MSK Session 4 - Hand and Wrist

Question 1

What is the carpal tunnel?

Answer 1

• The carpal tunnel is a narrow passageway found on the anterior portion of the wrist.
• It serves as the entrance to the palm for several tendons and the median nerve.

Question 2

Describe the borders of the carpal tunnel.

Answer 2

• The carpal tunnel is formed by two layers: a deep carpal arch and a superficial flexor retinaculum.
• The deep carpal arch forms a concave surface, which is converted into a tunnel by the overlying flexor retinaculum.
• To find where the carpal tunnel begins on yourself, locate your distal wrist crease, which aligns with the entrance of the carpal tunnel.

Question 3

Describe the features of the carpal arch.

Answer 3

• Concave on the palmar side
• Formed laterally by the scaphoid and trapezium tubercles
• Formed medially by the hook of the hamate and the pisiform

Question 4

Describe the features of the flexor retinaculum.

Answer 4

• Thick connective tissue
• Turns the carpal arch into the carpal tunnel by bridging the space between the medial and lateral parts of the arch.
• Originates on the lateral side and inserts on the medial side of the carpal arch.

Question 5

Briefly describe the contents of the carpal tunnel.

Answer 5

The carpal tunnel contains a total of 9 tendons, surrounded by synovial sheaths, and the median nerve.

Question 6

Describe the characteristics and features of the tendons of the carpal tunnel.

Answer 6

• Tendons

I. The tendon of flexor pollicis longus

II. Four tendons of flexor digitorum profundus

III. Four tendons of flexor digitorum superficialis

• The 8 tendons of the flexor digitorum profundus and flexor digitorum superficialis are surrounded by a single synovial sheath. The tendon of flexor pollicis longus is surrounded by its own synovial sheath. These sheaths allow free movement of the tendons.
• Sometimes you may hear that the carpal tunnel contains another tendon, the flexor carpi radialis tendon, but this is located within the flexor retinaculum and not within the carpal tunnel itself!

Question 7

Describe the features of median nerve.

Answer 7

• Once it passes through the carpal tunnel, the median nerve divides into 2 branches: the recurrent branch and palmar digital nerves.
• The palmar digital nerves give sensory innervation to the palmar skin and dorsal nail beds of the lateral three and a half digits. They also provide motor innervation to the lateral two lumbricals. The recurrent branch supplies the thenar muscle group.

Question 8

What is the anatomical snuffbox?

Answer 8

• The anatomical snuffbox (also known as the radial fossa), is a triangular depression found on the lateral aspect of the dorsum of the hand.
• It is located at the level of the carpal bones, and best seen when the thumb is abducted. I
• n the past, this depression was used to hold snuff (ground tobacco) before inhaling via the nose – hence it was given the name ‘snuffbox’.

Question 9

Describe the borders of the anatomical snuffbox.

Answer 9

• As the snuffbox is triangularly shaped, it has three borders, a floor and a roof:

I. Ulnar (medial) border: Tendon of the extensor pollicis longus.

II. Radial (lateral) border: Tendons of the abductor pollicis longus and extensor pollicis brevis.

III. Proximal border: Styloid process of the radius.

IV. Floor: Carpal bones; scaphoid and trapezium.

V. Roof: Skin.

• It is important to note that the tendons of the muscles form the borders, not the muscles themselves.

Question 10

Describe the contents of the anatomical snuffbox.

Answer 10

• The main contents of the anatomical snuffbox are the radial artery, a branch of the radial nerve, and the cephalic vein.
• The radial artery crosses the floor of the anatomical snuffbox in an oblique manner. It runs deep to the extensor tendons. The radial pulse can be palpated in some individuals by placing two fingers on the proximal portion of the anatomical snuffbox.
• Subcutaneously, terminal branches of the superficial branch of the radial nerve run across the roof of the anatomical snuffbox, providing innervation to the skin of the lateral 3 1/2 digits on the dorsum of the hand, and the associated palm area.
• Also subcutaneously, the cephalic vein crosses the anatomical snuffbox, having just arisen from the dorsal venous network of the hand.

Question 11

Describe the muscles of the hand.

Answer 11

• Muscles acting on the hand can be divided into two groups: extrinsic and intrinsic muscles.

I. The extrinsic muscles are located in the anterior and posterior compartments of the forearm. They control crude movements and produce a forceful grip.

II. The intrinsic muscles of the hand are located within the hand itself. They are responsible for the fine motor functions of the hand.

• These include the adductor pollicis, palmaris brevis, interossei, lumbricals, thenar and hypothenar muscles.

Question 12

Outline the structure of the thenar muscles.

Answer 12

• The thenar muscles are three short muscles located at the base of the thumb.
• The muscle bellies produce a bulge, known as the thenar eminence.
• They are responsible for the fine movements of the thumb.
• The median nerve innervates all the thenar muscles.

Question 13

Describe the structure, attachments and actions and innervation of the opponens pollicis.

Answer 13

• Structure: The opponens pollicis is the largest of the thenar muscles, and lies underneath the other two.

- Attachments: Originates from the tubercle of the trapezium, and the associated flexor retinaculum. It inserts into the lateral margin of the metacarpal of the thumb (i.e. the first metacarpal).

- Actions: Opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium.

- Innervation: Median nerve.

Question 14

Describe the structure, attachments and actions and innervation of the abductor pollicis brevis.

Answer 14

• Structure: This muscle is found anteriorly to the opponens pollicis and proximal to the flexor pollicis brevis.

- Attachments: Originates from the tubercles of the scaphoid and trapezium, and from the associated flexor retinaculum. Attaches to lateral side of proximal phalanx of the thumb.

- Actions: Abducts the thumb.

- Innervation: Median nerve.

Question 15

Describe the structure, attachments, actions and innervation of the flexor pollicis brevis.

Answer 15

• Structure: The most distal of the thenar muscles.

- Attachments: Originates from the tubercle of the trapezium and from the associated flexor retinaculum. Attaches to the base of the proximal phalanx of the thumb.

- Actions: Flexes the metacarpophalangeal (MCP) joint of the thumb.

- Innervation: Median nerve.

Question 16

Describe the structure, attachments, actions and innervation of the opponens digiti minimi.

Answer 16

• Structure: The opponens digit minimi lies deep to the other hypothenar muscles.

- Attachments: Originates from the hook of hamate and associated flexor retinaculum, inserts into the medial margin of metacarpal V.

- Actions: It rotates the metacarpal of the little finger towards the palm, producing opposition.

- Innervation: Ulnar nerve.

Question 17

Describe the structure, attachments, actions and innervation of the abductor digiti minimi.

Answer 17

• Structure:The most superficial of the hypothenar muscles.

- Attachments: Originates from the pisiform and the tendon of the flexor carpi ulnaris. It attaches to the base of the proximal phalanx of the little finger.

- Actions: Abducts the little finger.

- Innervation: Ulnar nerve.

Question 18

Describe the structure, attachments, actions and innervation of the flexor digiti minimi brevis

Answer 18

• Structure: This muscles lies laterally to the abductor digiti minimi.

- Attachments: Originates from the hook of hamate and adjacent flexor retinaculum, and inserts into the base of the proximal phalanx of the little finger.

- Actions: Flexes the MCP joint of the little finger.

- Innervation: Ulnar Nerve.

Question 19

What are the lumbricals?

Answer 19

• These are four lumbricals in the hand, each associated with a finger. They are very crucial to finger movement, linking the extensor tendons to the flexor tendons.
• Denervation of these muscles is the basis for the ulnar claw and hand of benediction.

Question 20

Describe the attachments, actions and innervation of the lumbricals.

Answer 20

• Attachments: Each lumbrical originates from a tendon of the flexor digitorum profundus. They pass dorsally and laterally around each finger, and inserts into the extensor hood.
• Actions: The flex at the MCP joint, and extend at the interphalangeal (IP) joints of each finger.
• Innervation: The medial two lumbricals (of the little and ring fingers) are innervated by the ulnar nerve. The lateral two lumbricals (of the index and middle fingers) are innervated by the median nerve.

Question 21

What are the interossei muscles?

Answer 21

• The interossei muscles are located between the metacarpals. They can be divided into two groups: the dorsal and palmar interossei.
• In addition to their actions of abduction (dorsal interossei) and adduction (palmar interossei) of the fingers, the interossei also assist the lumbricals in flexion and MCP joints and extension at the IP joints.

Question 22

Describe the structure, attachments, actions and innervation of the dorsal interossei.

Answer 22

• Structure: The most superficial of all dorsal muscles, these can be palpated on the dorsum of the hand. There are four dorsal interossei muscles.

- Attachments: Each interossei originates from the lateral and medial surfaces of the metacarpals. They attach into the extensor hood and proximal phalanx of each finger.

- Actions: Abduct the fingers at the MCP joint.

- Innervation: Ulnar nerve.

Question 23

Describe the structure, attachments, actions and innervation of the palmar interossei.

Answer 23

• Structure: These are located anteriorly on the hand. There are three palmar interossei muscles.

- Attachments: Each interossei originates from a medial or lateral surface of a metacarpal, and attaches into the extensor hood and proximal phalanx of same finger.

- Actions: Adducts the fingers at the MCP joint.

- Innervation: Ulnar nerve.

Question 24

Describe the structure, attachments, actions and innervation of the palmaris brevis

Answer 24

• Structure: This is a small, thin muscle, found very superficially in the subcutaneous tissue of the hypothenar eminence.

- Attachments: Originates from the palmar aponeurosis and flexor retinaculum, attaches to the dermis of the skin on the medial margin of the hand.

- Actions: Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip.

- Innervation: Ulnar nerve.

Question 25

Describe the structure, attachments, actions and innervation of the adductor pollicis.

Answer 25

• Structure: This is large triangular muscle with two heads. The radial artery passes anteriorly through the space between the two heads, forming the deep palmar arch.

- Attachments: One head originates from metacarpal III. The other head originates from the capitate and adjacent areas of metacarpals II and III. Both attach into the base of the proximal phalanx of the thumb.

- Actions: Adductor of the thumb.

- Innervation: Ulnar nerve.

Question 26

Identify the bones of the wrist and hand.

Answer 26

The bones of the hand provide support and flexibility to the soft tissues. They can be divided into three categories:

I. Carpal bones (Most proximal) – A set of eight irregularly shaped bones. These are located in the wrist area.

II. Metacarpals – There are five metacarpals, each one related to a digit.

III. Phalanges (Most distal) – The bones of the fingers. Each finger has three phalanges, except for the thumb, which has two.

Question 27

Describe the carpal bones according to their organisation proximally and distally.

Answer 27

• The carpal bones are a group of eight, irregularly shaped bones. They are organised into two rows – proximal and distal.
• In the proximal row, the bones are (lateral to medial):

I. Scaphoid

II. Lunate

III. Triquetrum

IV. Pisiform – A sesamoid bone, formed within the tendon of the flexor carpi ulnaris

• In the distal row, the bones are (lateral to medial):

I. Trapezium

II. Trapezoid

III. Capitate

IV. Hamate – has a projection on its palmar surface called the hook of hamate

• Proximally, the scaphoid and lunate articulate with the radius to form the wrist joint. In the distal row, all of the carpal bones articulate with the metacarpals.

Question 28

Describe the arrangement and components of the metacarpal bones.

Answer 28

• The metacarpal bones articulate proximally with the carpals, and distally with the proximal phalanges.
• They are numbered, and each associated with a digit:

I. Metacarpal I – Thumb.

II. Metacarpal II – Index finger.

III. Metacarpal III – Middle finger.

IV. Metacarpal IV – Ring finger.

V. Metacarpal V – Little finger.

• Each metacarpal consists of a base, shaft and a head. The medial and lateral surfaces of the metacarpals are concave, allowing attachment of the interoessei muscles.

Question 29

Describe the structure of the phalanges.

Answer 29

• The phalanges are the bones of the fingers.
• The thumb has a proximal and distal phalanx, while the rest of the digits have proximal, middle and distal phalanges.

Question 30

Briefly outline the blood supply of the hand.

Answer 30

• The hand has a very good blood supply, with many anastomosing arteries, allowing the hand to be perfused when grasping or applying pressure.
• A good majority of these arteries are superficial, allowing for heat loss when needed.
• In the hand, the ulnar and radial arteries interconnect to form two arches, from which branches to the digits emerge.

Question 31

Describe the structure and function of the radial and ulnar arteries.

Answer 31

- Radial artery – contributes mainly to supply of the thumb and the lateral side of the index finger

- Ulnar artery – contributes mainly to the supply of the rest of the digits, and the medial side of the index finger

Question 32

Describe the anatomical course of the arteries of the hand, in relation to the palmar arches.

Answer 32

• The ulnar artery moves into the hand anteriorly to the flexor retinaculum, and laterally to the ulnar nerve.
• In the hand, it divides into two branches, the superficial palmar arch, and the deep palmar branch.
• From the superficial palmar arch, common palmar digital arteries arise, supplying the digits.
• The superficial palmar arch then anastamoses with a branch of the radial artery.
• The superficial palmar arch is found anteriorly to the flexor tendons in the hand, deep to the palmar aponeurosis.

The radial artery enters the hand dorsally, crossing the floor of the anatomical snuffbox. It turns medially and moves between the heads of the adductor pollicis. The radial artery then anastamoses with the deep palmar branch of the ulnar artery, forming the deep palmar arch, which gives rise to five arteries supplying the digits.

Question 33

Describe Allen’s test and how to interpret the result.

Answer 33

• The Allen test is a worldwide used test to determine whether the patency of the radial or ulnar artery is normal.
• It is performed prior to radial cannulation or catheterisation, because placement of such a catheter often results in thrombosis.
• Therefore, the test is used to reduce the risk of ischemia to the hand.
• The Allen test can also be used to gather information preceding removal of the radial artery for a coronary bypass graft.
• A positive Allen’s test means that the patient does not have dual blood supply to the hand, which is a negative indication for catheterisation or removal of the radial arteries.

Question 34

Describe the cutaneous distribution of the ulnar, median and radial nerves in the dorsum and palm of the hand.

Answer 34

Dorsum of Hand

Radial Nerve

Skin of dorsum of thumb and 2.5 digits as far as the distal interphalangeal joint

Ulnar Nerve

Ulnar 1 1/2 digits and adjacent part of dorsum of hand

Palm of Hand

Ulnar Nerve

• Sensory to skin of ulnar 1 1/2 digits
• Motor to muscles of hypothenar eminence
• Motor to ulnar two lumbricals
• Motor to 7 interossei
• Motor to adductor pollicis muscle

Median Nerve

• Sensory to skin of palmar aspect of thumb and 2 1/2 digits including the skin on the dorsal aspect of the distal phalanges
• Motor to muscles of thenar eminence
• Motor to radial two lumbrical muscles

Question 35

Give a brief description of the features of the following clinical condition: Osteoarthritis of the 1^st CMC joint and interphalangeal joints including Herberden’s nodes

Answer 35

• Carpometacarpal (CMC) osteoarthritis (OA) is a reparitive joint disease affecting the first carpometacarpal joint (CMC1).
• This joint is formed by the trapezium bone of the wrist and the first metacarpal bone of the thumb.
• Because of its relative instability, this joint is a frequent site for osteoarthritis.
• Carpometacarpal osteoarthritis (CMC OA) of the thumb occurs when the cushioning cartilage of the joint surfaces wears away, resulting in damage of the joint.

Question 36

Give a brief description of the features of the following clinical condition: Osteoarthritis of the hand

Answer 36

• Distal interphalangeal (DIP) joints are most often affected
• Proximal interphalangeal (PIP) joints and the joints at the base of the thumb are also typically involved
• Heberden nodes, which represent palpable osteophytes in the DIP joints, are more characteristic in women than in men
• Inflammatory changes are typically absent, less pronounced, or go unnoticed.

Question 37

Give a brief description of the features of the following clinical condition: Boxer’s fractures

Answer 37

• Boxer’s Fracture is a colloquial term for a fracture of one of the metacarpal bones of the hand.
• Classically, the fracture occurs transversely across the neck of the bone, after the patient strikes an object with a closed fist.
• Alternate terms include scrapper’s fracture or bar room fracture.

Question 38

Give a brief description of the features of the following clinical condition: De Quervain’s tenosynovitis

Answer 38

• De Quervain’s tenosynovitis is a painful condition affecting the tendons on the thumb side of your wrist.
• If you have de Quervain’s tenosynovitis, it will probably hurt when you turn your wrist, grasp anything or make a fist.
• Although the exact cause of de Quervain’s tenosynovitis isn’t known, any activity that relies on repetitive hand or wrist movement can make it worse.

Question 39

Give a brief description of the features of the following clinical condition: Carpal tunnel syndrome

Answer 39

• Carpal tunnel syndrome (CTS) is a common condition that causes a tingling sensation, numbness and sometimes pain in the hand and fingers.
• These sensations usually develop gradually and start off being worse during the night.
• They tend to affect the thumb, index finger and middle finger.

Question 40

Give a brief description of the features of the following clinical condition: Compression of the ulnar nerve in Guyon’s canal

Answer 40

• Ulnar tunnel syndrome, also known as Guyon’s canal syndrome or Handlebar palsy, is caused by entrapment of the ulnar nerve in the Guyon canal as it passes through the wrist.
• Symptoms usually begin with a feeling of pins and needles in the ring and little fingers before progressing to a loss of sensation and/or impaired motor function of the intrinsic muscles of the hand which are innervated by the ulnar nerve.
• Ulnar tunnel syndrome is commonly seen in regular cyclists due to prolonged pressure of the Guyon’s canal against bicycle handlebars.

Question 41

Give a brief description of the features of the following clinical condition: Dupuytrens contracture

Answer 41

• Dupuytren’s contracture (Dupuytren’s disease) is a condition that affects the hands and fingers.
• It causes one or more fingers to bend into the palm of the hand.
• It can affect one or both hands, and sometimes affect the thumb.

Question 42

Give a brief description of the features of the following clinical condition: Reflex sympathetic dystrophy

Answer 42

• Type 1 complex regional pain syndrome (CRPS 1), formerly known as reflex sympathetic dystrophy (RSD), is a clinical syndrome of variable course and unknown cause characterized by pain, swelling, and vasomotor dysfunction of an extremity.
• This condition is often the result of trauma or surgery.
• Limb immobility may lead to CRPS 1; in a hemiplegic upper limb after stroke, the syndrome is often termed shoulder-hand syndrome.
• CRPS 1 may also develop in the absence of an identifiable precipitating event.

Question 43

What is a joint?

Answer 43

• A joint or articulation or arthrosis is a point of contact between neighbouring bones, between cartilage and bones, or between teeth and bones.
• The structural characteristics of a specific joint affect the strength, magnitude of movement, and types of movement that may occur at a specific joint.

Question 44

How does one go about classifying joints?

Answer 44

Based on the presence or absence of a synovial cavity and the type of connective tissue that binds the bones together, the structural classification of joints categorizes joints into three major types:

• Fibrous joints
• Cartilaginous joints
• Synovial joints

Question 45

Describe the structure, functions and examples of fibrous joints.

Answer 45

• Fibrous joints lack a synovial cavity and the articulating bones are held very closely together by fibrous connective tissue; they permit little or no movement.
• Examples of fibrous joints include the sutures of the skull, the inferior tibiofibular joint, the radioulnar interosseous membrane, the posterior sacroiliac joint and the joints that occur between the roots of the teeth and the bone of mandible or maxilla.

Question 46

Describe the structure, types and examples of cartilaginous joints.

Answer 46

• Cartilaginous joints lack a synovial cavity, and the articulating bones are tightly connected by cartilage; they permit little or no movement.There are two types of cartilaginous joints:
• Primary cartilaginous joints

I. The connecting tissue is hyaline cartilage

II. An example is an epiphyseal plate

• Secondary cartilaginous joints (symphyses)

I. The connecting tissue is a disc of fibrocartilage

II. An example is the pubic symphysis

Question 47

What are important characteristics of synovial joints?

Answer 47

• Synovial joints are characterized by the presence of a synovial (joint) cavity. Additional important characteristics include:

- Articular cartilage

• Articular capsule composed of two layers:

I. Outer fibrous capsule that may have ligaments

II. Inner synovial membrane which secretes the lubricating synovial fluid that fills the synovial cavity

• Many synovial joints also contain:

I. Accessory ligaments, including extracapsular ligaments and intracapsular ligaments

II. Articular discs or menisci

• Rich blood and nerve supply

Question 48

What are bursae?

Answer 48

Fluid-filled sacs called bursae and tube-like bursae called tendon sheaths reduce friction at some joints during movements.

Question 49

Identify the types of synovial joints.

Answer 49

• Planar joint
• Hinge joint
• Pivot joint
• Condyloid or ellipsoidal joint
• Saddle joint
• Ball-and-socket joint

Question 50

Outline the structure and function of planar joints and provide and example.

Answer 50

• Planar joint at which gliding movements may occur
• Articulating surfaces are usually flat or slightly curved
• Only side-to-side and back-and-forth movements are permitted without movement around any axis; it is a nonaxial joint
• An example is the sternoclavicular joint

Question 51

Outline the structure and function of hinge joints and provide and example.

Answer 51

• Monaxial or uniaxial joint at which the convex surface of one bone fits into the concave surface of another bone
• Flexion and extension (and sometimes hyperextension) may occur
• Examples include the knee joint, elbow joint, and ankle joint

Question 52

Outline the structure and function of pivot joints and provide and example.

Answer 52

• Monaxial joint at which rounded or pointed surface of one bone articulates within a ring formed partly by another bone and partly by a ligament
• Rotation may occur
• An example is rotation of the atlas around the dens of the axis when turning the head

Question 53

Outline the structure and function of condyloid joints and provide and example.

Answer 53

• Aka Ellipsoidal joint
• Biaxial joint at which the oval-shaped condyle of one bone rests against the elliptical cavity of another bone
• The four angular movements (and circumduction) may occur
• An example is the wrist joint

Question 54

Outline the structure and function of saddle joints and provide and example.

Answer 54

• Biaxial joint at which articular surface of one bone is saddle-shaped and the articular surface of the other bone resembles the legs of a rider sitting in a saddle
• Is technically a modified ellipsoidal joint in which movement is less restricted.
• An example is the joint between the trapezium and the base of the first metacarpal

Question 55

Outline the structure and function of ball-and-socket joints and provide and example.

Answer 55

• Multiaxial (or polyaxial) joint at which the ball-like surface of one bone rests against the cuplike depression of another bone
• The four angular movements and rotation may occur
• The only examples are the shoulder and hip joints

Question 56

Outline the general types of movement that occur at synovial joints.

Answer 56

• Gliding movements in which articulating surfaces slide across each other

- Angular movements in which there is a change in the angle between articulating bones. Examples include flexion, extension, abduction, adduction, and circumduction

- Rotation in which a bone turns around its own longitudinal axis. There are two types: medial (or internal) rotation and lateral (or external) rotation.

Question 57

Identify and describe special movements which occur only at certain joints.

Answer 57

• Elevation and depression are, respectively, an upward movement of a part of the body (e.g., elevating the mandible to close the mouth), and a downward movement of a part of the body (e.g., depressing the mandible to open the mouth)

- Protraction and retraction are movements of the mandible or shoulder girdle forward or backward, respectively, on a plane parallel to the ground

- Inversion and eversion are movements of the sole of the foot medially or laterally, respectively. These facilitate walking on uneven surfaces.

- Dorsiflexion and plantar flexion are bending of the ankle joint so that the foot moves in a dorsal or plantar (sole) direction, respectively

- Supination and pronation are movements of the forearm in which the palm turns anteriorly/superiorly posteriorly/inferiorly, respectively

- Opposition is the movement of a thumb across the palm to touch the fingertips on the same hand.

Question 58

What are the factors affecting contact and range of motion at synovial joints.

Answer 58

• Structure or shape of the articulating bones
• Strength and tension (tautness) of the joint ligaments
• Arrangement and tone of muscles around the joint
• Apposition of neighbouring soft tissues
• Effect of hormones (e.g., relaxin relaxes pelvic joints toward the end of pregnancy)
• Disuse of a joint

Question 59

Describe the effects of ageing on joints

Answer 59

The effects of ageing on joints are variable among individuals and are affected by genetic factors and wear and tear; the ageing process usually results in:

• Decreased production of synovial fluid
• Thinning of articular cartilage
• Shortening of ligaments and a decrease in ligamentous flexibility
• Degenerative changes in load-bearing joints

Question 60

What is arthritis?

Answer 60

• Arthritis is characterised by inflammation and stiffness of a joint.
• There are more than 100 different forms of arthritis.
• However, they have in common the symptoms of pain, swelling and stiffness and the signs of erythema (redness) overlying the affected joint, swelling deformity, tenderness, and reduced range of movement.
• When walking, this commonly manifests in an abnormal gait

Question 61

Outline Osteoarthritis.

Answer 61

• This is ‘wear and tear’ arthritis and is the most common form of arthritis.
• In osteoarthritis, we see wearing away of the articular surfaces with consequent loss of joint space and ultimately bone grinding on bone, generating severe pain and loss of range of movement

Question 62

What are the X ray features of osteoarthritis.

Answer 62

• Joint space narrowing
• Subchondral sclerosis (a thin layer of increased bone density beneath the articular cartilage)
• Osteophytes (bony spurs due to new bone formation at the margins of arthritic joints)
• Subchondral cysts (fluid filled sacs in the bone beneath the articulating cartilage).

Question 63

Outline Rheumatoid arthritis

Answer 63

• RA is an autoimmune disease in which autoantibodies, known as rheumatoid factor, attack the synovial membrane.
• This leads to joint erosion and deformity particularly affecting the MCPJ and PIPJ of the hands, the feet and the cervical spine. It can also involve the large joints.
• The autoimmune process also leads to damage to other organs, including the eyes, skin, lungs, heart and blood vessels and the kidneys.
• Patients with rheumatoid arthritis also commonly have anaemia of chronic disease.
• Approximately 1% of the population are affected and the peak age of onset is 40-50 years, but there is also a juvenile form that affects children. Women more commonly affected than men in 2 or 3:1 ratio.