Clinical Conditions

Question 0

Thoracic outlet syndrome

Answer 0

apex of axilla: vessels and nerves may become compressed between the bones

Common causes: trauma (e.g fractured clavicle) and repetitive (lifting of the arms)

presents: pain in the affected limb, tingling, muscle weakness and discolouration

Question 1

Winged scapula:

What is damaged
Consequence
Clinical presentation/test
How damage can occur

Answer 1

long thoracic nerve
serratus anterior muscle paralysed

When pushing with the affected limb, the scapula is no longer held against the rib cage, and protrudes out of the back

long thoracic nerve can become damaged by trauma to the shoulder, repetitive movements involving the shoulder or by structures becoming inflamed and pressing on the nerve.

Question 2

Lymph node biopsy & axillary clearance

Answer 2

Approx 75% of lymph from the breast drains into the axilla lymph nodes; biopsied if breast cancer is suspected.

axillary nodes may need to be removed to prevent the cancer spreading (axillary clearance)

long thoracic nerve may become damaged, resulting in winged scapula.

Question 3

Erb’s palsy

Answer 3

Upper brachial plexus injury
commonly in excessive increase in the angle between the neck and shoulder; stretches/tear nerve roots (e.g. From difficult birth or shoulder trauma)

Nerves affected: solely C5 or C6 roots; musculocutaneous, axillary, suprascapular and nerve to subclavius.

Muscles paralysed: Supraspinatus, infraspinatus, subcalvius, biceps brachii, brachialis, coracobrachialis, deltoid and teres minor.

Motor functions (lost/greatly weakened): abduction at shoulder, lateral rotation of arm, supination of forearm, and flexion at shoulder.

Sensory functions: Loss of sensation down lateral side of arm (sensory innervation of the axillary and musculcutaneous nerves)

Waiter’s tip position: affected limb hangs limply, medially rotated by the unapposed action of pectoralis major. The forearm is pronated due to the loss of biceps brachii.

Question 4

Klumpke palsy

Answer 4

Lower brachial plexus injury

From excessive abduction of the arm (e.g person catching a branch as they fall from a tree).
lower incidence than Erb’s palsy.

Nerves affected: from T1 root – ulna and median nerves.

Muscles paralysed: small muscles of the hand
(flexors muscles in the forearm are supplied by the ulna and median nerves, but are innervated by different roots).

Sensory functions: Loss of sensation along medial side of arm.

Clawed hand: The metacarpophalangeal joints are hyperextended, and the interphalangeal joints are flexed

Question 5

Bursitis in elbow joint:

Subcutaneous bursitis
Subtendinosus bursitis

Answer 5

Subcutaneous bursitis: Repeated friction and pressure on the bursa can cause it become inflamed. Because this bursa lies relatively superficially, it can also become infected (e.g cut from a fall on the elbow), and this would also cause inflammation

Subtendinosus bursitis: This is caused by repeated flexion and extension of the forearm, commonly seen in assembly line workers. Usually flexion is more painful as more pressure is put on the bursa.

Question 6

Elbow dislocation

Answer 6

usually occurs when a young child falls on a hand with the elbow flexed.
distal end of the humerus is driven through the weakest part of the joint capsule, which is the anterior side.
ulnar collateral ligament is usually torn and there can also be ulnar nerve involvement

Most are posterior
named by the position of the ulna and radius, not the humerus.

Question 7

Epicondylitis (Tennis elbow or Golfer’s Elbow)

Answer 7

overuse/strain of the common tendon
results in pain and inflammation around the area of the affected epicondyle.

Most of the flexor and extensor muscles in the forearm have a common tendonous origin. flexor muscles originate from the medial epicondyle, and the extensor muscles from the lateral.

Typically, tennis players experience pain in the lateral epicondyle from the common extensor origin.
Golfers experience pain in the medial epicondyle from the common flexor origin.

Question 8

Supraepicondylar Fracture

Answer 8

falling on a flexed elbow
transverse fracture, spanning between the two epicondyles.

Direct damage, or swelling can cause the interference to the blood supply of the forearm via the brachial artery.
resulting ischaemia can cause Volkmann’s ischaemic contracture – uncontrolled flexion of the hand, as flexors muscles become fibrotic and short.
also can be damage to the medial, ulnar or radial nerves.

Question 9

Dislocation of the Shoulder Joint

Answer 9

described by where the humeral head lies in relation to the infraglenoid tubercle.

Anterior dislocations are the most prevalent, although posterior dislocations can sometimes occur.
Superior movement of the humeral head is prevented by the coraco-acromial arch.

An anterior dislocation is usually caused by excessive extension and lateral rotation of the humerus. The humeral head is forced anteriorly and inferiorly – into the weakest part of the joint capsule. Tearing of the joint capsule is associated with an increased risk of future dislocations.

The axillary nerve runs in close proximity to the shoulder joint, and can be damaged in the dislocation. Injury to the axillary nerve causes paralysis of the deltoid, and loss of sensation over regimental badge area. A dislocation can also stretch the radial nerve, as it is tightly bound in the radial groove.

Question 10

Rotator Cuff Tendonitis & Painful Arc

Answer 10

rotator cuff muscles stabilise the glenohumeral joint.
Injuries of these muscles is relatively common.

Tendonitis = inflammation of the muscle tendons – usually due to overuse.
Over time, this causes degenerative changes in the subacromial bursa, and the supraspinatus tendon.
increases friction between the structures of the joint.

The characteristic sign of rotator cuff tendonitis is the ‘painful arc’ – pain in the middle of abduction, where the affected area comes into contact with the acromion.

Question 11

Acromioclavicular joint dislocation (separated shoulder)

Answer 11

occurs when the two articulating surfaces of the joint are separated. It is associated with joint soft tissue damage.

It commonly occurs from a direct blow to the joint, or a fall on an outstretched hand.

The injury is more serious if ligamental rupture occurs (acromioclavicular or coracoclavicular). If the coracoclavicular ligament is torn, weight of the upper limb is not supported, and the shoulder moves inferiorly. This increases the prominence of the clavicle.

Management of AC joint dislocation is dependent on injury severity and impact on quality of life. The treatment options range from ice and rest, to ligament reconstruction surgery.

Note: this injury is not to be confused with shoulder dislocation – an injury affecting the glenohumeral joint.

Question 12

Fracture of the Clavicle

Answer 12

A function of the clavicle is to transmit forces from the upper limb to the axial skeleton. Thus, the clavicle is the most commonly fractured bone in the body. Fractures commonly result from a fall onto the shoulder, or onto an outstretched hand.

The most common point of fracture is the junction of the medial 2/3 and lateral 1/3. After fracture, the lateral end of the clavicle is displaced inferiorly by the weight of the arm, and medially, by the pectoralis major. The medial end is pulled superiorly, by the sternocleidomastoid muscle.

The suprascapular nerves (medial, intermedial and lateral) may be damaged by the upwards movement of the medial part of the fracture. These nerves innervate the lateral rotators of the upper limb at the shoulder – so damage results in unopposed medial rotation of the upper limb – the ‘waiters tip’ position.

Question 13

Surgical Neck Fracture of the Humerus

Answer 13

occurs by a direct blow to the area, or by falling on an outstretched hand.

It is important to consider the regional anatomy of this area to assess which vessels and nerves are a risk of damage. The key structures of concern is this scenario are the axillary nerve and posterior circumflex artery.

Damage to the axillary nerve will result in paralysis to the deltoid and teres minor muscles; the patient will not being able to abduct their arm.

The axillary nerve also innervates the skin over the lower deltoid (known as the regimental badge area), and so sensory innervation here could be lost.

Question 14

Mid-shaft Fracture to humerus

Answer 14

could easily damage the radial nerve and profunda brachii artery, as they are tightly bound in the radial groove.

The radial nerve innervates the extensors of the wrist. In the event of damage to this nerve, the extensors will be paralysed. This results in unopposed flexion of the wrist occurs, known as ‘wrist drop’.

There is also some sensory loss over the dorsal (posterior) surface of the hand, and the proximal ends of the lateral 3 and a half fingers dorsally.

Question 15

Distal Humeral Fractures

Answer 15

Supracondylar fractures and medial epicondyle fractures are common fracture types of the distal humerus. A supraepicondylar fracture occurs by falling on a flexed elbow. It is a transverse fracture, spanning between the two epicondyles

Direct damage, or swelling can cause interference to the blood supply of the forearm from the brachial artery. The resulting ischaemia can cause Volkmann’s ischaemic contracture – uncontrolled flexion of the hand, as flexors muscles become fibrotic and short. There also can be damage to the medial, ulnar or radial nerves.

A medial epicondyle fracture could damage the ulnar nerve, a deformity known as ulnar claw is the result. There will be a loss of sensation over the medial 1 and 1/2 fingers of the hand, on both the dorsal and palmar surfaces.

Question 16

Fracture of the Scaphoid

Answer 16

In the event of a blow to the wrist (e.g falling on a outstretched hand), the scaphoid takes most of the force. A fractured scaphoid is more common in the younger population.

The scaphoid has a unique blood supply, which runs distal to proximal. A fracture of the scaphoid can disrupt the blood supply to the proximal portion – this is an emergency. Failure to revascularise the scaphoid can lead to avascular necrosis, and future arthritis for the patient.

The main clinical sign of a scaphoid fracture is tenderness in the anatomical snuffbox.

Question 17

Anterior Dislocation of the Lunate

Answer 17

This can occur by falling on a dorsiflexed wrist. The lunate is forced anteriorly, and compresses the carpal tunnel, causing the symptoms of carpal tunnel syndrome.

This manifests clinically as paresthesia in the sensory distribution of the median nerve and weakness of thenar muscles. The lunate can also undergo avascular necrosis, so immediate clinical attention to the fracture is needed.

Question 18

Colles’ Fracture

Answer 18

most common pathology involving the wrist. It is caused by falling onto an outstretched hand.

The radius fractures, with the distal fragment being displaced posteriorly. The ulnar styloid process can also be damaged, and is avulsed in the majority of cases.

This clinical condition produces what is known as the ‘dinner fork deformity’.

Question 19

Fractures to the Radius and Ulna

Answer 19

Although the radius and ulnar are two distinct and separate bones, when dealing with injuries to the forearm, they can be thought of as a ring.

A ring, when broken, usually breaks in two places. The best way of illustrating with is with a polo mint – it is very difficult to break one side without breaking the other.

This means that a fracture to the radius or the ulna usually causes a fracture or dislocation of the other bone. There are two classical fractures:

Monteggia’s Fracture – Usually caused by a force from behind the ulna. The proximal shaft of ulna is fractured, and the head of the radius dislocates anteriorly at the elbow.

Galeazzi’s Fracture – A fracture to the distal radius, with the ulna head dislocating at the distal radio-ulnar joint.

Question 20

Smith’s Fracture

Answer 20

caused by falling onto the back of the hand.

opposite of a Colles’ fracture, as the distal fragment is now placed anteriorly.

Question 21

2 common Fractures of the Metacarpals

Answer 21

Boxer’s fracture – A fracture of the 5th metacarpal neck. It is usually caused by a clenched fist striking a hard object. The distal part of the fracture is displaced posteriorly, producing shortening of the affected finger.

Bennett’s fracture – A fracture of the 1st metacarpal base, extending into the carpometacarpal joint. It is caused by hyperabduction of the thumb.

Question 22

Carpal Tunnel Syndrome

Answer 22

Compression of the median nerve within the carpal tunnel can cause carpal tunnel syndrome (CTS). It is the most common mononeuropathy and can be caused by thickened ligaments and tendon sheaths. Its aetiology is, however, most often idiopathic. If left untreated, CTS can cause weakness and atrophy of the thenar muscles.

The patients history will comment on numbness, tingling and pain in the distribution of the median nerve. The pain will usually radiate to the forearm. Symptoms are often associated with waking the patient from their sleep and being worse in the mornings.

Tests for CTS can be performed during physical examination:

Tapping the nerve in the carpal tunnel to elicit pain in median nerve distribution (Tinel’s Sign)
Holding the wrist in flexion for 60 seconds to elicit numbness/pain in median nerve distribution (Phalen’s manoeuvre)
Treatment involves the use of a splint, holding the wrist in dorsiflexion overnight to relieve symptoms. If this is unsuccessful, corticosterioid injections into the carpal tunnel can be used. In severe case, surgical decompression of the carpal tunnel may be required.

Causes:
Tenosynovitis (thickening of the synovium), repetitive trauma (compression forces & stretching), oedema, fractures, dislocations, inherited small bone structures.

Risk factors:
occupation involving repetitive tasks, diabetes, rheumatoid arthritis,
hypothyroidism, PREGNANCY, menopause, obesity

Question 23

Injury to the Axillary Nerve

Answer 23

The axillary nerve is most commonly damaged by trauma to the shoulder or proximal humerus – such as a fracture of the humerus surgical neck.

Motor functions: Paralysis of the deltoid and teres minor muscles. This renders the patient unable to abduct the affected limb.
Sensory functions: The upper lateral cutaneous nerve of arm will be non functional, resulting in loss of sensation over the regimental badge area.
Characteristic clinical signs: In long standing cases, the paralysed deltoid muscle rapidly atrophies, and the greater tuberosity can be palpated in that area.

Question 24

Lesions of the Musculocutaneous Nerve

Answer 24

How it commonly occurs: An injury to the musculocutaneous nerve is relatively uncommon, as it is well protected within the axilla. The most common cause is a stab wound to the axilla region.

Motor functions: The coracobrachialis, biceps brachii and brachialis muscles are paralysed. Flexion at the shoulder is weakened, but can still occur due to the pectoralis major. Flexion at the elbow is also affected, but can still be performed because of the brachioradialis muscle. Also, supination of the affected limb is greatly weakened, but is produced by the supinator muscle.

Sensory functions: Loss of sensation over the lateral side of the forearm.

Question 25

Lesions of the Median Nerve

Damage to elbow vs wrist

Answer 25

Damaged at the Elbow-
How it commonly occurs: Supracondylar fracture of the humerus.

Motor functions: The flexors and pronators in the forearm are paralysed, with the exception of the flexor carpi ulnaris and medial half of flexor digitorum profundus. The forearm constantly supinated, and flexion is weak (often accompanied by adduction, because of the pull of the flexor carpi ulnaris).

Flexion at the thumb is also prevented, as both the longus and brevis muscles are paralysed.

The lateral two lumbrical muscles are paralysed, and the patient will not be able to flex at the MCP joints or extend at IP joints of the index and middle fingers.

Sensory functions: Lack of sensation over the areas that the median nerve innervates.

Characteristic signs: The thenar eminence is wasted, due to atrophy of the thenar muscles. If patient tries to make a fist, only the little and ring fingers can flex completely. This results in a characteristic shape of the hand, known as hand of benediction.

Damaged at the Wrist -

How it commonly occurs: Lacerations just proximal to the flexor reticaculum.

Motor functions: Thenar muscles paralysed, as are the lateral two lumbricals. This affects opposition of the thumb and flexion of the index and middle fingers.

Sensory functions: Same as an injury at the elbow.

Characteristic signs: Same as an injury at the elbow.

Question 26

Injury to the Radial Nerve

4 main types

Answer 26

In the Axilla

How it commonly occurs: Dislocation of humerus at the glenohumeral joint or fracturesof proximal humerus. Can also happen via excessive pressure on the axilla, e.g. a badly fitting crutch.
Motor functions: Triceps brachii and muscles in posterior compartment are paralysed. The patient is unable to extend the forearm, wrist and fingers. Unopposed flexion of wrist occurs, known as wrist drop.
Sensory functions: All four cutaneous branches of the radial nerve are affected. There will be a loss of sensation over the lateral and posterior upper arm, posterior forearm, and dorsal surface of the lateral three and a half digits.

In the Radial Groove

How it commonly occurs: Fracture of the shaft of the humerus – damaging the radial nerve when it is bound in the radial groove.
Motor functions: The triceps brachii may be weakened, but is not paralysed. The deep branch of the radial nerve is affected, so the muscles in the posterior compartment of the forearm are paralysed. The patient is unable to extend the wrist and fingers. Unopposed flexion of wrist occurs, known as wrist drop.
Sensory functions: The cutaneous branches to the arm and forearm have already arisen. The superficial branch of the radial nerve will be damaged, resulting in sensory loss on the dorsal surface of the lateral three and half digits, and their associated palm area.

Deep Branch of Radial Nerve

How it commonly occurs: Fractures of the radial head, or a posterior dislocation of the radius at the elbow joint.
Motor functions: Muscles in posterior compartment of the forearm are affected – except for the supinator and extensor carpi radialis longus. The extensor carpi radialis longus is a strong extensor at the wrist, and so wristdrop does not occur.
Sensory functions: None, as it is a motor nerve.

Superficial Branch of the Radial Nerve

How it commonly occurs: Stabbing or laceration of the forearm.
Motor functions: None, as it is a sensory nerve.
Sensory functions: There will be sensory loss affecting the dorsal surface of the lateral three and half digits and their associated palm area.

Question 27

Lesions of the Ulnar Nerve

injury at the elbow vs wrist.

Answer 27

Damaged at the Elbow

How it commonly occurs: The nerve is most vulnerable to injury at the medial epicondyle, so fracture of the medial epicondyle is the most common way of damaging the ulnar nerve

Motor functions: Flexor carpi ulnaris and medial half of flexor digitorum profundus paralysed. Flexion of the wrist can still occur, but is accompanied by abduction. The interossei are paralysed, so abduction and adduction of the fingers cannot occur. Movement of the little and ring fingers is greatly reduced, due to paralysis of the medial two lumbricals.

Sensory functions: All sensory branches are affected, so there will be a loss of sensation over the areas that the ulnar nerve innervates.

Characteristic signs: Patient cannot grip paper placed between fingers.

Damaged at the Wrist

How it commonly occurs: Lacerations to the wrist

Motor functions: The interossei are paralysed, so abduction and adduction of the fingers cannot occur. Movement of the little and ring fingers is greatly reduced, due to paralysis of the medial two lumbricals. The two muscles in the forearm are unaffected. results from long term damage to the ulnar nerve

Sensory functions: The palmar branch and superficial branch are usually severed, but the dorsal branch is unaffected. Sensory loss over palmar side of medial one and a half fingers only.

Characteristic signs: Patient cannot grip paper placed between fingers. For long-term cases, a hand deformity called ‘Ulnar Claw’ develops.

Ulnar claw consists of:

Hyper-extension of the metacarpophalangeal joints of the little and ring fingers – this is because of the paralysis of the medial two lumbricals, and the now unopposed action of the extensor muscles
Flexion at the interphalangeal joints (if the lesion has occurred close to the elbow, this might not be evident, as the flexor digitorum profundus will be paralysed)

Question 28

Ulnar Paradox

Answer 28

The ulnar claw is a deformity produced by an ulnar nerve lesion at the wrist. We shall now look at what happens if the ulnar nerve is damaged more proximally – at the elbow.

In a high ulnar nerve injury, some muscles in the anterior forearm are paralysed (in addition to the hand muscles mentioned above):

Medial half of flexor digitorum profundus: Flexes at the distal IP joints of the ring and little fingers.
Flexor carpi ulnaris: Flexes and adducts the wrist.
The ulnar claw will develop as before, but with one key difference. The flexor digitorum profundus is paralysed, and there will not be any flexion at the distal IP joints of the ring and little fingers. Now the ulnar claw only consists of hyperextension at the MCP joints and flexion at the proximal IP joints. This produces a much less evident claw hand.

This is known as the ‘ulnar paradox‘ – you would expect a more debilitating injury to produce a more pronounced deformity, but in fact the opposite occurs.

Question 29

Herniated Intervertebral Disks

Answer 29

The intervertebral disk is a fibrocartilage cylinder that lies between the vertebrae, joining them together. They act to permit the flexibility of the spine, and also as a shock absorber. In the lumbar and thoracic regions, they are wedge shaped, supporting the curvature of the spine.

There are two regions in the vertebral disk; the nucleus pulposus and annulus fibrosus. The annulus fibrosis is tough and collagenous, surrounding the nucleus pulposus. The nucleus pulposus is jelly-like, and is located posteriorly.

In a herniation of the intervertebral disk, the nucleus pulposus ruptures, breaking through the annulus fibrosus. This most commonly occurs in a posterior and lateral direction, putting pressure on the spinal cord, resulting in a variety of neurological and muscular symptoms.

Normally: tension within disc maintained by imbibition
of fluid @ cellular level (absorption of fluid into cellular
matrix during spinal mvmt)

Question 30

4 abnormal morphologies of the spine

Answer 30

Kyphosis: Excessive thoracic curvature, causing a hunchback deformity.

Lordosis: Excessive lumbar curvature, causing a swayback deformity.

Scoliosis: A lateral curvature of the spine, usually of unknown cause.

Cervical Spondylosis: A decrease in the size of the intervertebral foramina, usually due to degeneration of the joints of the spine. The smaller size of the intervertebral foramina puts pressure on the exiting nerves, causing pain.
Normal ‘wear & tear’ of vertebrae & discs in neck

Question 31

Fractured neck of femur

Answer 31

40 year olds, femoral neck fractures are more likely to occur from falls. They are more likely to occur in women, as they generally have more brittle necks from osteoporosis.

The affected limb is often laterally rotated.
The arteries arising from the medial circumflex femoral artery are usually torn, disrupting the blood supply.
This can cause asvascular necrosis of the femoral head and neck.

Question 32

Dislocation of Femoral Head

2 types

Answer 32

Congenital dislocation:
more common in girls (8x as likely), and occurs ~1.5 per 1000 births, which makes it a relatively common abnormality.
During development the femoral head is not placed within the acetabulum, resulting in a dislocated joint.

Common symptoms:
Inability to abduct at the hip joint
Affected limb is shorter
Positive Trendelenburg sign
Having a congenital displacement of the hip predisposes the patient to arthritis of the hip in later life.

Acquired dislocations:
quite uncommon, owing to the strength and stability of the joint.
It is usually during traumatic accidents that a dislocation will occur.

two types:

Posterior dislocations: more common type. The femoral head is forced posteriorly (backwards), and tears through the inferior and posterior part of the joint capsule, where it is at its weakest. The affected limb becomes shortened and medially rotated. The sciatic nerve runs posteriorly to the hip joint, and can be damaged in such an injury. This would cause paralysis of the hamstrings, and the muscles distal to the knee (all of which are supplied by the sciatic nerve).

Anterior dislocations: far more rare, and is a consequence of extension, abduction and lateral rotation. The femoral head ends up anterior and inferior to the acetabulum, and often pulls the acetabular labrum with it.

Question 33

Femoral hernia

Answer 33

common site of bowel herniation.
part of the small intestine protrudes through the femoral ring, underneath inguinal ligament

presents as a lump situated inferolaterally to the pubic tubercle.

more common in women, due to their wider bony pelvis.

The borders of the femoral canal are tough, and not particularly extendible. This can compress the hernia, interfering with its blood supply (strangulated hernia)

usually requires surgical intervention to treat.

Question 34

Proximal femur fractures

2 main groups

Answer 34

Fractures of the femoral neck are a very good predictor of mortality – within a year 1/3 of people with a hip fracture will die.

Intracapsular Fracture:
more common in the elderly, especially women. They are a result of a minor trip or stumble. This fracture occurs within the capsule of the hip joint. It can damage the medial femoral circumflex artery – and cause avascular necrosis of the femoral head.
The distal fragment is pulled upwards and rotated laterally. This manifests clinically as a shorter leg length, with the toes pointing laterally

Extracapsular Fractures:
more common in young and middle aged people. In these fractures, the blood supply to the head of femur is intact, and so no avascular necrosis can occur. Like the subcapital fracture, the leg is shortened and laterally rotated.

Question 35

Femoral shaft fractures

Answer 35

relatively uncommon, and require a lot of force. Such fractures are usually a consequence of a traumatic injury, such as a vehicular accident.

One particular classification is the spiral fracture – this can present with leg shortening. The loss of leg length is due the fragments overriding, pulled by the attached muscles.

As the method of injury is typically high energy, the surrounding soft tissues may also be damaged. One possible sequelae of a femoral shaft fracture is femoral nerve palsy. It is also important to ensure the blood supply from the femoral artery hasn’t been compromised, as it supplies the remainder of the lower limb.

Question 36

Fractures of tibia

Answer 36

relatively common, and occur most frequently in the middle aged and elderly.
If the fibula is not fractured, it supports the tibia, and displacement of the fragments is minimal.

The proximal end of the tibia is the site that is most vulnerable to damage, resulting usually from some traumatic accident e.g vehicular. The condyles may be broken up in the fracture and it is not uncommon for there to be injury to the ligaments of the knee.

At the ankle, the medial malleolus can be fractured. This is caused by the ankle being twisted inwards (overinversion) – the talus of the foot is forced against the medial malleolus, causing a spiral fracture.

Question 37

Fractures of the fibula

Answer 37

At the ankle, the lateral malleolus of the fibula is prone to fracture.

There are two main ways in which this occurs:

forced external rotation of the ankle. This force of the talus against the bone causes a spiral fracture of the lateral malleolus.

less common way, by the foot being twisted outwards (called eversion). Again, the talus presses against the lateral malleolus, and this time causes a transverse fracture.

Question 38

Stripping of the Saphenous Vein

Answer 38

The saphenous vein is often stripped in individuals with problematic varicose veins. The long saphenous vein is accompanied in its course by the saphenous nerve. Damage to the saphenous nerve during this procedure can lead to pain, paraesthesia or complete loss of sensation the medial side of the lower leg

Question 39

Femoral Nerve Block

Answer 39

(in combination with a sciatic nerve block) may be indicated in patients requiring lower limb surgery who cannot tolerate a general anaesthetic. A femoral nerve block can also be used as peri and post operative analgesia for patients with a fractured neck of femur who cannot tolerate particular analgesics.

Question 40

Damage to obturator nerve

Answer 40

The obturator nerve can be damaged during surgery involving the pelvis or abdomen. Symptoms include numbness and paraesthesia on the medial aspect of the thigh and weakness in adduction of the thigh. Alternatively, the patient could present with posture and gait problems due to the loss of adduction.

Question 41

Damage to tibial nerve

Answer 41

Damage to the tibial nerve is rare, and is often a result of direct trauma, entrapment through narrow space or compression for long period of time. Damage results in loss of plantar flexion, loss of flexion of toes and weakened inversion (The tibialis anterior can still invert the foot).

Question 42

Damage to common fibular nerve

Answer 42

most commonly damaged by a fracture of the fibula, or the use of a tight plaster cast.

The anatomical course of the common fibular nerve causes it to wrap round the neck of the fibular, and so any fractures of the fibular neck can cause nerve palsy.

Patients with common fibular nerve damage will lose the ability to dorsiflex the foot at the ankle joint. Hence the foot will appear permanently plantarflexed – known as footdrop. They may also present with a characteristic gait, as a result of the footdrop

There will also be a loss of sensation over the dorsum of the foot, and lateral side of the leg. Innervation is preserved on the medial side of the leg (supplied by the saphenous nerve, a branch of the femoral), and the heel and sole (supplied by the tibial nerve, a branch of the sciatic).

Question 43

Superficial fibular nerve entrapment

Answer 43

Superficial peroneal nerve entrapment (also known as nerve compression) can cause pain, and paresthesia over the lower leg and dorsum of the foot. Entrapment frequently results from ankle sprains or twisting of the ankle, as this causes the nerve to stretch in the lower leg.

Another cause of nerve entrapment occurs at the point where the nerve exits the deep fascia of the leg, the nerve becoming compressed by this fascia. Surgical decompression of the nerve therefore is used to provide relief from the symptoms and pain.

Question 44

Damage to superficial fibular nerve

Answer 44

The superficial fibular nerve may be damaged by fracture of the fibula, or by a perforating wound to the lateral side of the leg.

As the muscles that the superficial fibular nerve innervates are evertors, injury to the nerve may result in a loss of eversion. A loss of sensation over the majority of the dorsum of the foot and the anterolateral aspect of the lower leg could also result.

Question 45

Foot drop

Answer 45

The deep fibular nerve can become entrapped or compressed during its course through the anterior compartment of the leg. This causes paralysis of the muscles in the anterior compartment of the leg, and so a patient loses the ability to dorsiflex the foot.

With unopposed plantarflexion, their foot drops. Footdrop gives the patient’s foot difficulty in clearing the ground during the swing phase of walking, and the limb looks too long. In addition, the foot will slap down on the floor when the patient walks, because it can’t be lowered in a controlled manner. To compensate for this, the patient develops an abnormal gait:

Waddling gait: The patient leans excessively onto the normal limb.
Swing-out gait: he patient abducts the abnormal limb
High steppage gait: the patient flexes the hip and knee excessively on the abnormal limb, so as to clear the dropped foot from the floor.

There are two main reasons why the deep fibular nerve could be compressed.

anterior leg muscles have been excessively used and so are compressing the nerve within the anterior compartment. The patient will experience pain in the anterior leg.

tight-fitting shoes, compressing the nerve beneath the extensor retinaculum. This commonly occurs with wearing tight ski boots (referred to as ski boot syndrome). The patient will experience pain in the dorsum of the foot.

Question 46

Trendelenberg gair

Answer 46

During the leg lift and swing phases of walking, the body weight is placed on one limb. The key abductor muscles (the gluteus medius and minimus) contract to stop the pelvis dropping towards the raised leg, as gravity dictates.

The Trendelenburg sign is where the pelvis drops towards the side of the raised limb. This signifies that the abductor muscles on the standing limb are greatly weakened or paralysed. For example, if the left leg was raised, and pelvic drop was observed on that side, the abductor muscles on the right leg are the cause. This is due to a lesion of the superior gluteal nerve which innervates the abductors.

During walking, a weakness in the abductor muscles gives rise to a characteristic gait. As the pelvis drops on one side, the trunk lurches to the opposite side, in an effort to maintain a steady pelvic level.

During the next step, the trunk is whipped back over the pelvis towards centre. Often the momentum of this is too much for the abdominals, causing the trunk to overcompensate and fall slightly past centre to the opposite side. This highly recognisable lurching walk is called the Trendelenberg gait.

Question 47

Popliteal aneurysm

Answer 47

An aneurysm is a dilation of an artery, which is greater than 50% of the normal diameter. The popliteal fascial layer (the roof of the popliteal fossa) is tough and non extensible, and so an aneurysm of the popliteal artery has consequences for the other contents of the popliteal fossa.

The tibial nerve is particularly susceptible to compression from the popliteal artery. Damage to this nerve will present as leg anesthesia, or loss of leg motor function.

An aneurysm of the popliteal artery can be detected by an obvious palpable pulsation in the popliteal fossa, with abnormal arterial sounds.

Question 48

Varicose veins

Answer 48

In the lower limbs, venous blood flows from the skin to superficial veins, which drain into the deep veins.

With the veins there are valves that prevent back flow of blood. If these valves become incompetent, blood can flow back into the superficial veins. This results in an increased intra-luminal pressure, which the veins cannot withstand, causing them to become dilated and torturous. This condition is known as varicose veins.

There are various soft tissue changes that can occur with chronic varicose veins. Due to the incompetence of the valves, the pressure in the venous system rises. This damages the cells, causing blood to extrude into skin. Further complications can produce a brown pigmentation and ulceration of the surrounding tissue.

Varicose veins can be treated by;

Surgical movement of the saphenous systems.
Reconstruction of valves.
Tying off the affected valves.

Question 49

Baker’s cyst

Answer 49

(or popliteal cyst)
inflammation and swelling of the semimembranosus bursa - a fluid filled sac found in the knee joint.
usually arise in conjunction with arthritis of the knee (rhuematoid or osteoarthritis).
usually self-resolves, but the cyst can rupture and produce symptoms similar to deep vein thrombosis.

Question 50

Injury to collateral ligaments of the knee

Answer 50

most common pathology affecting the knee joint.
caused by a force being applied to the side of the knee when the foot is placed on the ground.

Damage to the collateral ligaments can be assessed by asking the patient to medially rotate and laterally rotate the leg. Pain on medial rotation indicates damage to the medial ligament, pain on lateral indicates damage to the lateral ligament.

If the tibial collateral ligament is damaged, it is more than likely that the medial meniscus is torn, due to their attachment.

Question 51

Injury to anterior cruciate ligament

Answer 51

can be torn by hyperextension of the knee joint, or by the application of a large force to the back of the knee with the joint partly flexed.

To test for this, you can perform an anterior drawer test, where you attempt the pull the tibia forwards, if it moves, the ligament has been torn.

Damage to the ACL can cause a triad of injuries – known as the ‘unhappy triad’. Tearing of the ACL causes the unstable femur to shift medially, tearing the lateral meniscus and the tibial collateral ligament. In addition, the medial meniscus can also be torn, due to its attachment to the tibial collateral ligament

Question 52

Injury to the posterior cruciate ligament

Answer 52

The most common mechanism of posterior cruciate ligament (PCL) damage is the ‘dashboard injury’. This occurs when the knee is flexed, and a large force is applied to the shins, pushing the tibia posteriorly. This is often seen is car accidents, where the hits the dashboard.

The posterior cruciate ligament can also be torn by hyperextension of the knee joint, or by damage to the upper part of the tibial tuberosity.

To test for PCL damage, perform the posterior drawer test. This is where the clinical holds the knee in flexed position, and pushes the shin posteriorly. If there is movement, the ligament has been torn.

Question 53

Inflammation of bursae of the knee

Answer 53

Friction between the skin and the patella cause the prepatella bursa to become inflamed producing a swelling on the anterior side of the knee, known as housemaids knee.

Friction between the skin and tibia can cause the infrapatella bursa to become inflamed resulting in what is known as clergyman’s knee. (frequently injured by clergymen kneeling on hard surfaces during prayer).

Question 54

Foot drop

Answer 54

Footdrop is a clinical sign indicating paralysis of the muscles in the anterior compartment of the leg. It is most commonly seen when the common fibular nerve (from which the deep fibular nerve arises) is damaged.

In footdrop, the muscles in the anterior compartment are paralysed. The unopposed pull of the plantarflexor muscles (found in the posterior leg) produces permanent plantarflexion. This can interfere with walking – as the affected limb can drag along the ground. To circumvent this, the patient can flick the foot outwards while walking – known as an ‘eversion flick‘.

Question 55

Popliteal aneurysm

Answer 55

An aneurysm is a dilation of an artery, which is greater than 50% of the normal diameter. The popliteal fascial layer (the roof of the popliteal fossa) is tough and non extensible, and so an aneurysm of the popliteal artery has consequences for the other contents of the popliteal fossa.

The tibial nerve is particularly susceptible to compression from the popliteal artery. Damage to this nerve will present as leg anesthesia, or loss of leg motor function.

An aneurysm of the popliteal artery can be detected by an obvious palpable pulsation in the popliteal fossa, with abnormal arterial sounds.

Question 56

Ruptured Calcaneal tendon

Answer 56

Rupture of the calcaneal tendon refers to a partial or complete tear of the tendon. It is more likely to occur in people with a history of calcaneal tendinitis (chronic inflammation of the tendon).

The injury is usually sustained during forceful plantarflexion of the foot. The patient will be unable to plantarflex the foot against resistance, and the affected foot will be permanently dorsiflexed. The soleus and gastrocnemius can contract to form a lump in the calf region.

Treatment of a ruptured calcaneal tendon is usually non-surgical, except in those with active lifestyles.

Question 57

Pulse points in the lower limb

Answer 57

There are three main pulse points in the lower limb; femoral, popliteal and dorsalis pedis.

The femoral pulse can be palpated as it enters the femoral triangle, midway between the anterior superior iliac spine of the pelvis, and the pubis synthesis (the mid-inguinal point).
The popliteal artery is the hardest pulse to find. It lies deep in the popliteal fossa, and requires deep palpation to feel. To make it easier, you can ask the patient to slightly flex their leg – this relaxes the fascia around the popliteal fossa.
The dorsalis pedis pulse is found by palpating on the dorsum of the foot, just lateral to extensor hallucis longus tendon.

Question 58

Fractures of the talus

Answer 58

Talar fractures occur in two places – the neck of the talus, or the body:

Neck fractures are caused by excessive dorsiflexion of the foot. The neck of the talus is pushed against the tibia. In this type of fracture, the blood supply to the talus may be disturbed, leading to avascular necrosis of the bone.
Body fractures usually occur from jumping from a height.
In any fracture of the talus, the malleoli of the leg bones act to hold the fragments together, so there is little displacement of the fracture pieces.

Question 59

Fractures of the calcaneus

Answer 59

The calcaneus is often fractured in a ‘crush‘ type injury. The most common mechanism of damage is falling onto the heel from a height – the talus is driven into the calcaneus. The bone can break into several pieces – known as a comminuted fracture. Upon x-ray, the calcaneus will appear shorter and wider.

Even after treatment, a calcaneal fracture can cause further problems. The sub-talar joint is usually disrupted, causing the joint to become arthritic. The patient will experience pain upon inversion and eversion – which can make walking on uneven ground particularly painful.

Question 60

Fractures of the metatarsal bones

Answer 60

Metatarsal fractures can occur by three mechanisms.

The most common method of fracture is a direct blow to the foot – usually from a heavy object dropping onto the foot.

Another type of metatarsal injury is a stress fracture, an incomplete fracture caused by repeated stress to the bone. It is common in athletes, and occurs most frequently to metatarsals II, III and IV.

The metatarsals can also be fractured by excessive inversion of the foot. If the foot is violently inverted, the fibularis brevis muscle can avulse (‘tear off’) the base of metatarsal V.

Question 61

Damage to the common fibular nerve

Answer 61

The common fibular nerve is most commonly damaged by a fracture of the fibula, or the use of a tight plaster cast. The anatomical course of the common fibular nerve causes it to wrap round the neck of the fibular, and so any fractures of the fibular neck can cause nerve palsy.

Patients with common fibular nerve damage will lose the ability to dorsiflex the foot at the ankle joint. Hence the foot will appear permanently plantarflexed – known as footdrop. They may also present with a characteristic gait, as a result of the footdrop (for more information, see Walking and Gaits).

There will also be a loss of sensation over the dorsum of the foot, and lateral side of the leg. Innervation is preserved on the medial side of the leg (supplied by the saphenous nerve, a branch of the femoral), and the heel and sole (supplied by the tibial nerve, a branch of the sciatic).

Question 62

Trendelenberg Gait

Answer 62

During the leg lift and swing phases of walking, the body weight is placed on one limb. The key abductor muscles (the gluteus medius and minimus) contract to stop the pelvis dropping towards the raised leg, as gravity dictates.

The Trendelenburg sign is where the pelvis drops towards the side of the raised limb. This signifies that the abductor muscles on the standing limb are greatly weakened or paralysed. For example, if the left leg was raised, and pelvic drop was observed on that side, the abductor muscles on the right leg are the cause. This is due to a lesion of the superior gluteal nerve which innervates the abductors.

During walking, a weakness in the abductor muscles gives rise to a characteristic gait. As the pelvis drops on one side, the trunk lurches to the opposite side, in an effort to maintain a steady pelvic level.

During the next step, the trunk is whipped back over the pelvis towards centre. Often the momentum of this is too much for the abdominals, causing the trunk to overcompensate and fall slightly past centre to the opposite side. This highly recognisable lurching walk is called the Trendelenberg gait.

Question 63

Foot drop

Answer 63

Has a characteristic gait
damage to the common or deep fibular nerve. The common fibular nerve wraps around the head of fibula, so blunt trauma or fracture here can lead to foot drop.

The deep fibular nerve innervates the muscles in the anterior compartment of the leg. These muscles dorsiflex the foot, which is required during the swing phase to clear the toes away from the ground.

If the deep fibular nerve is damaged, then the foot cannot be dorsiflexed, and drags along the ground during the swing phase. To try and dorsiflex the foot during the swing phase, the patient may evert the foot in a sudden motion, called an ‘eversion flick’.

Question 64

Antalgic gait

Answer 64

Patients suffering from long standing joint problems may develop a gait that reduces pain, called an antalgic gait. For example, a patient with osteoporosis in one limb may spend less time on that limb, reducing pain. This is easily noticed when checking to see whether the cadence of the gait is even.