Overview of the anatomy of the upper and lower limbs Flashcards
What are some key clinical points relating to limbs? ( vascular, NM, Musculoskeletal)§
Vascular:
- pulses
- varicose veins
- DVT
- superficial veins for injections, veins, harvesting, etc.
- arteries for access to cardiac vessles
- compartment syndrome
Neuromuscular:
- spinal root injury
- peripheral nerve injury
- muscular deficits after nerve injuries
Musculoskeletal:
- fractures
- tendon/ligament sprains and tears
- arthritis and other joint problems
Which roots innervate the upper and lower limb?
upper: C5-T1
lower: L2-S3
Location of flexors and extensors in the upper and lower limb
U: flexors are anterior, extensors are posterior
L: extensors are anterior, flexors are posterior (the limb rotates internally) -> in addition the dermatomes have twisted
Compartments in Limb Anatomy
- The limbs are divided into compartments
- tend to have a distinct function
- tend to have the same nerve supply
- tend to have the same blood supply
List the compartments of the upper limb (7)
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 muscle
What do movements of the shoulder involve?
- movements of the arm relative to the scapula
- movements of the scapula relative to the chest wall
Muscles acting on the shoulder joint have attachments in the neck, anterior chest, back and arm.
Where do muscles acting on the shoulder joint have attachments?
Muscles acting on the shoulder joint have attachments in the neck, anterior chest, back and arm.
List the compartments of the lower lomb (10)
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 are the different names fo the lateral compartment of the leg?
- lateral
- peroneal (UK)
- fibular (USA)
Where do the nerves supplying the lower limb arise from?
the lumbosacral plexus (L2-S3)
Which muscles act as flexors of the hip?
Muscles with attachments in the abdomen and pelvis are flexors of the hip
- iliacus, psoas
Arterial Supply to 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
Venous drainage of the upper limb
Superficial and deep systems:
- Dorsal venous arch (sup.); Cephalic vein and basilic vein (sup.);
Venae comitantes (deep -> radials and ulnaris); Axillary vein (deep);
-> Subclavian vein; Superior vena cava
Is the median cubital vein always present? (the vein linking the basilica and cephalic veins in the cubital fossa)
No
Arterial supply of the lower limb
- Aorta
- Common iliac arteries
- Internal iliac artery
- External iliac artery
- External iliac artery
- Femoral artery (pulse)
- Deep femoral artery
- Popliteal artery (pulse)
- Posterior tibial artery (pulse)
- Anterior tibial artery (pulse)
- Peroneal artery
- Dorsalis pedis (pulse)
What is dorsi and plantar flexion of the foot?
plantar flexion = pointed toes like a ballerina
dorsiflexion -> do mnie -> towards face
What is flexion and extension at the knee?
Flexion: moving the foot up and behind (like you are preparing to kick)
Extension: straightening the leg, i.e. kicking forwards and down.
When does the femoral artery become the popliteal A?
When it passes posteriorly through the adductor hiatus
Venous drainage of the lower limb
-> mirrors the arterial supply
Deep System
- Ant & Post Tibial Venae Comitantes
- Popliteal Vein
- Femoral Vein
- External iliac vein
Superficial system
- Venous arches
- Long saphenous vein
- Short saphenous vein
What are the branches of the popliteal A?
- anterior tibial A
- posterior tibial A -> continues as PTA and also gives off the fibular/peroneal A
- dorsalis pedis comes from the anterior tibial A
Which pulses do you check in the lower limb?
- femoral
- popliteal
- posterior tibial
- anterior tibial
- dorsalis pedis
Where is the posterior tibial artery in when it comes to the foot?
runs by the medial malleolus between the tendon of flexor hallucis longus and tendon flexor digitorum longus
next to tibial nerve and its venae comitantes.
What runs by the medial malleoulus?
- tibial N
- posterior tibial A
- its venae comitantes
- tendon of flexor hallucis longus
- tendon of flexor digitorum longus
- tendon of tibialis posterior
Summarise the superficial veins of the lower limb?
- Both the great and small saphenous veins arise from the venous network of the dorsum of the foot.
- 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
- Saphenous veins are consistent; other superficial veins are more variable
- there are numerous perforating veins linking the superficial and deep vessles
Why is the femoral triangle clinically important?
- 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.
What causes varicose veins?
- 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.
Why do patients wear compression socks?
- Valves in the veins allow flow only up towards the heart. - In the leg, 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.
- Immobility (e.g. a long plane journey) 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.
MORE VIGOROUS VENOUS RETURN
How many spinal nerves are there in each region?
8 cervical 12 thoracic 5 lumbar 5 sacral 1(or 2) coccygeal
Which spinal nerves innervate what?
C1-4 : neck C5-T1 : upper limb T2-L1 : trunk L2-S3 : lower limb S2-C2 : perineum
Summarise the main nerves of the lower limb and what they supply
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)
Summarise the principles of segmental motor supplies
- Muscles supplied by two adjacent segments
- Same action on joint = same nerve supply
- Opposing muscles 1-2 segments above or below
- More distal in limb = more caudal in spine
Segmental Motor Supplyto the Upper Limb - which roots innervate which movement?
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
Segmental motor supply to the lower limb
HIP Flex L2L3
Extend L4L5
KNEE Extend L3L4
Flex L5S1
ANKLE Dorsiflex L4L5
Plantarflex S1S2
Summarise the C and T dermatomes
C4 infraclavicular region
C5 lateral arm C6 lateral forearm and thumb C7 middle finger C8 little finger and medial forearm T1 medial arm
T2 axilla and trunk
T4 nipple
T10 umbilicus
T12 lower abdomen
Lesion of CPN at fibular neck
Motor – foot drop
Sensory – dorsum of foot at least
Reflex – none
Autonomic – minimal
High stepping gait or swinging gait to compensate for not being able to lift toes.
Anterior compartment of the arm
- Brachialis, biceps and coraco-brachialis
- C5,6,7 segmental supply
- Musculocutaneous nerve
- Deep brachial artery
- Flexes the elbow
- Biceps is also a strong supinator of the forearm through its attachment to the radius bone
What is compartment syndrome and why does it occur?
- 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)
How do you treat acute compartment syndrome?
Emergency fasciotomy required to prevent the death of muscles, and other tissues, in the affected compartment.
Emergency surgery is necessary, if you don’t do it you can lose the muscles.
