Upper Limb IV

Question 1

median nerve supplies which muscles in hand

Answer 1

Motor:The abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
The radial two lumbricales
Sensory: The skin of the lateral three and half fingers
The ulnar nerve supplies all the interossei and the rest of the hand muscles.

Question 2

erb’s palsy

Answer 2

A C5/C6 lesion, Erb’s palsy, produces sensory loss over the lateral aspect of the upper arm (deltoid paralysis), with loss of shoulder abduction, and paralysis of the biceps, brachialis and coracobrachialis. In addition to loss of elbow flexion, the biceps is also a powerful supinator of the forearm, so the forearm assumes a pronated position. A T1 lesion produces a claw hand, (Klumke’s palsy). Sympathetic chain injury results in a Horner’s syndrome, with ptosis of the upper eyelid and constriction of the pupil (meiosis) on the affected side

Question 3

brachial artery

Answer 3

The median nerve crosses from lateral to medial at the mid-humerus. The artery is accompanied by two vena comitantes and gives off its profunda branch near the upper end of the humeral shaft, where it accompanies the radial nerve. As with all joints, there is an excellent circulation around the elbow joint.

The brachial artery bifurcates into the ulnar and radial arteries just below the level of the elbow crease

Question 4

ulnar nerve palsy

Answer 4

The ulnar nerve (usually) supplies sensation to the skin of the fifth and the ulnar side of the fourth finger, front and back. There is sympathetic interruption, with absence of sweating in the affected area. The thenar muscles are supplied by the median nerve and are therefore spared. Although the fourth and fifth digits are held in the clawed position when the nerve is injured at the wrist, a high lesion paralyses the long flexors to these two fingers and results in the loss of this sign. A test for paralysis of the palmar interossei, supplied by the ulnar nerve, is the inability to adduct the fingers and thus to be unable to grip a sheet of paper between them.

Question 5

median nerve paralysis

Answer 5

The median nerve supplies all the muscles in the anterior compartment of the forearm, apart from the flexor carpi ulnaris and the flexor digitorum profundus to the ulnar two fingers: so these two fingers can still be flexed. The radial nerve supplies the extensors – hence no wrist drop. The ulnar nerve supplies the skin of the ulnar side of the hand, hence no anaesthesia there. It also supplies the interossei muscles of the hand, which effect abduction and adduction of the fingers. Absence of thumb abduction, due to paralysis of abductor pollicis brevis, is a good test for median nerve paralysis.

Question 6

deltoid muscle waste

Answer 6

Poliomyelitis only affects the anterior horn cells of the spinal cord, so there is no sensory loss. Although the shoulder appears flattened, due to deltoid wasting, the greater tubercle of the humerus remains the most lateral bony landmark of the shoulder. It is paralysis of trapezius that results in shoulder drop.
Even if the supraspinatus is fully functional, it is far too weak a muscle to be able to abduct the whole weight of the arm. The deltoid, in addition to being the powerful abductor of the humerus, also assists in flexion and medial rotation (and extension and lateral rotation) of the shoulder by means of its anterior and posterior fibres, respectively. Weakness of these movements compared to the normal side can be detected on careful examination.

Question 7

Scapula muscle attachments

Answer 7

Seven muscles attach the scapula (shoulder blade) to the chest wall and help maintain normal scapular control. These muscles are trapezius, levator scapulae, rhomboids major, rhomboids minor, pectoralis minor, omohyoid and serratus anterior. The latissimus dorsi has a small attachment at the base of the scapula but does not significantly contribute to scapular stability.Of these muscles, the serratus anterior and the trapezius are the most important. A winging scapula is nearly always associated with partial or complete paralysis of either of these muscles. Weakness or paralysis of the serratus anterior, secondary to palsy of the long thoracic nerve, is the commonest cause of winging. The long thoracic nerve (origin C5,6 motor roots, with sometimes a contribution from C4 +/- C7) is thin, fragile and runs an anatomical course in the neck and upper thorax that makes it susceptible to damage by compression or trauma. Commoner causes include: surgery (e.g. radical mastectomy, lymph node biopsy from axilla); stretch injury during sports (as in this case); viral/ post-infectious (brachial neuritis); other causes of neuropathy (vascular, toxic etc.).Accessory nerve (XI) damage can also produce scapular winging via weakness of trapezius, but this would be milder and would be expected to be associated with weakness of shoulder elevation, which this patient does not have. The other options listed would tend to be associated with other symptoms and signs. Nerve conduction studies and electromyography would help confirm the diagnosis

Question 8

klumpkes paralysis

Answer 8

He has sustained an injury to the brachial plexus, affecting the lowest roots (C8, T1), which provides the motor supply to the intrinsic muscles of the hand and the long flexors and extensors of the fingers. This deformity is known as Klumpke’s paralysis. C6 and C7 mediate the movements of the shoulder and elbow, and C7 the movements of the elbow and wrist. The radial nerve is required for normal positioning of the arm. A proximal ulnar nerve lesion affects the small muscles of the hand and wrist flexion but not the positioning of the arm.

Question 9

global muscle wasting

Answer 9

The median nerve supplies the lateral two lumbricals, opponens pollicis, abductor pollicis brevis and flexor pollicis brevis; the remainder are served by the ulnar nerve. Global muscle wasting of the hand indicates damage to both the median and ulnar nerves with damage to the T1 nerve root. Isolated wasting of abductor pollicis brevis occurs in association with median nerve damage from carpal tunnel syndrome. More extensive wasting may suggest a broader diagnosis such as syringomyelia or motor neurone disease.

Question 10

index and thumb numbness

Answer 10

One of the most common lesions at this site is carpal tunnel syndrome, in which the median nerve is compressed as it passes deep to the flexor retinaculum.
The usual presentation is with acroparaesthesias. This consists of numbness, tingling and burning sensations felt in the hand and fingers; the pain sometimes radiates up the forearm as far as the elbow or even as high as the shoulder or root of the neck. Although the paraesthesias are sometimes restricted to the radial fingers, they may affect all the digits as some fibres from the median nerve are distributed to the fifth finger through a communication with the ulnar nerve in the palm.
The attacks of pain and paraesthesias are most common at night and often wake the patient from sleep. They are then relieved by shaking the hand. The hand tends to feel numb and useless on waking in the morning but recovers after it has been used for some minutes. The symptoms may recur during the day following use, or at other times if the patient sits with the hands immobile.
Such symptoms of acroparaesthesias may persist for many years without the appearance of symptoms of median nerve damage. In other patients, weakness of the thenar muscles develops, particularly with abduction of the thumb, and is associated with atrophy of the lateral aspect of the thenar eminence. Sensory loss may appear over the tips of the median innervated fingers.

Question 11

Post operatively she notices numbness in her axilla and upper inner arm

Answer 11

During axillary node clearance the intercostobrachial nerve which gives the cutaneous innervations of the axilla and the inner upper arm is encountered and is divided in many of the cases to ease the exposure to the axilla. The long thoracic nerve of Bell (nerve to serratus anterior) and the thoracodorsal nerve to latissimus dorsi are encountered during dissection and they are preserved.

Question 12

low level median nerve injury

Answer 12

Features of high median nerve injury (more at the level of elbow ), which affects the long flexors of the forearm (Except flexor carpi ulnaris and flexor digitorum profundus) and the pronators. Lesions at the wrist level affect the sensation in the radial 3 ½ fingers (but not the ulnar aspect of ring finger which is supplied by ulnar nerve) . Median nerve at wrist also supplies the three thenar muscles (abductor and flexor polices brevis, and opponens polices) and the two radial lumbricals.

Question 13

Features of high median nerve injury (more at the level of elbow )

Answer 13

The long flexors will be affected causing wasting the front of the forearm on the long run
Flexor polices longus will be affected
The hand is held typically with the index finger straight ‘pointing finger’

Question 14

Ligaments of cooper

Answer 14

The suspensory ligaments of the breast (Ligaments of Cooper) are fibrous bands of connective tissue that interdigitate between the breast tissues and extend from the deep layers of the superficial fascia to the dermis. These ligaments provide some shape to the breast tissue and are partly responsible for the “peau d’orange” appearance associated with lymphoedema of malignancy. Tubercles of Montgomery are small accessory glands on the areola. The retromammary bursa is the posterior aspect of the breast between the deep layer of the superficial fascia and deep investing fascia of pectoralis major. Poupart’s ligament is the inguinal ligament

Question 15

Surgical neck of humerus fracture

Answer 15

The important anatomical relationships to the humerus are the axillary nerve and circumflex humeral vessels at the surgical neck, the ulnar nerve at the posterior aspect of the medial epicondyle, and the radial nerve and the profunda brachii vessels at the surgical groove. Fractures affecting those sites might affect the related structures.In proximal humeral fractures, Surgical neck fractures (Neer group III) might cause axillary nerve damage, anatomical neck fractures (Neer Group II) might result in avascular necrosis of the humeral head while greater tuberosity fractures (Neer group IV) might result in painful arc syndrome.

Question 16

Colles’ smith and barton fracture

Answer 16

The three commonest distal radial fractures are Colles’, Smith’s and Barton’s. Colles’ and Smith’s are extra-articular while Barton’s is Intra-Articular
Smiths: It is an extra-articular distal radial fracture with volar displacement
Colles: is an extra-articular fracture with dorsal and radial displacements of the distal fragment
Bartons: It is an intra-articular distal radial fracture either volar or dorsal where the articular surface of the distal radius subluxes from the carpals

Question 17

breast surface anatomy overlies what structures

Answer 17

The breast extends from the second to the 6th rib overlying the pectoralis major muscle, extending over the serratus anterior laterally, the rectus sheath inferomedially, the external oblique inferolaterally and the costal cartilage medially.

Question 18

axillary artery branches by what muscle

Answer 18

The axillary artery is the continuation of the subclavian artery starting from the outer part of the 1st rib to the lower border of teres major. Along with the axillary vein and the brachial plexus it is enclosed in the axillary sheath. The vein is medial to the artery and the cords of the brachial plexus lie around it. Pectoralis major covers most of the artery except for its lateral edge.

Question 19

Branches of axillary artery

Answer 19

The branches are;First part: superior thoracic arterySecond part: acromiothoracic and lateral thoracic arteriesThird Part: Subscapular, anterior circumflex humeral and posterior circumflex humeral arteries

Question 20

The following structure passes under the brachioradialis emerging distally on its medial side. Distally it is covered only by skin and fascia and lies on the radius

Answer 20

This describes the course of the radial artery which starts at the level of the neck of the radius lying on the tendon of the biceps. It passes under the brachioradialis as described reaching the wrist where its pulsations are felt against the radius. After that it winds laterally and enters the palm between the heads of the first dorsal interosseous muscle, it ends as the deep palmar arch supplying the hand.The ulnar artery on the other hand passes inferiorly and medially in the anterior compartment of the forearm. It runs laterally to the ulnar nerve deep to the flexor carpi ulnaris and ends in the hand forming the superficial palmar arch.

Question 21

Canal of Guyon

Answer 21

The canal of Guyon is a fibrous band of fascia covering both the ulnar artery and nerve at the level of the wrist. Both the artery and nerve pass in front of the retinaculum lateral to the pisiform bone. The ulnar artery lies lateral to the nerve at this level. The ulnar nerve might be occasionally compressed at the canal of Guyon.

Question 22

Radial nerve and humerus

Answer 22

The radial nerve runs in the spiral groove and injury at that level will affect the extensors of the wrist and fingers resulting in ‘wrist drop’. Sensory loss will be localised to the back of the radial side of the hand

Question 23

On examination there is no distal sensory deficit, but unable to flex his thumb and index finger to make the “OK” sign. Which nerve has been damaged?

Answer 23

The anterior Interosseous Nerve is a branch of the median nerve. It does not have a sensory component and supplies both flexor pollicis longus and flexor digitorum profundus to the index and middle fingers. Both of these muscles are required to make an “OK” sign. It is the most commonly injured nerve in supracondylar fractures of the elbow

Question 24

compartments in the extensor retinaculum

Answer 24

There are six extensor compartments in the extensor retinaculum on the dorsum of the wrist. They contain in order: 1st - Extensor Pollicis Brevis and Abductor Pollicis Longus2nd - Extensor Carpi Radialis Longus and Extensor Carpi Radialis Brevis3rd - Extensor Pollicis Longus4th - Extensor Digitorum and Extensor Indicis5th - Extensor Digiti Minimi6th - Extensor Carpi Ulnaris The second and third compartments are separated by Lister’s Tubercle.

Question 25

Winging of scapula

Answer 25

The Long Thoracic Nerve arises from the roots of C5, C6 and C7. The nerve passes just posterior to the mid-axillary line deep to the fascia of serratus anterior and supplies this muscle in a segmental fashion. Serratus anterior protracts the scapula in punching and pushing and keeps the vertebral border of the scapula in firm apposition with the chest wall. The nerve is potentially damaged by malpositioned chest drains

Question 26

On examination, his hand is extended at all the MCP joints and all the interphalangeal joints are in fixed flexion. The wrist flexors appear to be slightly weaker

Answer 26

This is a classical history for a “Klumpke’s Palsy”. It is produced by a traction type injury to the lower brachial plexus nerve roots. It is commonly associated with traction to the arm when it is in an extended overhead position. Occasionally damage to T1 may also cause a Horner’s syndrome.All the intrinsic muscles of the hand are affected as opposed to an ulnar nerve lesion producing a claw hand affecting only the little and ring fingers. In ulnar nerve injuries, the index and middle fingers are spared as the radial 2 lumbricals are supplied by the median nerve

Question 27

Olecranon fracture

Answer 27

Triceps attaches to the olecranon and is responsible for extension of the elbow. If olecranon fractures are treated conservatively, an excellent range of movement can be achieved, however functional outcome is impaired due to lack of power of extension. This would be most apparent pushing up against gravity as you have to do when pushing out of a chair. Brushing hair, reaching into cupboards and pouring kettles are functions mainly achieved by movements of the shoulder, whilst fastening buttons requires dexterity and may be adversely affected by injuries to the wrist or hand

Question 28

Sensory loss over the lateral aspect of the arm and weakness of shoulder abduction

Answer 28

The axillary nerve supplies the “regimental patch” area of skin over the upper lateral aspect of the arm. Its motor component is to deltoid and to teres minor. The motor deficit resulting from an axillary nerve injury is weakness of these muscles. The most noticeable is abduction, since flexion and extension are assisted by pectoralis major and latissimus dorsi respectively. There is not complete loss of abduction as supraspinatus will still be intact which mainly initiates abduction

Question 29

palmaris longus and flexor retinaculum

Answer 29

Palmaris longus lies anterior to the flexor retinaculum, partly adherent to the retinaculum. The tendons of flexor pollicis longus and flexor carpi radialis lie within their own synovial sheaths within the carpal tunnel

Question 30

internal rotation of shoulder

Answer 30

Subscapularis produces internal rotation of the shoulder joint. It arises from the costal surface of the scapula and inserts into the lesser tubercle. Pectoralis major and latissimus dorsi contribute to internal rotation so there is not a complete loss of internal rotation if only subscapularis has been injured. Supraspinatus initiates abduction and helps in abducting the shoulder joint between 90° and 120°. Teres minor along with infraspinatus externally rotates the shoulder. Deltoid flexes and abducts the shoulder

Question 31

Carpal tunnel syndrome

Answer 31

The history described above is typical of carpal tunnel syndrome. Entrapment of the median nerve at the carpal tunnel affects the muscles of the thenar eminence. These are abductor pollicis brevis, flexor pollicis brevis and opponens pollicis. The nerve supply of flexor pollicis brevis is extremely variable however, so the best test to perform would be to see if opposition is affected. In addition the motor branch of the median nerve after the level of the carpal tunnel also innervates the radial 2 lumbricals. Flexion would not be affected as the nerve supply to the long flexors comes off the median nerve proximal to the carpal tunnel. Abduction and adduction of the fingers is produced by the interossei, which are supplied by the ulnar nerve

Question 32

Long thoracic nerve

Answer 32

Serratus anterior is innervated by the long thoracic nerve. Serratus anterior keeps the scapula held forward, balancing trapezius and the rhomboids, which retract the scapula. If the long thoracic nerve is injured (which is common in surgery, because the long thoracic nerve is on the superficial side of serratus anterior), you may see a ‘winged scapula’ protruding posteriorly. The anterior scalene muscle is innervated by C5-C7 and the middle scalene muscle is innervated by C3-C8. Teres major is innervated by the lower subscapular nerve from the posterior cord of the brachial plexus. Subscapularis is innervated by the upper and lower subscapular nerves from the posterior cord of the brachial plexus

Question 33

humerus extension

Answer 33

The thoracodorsal nerve, a branch of the posterior cord of the plexus, derives its fibres from the fifth, sixth and seventh cervical nerves. It follows the course of the subscapular artery, along the posterior wall of the axilla to the latissimus dorsi, in which it can be traced as far as the lower border of the muscle. Latissimus dorsi is responsible for extension of the humerus and in this scenario it is the affected muscle due to injury to the thoracodorsal nerve

Question 34

Annular ligament

Answer 34

The annular ligament is a strong band of fibres, which encircles the head of the radius and retains it in contact with the radial notch of the ulna. It forms about four-fifths of the osteofibrous ring and is attached to the anterior and posterior margins of the radial notch. A few of its lower fibres are continued around below the radial notch and form at this level a complete fibrous ring. Its upper border blends with the anterior and posterior ligaments of the elbow, while from its lower border a thin, loose membrane passes to be attached to the neck of the radius. A thickened band that extends from the inferior border of the annular ligament below the radial notch to the neck of the radius is known as the ‘quadrate ligament’. The superficial surface of the annular ligament is strengthened by the radial collateral ligament of the elbow and affords origin to part of the supinator. Its deep surface is smooth and lined by synovial membrane, which is continuous with that of the elbow joint

Question 35

Muscle to depress glenoid fossa

Answer 35

The pectoralis minor is a thin, triangular muscle, situated at the upper part of the thorax, beneath the pectoralis major. It arises from the upper margins and outer surfaces of the third, fourth and fifth ribs, near their cartilage and from the aponeurosis covering the intercostals. The fibres pass upward and lateralward and converge to form a flat tendon, which is inserted into the medial border and upper surface of the coracoid process of the scapula. The pectoralis minor receives its fibres from the eighth cervical and first thoracic nerves through the medial anterior thoracic nerve. The pectoralis minor depresses the point of the shoulder (glenoid fossa), drawing the scapula downward and medialward toward the thorax and throwing the inferior angle backward.

Question 36

spinal injury to C8

Answer 36

The hypothenar muscles include the palmaris brevis, opponens digiti minimi, abductor digiti minimi and flexor digiti minimi brevis. All the muscles of this group are supplied by the eighth cervical nerve through the ulnar nerve and will be completely paralysed in a lesion at spinal level C8

Question 37

Extensor retinaculum of the wrist

Answer 37

The extensor tendons are held closely applied to the dorsal surface of the distal radius and ulna by the extensor retinaculum. This is a ribbon-like fascial band, 2.5 cm wide, that extends obliquely from the anterolateral surface of the radius across the dorsum of the wrist, inserting into the pisiform and triquetral bones, but not directly into the ulna. The radius and carpus are free to rotate about the ulna without affecting tension in the extensor retinaculum. The extensor retinaculum prevents bowstringing of the extensor tendons with wrist extension and bony attachments of the retinaculum produce six extensor compartments that control the tendons with wrist movement

Question 38

Elbow joint type

Answer 38

The elbow joint is a ginglymus or hinge joint. The trochlea of the humerus is received into the semilunar notch of the ulna and the capitulum of the humerus articulates with the fovea on the head of the radius. The articular surfaces are connected by a capsule, which is thickened medially and laterally and, to a lesser extent, in front and behind. These thickened portions are usually described as distinct ligaments under the following names: anterior ligament, posterior ligament, ulnar collateral ligament and radial collateral ligament

Question 39

A road traffic accident victim injured a nerve, which resulted in loss of action of the muscle inserting on to the crest of the lesser tubercle of the humerus

Answer 39

The lower subscapular nerve supplies the lower part of the subscapularis, which inserts onto the crest of the lesser tubercle of the humerus and ends in the teres major. The latter muscle is sometimes supplied by a separate branch

Question 40

Suprascapular nerve

Answer 40

The suprascapular nerve arises from the trunk formed by the union of the fifth and sixth cervical nerves. It runs lateralward beneath the trapezius and the omohyoid and enters the supraspinatus fossa through the suprascapular notch, below the superior transverse scapular ligament. It then passes beneath the supraspinatus and curves around the lateral border of the spine of the scapula to the infraspinatus fossa. In the supraspinatus fossa, it gives off two branches to the supraspinatus muscle and an articular filament to the shoulder joint; and in the infraspinatus fossa it gives off two branches to the infraspinatus muscle, as well as some filaments to the shoulder joint and scapula