Download The superficial veins of the lower limb begin as the dorsal venous

Dissector Answers - Superficial Limbs
Learning Objectives:
Upon completion of this session, the student will be able to:
1. Identify and demonstrate the areas of distribution of the major cutaneous nerves
of the upper limb.
2. Identify and demonstrate the major superficial veins of the upper limb.
3. Describe the subcutaneous venous drainage of the lower limb, its relation to the
deep veins and the significance of perforating veins.
4. Describe the lymphatic drainage of the lower limb and areas draining into the
superficial and deep inguinal lymph nodes.
5. Identify the major cutaneous nerves of the lower limb, their source and the areas
they innervate.
6. Define the regional deep fascias of the lower limb and their regional
specialization such as iliotibial tract, etc.
Learning Objectives and Explanations:
1. Identify and demonstrate the areas of distribution of the major cutaneous nerves of the upper
limb. (W&B 102-106, N 429,430,431, 432,474,477, 478, 479, 480, 481, 482, TG 2-02,2-14,251A,2-51B,2-52A,2-52B,2-33)
Images from "Anatomy of the Human Body" by Henry Gray are provided by:
The major cutaneous nerves of the upper limb:
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radial nerve:
o posterior brachial cutaneous nerve
o posterior antebrachial cutaneous nerve
o inferior lateral brachial cutaneous nerve
musculocutaneous nerve (continues below the elbow as the lateral antebrachial
cutaneous nerve)
medial cord of the brachial plexus:
o medial brachial cutaneous nerve
o
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medial antebrachial cutaneous nerve
Also remember that the ulnar and radial nerves both have superficial extensions
which cover the dorsum of the hand, namely the dorsal cutaneous branch of the
ulnar nerve and the superficial branch of radial nerve.
2. Identify and demonstrate the major superficial veins of the upper limb. (W&B 101-103, N
189,479, 480,483, TG 2-02,2-53)
Arising from the dorsal venous network (arch) on the dorsum of the hand are the two most
important superficial veins: the cephalic and basilic veins. The cephalic vein ascends along the
lateral aspect of the forearm. (This side of your arm is considered "cephalic" because the limbs
develop projecting laterally from the body, with the lateral side closest to the head. Or, you can
remember that the cephalic side is on the side of your thumb, the digit you stick in your cephalic
orifice (mouth) when you are a baby.) Upon completing its ascent, the cephalic vein crosses
through the deltopectoral groove before diving deep through the fascia and joining the axillary
vein. The basilic vein ascends on the medial aspect of forearm and pierces the deep fascia of the
inferior arm. It ascends to unite with the paired brachial veins, forming the axillary vein. The
cephalic and basilic veins are connected by the median cubital vein in the cubital fossa.
3. Describe the subcutaneous venous drainage of the lower limb, its relation to the deep veins,
and the significance of perforating veins. (W&B 577-579, N 544,545, TG 3-02,3-03)
The superficial veins of the lower limb begin as the dorsal venous arch of the foot. This dumps
into two primary veins:
greater saphenous vein: on the medial side. It receives blood from the dorsal venous arch. The
greater saphenous vein then heads north, traveling anterior to the medial malleolus, up the leg,
through the knee region on the posterior aspect of the medial condyle of the femur, then turns
anteriorly and laterally as it travels up the thigh. The greater saphenous vein travels through the
saphenous opening, a passageway in the fascia of the femoral triangle, to drain into the femoral
vein. Along its course the greater saphenous vein receives tributaries from the dorsum of the
foot, the heel, the front of the leg, and anterior, medial, and lateral portions of the thigh. Also
important, right before emptying into the femoral vein, the greater saphenous vein receives the
superficial epigastric, superficial circumflex iliac, and superficial external pudendal veins.
lesser saphenous vein: on the lateral side. It runs posterior to the lateral malleolus and up the
middle of the back of the leg. It usually pierces the crural fascia about halfway up the leg,
running the rest of the way deep to the fascia. In most cases, the lesser saphenous vein terminates
in the popliteal vein.
Images from "Anatomy of the Human Body" by Henry Gray are provided by:
4. Describe the lymphatic drainage of the lower limb and areas draining into the superficial and
deep inguinal lymph nodes. (W&B 578-580, N 546, TG 3-70)
The superficial lymph vessels of the lower limb accompany the superficial veins. They end in
the superficial inguinal lymph nodes. From there, most lymph passes directly to the external
iliac lymph nodes, but some flows to the deep inguinal lymph nodes. The deep lymphatic
vessels accompany the deep veins, and drain directly into the deep inguinal lymph nodes.
5. Identify the major cutaneous nerves of the lower limb, their source, and the areas they
innervate. (W&B 580-583, N 540, 541, 542, 544, TG 3-68,3-44,3-48,3-69A,3-69B)
The figures on W&B 581 and N543 or TG3-69A and TG3-69B are handy views of dermatomes
of the lower limb, though they don't technically show how the fibers get there, i.e., via which
nerve. But, if you check out W&B 582, and N540, N542, N544, TG3-63, N542, TG3-64, TG365A,TG3-65B,TG3-66,TG3-67, or check out the images below, you'll get the idea.
Images from "Anatomy of the Human Body" by Henry Gray are provided by:
Images from "Anatomy of the Human Body" by Henry Gray are provided by:
knee and above:
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subcostal nerve: from T12. Supplies the skin of the thigh over greater trochanter
of femur.
iliohypogastric nerve: from L1 (lumbar plexus). The lateral cutaneous branch
supplies the skin of the superolateral buttock, while the anterior cutaneous
branch supplies the skin superior to pubis.
ilioinguinal nerve: from L1 (lumbar plexus). Branches supply the skin of the
proximal, medial thigh, near the external genitalia.
genitofemoral nerve: from L1 and L2 (lumbar plexus). Femoral branches
supply the skin of the proximal, anterior thigh, just inferior to inguinal ligament.
lateral femoral cutaneous nerve: from L2 and L3 (direct branch of the lumbar
plexus). Anterior branches supply the skin of the lateral and anterior thigh. The
posterior branch supplies the skin of the thigh from the greater trochanter to just
proximal to the knee.
anterior femoral cutaneous nerves: from the femoral nerve (L2 through L4,
lumbar plexus). Supply to the skin of the medial and anterior thigh.
obturator nerve: (L2 through L4, lumbar plexus). A branch (variable)
sometimes supplies the skin of the medial aspect of the proximal thigh.
posterior femoral cutaneous nerve: from S1 through S3 (sacral plexus).
Supplies the skin of the lower buttock, posterior thigh, and the skin of the
posterior knee.
below the knee:
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saphenous nerve: from the femoral nerve (L2 through L4, lumbar plexus).
Supply to the skin of the anterior and medial side of the leg and the medial side of
the foot.
sural nerve: from both tibial and common fibular nerves (which come from the
sciatic nerve, L4 through S3): Supplies the skin on the posterior and lateral
aspects of the leg and lateral side of the foot.
lateral sural cutaneous nerve: from the common fibular nerve (which comes
from the sciatic nerve, L4 through S3): Supplies the skin of the posterolateral leg.
superficial fibular nerve: from the common fibular nerve (which comes from
the sciatic nerve, L4 through S3): Supplies the skin of the inferior third of the
anterior leg and the dorsal part of the foot.
6. Define the regional deep fascias of the lower limb and their regional specializations. (W&B
584-588, 608-610, N 509,522,530, TG 3-02,3-03,3-45)
The deep fascia of the lower limb is called the fascia lata in the thigh and the crural fascia in the
leg. These have the following specializations:
fascia lata:
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iliotibial tract: a thickening of the fascia lata that stretches from the tubercle of
the crest of the ilium to attach to the lateral condyle of the tibia. Serves as
insertion point for the tensor fascia lata and part of the insertion for the gluteus
maximus.
lateral intermuscular septum: from the iliotibial tract to the lateral epicondylar
line and the lateral lip of the linea aspera, both on the femur. It separates the
vastus lateralis muscle from the biceps femoris muscles, therefore separating the
quadriceps group from the hamstrings.
medial intermuscular septum: attaches to the medial lip of the linea aspera of
the femur. It separates the vastus medialis muscle (quadriceps) from the adductor
group (medial) of muscles.
saphenous opening (hiatus): a passageway through the fascia lata for the great
saphenous vein.
crural fascia:
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retinacula of the patella: formed by the attachments of the crural fascia to the
medial and lateral condyles of the tibia and the head of the fibula. This also
includes tendinous fibers from the vastus muscles. (Latin, retinacula = halter,
cable)
anterior intermuscular septum: from the crural fascia to the anterior aspect of
the fibula. It separates the anterior (extensor) muscles from the lateral (fibular)
muscles. Also, one could say that it is the boundary between the anterior and
lateral compartments.
posterior intermuscular septum: from the crural fascia to the posterior aspect of
the fibula. It separates the posterior (flexor) muscles from the lateral (fibular)
muscles. Also, one could say that it is the boundary between the posterior and
lateral compartments.
transverse intermuscular septum: from the posterior intermuscular septum,
around to the anteromedial aspect of the tibia. It separates the deep posterior
muscles from the superficial posterior muscles.
popliteal fascia: two layers, superficial and deep, that cover the popliteal fossa.
This fascia stretches with the movement of the knee joint, providing protection for
the neurovascular structures traveling through the area.
In the ankle region, the crural fascia thickens to form retinacula that hold tendons close to the
bone, creating a sort of pulley sytem. They are listed here:
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superior extensor retinaculum: superior to the ankle, on the anterior aspect of
the leg
inferior extensor retinaculum: on the anterior aspect of the ankle. It is Yshaped, extending onto the dorsum of the foot.
flexor retinaculum: on the posteromedial aspect of the ankle
superior and inferior fibular retinacula: on the posterolateral aspect of the
ankle
Cultural enrichment: Check out these sections from the 1918 version of Gray's Anatomy of the
Human Body! Some of the terms are (of course) out-of-date, but the illustrations are timeless.
The Femur - The Muscles and Fascia of the Thigh - The Veins of the Lower Extremity,
Abdomen, and Pelvis - The Arteries of the Lower Extremity - Surface Anatomy of the Lower
Extremity - Surface Markings of the Lower Extremity
Questions and Answers:
7. Identify the dorsal digital veins and intercapitular veins. What do these do?
Dorsal digital veins drain the dorsal cutaneous aspect of the fingers. There are two per finger.
Intercapitular veins are found between the knuckles (heads of the metacarpals). They drain the
fingers and palm to the dorsal side of the hand. N480,TG2-02
8. Does the basilic vein perforate the brachial fascia in your cadaver? As you traced the basilic
vein did you find accompanying nerves? What are these?
The basilic vein normally perforates the brachial fascia above the medial epicondyle, or even as
high as mid-arm. Distally near the hand, the vein is accompanied by the dorsal branch of the
ulnar nerve. As the vein ascends it is accompanied by the anterior and posterior branches of the
medial antebrachial cutaneous nerve. N479,TG2-02
9. Where does the cephalic vein penetrate the deep fascia?
As mentioned above, the cephalic vein penetrates the deep fascia after it has traversed the
deltopectoral groove at the clavicle. N424,TG2-07
10. Does the cephalic vein extend into the arm?
Of course, though in some arms it may be very small. N479,N480,TG2-02
11. What is the course and direction of the median cubital vein? Look at other arms to determine
pattern. What are other variations?
Median cubital vein shunts blood from cephalic vein obliquely across the cubital fossa to reach
the basilic vein. There is often a median antebrachial vein lying on the anterior forearm that
splits to drain to both cephalic and basilic veins at the cubital fossa.
12. Trace the superficial branch of the radial nerve into the hand and identify its dorsal digital
branches and their areas of distributions. Do any branches communicate with branches of the
ulnar nerve?
The two nerves usually communicate on the dorsum of the hand. N480,N481,TG2-02,TG2-51
13. Do you see accessory tributaries or varicosities of the superficial veins?
There is usually a fairly large accessory saphenous vein draining the medial thigh, in addition to
numerous smaller accessory tributaries. The superficial veins communicate with the deep veins
of the lower limb via perforating veins through the deep fascia of the lower limb. These
perforating veins have valves that direct the blood superficial to deep as the result of limb
motions and muscle contractions. However, the valves may become incompetent, resulting in
retrograde blood flow from deep to superficial. The superficial veins may become dilated and
torturous, especially in the leg.
14. To what vein does the greater saphenous vein drain?
The greater saphenous vein drains to the femoral vein, through the saphenous hiatus. N544,TG302
15. From what regions do the superficial inguinal lymph nodes receive lymph?
The superficial inguinal lymph nodes receive lymph from the superficial tissues of lower
abdominal wall, the external genitalia, the perineum, the buttocks, and the lower limb.
N546,TG3-70
16. Where do the superficial inguinal lymph nodes drain?
They drain primarily to external iliac lymph nodes, but some drain to the deep inguinal lymph
nodes.
17. Where would you find the deep inguinal lymph nodes?
The deep inguinal lymph nodes, approximately three in number, lie within the femoral canal,
within the femoral sheath, medial to the femoral vein. N546,TG3-70
18. What is the distribution of the femoral branch of genitofemoral nerve?
This small branch of the genitofemoral nerve within the abdomen passes beneath the inguinal
ligament on the external iliac artery. It innervates a small area of skin on the upper medial thigh.
N544,TG3-02
19. From what are the cutaneous nerves of the anterior thigh derived?
The lateral femoral cutaneous nerve is from the lumbar plexus, specifically L2 and L3. The
anterior femoral cutaneous nerves are branches of femoral nerve. The femoral branch of
genitofemoral nerve is from the lumbar plexus, specifically L1 & L2. N544TG3-14
20. What is the source of the saphenous nerve?
The femoral nerve is the source of the saphenous nerve. N545,TG3-24
21. What nerves accompany the lesser saphenous vein?
The medial sural cutaneous nerve and sural nerve accompany the lesser saphenous vein.
N538,TG3-03
22. Where does the lesser saphenous vein disappear? Where does it terminate?
The lesser saphenous vein pierces the popliteal fascia covering the popliteal fossa at the back of
the knee. In that area it drains into the popliteal vein. N545,TG3-03,TG3-33
23. How is the sural nerve formed?
The sural nerve is formed from fibers contributed by both the tibial and common fibular nerves.
N545,TG3-03
24. Where does the sural nerve distribute and by what name?
It distributes to the posterolateral aspect of the lower leg, the ankle, and the heel. Its continuation
on the lateral side of the foot, all the way down to the little toe, is called the lateral dorsal
cutaneous nerve. N545,TG3-03,TG3-44
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Unauthorized use prohibited.