Living Anatomy Course Objectives for Medicine I Students

Living Anatomy Learning Objectives [RB]

Upper Limb:

Upper Limb

Living Anatomy of Shoulder Region

A. Scapula

(i) Acromion process

Lies immediately superiorly and medially to the point of the shoulder and can be traced backwards to join the spine of the scapula. It can be outlined well when the deltoid contracts against resistance. At its lateral end, it forms the tip of the shoulder.

(ii) Spine

Felt as a prominent ridge of bone, marked on the surface as an oblique depression, terminating a little before the spinous process of the vertebra, at level of TV 3-4.

(iii) Vertebral border

This can be traced running down and lateral from medial end of spine, to the inferior angle.

(iv) Inferior angle

Covered by latissimus dorsi, but can be palpated at the level of the 7th rib or 7th intercostal space (ICS), or at the level of TV 7 (spinous process) when the arm is by the side.

(v) Lateral border

May be traced, though with difficulty, through the covering of latissimus dorsi and teres major. (vi) Coracoid process Palpated 2cm below the lateral third of clavicle, through the anterior fibres of deltoid.

(vii) Superior angle

Opposite 2nd rib or TV 2, but is a difficult landmark to feel.

B. Sterno-Clavicular Joint

Palpate by feeling the sternal end of the clavicle, bend the head forward (thus relaxing the sterno-mastoid muscle which overlies the joint) and move your finger to the depression medial to the clavicle. The cavity of the joint is V-shaped when the arm hangs by the side.

C. Acromio-Clavicular Joint

Palpated medial to lateral part of acromion, lying in a plane of a vertical line passing up the middle of the anterior surface of the arm.

D. Humerus

The head of the humerus may be felt deeply in the upper part of the axilla, especially in thin subjects with the arm slightly abducted, the forearm suported and the muscles relaxed.

The greater tubercle is the most lateral bony point of the shoulder region, and prevents a straight edge from touching simultaneously the tip of the acromion and the lateral epicondyle of the humerus.

It is the most prominent bony part of this region, extending beyond the acromion process and covered by the deltoid. It is best felt with the arm lying loosely by the side.

The lesser tuberosity, directed forward and inward, may be felt to the inner side of the greater tuberosity just below the acromio-clavicular joint.

Surface Anatomy of Upper Limb Nerves

In the forearm, the median nerve extends down the middle of the limb starting from a point deep to the bicipital aponeurosis to the midpoint between styloid process of radius and ulna. It is found between the tendons of F.C.R. and P.L. It passes under the flexor retinaculum and into the hand, where it divides.

The ulnar nerve can be traced accompanying the brachial artery to the level of insertion of coracobachialis where it begins to diverge heading behind the medial epicondyle, and then to the medial side of the coranoid process. Posterior to the medial epicondyle one can palpate the nerve by gently rolling it against the bone. This is a common site of injury to the ulnar nerve. In the forearm, the course of the ulnar nerve is indicated by a line from the medial epicondyle to the lateral margin of the pisiform (and medial to the hook of hamate).

The radial nerve is indicated on the surface, extending from the medial margin of the biceps, opposite the posterior axillary fold, obliquely across the back of the arm, below the posterior border of the deltoid and descending to the front of the lateral epiondyle where it divides into superficial and deep terminal branches. In thin persons it may be palpated as it winds around the humerus, especially 1-2 cm below the deltoid insertion and in the interval between brachialis and brachioradialis.

In the forearm, the superficial branch of the radial nerve continues deep to brachioradialis to a point 7 cm above the wrist where it turns deep to the brachioradialis, winding around the lateral side of the radius. It crosses the anatomical snuff box and its terminal digital branches can be felt crossing the tendon of E.P.L. (This can be performed by using a fingernail on the taut tendon - tingling pain (paraesthesia) may be experienced in the digital distribution area).

Surface Markings of Upper Limb Arteries

The subclavian artery can be represented by a broad line, convex upwards (1-3 cm above clavicle), drawn from the sternoclavicular joint to the middle of the lower border of the midpoint of the clavicle.

The axillary artery can be mapped out extending from the midpoint of the clavicle (lower border) to the medial margin of biceps, opposite the posterior axillary fold.

The brachial artery is represented by a line commencing from the lower border of tendon of teres major, medial to the humerus in the upper arm and medial to biceps and coracobrachialis. In the lower arm it spirals more anteriorly and extends to the cubital fossa, to the midpoint of the humeral epicondyles.

The radial artery extends from the brachial artery to the wrist, lateral to the tendon of F.C.R. Then it passes deep to the tendons of A.P.L. and E.P.B. and distal to the styloid process of the radius to enter the anatomical snuff box. The deep palmar arch (formed by anastomoses between the radial artery and a deep palmar branch of the ulnar artery) is represented by a horizontal line, approximately 4 cm long, drawn from a point just distal to the hook of the hamate (in line with the proximal border of the outstretched thumb). The superficial palmar arch (formed by anastamoses between the ulnar artery and the superficial palmar branch of the radial artery). The distal convexty of the arch lies in line with the distal border of the outstretched thumb.

The ulnar artery commences in the midline of the limb opposite the neck of the radius. It has a curved course, convex medially to the lateral edge of the pisiform bone.

Palpation of Upper Limb Arterial Pulses

The size of the lumen of an artery and its distance from the skin surface determine if a particular artery can be felt with the palpating finger. In the upper limb, the subclavian, axillary, brachial, radial and ulnar arteries may all be felt in one or more parts of their course. The ability to palpate the pulse in three of these is of major clinical significance.

The subclavian pulse can be felt in the angle between the medial end of the clavicle and the sternomastoid muscle. (This is a strap muscle easily seen extending between the sternum and the medial end of the clavicle, upwards and laterally to an area below the ear. It is best inspected by turning the head towards the side opposite the muscle) Using firm but gentle pressure behind the clavicle, the pulse can be felt by deep palpation of the artery against the superior surface of the first rib opposite the midpoint of the clavicle. This is of clinical significance, since compression of the artery downwards against the first rib can reduced uncontrolled bleeding from the axilla and arm following trauma.

The brachial pulse can be palpated by firm pressure along most of its course. In the upper arm, pressing it laterally against the humerus in the bicipital groove; in the lower part of the arm, pressing it posteriorily against the humerus. It is best felt in the middle of the arm, by pressing it laterally. The brachial artery is the one usually utilized in determining the blood pressure.

The radial pulse is best felt lateral to the tendon of F.C.R. at the wrist, and also in the anatomial snuff box. The former is the pulse usually felt in routine physical examination.

Lower Limb

Surface Anatomy of Lower Limb Nerves

Use a skin pencil to indicate on a colleague the courses of the major peripheral nerves of the lower limb.

The sciatic nerve emerges from the pelvis about 1/3rd of the way along a line from the posterior superior iliac spine to the ischial tuberosity. It then descends, lateral to the ischial tuberosity, not quite half-way between it and the greater trochanter. From this point, it passes down the middle of the back of the thigh. It ends in the region, of the lower third of the thigh to the middle of the upper part of the popliteal fossa, by separating into its major components.

The common peroneal nerve descends from the sciatic nerve at the superior angle of the popliteal fossa, along the medial margin of the biceps femoris to the back of the head of the fibula. It winds forward around the neck of the fibula (it is palpable here against the fibula) and then divides in the substance of peroneus longus.

The tibial nerve usually begins at the superior angle of the popliteal fossa and descends, in the direction indicated by a line descending vertically to the level of the tuberosity of the tibia, and then runing downward to the midpoint between the medial malleolus and the heel.

The femoral nerve descends behind the inguinal ligaments about 1 cm lateral to the femoral artery and divides after a very short course (2-3 cm) in the thigh.

The saphenous nerve can be regarded as the termination of the femoral nerve and is indicated by a line commencing in the femoral triangle, crossing the femoral artery to its medial side, and extending to the medial side of the knee where it emerges just behind the sartorius. From here, it travels in the company of the great saphenous vein to reach the anterior aspect of the medial malleolus.

Surface Markings of Lower Limb Vessels

Femoral artery is indicated by the upper 2/3rds of a line from the midpoint between the anterior superior iliac spine and the pubic symphysis to the adductor tubercle.

Popliteal artery is indicated by a line from the superior angle of the popliteal fossa to the middle of the back of the leg at the level of the tibial tuberosity.

Posterior tibial artery is indicated by a line on the back of the leg, from the level of the tibial tuberosity, downward to the midpoint between the medial malleolus and the heel.

Anterior tibial artery is indicated by a line on the front of the leg starting at the midpoint between the tibial tuberosity and fibula to the midpoint between the two malleoli.

Dorsalis pedis artery extends from midway between the malleoli anteriorily to the distal end of the first inter-metatarsal space.

Palpation of Arterial Pulses

You should now palpate the pulses of the major arteries of the lower limb. The practical application of this technique will be used frequently during your future clinical practice in order to detect any disturbance in blood flow in the lower limbs from peripheral vascular disease.

The femoral pulse can be felt by pressing directly backward at the midpoint between the anterior superior iliac spine and the pubic symphysis. It is best felt when the thigh is flexed, abducted and laterally rotated.

The popliteal pulse can be detected when the knee is passively flexed and pressure exerted forwards by the fingers of each hand against the posterior aspect of the tibia. The popliteal pulse is not always easily felt.

The posterior tibial pulse is palpable midway between the medial malleolus and the heel.

The dorsalis pedis pulse may be felt on the lateral side of the extensor hallucis longus tendon.

Demonstration of Superficial Veins

You understand, by now, that there exist two sets of veins in the lower limb, superficial and deep, connected by communication vessels (perforators). Their valves are positioned so that blood flows from superficial to deep. However, valvular incompetence may permit blood flow in the opposite direction. This can cause distension and tortuosity of the superficial veins, which is referred to as varicose veins.

The superficial veins in the lower extremity are best demonstrated in a normal subject after vigorous exercise (e.g., repeated steping up and down from a chair) when, in the resting erect posture, they usually become visible in their distal parts. You will probably be able to visualize the dorsal venous arch and the commencements of the great saphenous and small saphenous veins. If not, you will certainly be able to feel the great saphenous vein. Note the relationship of these veins to their respective malleoli.

[back to top]

© Anatomy & Histology - University of Sydney | Back to top | Courses & Teaching Index