Introduction to the limbs

Question 1

What is the function of the upper limbs ?

Answer 1

They enable the hand to be brought to any point in space and keep it steady.

Question 2

State some features of the upper limbs

Answer 2

Highly mobile joints
Levers

Question 3

What is the function of the lower limbs ?

Answer 3

Supports the body weight

Involved mainly in locomotion

Question 4

State some features of the lower limbs

Answer 4

The bones are more robust

Joints are more stable

Question 5

Briefly describe the development of the limbs

Answer 5

Week 4
- Ventrolateral body wall
- Contain cells from somites and lateral plate mesoderm

Question 6

Where do the upper limbs bud ?

Answer 6

Opposite somites C5-T1

Question 7

Where do the lower limbs bud ?

Answer 7

Opposite somites L2-S2

Question 8

What buds first, the upper or lower limbs ?

Answer 8

The upper limbs. 2 days earlier

Question 9

State the 3 types of muscle

Answer 9

Skeletal
Cardiac
Smooth

Question 10

Where do limbs originate from ?

Answer 10

(usually) at the proximal end of the muscle, which remains fixed during muscle contraction.

Question 11

Where is insertion of the limbs from ?

Answer 11

(usually) at the distal end of the muscle, which is moveable.

Question 12

What happens to muscle when stimulated ?

Answer 12

The muscle contracts and tries to bring its 2 ends closer.

Question 13

What happens when muscle contracts ?

Answer 13

The muscle shortens, and usually shortens in the insertion –> origin direction.

Question 14

What is meant by isometric contraction ?

Answer 14

Muscle tone changes
(muscle “meter” - length is not changed)

Question 15

What is meant by isotonic contraction ?

Answer 15

Muscle length changes
(muscle “tone” is not changed )

Question 16

What are the 2 types of isotonic contraction ?

Answer 16

Concentric
Eccentric

Question 17

What is meant by concentric contraction ?

Answer 17

Muscle contracts according to the sliding filament mechanism and shortens

Question 18

What is meant by eccentric contraction ?

Answer 18

Muscle elongates whilst under tension due to an opposing force greater than the muscle generates.

Question 19

How do concentric and eccentric contractions protect from injury ?

Answer 19

Eccentric contraction acts as a braking force in opposition to a concentric contraction to protect from injury.

Question 20

Prime mover (muscles)

Answer 20

Muscles that play the primary role in moving a body part.

Question 21

Agonist (muscles)

Answer 21

Muscle that acts directly to produce a desired movement.

Question 22

Synergist (muscles)

Answer 22

Muscles which assist the prime mover but are doing less of the work OR prevent unwanted movements associated with the action of the prime movers.

Question 23

Antagonist (muscles)

Answer 23

Muscles which directly oppose a movement

Question 24

Fixator (muscles)

Answer 24

Muscles that provide the necessary support to assist in holding the rest of the body in place whilst the movement occurs.

Question 25

What is fascia ?

Answer 25

A sheet of connective tissue

Question 26

Briefly describe superficial fascia

Answer 26

Just beneath the skin Contains adipose tissue

Question 27

Briefly describe deep fascia

Answer 27

Ensheaths muscles but continuous Sometimes named

Question 28

State some functions of deep fascia (6)

Answer 28

Facilitates contraction Barrier between muscles Compartments of muscles Passages for nerves and vessels Attachment for muscles Holds tendons in place

Question 29

What is the function of septa ?

Answer 29

Septae form potential spaces to allow passage of nerves and blood vessels

Question 30

Function of deep fascia

Answer 30

Deep fascia sends septae between muscles to separate them into compartments.

Question 31

What is a downfall of septae ?

Answer 31

Potential spaces are also potential tracts for infection spread and blood loss.

Question 32

Briefly describe compartment syndrome

Answer 32

An injury to the muscle within a tough compartment may cause swelling and increased pressure that compresses the neurovascular bundles.

Question 33

State some general rules about muscles in a compartment

Answer 33

Generally muscles in a compartment have... - the same action - the same nerve supply

Question 34

State some features of deep fascia in the arm

Answer 34

The medial and lateral intramuscular septum separate into 2 compartments : - anterior and posterior compartments

Question 35

Function of the anterior compartment in the arm

Answer 35

Flexing movement (flexor)

Question 36

Function of the posterior compartment in the arm

Answer 36

Extending movement (extensor)

Question 37

What surrounds the arm ?

Answer 37

Brachial fascia

Question 38

State some features of deep fascia in the forearm

Answer 38

The antebrachial fascia surrounds and separates the anterior and posterior compartments and forms an interosseous membrane.

Question 39

Function of the anterior compartment in the forearm

Answer 39

Flexor - pronator

Question 40

Function of the posterior compartment in the forearm

Answer 40

Extensor - supinator

Question 41

Describe the formation of the carpal tunnel

Answer 41

At the wrist the interosseous membrane thickens to form a flexor retinaculum.

Question 42

How does the deep fascia of the thigh differ from that of the upper limb ?

Answer 42

It is thicker that the upper limbs

Question 43

What is the Iliotibial tract ?

Answer 43

The fascia lata (deep fascia) thickens laterally in the thigh to form the iliotibial tract.

Question 44

What is the deep fascia of the thigh called ?

Answer 44

Fascia lata

Question 45

Function of the iliotibial tract

Answer 45

Stabilises the hip and knee

Question 46

What 3 compartments in the thigh are formed by septae ?

Answer 46

Anterior - Extensor Medial - Adductor Posterior - Flexor

Question 47

What is the deep fascia of the leg called ?

Answer 47

Crural fascia

Question 48

How is the interosseous membrane of the leg formed ?

Answer 48

The crural fascia fuses with the tibia

Question 49

State the 3 compartments of the leg

Answer 49

Anterior - extensor Lateral - everters Posterior - flexor and plantar flexor (posterior = deep and superficial)

Question 50

What are neurons ?

Answer 50

Excitable nerve cells which transmit information as electrical signals (or action potentials)

Question 51

What is a neurite ?

Answer 51

Either a dendrite or an axon

Question 52

State the 2 types of neuron

Answer 52

Motor Sensory

Question 53

What are the 2 types of motor neurons ?

Answer 53

Somatic Autonomic

Question 54

What is a dermatome ?

Answer 54

An area of skin supplied by neurons from one spinal segment (spinal nerve)

Question 55

What is a myotome ?

Answer 55

A muscle or groups of muscles supplied by neurons from a single spinal segment - usually having the same action.

Question 56

Briefly describe rotation of the limbs

Answer 56

The upper limb rotates laterally from its in-utero position The lower limb rotates medially The dermatomes rotate too

Question 57

Describe rotation of the upper limbs

Answer 57

Lateral rotation - thumb moves from superior to lateral - flexor muscle groups move to an anterior position - extensors move to a posterior position

Question 58

Describe rotation of the lower limbs

Answer 58

Medial rotation - hallux moves from superior to medial - flexor muscle groups move from an anterior to a posterior position - extensors move to an anterior position

Question 59

Describe the initial position of the thumb and hallux

Answer 59

Found on the cranial side of each limb, and both the palm and sole face anteriorly (or medially)

Question 60

Describe the brachial plexus

Answer 60

Formed in axilla C5-T1

Question 61

Describe the lumbosacral plexus

Answer 61

Major feature of posterior abdominal wall L1-S5 (L2-S2 for limb)

Question 62

Where is the brachial plexus located ?

Answer 62

Upper limbs

Question 63

What does the lumbosacral plexus supply ?

Answer 63

Supplies abdominal wall, pelvis and viscera

Question 64

State the artery that supplies the upper limb

Answer 64

Subclavian artery

Question 65

State the artery (arteries) that supply the lower limb

Answer 65

(COMMON) External iliac artery - also some internal iliac artery

Question 66

Briefly describe how veins drain blood

Answer 66

From superficial to deep via perforating veins The back flow of blood is prevented by valves

Question 67

Name superficial veins in the upper and lower limbs

Answer 67

UL : - Median cubital - Cephalic - Basilic - Superficial venous palmar arch LL : - Small saphenous - Great saphenous

Question 68

Describe deep veins

Answer 68

Accompany arteries Usually as venue comitantes - taking the arteries name

Question 69

What 3 things help blood return to the heart against gravity ?

Answer 69

Muscle pump Arterial pulsation Negative intrathoracic pressure (also valves in veins)

Question 70

What are some negative aspects of lymphatics ?

Answer 70

Allow the spread of metates or infection

Question 71

What lymph node is associated with the upper limbs ?

Answer 71

Axillary

Question 72

What lymph node is associated with the lower limbs ?

Answer 72

Inguinal

Question 73

What is Hiltons law ?

Answer 73

A nerve innervating a particular muscle acting on a certain joint will also innervate the particular joint and skin overlying the muscle.