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Class notes

  • Today we're covering blood supply/drainage from the head/neck/upper/lower limbs

Lecture contents

  • Blood supply to the head
  • Venous drainage of the head
  • Blood supply to the upper limb
  • Venous drainage of the upper limb
  • Blood supply to the lower limb
  • Venous drainage of the lower limb

Branches of the arch of aorta

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  • Note the branches of the arch of aorta: brachiocephalic trunk and Lt common carotid and Lt subclavian
  • Brachiocephalic trunk branches behind the sternoclavicular jt to form the internal jugular vein and the subclavian vein on each side. The subclavian vein receives the external jugular vein (laterally) and the vertebral vein (medially)

Head and neck blood supply

Arterial supply

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  • Most supply to the head comes from the common carotid, which sits lateral to the viscera of the neck (thyroid, trachea and etc)
  • Common carotid branches at the upper border of the thyroid cartilage (C4), into the external carotid (anteriorly) and the internal carotid (posteriorly)
    • Swelling: the carotid sinus, is just around this bifurcation, and has baroreceptors
  • Internal carotid artery just supplies the brain (no branches in the neck); passes through the carotid canal (see AEB)
  • External carotid artery runs further forward, and gives branches to the thyroid gland, larynx
    • Lingual artery (goes into the mouth to supply the tongue and inside the mouth)
    • Facial artery (goes up, across the surface of the mandible and heads diagonally across the cheek)
    • Other branches go to the scalp etc
  • External carotid divides into the maxillary artery (to supply nose, pharynx - deep structures) and superficial temporal artery, that supplies surface structures
  • From the subclavian, the first branch is the vertebral artery, which goes backwards, and into foramina transversaria (holes at base of TPs of cervical vertebrae), until it gets to C1 vertebra, where it enters the cranial cavity to supply the hindbrain (brainstem and cerebellum) (see AEB)

Venous drainage of the head

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  • Largest vein draining the head is the internal jugular vein, which runs along with the common carotid and internal carotid. It also drains deep structures within the neck
    • Undercover of sternomastoid muscle
  • External jugular vein is smaller, which drains superficial structures like the scalp
    • Sits on top of the sternomastoid muscle
  • Internal jugular vein and the common carotid artery/internal carotid artery and the vagus nerve are held together inside the carotid sheath
  • The internal jugular vein and subclavian vein on each side joins to form the brachiocephalic vein, which joins with its peer on the other side to form the SVC

Upper limb

Axilla

The axilla

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  • Is the pyramidal space at the beginning of the upper limb (armpit). All the major blood vessels and nerves of the upper limb pass through that space. These run together forming a 'neurovascular bundle'
  • Neurovascular bundle (V,A,N together) runs into the upper limb. Axillary vein and artery, surrounded by the brachial plexus

Arterial supply

Blood vessels in the cubital fossa
Deep and superficial palmar arches; digital aa.
Deep and superficial palmar arches; digital aa.
  • Upper limb blood supply is derived from the subclavian artery. Once the subclavian crosses the lateral border of the first rib, its name changes to be the axillary artery (3 parts of the axillary artery, based on relations to pectoralis major and minor).
    • Anterior and posterior circumflex humeral aa. branch off of axillary artery, to wrap around the surgical neck of the humerus, and anastamose anteriorly. This sets up a collateral circulation, providing a constant blood supply whether we're fully flexing or extending the arm
    • Such collateral supply is present around all joints
    • Around about this part of the humerus, there is the teres major
    • When the axillary artery passes by the lateral border of teres major, its name becomes the brachial artery
  • Branch of the brachial artery: profunda brachii a. (deep brachial artery), which winds around posteriorly (deep to the triceps muscle) and is the main blood supply to the back of the arm. It crosses over down the distal end of the forearm
  • Brachial artery divides at the neck of the ulna into the radial artery (laterally) and the ulnar artery (medially)
  • There are lots of communications between arteries, because we have collateral supply around the elbow
  • Space in the front of the elbow is the cubital fossa, bounded by the brachioradialis muscle and the pronator teres muscle
  • Within the cubital fossa: tendon of biceps, brachial artery and median nerve
  • Ulnar artery is covered by flexor carpi ulnaris
  • Ulnar artery passes superficially in the hand, over (?) the pisiform bone and the radial artery passes deeply
  • Radial artery forms a deep palmar arch. Ulnar artery forms a superficial palmar arch.
    • These two arches anastamose, to give collateral supply when fist is clenched
  • The superficial palmar arch divides into digital aa.
    • These all run on the lateral/medial sides of the fingers, and on the palmar surface of the thumb. Hence the thumb's palmar surface has a
    • Palpate radial artery: feel most lateral tendon, then push down on the bone lateral to that to feel the radial pulse.

Arterial pulses in the upper limb

  • Axillary pulse, brachial pulse in mid arm or cubital fossa, radial pulse in distal forearm, ulnar pulse in distal forearm, and radial pulse in the anatomical snuffbox

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Venous drainage

Deep veins of the upper limb
Venous drainage of hand - dorsal venous network
Superficial veins carry most of the venous blood from the upper limb
  • There are two sets of veins in the upper and lower limbs. Deep veins run with the arteries and are usually paired.
  • Deep veins in the upper limb are relatively small and accompany arteries of the same name. They are usually paired (known as venae comitantes)
  • Radial artery is surrounded by two small radial veins (surrounding the artery and joining with each other). These drain into brachial veins (usually two, but occasionally only one)
  • The two brachial veins drain into a single axillary vein
  • Usually, veins lie superficially to the skin.
  • Axillary vein lies anteriorly to the axillary artery, and joins with the subclavian vein.
  • Venae comitantes is the name of the deep veins, which accompany their arteries
  • Most of the blood in the upper limb drains through superficial veins, which run in the subcutaneous tissue.
  • On the back of the hand, these veins are called the dorsal venous network. These are highly variable.
  • There is a lot of variation in superficial veins
  • Posteriorly, the lateral side of the forearm is the cephalic vein. The medial side of the forearm has the basilic vein
  • Cephalic vein runs up the arm to go into a groove in the deltoid (between deltoid and pectoralis major), along lateral side of limb and drain into the axillary vein
  • Basilic vein runs up medial side of forearm, medial side of elbow, to drain into the brachial vein
  • Basilic and cephalic vein have a vein joining them in the cubital fossa, which is called the median cubital vein. Blood samples are typically taken from the median cubital vein.
  • Note also the median vein of the forearm, which runs between the cephalic and basilic vv.

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Lower limb

Arterial supply

Blood supply to the lower limb
Arteries of the thigh
Femoral triangle
Pulses of the lower limb


  • Descending aorta branches at L4 to divide into two common iliac arteries. At SI joint, the common iliac divides into the internal iliac a (pelvic organs) and an external iliac a (towards the front of the upper limb). Artery crosses under the inguinal ligament from "external iliac artery" to "femoral artery" - the landmark for this is the midpoint between the ASIS and the pubic tubercle). This is the wikipedia:Femoral triangle.
    • Femoral triangle is bounded by adductor longus and sartorius, and by inguinal ligament. Remember Dick VAN Dyke - the vein is medial and the nerve is lateral. Can take the femoral pulse here
  • About 4-5cm after the inguinal ligament, the femoral artery divides into 1. the deep artery of the thigh (profunda femoris a.) 2. Main trunk of the femoral artery
    • Profunda goes deep into the thigh muscles, and sends perforating arteries through, to supply the muscles of the posterior thigh (hamstrings). It has a large branch (transverse branch) that supplies the lateral thigh. This artery fades out down near the knee
    • Main trunk passes medially (between vastus medialis and adductor magnus; following sartorius) in the adductor canal and through the adductor hiatus (in adductor magnus) to enter the posterior compartment. Supplies muscles in anterior thigh muscle. The femoral artery then passes into the popliteal fossa (behind the knee) and becomes called the popliteal artery.
  • The popliteal fossa lies between the hamstring tendons (semimembranosus and biceps femoris). The popliteal artery is the deepest structure in this fossa, above it is the popliteal vein, and above that is the tibial nerve and the common fibular nerve. You can find a popliteal pulse here (sometimes)
  • On the posterior surface of the tibia, the popliteal artery divides into an anterior tibial and posterior tibial artery
    • Posterior tibial: runs straight down in posterior of the leg (appearing to pass between the two heads of gastrocnemius, but passing deep to gastrocnemius and deep to soleus) and has a little branch called the fibular artery. Posterior tibial wraps around the medial side of the ankle and onto the anterior of the foot.
      • Tibial pulse can be taken from the posterior tibial artery, behind and below the medial malleolus beneath the flexor retinaculum. It enters the sole of the foot, and becomes medial and lateral plantar arteries, and forms an arch (similar to hand)
    • Anterior tibial passes through a hole in the interosseous membrane and into the anterior of the limb, passes down the anterior of the leg, between the two malleoli and onto the dorsum of the foot, where it becomes called the dorsalis pedis artery. It is between the tendon for the big toe and the digital tendons

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Venous drainage

  • Both deep and superficial veins
  • In upper limb, most blood goes through superficial veins. In lower limb, most blood goes in deep veins. There are communicating veins connecting deep and superficial systems
  • Note venae commitantes
  • Dorsal venous arch on dorsum of foot, draining into one vein on medial side and one on lateral side
  • Two superficial veins:
    • Passes in front of distal part of tibia, runs up MEDIAL side of the leg and drains into the femoral vein at the femoral triangle -- this is the great saphenous vein
    • Small saphenous vein -- receives LATERAL part of the dorsal venous arch, and up the back of the leg to drain into the popliteal vein. Prone to varicosities
  • Blood mainly drains away in the deep veins because they are in between the muscles, which pump the blood back up against gravity. This is called the calf pump.
    • Valves of veins prevents blood being pushed out into the superficial veins, so they stay in the calf pump. Some people have faulty valves (genetic), so that calf pump is inefficient, pushing blood out into superficial veins, and these veins become dilated, painful. These are varicose veins.

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Official notes

Blood supply to the head

  • The blood supply to the head is derived from the common carotid and vertebral arteries.
  • Common carotid a. - ascends in the neck deep to the sternomastoid m. At the level of the upper border of the thyroid cartilage (C4) it divides into the internal and external carotid arteries.
  • Internal carotid a. - has no branches in the neck and enters the skull to supply the brain (covered in AEB).
  • External Carotid a. - supplies muscles and viscera of the anterior neck, scalp, face (facial a), oral cavity (lingual a), pharynx and nasal cavity. It ends by dividing into the superficial temporal a. and maxillary a.
  • Vertebral a. - 1st branch of the subclavian - supplies brain and will be covered in A&E

Venous drainage of the Head

  • Internal jugular vein - drains blood from the cranial cavity (brain) and deep structures of the neck. Passes through the neck in the carotid sheath (with internal carotid a. and vagus n.). Unites with subclavian vein to form brachiocephalic vein. The R and L brachiocephalic veins unite to form the superior vena cava.
  • External jugular vein - drains blood from face and scalp

Blood Supply to Upper Limb

  • The upper limb receives its blood supply from the subclavian a. The subclavian passes over the first rib then changes its name to the axillary a. which then enters the axilla (armpit).
  • The axilla (armpit) is a pyramidal region bounded by the chest wall medially, and the anterior and posterior axillary folds. It contains the major veins, arteries and nerves passing to and from the upper limb, and the axillary lymph nodes..
  • Axillary a. - enclosed within the axillary sheath (with the axillary vein and cords of the brachial plexus of nerves). Branches:
    • several branches to the breast and chest wall and scapula region (you do need to name these).
    • circumflex humeral aa., which encircle the anatomical neck of the humerus
  • The two circumflex humeral aa. anastomose (unite) with each other to provide what is known as a collateral circulation. If one artery is compressed blood can still reach the tissues it normally supplies via its anastomosis with the other artery, ie. it allows for a continuous blood supply to the tissues regardless of the position of the joint. Such anastomoses occur around all major joints in the limbs.
  • Brachial a. – continuation of the axillary a. - begins at lower border of teres major m., passes along the medial border of the biceps muscle (where its pulse can be felt). It gives off a branch known as the profunda brachii a., which passes deep to the triceps m. (which it supplies), and spirals around the shaft of humerus accompanied by the radial n.
  • The brachial a. then enters the cubital fossa on the front of the elbow, where it divides (at the level of the neck of the radius) into radial and ulnar aa.
  • Ulnar a. – gives off common interosseous a. in the cubital fossa, which gives branches to the deep structures of the forearm. It then passes down medial (ulna) side of the forearm beneath the flexor carpi ulnaris m. It crosses the wrist superficial to the flexor retinaculum on the lateral side of the pisiform bone and then forms the superficial palmar arch.
  • Radial a. - passes down the lateral side of the anterior (flexor) compartment of the arm deep to the brachioradialis m. At the wrist it becomes superficial and lies on the anterior surface of the radius where it can be easily palpated (radial pulse). It then passes dorsally around the wrist before passing between the first and second metacarpals (piercing the first dorsal interosseous m) to enter the palm. It gives off a single branch to the thumb before forming the deep palmar arch. The deep & superficial palmar arches anastomose with each other at their radial and ulnar ends forming a collateral circulation for the hand.

Both palmar arches give off common digital aa. that anastomose with each other before dividing at the webs of the fingers into (proper) digital aa., which run along each side of digits 2-5. 

Venous drainage of Upper Limb

The upper and lower limbs are drained by two sets of veins, which are joined to each other by communicating branches. Because the pressure in veins is low, they contain valves that prevent backflow of blood.

  • (i) Deep veins – accompany each of the major aa. – usually paired – known as venae comitantes. They drain into the brachial vv, which then drains into a single the axillary v. As a rule, when veins accompany large arteries they are usually located more superficially.
  • (ii) Superficial veins – important because they are common sites of venipuncture – highly variable but some branches relatively constant:
  • Dorsal venous arch - on dorsum of hand - drains into basilic and cephalic vv.
  • Basilic v. – arises from ulnar side of dorsal venous arch and winds around onto medial side of forearm. Joins with brachial v to form the axillary v.
  • Cephalic v. – arises from radial side of dorsal venous arch, passes along lateral side of upper limb.

Usually passes over the surface of the deltoid m. to enter axillary v. just below the clavicle (in the delto-pectoral groove).

  • Median cubital v. – crosses cubital fossa and joins to both cephalic and basilic vv.

Axillary v. – within axillary sheath, medial to the axillary a. After crossing rib 1 becomes subclavian v. which unites with internal jugular to form brachiocephalic v (on both sides). The R & L brachiocephalic veins then unite to form the superior vena cava.

Blood Supply to the Lower Limb

Derived from the common iliac arteries. Descending aorta divides into the two common iliac aa. at the level of L4 vertebra. At the sacroiliac joint, each common iliac divides into internal and external iliac aa.

Internal iliac a. - passes down into pelvic cavity and gives branches to the pelvic viscera. Two of its branches, superior and inferior gluteal aa. pass posteriorly to emerge in the gluteal region above and below the piriformis m. (respectively) to supply muscles of the gluteal region and the hip joint.

External Iliac a. – passes forward along pelvic brim to pass beneath the inguinal ligament, and enter the femoral triangle, where it changes its name to the femoral a.

Femoral triangle – region on anterior thigh bounded superiorly by inguinal ligament, laterally by the sartorius m. and medially by medial border of adductor longus m.

Femoral a. – pulse felt just below the midpoint of the inguinal ligament (pulse can be felt here) – in femoral triangle femoral v. is on its medial side and femoral n. laterally. Femoral a. & v. surrounded by femoral sheath (loose CT). On medial side of thigh it passes through the ‘adductor hiatus’ to enter the popliteal fossa (behind the knee), where it changes its name to the popliteal a.

Branches of femoral a.:

  • Branches to the genital area and muscles of the anterior thigh (you do not need to name them)
  • Medial and lateral circumflex aa - supply hip joint (anastomose around neck of femur) & lateral thigh mm.
  • Profunda femoris a – very large – arises about 5 cm below inguinal ligament. Passes in a deeper

plane to the femoral and gives 3-4 perforating branches which supply muscles of posterior thigh. Popliteal a. – located in popliteal fossa, deep to popliteal v. and tibial n. Gives off several (genicular) branches which provide collateral circulation to knee, before dividing into anterior and posterior tibial aa. The posterior tibial a. is larger.

  • Posterior tibial a. – passes down middle of posterior leg between superficial and deep muscles. Gives branches to the muscles and bones of the posterior and lateral compartments of the leg. It then winds around medial malleolus to enter medial side of sole of the foot, where it divides into medial and lateral plantar aa, which eventually anastomose to form the plantar arch. The posterior tibial pulse can be felt on the medial side of the foot just below the medial malleolus.
  • Anterior tibial a. – passes between tibia and fibula (superior to interosseous membrane) to reach anterior compartment of the leg, which it supplies. Emerges at the front of the ankle midway between the medial and lateral malleoli (pulse can be felt here), where it changes its name to the dorsalis pedis a.

Venous drainage of the lower limb

As for the upper limb there are both deep veins (accompanying arteries) and superficial veins. The popliteal v is superficial to the popliteal a. and, in the femoral triangle, the femoral v. lies medial to the femoral a. Superficial veins

  • Small Saphenous v. - arises from lateral side of the dorsal venous arch of the foot, passes below the lateral the lateral malleolus and up the back of the leg to the popliteal fossa, where it empties into the popliteal v. it si a common site of varicosities.
  • Great Saphenous v. – arises from the medial side of the dorsal venous arch. Passes up in front of the medial malleolus to ascend along the medial side of the leg and thigh. It eventually reaches the femoral triangle where it empties into the femoral v.
  • Varicose veins

As in the upper limb, the deep and superficial veins are connected by communicating veins, but, unlike the upper limbs, most of the blood from the lower limb drains via the deep veins. This is because blood flow in the deep veins can be assisted greatly (against gravity) by the contractions of surrounding muscles during standing and physical activity. This is particularly effective in the veins of the leg and is sometimes referred to as the ‘calf pump’. The deep veins connect via communicating veins to the superficial vv. These communicating veins contain valves that are designed to prevent blood from flowing out into the superficial vv. However, these valves may become faulty (due to genetic factors, prolonged standing, pregnancy) causing a build up of blood in the superficial veins (which are not assisted by gravity). This leads them to become distended, twisted and painful – known clinically as varicose veins.