Overview of Anatomy of the Upper and Lower Limbs Flashcards
What spinal nerves are the upper and lower limbs assciaited with?
Upper limbs are associated with spinal segments C5-T1
Lower limbs are associated with spinal segments L1/2-S3
What happens to lower limb rotation during development?
During development, as the limb buds grow out, they maintain the general arrangement of the segments
BUT, there is internal rotation below the hip region (in the upper to mid thigh) - therefore, everything that should be at the front is at the back, and vice versa
The lower limb internally rotates during its development meaning that, in the thigh and leg, the extensors are anterior and the flexors are posterior. In addition, the dermatomes have twisted, oblique fields, as opposed to the straighter fields in the upper limb
The upper limbs are maintained
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 iliopsoas?
The flexors of the hip joint have attachments up in the abdomen, almost to the thorax
These muscles are the psoas (attaches lateral spines of lumbar) and iliacus (on inner surface of ilium)
Together, they form the iliopsoas, which crosses the hip joint and attaches to the iliac tuberosity
When the muscles contract, they flex the hip
What connects the radius to the ulna and the tibia to the fibula?
interosseous membrane
Describe the arterial supply to and the venous drainage from the upper limbs?
Arteries:
- Aorta
- Subclavian artery (supply to both right and left upper limbs) – pulse
- When the subclavian artery enters the axilla, it becomes the axillary artery – pulse
- Continues as the brachial artery (pulse), and crosses the anterior of the elbow joint - deep brachial artery
- The brachial artery divides to form the ulnar (medial) and radial (lateral) arteries (pulses)
- Radial and ulnar arteries ANASTAMOSE to form the hand arches – superficial and deep arches
- This becomes the metacarpal and digital arteries
Veins:
There are superficial and deep systems for venous drainage:
- The DEEP venous drainage is the same as the arterial supply – the veins run with the arteries
- In the distal parts of the limb, there are not single arteries (usually pairs) – the venae comitantes
- DEEP VENOUS DRAINAGE: venae comitantes, axillary vein, subclavian vein, superior vena cava
- Superficially, there are dorsal venous arches, which give rise to two main superficial veins:
> The cephalic vein (radial side) – drains into the axilla region
> The basilic vein (ulnar side) – merges with venae comitantes to form axillary -> subclavian -> SV
Which veins are sued for phlebotomy or insertion of a venous line?
superficial veins in cubital fossa commonly used
- medial cubital vein not always present - when present, the median cubital vein is the vein of choice for collecting blood
** You MAY use other superficial vein
Describe the atrial supply to and the venous drainage from the lower limbs?
The aorta bifurcates to form the common iliac arteries (right and left) – main supply to the lower limbs
Arteries:
- Common iliac arteries -> Internal and external iliac arteries
- The external iliac artery provides most of the supply for the lower limb - crosses beneath the inguinal ligament to become the femoral artery (pulse) (Deep femoral artery is a branch)
- The femoral artery continues down the thigh, behind the knee to form the popliteal artery (pulse)
- The popliteal artery branches:
> Posterior tibial artery (pulse)
> Anterior tibial artery (pulse)
> Peroneal artery
> The anterior tibial artery rise rise to the dorsalis pedis (pulse)
- PULSES IN THE FOOT CAN TELL US ABOUT THE EFFICIENCY OF BLOOD SUPPLY TO THE DISTAL PARTS OF THE LIMB. A CONDITION, IN WHICH THE BLOOD SUPPLY MAY BE COMPROMISED, IS DIABETES
Veins:
- Deep System of Venous Drainage – venous return follows arterial supply
> Anterior & Posterior Tibial Venae Comitantes
> Popliteal Vein -> Femoral Vein -> External iliac vein
- Superficial system of Venous Drainage:
> Venous arches
> The venous arches give rise to the long saphenous vein (blood drains into the femoral vein)
> Short saphenous vein (blood drains into the popliteal vein behind the knee -> femoral vein)
What is the femoral triangle?
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. Catheters can be put into the big vessels of the femoral triangle, to access the heart chambers
What can cause 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. There is backflow of venous blood, causing painful swelling
What can cause deep vein thrombosis?
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
Describe the organisation of the spinal nerves?
C1-4: neck C5-T1: upper limb T2-L1: trunk L2-S3: lower limb S2-C2: perineum
What is the brachial plexus?
A plexus is a region where spinal nerves merge, swap fibres and form new branches. The nerves from different spinal roots merge. You eventually end up with big terminal branches, which end up supplying the limbs
This happens in the neck (roots C5-T1 merge in the lower region in the neck). Nerves enter the axillary region, and the big, terminal nerves come off to enter the arm
Which nerves supply the lower limbs?
The femoral nerve comes off the lumbosacral plexus. It supplies the anterior compartment of thigh (it goes under the inguinal ligament)
The obturator nerve supplies the medial (adductor) compartment of thigh, and enters through the obturator of the pelvis
The sciatic nerve (or its terminal branches Tibial and Common Peroneal nerves) supplies the remaining compartments (i.e. posterior compartment of the thigh, anterior and posterior leg and foot)
THESE NERVES ARE ALL COMING FROM LUMBAR AND SACRAL REGIONS OF THE SPINE
