Surface anatomy lower limb

1. Surface Markings
upper limb, lower limb, thorax
Dr M Idris Siddiqui

2. Axillary Artery
Hold the arm at right angles to the trunk with the palm
directed upwards. The artery is then marked as a straight
line by joining the following two points.
(i) Midpoint of the clavicle.
(ii) The second point at the junction of the anterior 1/3 and
posterior 2/3 of the lateral wall of axilla at its lower limit
where the arterial pulsations can be felt.
• At its termination the axillary artery, along with the
ccompanying nerves, forms a prominence which lies
behind another projection caused by the biceps and
coracobrachialis.

5. Brachial Artery
Brachial artery is marked by joining the following two points.
(i) A point at the junction of the anterior 1/3 and posterior 2/3
of the lateral wall of the axilla at its lower limit.
Here the axillary artery ends and the brachial artery begins.
(ii) The second point, at the level of the neck of the radius
medial to the tendons of the biceps brachii.
Thus the artery begins on the medial side of the upper part of the
arm, and runs downwards and slightly laterally to end
in front of the elbow. At its termination it bifurcates into the
radial and ulnar arteries.

7. Radial Artery
In the Forearm
Radial artery is marked by joining the following points.
(i) A point in front of the elbow at the level of the neck of the radius medial to the
tendons of the biceps brachii.
(ii) The second point at the wrist between the anterior border of the radius laterally
and the tendon of the flexor carpi radialis medially, where the radial pulse is
commonly felt. Its course is curved with a gentle convexity to the lateral side.
In the Hand
Radial artery is marked by joining the following three points.
(i) A point at the wrist between the anterior border of the radius and the tendon of the
flexor carpi radialis.
(ii) A second points just below the tip of the styloid process of the radius.
(iii) The third point at the proximal end of the first intermetacarpal space. In this part of
its course, the artery runs obliquely downwards and backwards deep to the tendons
of the abductor pollicis longus, the extensor pollicis brevis, and superficial to the
lateral ligament of the wrist joint. Thus it passes through the anatomical snuff box
to reach the proximal end of the first intermetacarpal space.

9. Ulnar Artery
Ulnar artery is marked by joining the following three
points.
(i) A point in front of the elbow at the level of the neck of
the radius medial to the tendon of the biceps brachii
(ii) A second point at the junction of the upper 1/3 and
lower 2/3 of the medial border of the forearm (lateral to
the ulnar nerve),
(iii) The third point lateral to the pisiform bone. Thus the
course of the ulnar artery is oblique in its upper 1/3, and
vertical in its lower 2/3.
The ulnar nerve lies just medial to the ulnar artery in the
lower 2/3 of its course. The ulnar artery continues in the
palm as the superficial palmar arch.

11. Superficial Palmar Arch
Superficial palmar arch is formed by the direct
continuation of the ulnar artery, and is marked as a
curved line by joining the following points.
(i) A point just lateral and distal to the pisiform bone.
(ii) The second point on the hook of the hamate bone,
(iii)The third point on the distal border of the thenar
eminence in line with the cleft between the index
and middle fingers.
The convexity of the arch is directed towards the
fingers, and its most distal point is situated at the
level of the distal border of the fully extended
thumb.

13. Deep Palmar Arch
Deep palmar arch is formed as the direct continuation
of the radial artery. It has a slight convexity towards
the fingers. It is marked by a more or less horizontal
line, 4 cm long, just distal to the hook of the
hamate bone.
The deep palmar arch lies 1.2 cm proximal to the
superficial palmar arch across the metacarpals,
immediately distal to their bases.
The deep branch of ulnar nerve lies in its concavity.

15. Axillary Nerve with its Divisions
Axillary nerve with its divisions is marked as a
horizontal line on the deltoid muscle, 2 cm above the
midpoint between the tip of the acromion process and
the insertion of the deltoid.
Intramuscular injections in the deltoid are given in
the lower part of the muscle nearer to its insertion to
avoid injury to the nerve and its accompanying
vessels.

17. Musculocutaneous Nerve
Musculocutaneous nerve is marked by joining the
following two points.
(i) A point lateral to the axillary artery 3 cm above its
termination.
(ii) A point lateral to the tendon of the biceps rachii
muscle 2 cm above the bend of the elbow. (Here it
pierces the deep fascia anc continues as the lateral
cutaneous nerve o the forearm).

18. Median Nerve
In the Arm
Mark the brachial artery. The nerve is then marke lateral to the artery in the upper half,
and medial to the artery in the lower half of the arm. The nerv crosses the artery
anteriorly in the middle of the am.
In the Forearm
Median nerve is marked by joining the following two points,
(i) A point medial to the brachial artery at the bend of the elbow.
(ii) A point in front of the wrist, over the tendon of the palmaris longus or 1 cm medial
to the tendon of the flexor carpi radialis.
In the Hand
Median nerve enters the palm by passing deep to flexor retinaculum, immediately
below which it divides into lateral and medial branches.
– Lateral branch supplies the three muscles of thenar eminence and gives two branches to the thumb,
and one to lateral side of index finger.
– Medial branch gives branches for the adjacent sides of index, middle and I ring fingers. The lateral
three and a half nail beds are also supplied.

21. Radial Nerve
In the Arm
Radial nerve is marked by joining the following points.
(i) The first point is at the junction of the anterior 1 /3 and posterior 2/3 of the lateral wall of the
axilla at its lower limit.
(ii) The second point is at the junction of the upper upper 1/3 and lower 2/3 of a line joining the
lateral epicondyle with the insertion of the Deltoid .
(iii) The third point is on the front of the elbow at the level of the lateral epicondyle 1 cm lateral
to the tendon of the biceps brachii . The first and second points are joined across the back of
the arm to mark the oblique course of the ' radial nerve in the radial (spiral) groove (posterior
compartment). The second and third points are joined on the front of the arm to mark the
vertical course of the nerve in the anterior compartment.
In the Forearm
Superficial branch of radial nerve is marked by joining the following three points.
(i) A point 1 cm lateral to the biceps tendon at the level of the lateral epicondyle .
(ii) The second point at the junction of the upper 2/3 and lower 1/3 of the lateral border of the
forearm just lateral to the radial artery.
(iii) The third point at the anatomical snuff box. The nerve is vertical in its course between points
one and two. At the second point it inclines backwards to reach the snuff box. The nerve is
closely related to the lateral side of the radial artery only in the middle 1/3 of the forearm.

23. Ulnar Nerve
In the Arm
Ulnar nerve is marked by joining the following points.
(i) A point at the j unction of the anterior 1/3 and posterior 2/3 of the lateral wall of the
axilla at its lower limit (lower border of the teres major muscle) .
(ii) The second point at the middle of the medial border of the arm.
(iii) The third point behind the base of the medial epicondyle of the humerus.
In the Forearm
Ulnar nerve is marked by joining the following two points.
(i) A point on the back of the base of the medial epicondyle of the humerus .
(ii) The second point lateral to the pisiform bone. In the lower 2/3 of the forearm, the
ulnar nerve lies medial to the ulnar artery.
In the Hand
Ulnar nerve lies superficial to the medial part of flexor retinaculum and medial to ulnar
vessels where it divides into superficial and deep branches. The superficial branch
supplies medial one and half digits including their nail beds. The deep branch passes
backwards between pisiform and hook of hamate to lie in the concavity of the deep
palmar arch.

25. Posterior Interosseous Nerve or
Deep Branch of Radial Nerve
It is marked by joining the following three points.
(a)A point 1 cm lateral to the biceps tendon at the level of
the lateral epicondyle.
(b)The second point at the junction of the upper 1/3 and
lower 2/3 of a line joining the middle of the posterior
aspect of the head of the radius to the dorsal tubercle at
the lower end of the radius or Lister's tubercle.
(c)The third point on the back of the wrist 1 cm medial to
the dorsal tubercle.

26. Internal Mammary (Thoracic) Artery
• It is marked by joining the following points.
• (i) A point 1 cm above the sternal end of the
clavicle, 3.5 cm from the median plane.
• (ii) Points marked over the upper 6 costal
cartilages at a distance of 1.25 cm from the
lateral sternal border.
• (iii) The last point is marked in the sixth space
1.25 cm from the lateral sternal border.

32. Pulmonary Trunk
• (i) First mark the pulmonary valve by a
horizontal line 2.5 cm long, mainly along the
upper border of the left 3rd costal cartilage and
partly over the adjoining part of the sternum.
• (ii) Then mark the pulmonary trunk by two
parallel lines 2.5 cm apart from the pulmonary
orifice upwards to the left 2nd costal cartilage.

33. Ascending Aorta
• (i) First mark the aortic orifice by a slightly
oblique line 2.5 cm long running downwards
and to the right over the left half of the
sternum beginning at the level of the lower
border of the left 3rd costal cartilage.
• (ii) Then mark the ascending aorta by two
parallel lines 2.5 cm apart from the aortic
orifice upwards to the right half of the sternal
angle.

34. Arch of the Aorta
• Arch of the aorta lies behind the lower half of the
manubrium sterni. Its upper convex border is
marked by a line which begins at the right end of the
sternal angle, arches upwards and to the left through
the centre of the manubrium, and ends at the sternal
end of the left second costal cartilage.
• Note that the beginning and the end of the arch lie
at the same level. When marked on the surface as
described above the arch looks much smaller than it
actually is because of foreshortening.

36. Descending Thoracic Aorta
• Descending thoracic aorta is marked by
two parallel lines 2.5 cm apart, which
begin at the sternal end of the left second
costal cartilage, pass downwards and
medially, and end in the median plane 2.5
cm above the transpyloric plane.

37. Brachiocephalic Artery
•Brachiocephalic artery is
marked by a broad line
extending from the centre of
the manubrium to the right
sternoclavicular joint.

38. Left Common Carotid Artery
•The thoracic part of this artery
is marked by a broad line
extending from a point a little
to the left of the centre of the
manubrium to the left
sternoclavicular joint.

39. Left Subclavian Artery
•The thoracic part of the left
subclavian artery is marked by
a broad vertical line along the
left border of the manubrium a
little to the left of the left
common carotid artery.

40. Superior Vena Cava
• Superior vena cava is marked by two
parallel lines 2 cm apart, drawn from
the lower border of the right first
costal cartilage to the upper border of
the third right costal cartilage,
overlapping the right margin of the
sternum.

41. Right Brachiocephalic Vein
• It is marked by two parallel lines
1.5 cm apart, drawn from the
medial end of the right clavicle to
the lower border of the right first
costal cartilage close to the
sternum.

42. Left Brachiocephalic Vein
• It is marked by two parallel lines
1.5 cm apart, drawn from the
medial end of the left clavicle to
the lower border of the first right
costal cartilage. It crosses the left
sternoclavicular joint and the
upper half of the manubrium.

43. Trachea (Thoracic Part)
•Trachea is marked by two
parallel lines 2 cm apart,
drwan from the lower border
of the cricoid cartilage to the
sternal angle, inclining slightly
to the right.

44. Oesophagus
It is marked by two parallel lines 2.5 cm apart by joining
the following points.
(i) Two points 2.5 cm apart at the lower border of the cricoid
cartilage across the median plane.
(ii) Two points 2.5 cm apart at the root of the neck a little to
the left of the median plane.
(iii) Two points 2.5 cm apart at the sternal angle across the
median plane,
(iv) Two points 2.5 cm apart at the left 7th costal cartilage 2.5
cm from the median plane.

45. Thoracic Duct
It is marked by joining the following points.
(i) A point 2 cm above the transpyloric plane slightly to
the right of the median plane.
(ii) A second point 2 cm to the right of medial plane below
manubriosternal angle.
(iii) A third point across to the left side at same level.
A fourth point 2.5 cm above the left clevicle 2cm from the
median plane.
A fifth point just above the sternal angle 1.3 cm to the left
of median plane.

47. Femoral Artery
• It corresponds to the upper two-thirds of a line joining the
following two points.
• (a) Midinguinal point: A point midway between the anterior
superior iliac spine and the pubic symphysis .
• (b) Adductor tubercle: It lies at the lower end of the cord-like
tendon of the adductor magnus. The tendon can be felt in a
shallow groove just behind the prominence of the vastus
medialis when the thigh is semiflexed, abducted and laterally
rotated.
• The upper one-third of the line represents the upper half of the
artery lying in the femoral triangle. The middle one-third of
the line represents the lower half of the artery lying in the
adductor canal. The lower one-third of the line represents the
descending genicular and saphenous branches of the artery.

49. Profunda Femoris Artery
• First mark the femoral artery. The profunda artery is
then marked by joining the following two points on
the femoral artery.
• (a) First point: .5cm below the midinguinalpoint.
• (b) Second point: 10 cm below the midinguinal
point.
• The artery is slightly convex laterally in its upper
part.

51. Popliteal Artery
• It is marked by joining the following points.
• (a) First point:
– At the junction of the middle and lower thirds of the
thigh, 2.5 cm medial to the midline on the back of the
limb.
• (b) Second point:
– On the midline of the back of the knee.
• (c) Third point:
– On the midline of the back of leg at the level of the tibial
tuberosity.

53. Anterior Tibial Artery
• It is marked by joining the following two
points.
• (a) First point: 2.5 cm below the medial
side of the head of the fibula.
• (b) Second point: Midway between the
two malleoli.
• The artery passes downwards and slightly
medially.

54. Posterior Tibial Artery
• It is marked by joining the following
two points.
• (a) First point: On the midline of the
back of the calf at the level of the
tibial tuberosity.
• (b) Second point: Midway between the
medial malleolus and the
tendocalcaneus.

55. Dorsalis Pedis Artery
• It is marked by joining the following
two points.
• (a) First point: Midway between the two
malleoli.
• (b) Second point: At the proximal end of
the first intermetatarsal spacea.

57. Femoral Vein
• Its marking is same as that of the femoral
artery, except that the upper point is taken
1 cm medial to the midinguinal point, and
the lower point 1 cm lateral to the
adductor tubercle.
• The vein is medial to the artery at the
upper end, posterior to it in the middle,
and lateral to it at the lower end.

58. Great Saphenous Vein
• It can be marked by joining the following points,
although it is easily visible in living subjects.
• (a) First point: On the dorsum of the foot at the medial
end of the dorsal venous arch.
• (b) Second point: On the anterior surface of the medial
malleolus.
• (c) Third point: On the medial border of the tibia at the
junction of the upper two-thirds and lower one-third of
the leg.
• (d) Fourth point: At the adductor tubercle.
• (e) Fifth point: Just below the centre of the saphenous
opening.

59. Small Saphenous Vein
• It can be marked by joining the following points,
although this vein is also easily visible in its lower
part.
• (a) First point: On the dorsum of the foot at the
lateral end of the dorsal venous arch.
• (b) Second point: Behind the lateral malleolus.
• (c) Third point: Just lateral to the tendocalcaneus
above the lateral malleolus.
• (d) Fourth point: At the centre of the popliteal fossa

60. Femoral nerve
• It is marked by joining the
following two points.
• (a) First point: 1.2 cm lateral to the
midinguinal point,
• (b) Second point: 2.5 cm vertically
below the first point.

62. Sciatic Nerve
It is marked by joining the following points.
(a) First point: 2.5 cm lateral to the midpoint between the
posterior superior iliac spine and the ischial tuberosity.
(b) Second point: Just medial to the midpoint between the
ischial tuberosity and the greater I trochanter.
(c) The third point: In the midline of the back of the thigh
at the junction of its upper two-thirds and
lower one-third, i.e. at the apex of the popliteal fossa.

64. Tibial nerve
• First point: In the midline of the back of the thigh at
the junction of its upper two-thirds and I lower one-
third, i.e. at the apex of the popliteal fossa.
• (b) Second point: In the midline of the back of the I
leg at the level of the tibial tuberosity.
• (c) Third point: Midway between the medial
malleolus and tendocalcaneus.
• The line joining (a) and (b) represents the tibial
nerve in the popliteal fossa, and the line joining (b)
and (c) represents it in the back of the leg.

65. Common Peroneal Nerve
• It is marked by joining the following two
points,
• (a) First point: At the upper angle of the
popliteal fossa.
• (b) Second point: On the back of the neck of
the fibula. At the lower end the nerve turns
forwards and ends deep to the upper fibres of
the peroneus longus.

67. Deep Peroneal Nerve
• It is marked by joining the following two points,
• (a) First point: On the lateral aspect of the neck of
the fibula.
• (b) Second point: fn front of the ankle, midway
between the two malleoli.
• (c ) first interosseous space
• The nerve lies lateral to the anterior tibial arteryin its
upper and lower thirds. But anterior to the artery in
its middle third.

69. Saphenous Opening
Femoral Ring
• Saphenous Opening
• Its centre lies 4 cm below and 4 cm lateral to the
pubic tubercle. It is about 2.5 cm long and 2 cm
broad, with its long axis directed downwards and
laterally.
• Femoral Ring
• It is represented by a horizontal line 1.25 cm long
over the inguinal ligament, 1.25 cm medial to the
midinguinal point.