What creates the differences in flexion/extension movements between the upper and lower limbs?
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
Which spinal segments innervate the upper and lower limbs?
Upper limb C5-T1 Lower limb L2-S3
What is the difference in the upper and lower limb dermatomes?
the dermatomes of the lower limb have twisted to oblique fields, as opposed to the straighter fields in the upper limb.
How are the limbs organised?
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
What are the compartments of the upper limb?
- 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
What are the compartments of the lower limb?
- 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
What is the artierial supply of the upper limb?
Aorta Subclavian artery Axillary artery Brachial artery (pulse) Deep brachial artery Ulnar and radial arteries (pulses) Hand palmar arches Metacarpal and digital arteries
What is the venous drainage of the upper limb?
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
What is the artierial supply of the lower limb?
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)
What is the Venous Drainage of the Lower Limb?
Deep System
- Ant & Post Tibial
- Venae Comitantes
- Popliteal Vein
- Femoral Vein
- External iliac vein
Superficial system
- Venous arches
- Long saphenous vein
- Short saphenous vein
Where does the superficial veins of the lower limb drain?
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.
How are varicose veins in the lower limb caused?
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.
How is blood moved towards the heart from the lower limb veins?
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.
Why do patients in hospitals wear elastic stockings?
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.
What plexuses innervate the upper and lower limb?
Upper limb = brachial plexus
Lower limb = lumbosacral plexus
What are the main nerves to the lower limb?
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)
Describe the types of limb innervation
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
What is the motor supply to each of the upper limb segments?
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
What is the motor supply to each of the lower limb segments?
Hip:
- Flex L2L3
- Extend L4L5
Knee:
- Extend L3L4
- Flex L5S1
Ankle:
- Dorsiflex L4L5
- Plantarflex S1S2
What are Venae comitantes?
a pair of veins, (occasionally more) that closely accompany an artery in such a manner that the pulsations of the artery aid venous return.
Why do veins run close to arteries?
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
What is compartment syndrome?
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)
What are the things you test for assessing nerve function?
- Motor Function
- Sensory Function
- Reflex Function
- Autonomic Function
Whats the Sensory Segmental Supply
to the Upper Limb?
- C4 infraclavicular region
- C5 lateral arm
- C6 lateral forearm and thumb
- C7 middle finger
- C8 little finger and medial forearm
- T1 medial arm
