abduct thigh

Question 2

Movement of thigh (hip joint)

Answer 2

hip flexors pass in front of hip joint
- lliopsoas (iliacus and psoas major): prime mover of flexion
- tensor fasciae latae
- rectus femoris (hip flexion)
- assisted by medial adductors (groin) and sartorius (cross leg)

thigh hip extensors
- hamstring muscles: prime movers of extension
- biceps femoris (lateral hamstring)
- semitendinosus (medial hamstring)
- semimembranosus (medial hamstring)
- gluteus maximus: assists hamstrings in forceful thigh extension

Question 3

thigh movements

Answer 3

abductors
- gluteus medius (medially rotates thigh)
- gluteus minimus (medially rotates thigh)
- gluteus maximus (laterally rotates thigh)

external lateral rotators
1. pirigormis
2. obturator externus
3. obturator internus
4/5. gamellus (superior + inferior)
5. quadratus femoris

Question 4

muscle of thigh moving knee joint

Answer 4

1. quadriceps femoris: 4 muscles
   - sole extensor of knee (anterior muscle)
   - rectus femoris
   - vastus lateralis
   - vastus medialis
   - vastus intermedius
2. hamstring muscles: flex knee (post mm)
   - biceps femoris
   - semitendinosus
   - semimembranosus

Question 5

Muscles of the leg movement

Answer 5

leg muscles produce following:
- ankle: dorsiflexion and plantar flexion
- intertarsal joint: inversion and eversion of food
- toes: flexion and extension

anterior compartment
- primary toe extensors + ankle dorsiflexors
- tibialis anterior (dorsiflexes foot)
- extensor digitorum longus (extends toes)
- extensor hallucis longus (extends great toes)

posterior compartment
- plantar flex ankle
- gastrocnemius
- soleus
- plantaris
- popliteus
- flexor digitorum longus (flex toes)
- flexor hallucis longus (flex great toe)
- tibialis posterior

Question 6

Bell’s palsy vs stroke

Answer 6

bell’s palsy: complete facial paralysis, right nerve/nucleus palsy
stroke: sparing of the forehead, right facial UMN lesion

Question 7

intrinsic muscles of the foot

Answer 7

• help flex, extend, abduct, adduct toes
• support arches of foot, some leg tendons assist
• extensor digitorum brevis: dorsal foot muscle, helps extend toes

Question 8

plantar muscles

Answer 8

4 layers of plantar muscles
- superficial layer: flexor digitorum brevis, abductor hallucis, abductor digiti minimi
- second later: flexor accessorius, lumbricals