Clinical Considerations of Upper Limb

After you learn all that you can about a part of the body, it will add to your knowledge if you can then relate your information to clincial problems. Throughout your study of Human Anatomy, you should always keep in mind how you will use this knowledge and for most, that will be in diagnosing problems of clinical concern.

Arteries

One of the things you should be able to do is to palpate arteries in order to check to see if the heart is still beating or not. There are several places in the upper limb that the arteries can be felt:
  1. subclavian artery in the neck just as it passes over the first rib
  2. the terminal part of the axillary artery as it crosses teres major muscle
  3. the brachial artery at the elbow just medial to the tendon of the biceps brachii muscle
  4. the radial artery at the wrist
  5. the ulnar artery at the wrist
Other considerations are the anastomses that are found in the upper limb. An arterial anastomsis is one where a number of arteries coming from different sources communicate around a special organ or region. The details of these anastomoses will be added at a later time. In the upper limb there are three regions where important anastomoses occur:
  1. scapula
  2. elbow
  3. palm of the hand
pulse points of upper limb
The hand is such an important part of the upper limb that we will present its anastomoses. It is rather simple -- there are two palmar arterial arches that are interconnected:
  • superficial palmar arch -- major source is the ulnar artery (11) but is completed by the superficial radial artery (4)
  • deep palmar arch -- major source is the deep radial (5) artery but is completed by the superficial ulnar artery (12)

The function of these communications can be checked easily:
If you compress the the radial artery at the wrist, then make a tight fist and release the fist, the hand will be white at first but then return to a pink color in seconds if the ulnar artery is intact.
On the other hand, if you compress the ulnar artery just lateral to the pisiform bone, make a tight fist and release, the hand will again be white and then turn pink in seconds if the radial artery is intact.
If the hand remains white, the opposite artery is not open or does not form a functional anastomosis with the arches. (This is called the Allen test)		 arteries of forearm and hand

Veins

The cephalic (1) and basilic (2) veins start from the dorsal venous plexus on the back of the hand.
Superficial veins are probably used more in a clinical situation that any other part of the body. They are used for venipuncture, transfusion, and catheterization. It important to be able to identify the location of the major available veins in the upper limb. In an emergency situation, a patient may arrive in shock, in which case, the veins are usually totally collapsed. It might be up to you to find a vein to get into even if you have to perform a cut down. These are the veins that you should be able to locate or see:
  • median cubital vein (2)
  • cephalic vein (1) just posterior to the styloid process of the radius at the wrist. This is the site most often used for a cut down in the upper limb.
  • frequently, the cephalic and basilic veins (3) can be seen on either side of the elbow where the medial cubital vein is located.
superficial veins of upper limb
Sometimes, when the superficial veins have collapsed, and you have to transfuse, you must perform what is known as a cutdown. In the upper limb, the best place to perform this is at the wrist, either laterally in the cephalic vein (1) or medially in the cephalic vein (2) as they arise from the dorsal venous arch.
superficial veins of the hand

Lymph Drainage

Lymph drainage of the upper limb usually follows the cephalic or basilic veins. The thumb, index finger and lateral part of palm usually drains along the path of the cephalic vein and empties into the infraclavicular group of lymph nodes of the axillary group.

Lymph drainage from the little finger and ring finger and medial palm travels through vessels along the basilic vein and is first filtered by the supratrochlear node just above the medial epicondyle of the humerus. From this node, the lymph reaches the lateral group of axillary lymph nodes where is again filtered.
Therefore, if, during a physical examination, you feel an enlarged node just above the medial epicondyle of the humerus, you should suspect some sort of infection in the medial part of the hand. Usually when there is lymphadenitis the lymph vessels draining the area are appear as reddened streaks.

Lymph Drainage of Mammary Gland

A very important structure that should be examined is the mammary gland. Early detection of changes in this structure is of prime importance in cases of malignancy. A knowledge of the lymph drainage of the mammary gland can help as part of the diagnosis of mammary disease. For the purpose of discussing the lymph drainage, the gland is subdivided into 4 quadrants (2 medial, 2 lateral). The lymph drainage of the mammary gland is:
  • medial quadrants -- drain medially into lymph nodes along the internal mammary artery.
  • lateral quadrants -- drain into the anterior or pectoral group of axillary lymph nodes.
The anterior group of lymph nodes are easily palpated and should always be part of a general examination in females.		 lymph drainage of mammary gland

Nerves

Upper Lesions of the Brachial Plexus
(Erb-Duchenne Palsy)



Upper lesions of the brachial plexus are usually the result of tearing the 5th and 6th roots of the brachial plexus away from the spinal cord. This may occur in infants during a difficult delivery or in adults following a fall on or a blow to the shoulder. The major nerves involved are:
  • the suprascapular nerve (1)
  • musculocutaneous nerve(2)
  • axillary(3)

lateral rotation of the humerus is lost, due to the suprascapular nerve lesion; therefore, the humerus is medially rotated

  • supraspinatus
  • infraspinatus
  • teres minor

flexion of forearm, supination of the forearm, weak flexion of shoulder

  • biceps brachialis
  • brachialis

abduction of shoulder

  • deltoid

Another name for this lesion is 'porters tip'

erb-duchenne palsy appearanceerbe-duchenne plexus

Lower brachial plexus lesion
(Klumpke Palsy)

Lower brachial plexus lesions are usually injuries caused by excessive abduction of the arm as a result of someone clutching for an object when falling from a height. The 1st thoracic nerve (T1) is usually torn. The fibers from this segment of the spinal cord help form the ulnar (1) and median (2) nerves

the small muscles of the hand (interossei and lumbricals) are affected

the hand has a clawed appearance due to hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints. The extensor digitorum is unopposed by the lumbricals and interossei and extends the metacarpophalangeal joints. Because the flexor digitorum superficialis and profundus are unopposed by the lumbricals and interossei, the middle and terminal phalanges are flexed.

There is also sensory loss along the medial side of the forearm, hand and medial 2 fingers

Lower brachial plexus lesions may also be the result of malignant metastases form the lungs in the lower deep cervical lymph nodes and a aberrant cervical rib.

Klumpkes palsy plexus

Long Thoracic Nerve Lesion
(Nerve to Serratus Anterior)

This nerve (1) may be injured by blows or pressure in the posterior triangle of the neck or during a radical mastectomy surgical procedure.

The serratus anterior muscle pulls the medial border of the scapula to the posterior thoracic wall and stabilizes it there. A way to check to see if this muscle is working properly is to have a person push against a wall or door. On the side that has the lesion of the nerve, the medial border of the scapula will be pushed away from the thoracic wall, and protrude like a wing would. Thus, the name 'winged scapula'.

winged scapula

Radial Nerve Injury

If the radial nerve is injured, the final results will depend on where along its path it is injured. The most complete injury is one that occurs in the axilla. The radial nerve may be injured in the axilla as a result of poor positioning of a crutch, shoulder dislocation or fractures of the upper part of the humerus.

This high injury results in paralysis of the triceps, anconeus and the long extensors of the wrist. The patient is unable to extend the elbow joint, the wrist joint and the fingers. One appearance of the limb when it is raised, is "wrist drop". This is a very disabling injury, since a person can't flex the fingers strongly for gripping an object. Even though the brachioradialis and supinator muscles are paralyzed, supination can still be performed. Do you know by which muscle this is done?

biceps brachii

 wrist drop

The radial nerve may be injured as it passes along the spiral groove of the humerus following factures of the humerus. The nerve has also been known to be injured due to prolonged pressure of the back of the arm on the edge of an operating table.

The branches to the triceps are spared in this injury so that extension of the elbow is possible.

The long extensors of the forearm are paralyzed and this will result in a "wrist drop". There is a small loss of sensation over the dorsal surface of the hand and the dorsla sufaces of the roots of the lateral three fingers.

 wrist drop

Ulnar Nerve Lesion

The ulnar nerve is a branch of the medial cord of the brachial plexus from C8 and T1 segments of the spinal cord. It passes into the anterior compartment of the forearm after passing behind the medial epicondyle of the humerus. It is at this site that the nerve can be injured following fractures of the medial epicondyle. The muscles paralyzed are the flexor carpi ulnaris, medial half of the flexor digitorum profundus, medial two lumbricals, all interossei and the adductor pollicis.

The appearance of the hand is indicative of the muscles involved. The thumb is abducted and extended with the distal phalanx flexed. The first two fingers are fully extended with a slight flexion of the distal phalanges. The medial two fingers are hyperextended at the metacarpophalangeal joints but flexed at the distal phalangeal joints. The hand resembles a "claw" and is called a claw hand.

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