Limb overview

Question 1

What creates the differences in flexion/extension movements between the upper and lower limbs?

Answer 1

Upper limb: Flexors are anterior Extensors are posterior The lower limb internally rotates during its development meaning that, in the thigh and leg, the extensors are anterior and the flexors are posterior

Question 2

Which spinal segments innervate the upper and lower limbs?

Answer 2

Upper limb C5-T1 Lower limb L2-S3

Question 3

What is the difference in the upper and lower limb dermatomes?

Answer 3

the dermatomes of the lower limb have twisted to oblique fields, as opposed to the straighter fields in the upper limb.

Question 4

How are the limbs organised?

Answer 4

The limbs are divided into compartments Compartments tend to have a distinct function Compartments tend to have the same nerve supply Compartments tend to have the same blood supply

Question 5

What are the compartments of the upper limb?

Answer 5

• Pectoral (= chest) girdle muscles
• Intrinsic shoulder muscles
• Anterior (upper) arm muscles - flexors
• Posterior (upper) arm muscles - extensors
• Anterior forearm muscles - flexors
• Posterior forearm muscles - extensors
• Intrinsic hand muscles

Question 6

What are the compartments of the lower limb?

Answer 6

• Hip abductors (Gluteal)
• Hip extensors (Gluteal)
• Hip Flexors
• Anterior thigh muscles – extensors
• Medial thigh muscles – adductors
• Posterior thigh muscles – flexors
• Anterior leg muscles – extensors (dorsiflexors)
• Lateral leg muscles – foot evertors
• Posterior leg muscles – flexors (plantarflexors)
• Intrinsic foot muscles – variety of functions

Question 7

What is the artierial supply of the upper limb?

Answer 7

Aorta Subclavian artery Axillary artery Brachial artery (pulse) Deep brachial artery Ulnar and radial arteries (pulses) Hand palmar arches Metacarpal and digital arteries

Question 8

What is the venous drainage of the upper limb?

Answer 8

Superficial and deep systems: Dorsal venous arch (sup.); Cephalic vein and basilic vein (sup.); Venae comitantes (deep); Axillary vein (deep); Subclavian vein; Superior vena cava

Question 9

What is the artierial supply of the lower limb?

Answer 9

Aorta

Common iliac arteries:

• Internal iliac artery
• External iliac artery

External iliac artery

Femoral artery (pulse) - becomes this once iliac artery passes under the inguinal ligament

• Deep femoral artery

Popliteal artery (pulse) - becomes this once femoral passes behind the knee

• Posterior tibial artery (pulse)
• Anterior tibial artery (pulse)
• Peroneal artery
• Dorsalis pedis (pulse)

Question 10

What is the Venous Drainage of the Lower Limb?

Answer 10

Deep System

• Ant & Post Tibial
• Venae Comitantes
• Popliteal Vein
• Femoral Vein
• External iliac vein

Superficial system

• Venous arches
• Long saphenous vein
• Short saphenous vein

Question 11

Where does the superficial veins of the lower limb drain?

Answer 11

The great (long) saphenous vein drains into the femoral vein at the groin.

The small (short) saphenous vein drains into the popliteal vein at the popliteal fossa.

Question 12

How are varicose veins in the lower limb caused?

Answer 12

Perforating veins connecting superficial and deep veins contain a valve that will allow flow only from superficial to deep. If such a valve is compromised, blood is pushed from deep to superficial veins leading to varicose veins.

Question 13

How is blood moved towards the heart from the lower limb veins?

Answer 13

The deep vessels are sandwiched between layers of calf muscles. During walking and running, contractions of these muscles squeeze the thin-walled veins and push blood up the veins: the calf pump.

Question 14

Why do patients in hospitals wear elastic stockings?

Answer 14

Immobility means less efficient venous return from the foot and leg. Sluggish deep venous return can lead to Deep Vein Thrombosis (DVT). Elastic surgical socks compress the superficial veins promoting more vigorous deep venous return.

Question 15

What plexuses innervate the upper and lower limb?

Answer 15

Upper limb = brachial plexus

Lower limb = lumbosacral plexus

Question 16

What are the main nerves to the lower limb?

Answer 16

Femoral n. supplies anterior compartment of thigh.

Obturator n. supplies medial (adductor) compartment of thigh.

Sciatic n. (or its terminal branches Tibial and Common Peroneal ns.) supply the remaining compartments (i.e. post. thigh, ant. and post. leg, foot)

Question 17

Describe the types of limb innervation

Answer 17

Peripheral

Segmental:

• Groups of motor nerve cell bodies in the spinal cord
• Anterior divisions = flexor muscles
• Posterior divisions = extensor muscles
• Muscles supplied by two adjacent segments
• More distal in limb = more caudal in spine

Question 18

What is the motor supply to each of the upper limb segments?

Answer 18

Shoulder:

• abduction C5, adduction C678
• external rotation C5, internal rotation C678

Elbow:

• flexion C56,
• extension C78

Forearm:

• supination C6,
• pronation C78

Wrist:

• flexion C67,
• extension C67

Long tendons to hand:

• flexion C78
• extension C78

Intrinsic hand:

• T1

Question 19

What is the motor supply to each of the lower limb segments?

Answer 19

Hip:

• Flex L2L3
• Extend L4L5

Knee:

• Extend L3L4
• Flex L5S1

Ankle:

• Dorsiflex L4L5
• Plantarflex S1S2

Question 20

What are Venae comitantes?

Answer 20

a pair of veins, (occasionally more) that closely accompany an artery in such a manner that the pulsations of the artery aid venous return.

Question 21

Why do veins run close to arteries?

Answer 21

there are often 2-3 veins running with the artieres

This is utilise pulsation of attieries and a type of counter current system for heat retention

Question 22

What is compartment syndrome?

Answer 22

Ischaemia caused by trauma-induced increased pressure in a confined limb compartment

Commonly the anterior, posterior and lateral compartments of the leg

Normal pressure = 25mmHg; only need 50-60 to collapse vessels, so pulse still present

Acute compartment syndrome (trauma associated)

Chronic compartment syndrome (exercise-induced)

Question 23

What are the things you test for assessing nerve function?

Answer 23

• Motor Function
• Sensory Function
• Reflex Function
• Autonomic Function

Question 24

Whats the Sensory Segmental Supply
to the Upper Limb?

Answer 24

• C4 infraclavicular region
• C5 lateral arm
• C6 lateral forearm and thumb
• C7 middle finger
• C8 little finger and medial forearm
• T1 medial arm

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Question 25

What is the Safe Area for intramuscular injection in the buttock? Into what muscle are such injections normally made?

Answer 25

The dorsogluteal site:

the injection is administered into the gluteus maximus muscle in the buttock.

The upper outer quadrant of this area must be used to avoid any damage to the sciatic nerve.

Question 26

What is the femoral triangle?

Answer 26

The femoral triangle is the region of the groin where the femoral artery is accessed e.g. access to the cardiac vessels to carry out angiograms and angioplasty. A pulse can be felt in this area.

Question 27

Why are intramuscular injections done?

Answer 27

Intramuscular injections may be used instead of intravenous injections because some drugs are irritating to veins, or because a suitable vein can’t be located.

It may be used instead of oral delivery because some drugs are destroyed by the digestive system when a drug is swallowed.

Intramuscular injections are absorbed faster than subcutaneous injections. This is because muscle tissue has a greater blood supply than the tissue just under the skin.

Muscle tissue can also hold a larger volume of medication than subcutaneous tissue - Solutions up to a volume of 5ml

The IM route is often used for medications that will not irritate soft tissue and can be suitably dissolved.

The delivery of medication into skeletal muscles, with fewer pain receptors and good blood perfusion, minimises pain.