Introduction to the Limbs

Question 1

Describe the development of the limbs

Answer 1

It begins at week four of development, Specialised cells migrate from the somites and later plate mesoderm. The limbs will then develop from limb buds.

Question 2

What are the two types of muscle contraction?

Answer 2

Isometric (muscle tone changes) and isotonic contraction (muscle length changes)

Question 3

What are the two types of isotonic contraction? and describe them

Answer 3

Concentric (muscle contracts according to the sliding filament mechanism and shortens) and Eccentric (muscle elongates while under tension)

Question 4

What is a prime mover?

Answer 4

Muscle/s that play the primary role in moving a body part

Question 5

What is an Agonist?

Answer 5

Muscle/s that act directly to produce the desired movement

Question 6

What are synergist muscles?

Answer 6

Prevents unwanted movements associated with the action of the prime movers

Question 7

What are antagonist muscles?

Answer 7

Directly oppose a movement

Question 8

What are fixating muscles?

Answer 8

Provide necessary support to hold the body in place while movement occurs

Question 9

What are the features of superficial fascia?

Answer 9

It is found just beneath the skin and contains adipose tissue

Question 10

What are the features if deep fascia?

Answer 10

Barrier between muscles, encloses muscles and creates compartments of muscles and allows for the attachment of muscles. It allows for the passage for nerves and vessels and holds tendons in place by forming Retinaculae

Question 11

What is retinaculae?

Answer 11

A band of thickened deep fascia that holds tendons in place

Question 12

How does deep fascia separate muscles into compartments?

Answer 12

By sending septae between muscles. They also form potential spaces for the passage of nerves and vessels.

Question 13

What is compartment syndrome?

Answer 13

An injury to a muscle within a tough compartment can cause swelling and increase the pressure which compresses neurovascular bundles.

Question 14

Describe the fascia of the upper arm

Answer 14

Intermusclar septae divide the arm into an anterior (flexor) and posterior (extensor) compartments

Question 15

Describe the deep fascia of the forearm

Answer 15

Antebrachial fascia forms interosseous membrane that separates anterior (flexor) and posterior (extensor) compartments. Also forms carpal tunnels

Question 16

What is deep fascia of the thigh called?

Answer 16

Fascia lata

Question 17

Describe the deep fascia of the thigh (fascia lata)

Answer 17

• It thickens laterally as the Iliotibial tract

- Sends septae to divide the thigh into anterior (extensor), medial (adductor) and posterior (flexor) compartments

Question 18

Describe the fascia of the leg (crural fascia)

Answer 18

It fuses with the tibia and forms the interosseous membrane. - It sends septae to divide the leg into anterior (extensor), Two posterior (superficial and deep flexor) and lateral (peroneal) compartments

Question 19

What is a dermatome?

Answer 19

A strip of skin supplied by one spinal nerve

Question 20

What is a myotome?

Answer 20

Muscle/group of muscles supplied by one spinal nerve

Question 21

Why is thumb lateral but bug toe medial

Answer 21

Upper limb rotates laterally, therefore the flexor muscles move to an anterior position but the lower limb rotates medially and so flexor muscles move to a posterior position

Question 22

What are the branches that come off the brachial plexus

Answer 22

Musculocutaneous, Axillary, Radial, Median and Ulnar

Question 23

What supplies the lower limbs with nerves

Answer 23

Lumbo-sacral plexus which is within the psoas major.

Question 24

What are the two main arterial supplies for the upper and lower limbs?

Answer 24

Subclavian and external iliac arteries

Question 25

What helps venous flow return to the heart?

Answer 25

Muscle pump, arterial pulsation and negative interthoracic pressure

Question 26

What does the lymphatic system do?

Answer 26

Absorb interstitial fluid via lymph capillaries and transport it to lymph nodes. All lymph will eventually return to the venous flow

Question 27

What us the largest lymph vessel?

Answer 27

The thoracic duct which opens at the junction between the left subclavian and internal jugular vein

Question 28

How does in-utero rotation effect dermatomes

Answer 28

It causes the dermatomes too rotate