Upper limb Flashcards
What does the radius articulate with?
The capitulum of the humerus at the elbow, and with the carpal bones at the wrist; with the ulna at the proximal and distal radioulnar joints
What is the significance of the radial tuberosity?
Place of attachment of the biceps brachii
What are the names of the projections of the radius at the distal end?
The lateral side projects distally as the styloid process
On the medial side there is the ulnar notch (articulates with ulna)
What is a Colles’ fracture?
FOOH, fracturing the radius, resulting in posterior displacement of the wrist and hand, it produces what is known as the ‘dinner fork deformity
What is a Smith’s fracture?
Falling onto the back of the hand, fracture of the distal radius; it is the opposite of a Colles’ fracture, as the distal fragment is now placed anteriorly
What bony landmarks articulate between the humerus and the ulna?
The trochlea of the humerus, the trochlear notch (formed by the coronoid process and olecranon) of the ulna
Describe the location and function of the radial notch
Found on the lateral surface of the trochlea notch, receives the broad periphery of the radial head
What is the significance of the tuberosity of the ulna?
It is where the brachialis muscle attaches
How many borders does the shaft of the ulna have?
3, it is triangular
Which border of the ulna shaft can be palpated on the postero-medial side of the arm?
The posterior border
Name the important feature of the distal end of the ulna
The styloid process; it projects from the posterior medial part of the bone. It is smaller and more proximal than the styloid process of the radius
How does the ulna participate in the wrist joint?
It doesn’t reach the wrist joint, and hence does not
Describe how a fracture of the olecranon process might occur, and what happens
Fall on a flexed elbow; one of the fragments can be pulled proximally by the triceps, although this depends on where the fracture occurs
Describe the palpation and importance of the olecranon
Can be palpated at the elbow, on the posterior side; the superior surface is the place of attachment of the triceps brachii
What is the importance of the interosseous membrane in respect to a fracture of either the radius or ulna?
A fracture of one bone is likely to be associated with the dislocation of the nearest joint
Describe the position of the proximal ulna fragment following a fracture of the shaft
Points posteriorly
Describe Monteggia’s fracture
Usually caused by a force from behind the ulna; the shaft of the ulna is fractured, and the head of the radius dislocates anteriorly at the elbow
Describe Galeazzi’s fracture
Fracture to the radius, the ulna head is dislocated at the distal radio-ulnar joint
Name the superficial, intermediate, and deep muscles of the anterior compartment of the forearm
Superficial: flexor carpi ulnaris, palmaris longus, flexor carpi radialis, pronator teres
Intermediate: flexor digitorum superficialis
Deep: flexor digitorum profundus, flexor pollicus longus, pronator quadratus
Name the superficial and deep muscles in the posterior compartment of the forearm
Superficial: brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, anconeus
Deep: supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis
The superficial muscles in the anterior compartment of the forearm all originate from where?
They all originate from a common tendon, which originates from the medial epicondyle of the humerus (they hence all cross the elbow joint)
What is the action of the flexor carpi ulnaris? What is its innervation?
Flexion and adduction at the wrist; ulnar nerve
What is the action of the palmaris longus? What is its innervation?
Flexion at the wrist; median nerve
Which structure is just underneath the palmaris longus? In what percentage of the population is the palmaris longus absent?
Median nerve; 15%
What is the action of the flexor carpi radialis? What is its innervation?
Flexion and abduction at the wrist; median nerve
What is the significance of the pronator teres with regard to the cubital fossa?
The lateral border of the pronator teres forms the medial border of the cubital fossa
What is the action of the pronator teres? What is its innervation?
Pronates the forearm; median nerve
Which two structures can be found passing between the two heads of the flexor digitorum superficialis?
The median nerve and ulnar artery
To where do the four distal tendons of the flexor digitorum superficialis attach?
The middle phlanges of the four fingers
What are the actions of the flexor digitorum superficialis?
Flexes the metacarpophalangeal joints, and proximal interphalangeal joints at the 4 fingers, and flexes the wrist
What is the innervation of the flexor digitorum superficialis?
The median nerve
The tendons of which two muscles pass through the carpal tunnel?
Flexor digitorum superficialis and flexor digitorum profundus
To what do the tendons of the flexor digitorum profundus attach?
The distal phlanges of the four fingers
What are the actions of the flexor digitorum profundus?
It is the only muscle that can flex the distal interphalangeal joints at the wrist; it also flexes the metacarpophalangeal joints and at the wrist
What is the innervation of the flexor digitorum profundus?
Medial half is innervated by the ulnar nerve; the lateral half is innervated by the median nerve
Describe the position of the flexor pollicis longus relative to the flexor digitorum profundus
The flexor pollicis longus lies laterally to the flexor digitorum profundus
What are the actions of the flexor pollicis longus?
Flexes the interphalangeal joint and metacarpophalangeal joint of the thumb
What is the innervation of the flexor pollicis longus?
Median nerve
Describe the shape and location of the pronator quadratus
Square shaped muscle, lies deep to the tendons of the flexor digitorum profundus and flexor pollicis longus
What is the action of the pronator quadratus? What is its innervation?
Acts to pronate the forearm; median nerve
When is the brachioradialis most visible?
When the forearm is half pronated, and flexing at the elbow against resistance
What is the action of the brachioradialis? Why is this of interest?
It produces flexion at the elbow, but as its origin and innervation are characteristic of an extensor muscle, it is classified in the extensor compartment
What is the innervation of the brachioradialis?
Radial nerve
Where are the extensor carpi radialis longus and extensor carpi radialis brevis found?
Laterally in the posterior forearm, the brevis lies deep to the longus
Where do the extensor carpi radialis longus and brevis attach?
II (longus) and III (brevis) metacarpal bones
What is the innervation of the extensor carpi radialis longus and brevis?
Radial nerve
What is the main extensor of the fingers?
The extensor digitorum; it makes up most of the posterior surface of the forearm
What is the action of the extensor digitorum?
Extension of the medial four fingers at the metacarpalpholangeal and interphalangeal joints of the hand
What is the action of the extensor digitorum?
Extension of the medial four fingers at the metacarpalpholangeal and interphalangeal joints of the hand
What is the innervation of the extensor digitorum?
Radial nerve
Describe the location of the extensor digiti minimi relative to the extensor digitorum
Medially, slightly deep
What is the action of the extensor digiti minimi?
Acts to extend the little finger, and also contributes to extension at the wrist
What is the innervation of the extensor digiti minimi?
Radial nerve
Where is the extensor carpi ulnaris found in the forearm
Posterior, medial
Where does the extensor carpi ulnaris attach?
The base of metacarpal V
What is the action of the extensor carpi ulnaris? What is its innervation?
Extends and adducts the wrist; the radial nerve
Which muscle is most medial of those in the extensor compartment of the forearm?
The anconeus
Which other muscle can it be hard to distinguish the anconeus from?
The anconeus is blended with the fibres of the triceps brachii
What is the action of the anconeus? What is its innervation?
Acts to move the ulna during pronation and extends at the elbow joint; radial nerve
What is wrist drop a characteristic sign of?
Radial nerve injury in the axilla or radial groove
What happens in wrist drop?
No radial innervation of extensors at wrist; they are paralysed. Unnoposed flexion (wrist drop) occurs due to action of flexor muscles (median nerve)
Which two muscles form the floor of the cubital fossa?
The supinator and brachialis
Which structure lies between the two heads of the supinator?
The radial nerve
What is the action of the supinator? What is its innervation?
Supinates the forearm; radial nerve
Which border of the anatomical snuffbox does the abductor pollicis longus contribute to?
Lateral border
Describe the location of the abductor pollicis longus
Distal to the supinator on the lateral side of the forearm
What is the action of the abductor pollicis longus? What is its innervation?
Abducts the thumb; radial nerve
What is the position of the extensor pollicis brevis relative to the abductor pollicis longus?
Medial
Apart from the abductor pollicis longus, which muscle makes up most of the lateral border of the anatomical snuffbox?
Extensor pollicis brevis
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| What is the action of the extensor pollicis brevis? What is its innervation?</p>
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| Extend the metacarpophlanageal and carpometacarpal joints of the thumb; radial nerve</p>
What is the action of the extensor pollicis longus? What is its innervation?
Extends all the joints of the thumb; radial nerve
What is the action of the extensor indices? Why is it important?
Extends the index finger; allows the index finger to be independent of the other fingers during extension
What is the innervation of the extensor indices?
Radial nerve
What type of joints are the radioulnar joints? What movement do they allow?
They are both synovial pivots, responsible for the pronation and supination of the forearm
What is the proximal radioulnar joint formed by?
The head of the radius, articulating with the radial notch of the ulna
Which ligament keeps the radius in place at the proximal radioulnar joint?
The anular radial ligament; it forms a collar around the joint
Which muscles produce pronation at the radioulnar joints?
The pronator teres and pronator quadratus
Which muscles produce supination at the radioulnar joints?
The biceps brachii, and the supinator
What is the distal radioulnar joint formed by?
The head of the ulnar and the ulnar notch on the medial side of the radius
Which ligaments strengthen the distal radioulnar joint?
The anterior (palmar radioulnar) and posterior (dorsal radioulnar) ligaments, and the articular ligament
What are the functions of the articular ligament at the distal radioulnar joint?
It binds the radius and ulna together, holding them together during movement of the joint; it separates the distal radioulnar joint from the wrist joint
What are the three functions of the interosseous membrane between the radius and ulna?
Holds the radius and ulna together during pronation and supination of the forearm; provides attachment for muscles; transfers force from the radius to the ulna
Name the carpal bones in the proximal and distal rows
Proximal: scaphoid, lunate, triquetrum, pisiform
Distal: trapezium, trapezoid, capitate, hamate
What is the shape of the lunate bone?
Crescent shaped
What type of bone is the pisiform? Name the tendon of relevance
Sesamoid, formed in the tendon of the flexor carpi ulnaris
What does the trapezium articulate with?
The metacarpal of the thumb
What is the name of the projection on the palmar surface of the hamate?
The hook of hamate
Which two carpal bones are most commonly fractured? How?
The scaphoid and lunate; fall on outstretched hand
What is the main clinical sign of a fractured scaphoid?
Tenderness/pain in the anatomical snuffbox
Why does a fracture of the scaphoid need to be dealt with quickly?
Fracture can cut off the blood supply to the proximal part, causing it to undergo avascular necrosis
What is the anatomical snuffbox?
Triangular depression found on the lateral aspect of the dorsum of the hand, at the level of the carpal bones
What is the lateral border of the anatomical snuffbox?
Tendons of the abductor pollicis longus and extensor pollicis brevis
Which structure is of importance in the anatomical snuffbox?
The radial nerve; it passes diagonally through the anatomical snuffbox on its path into the hand
What is the medial border of the anatomical snuffbox?
Tendon of the extensor pollicis longus
What is the proximal border of the anatomical snuffbox?
Styloid process of the radius
What is the base of the anatomical snuffbox?
Scaphoid and trapezium carpal bones
What articulation occurs in the anatomical snuffbox?
Scaphoid and radius articulate to form part of the wrist joint
Which bones articulate to form the wrist joint?
Distal end of radius, and proximal row of carpal bones (except pisiform)
Which three general things contribute to the stability of the wrist joint?
Joint capsule, structure of the joint, and associated ligaments
Describe the two layers of the wrist joint capsule
Fibrous outer layer attaches to the radius, ulna and proximal carpal bones; the internal layer is comprised of a synovial membrane, secreting synovial fluid which lubricates the joint
At the wrist joint, which bony landmark prevents excessive abduction?
Styloid process of the radius
Name the four important ligaments at the wrist joint
Palmar radiocarpal, dorsal radiocarpal, ulnar collateral, radial collateral
Describe the structure and function of the palmar radiocarpal ligament
Found on the anterior side of the hand; passes from the radius to both rows of carpals; adds to stability and ensures hand follows forearm during supination
Describe the structure and function of the dorsal radiocarpal ligament
Found on the posterior side of the hand; passes from the radius to both rows of carpals; contributes to stability and ensures that hand follows forearm during pronation
Describe the location of the ulnar collateral ligament
Runs from the styloid process to the triquetrum
Describe the location of the radial collateral ligament
Runs from the styloid process to the scaphoid
What type of joint is the wrist joint? What movements does it allow?
Synovial ellipsoid; allows for movement along two axes (flexion /extension, adduction/abduction)
Which muscles produce flexion at the wrist joint?
Mainly the flexor carpi radialis and flexor carpi ulnaris, with assistance from the flexor digitorum superficialis, flexor digitorum profundus and palmaris longus
Which muscles produce extension at the wrist joint?
Mainly the extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris, with assistance from the extensor digitorum, extensor pollicis longus and extensor indicis
Which muscles produce adduction at the wrist joint?
Extensor carpi ulnaris and flexor carpi ulnaris
Which muscles produce abduction at the wrist joint?
Abductor pollicis longus, flexor carpi radilias, extensor carpi radialis longus and brevis
How can you suffer an anterior dislocation of the lunate? What can this cause?
Falling on a dorsiflexed wrist; can compress carpal tunnel, causing carpal tunnel syndrome. The lunate can also undergo avascular necrosis
In which direction are the metacarpal bones numbered?
Thumb (I) to little finger (V)
How does the shape of the metacarpals aid in the attachment of interossei muscles?
They are concave both medially and laterally
What do the proximal ends of the metacarpal bones articulate with?
Each other, and the carpal bones
What do the distal ends of the metacarpal bones articulate with?
A phalanx, at metacarpophalangeal joints
What is boxer’s fracture?
Fracture of the neck of the 5th and occasionally fourth metacarpal bones; usually caused by a clenched fist striking a hard object
What do the fingers look like with a boxer’s fracture?
Shorter; the distal metacarpal fragments are pushed proximally
How many phalanges are there in the one hand?
14; 3 for digits II to IV (proximal, middle, distal) and 2 for digit I (proximal, distal)
What are the two groups of muscles that act on the hand? Where are they found?
Extrinsic muscles; found in forearm, largely produce fine motor skills
Intrinsic muscles; found within the hand, generally produce the fine motor skill
What are the intrinsic muscles of the hand?
Adductor pollicis, interossei, thenar, palmaris brevis, lumbricals and hypothenar muscles
What is the thenar eminence?
Prominent bulge at base of thumb on lateral side of palm; produced by thenar muscles
What is the action of the thenar muscles? Which other muscle is of note?
Along with the adductor pollicis, they are responsible for the fine movements of the thumb
Name the thenar muscles. What is their innervation?
Opponens pollicis, abductor pollicis brevis, flexor pollicis brevis; median nerve
Which is the largest of the thenar muscles? Briefly describe its position.
Opponens pollicis; lies deep to the other two thenar muscles
What is the action of the opponens pollicis?
It opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium
Describe the position of the abductor pollicis brevis, relative to the other thenar muscles
Anterior to opponens pollicis; proximal to flexor pollicis brevis
What is the action of the abductor pollicis brevis?
Abduction of the thumb
Which is the most distal of the thenar muscles?
The flexor pollicis brevis
What is the action of the flexor pollicis brevis?
Acts to flex the metacarpophalangeal joint of the thumb
What is the hypothenar eminence?
An eminence on the medial side of the palm, at the base of the little finger; it is produced by the hypothenar muscles
Name the hypothenar muscles. What is their innervation?
Opponens digiti minimi, abductor digiti minimi, flexor digiti minimi brevis; ulnar nerve
What is the position of the opponens digiti minimi relative to the other hypothenar muscles?
Deep
What is the action of the opponens digit minimi?
Rotates the metacarpal of the little finger towards the palm, producing opposition
What is the position of the abductor digiti minimi relative to the other hypothenar muscles?
Superficial
What is the action of the abductor digiti minimi?
Abduction of the little finger
What is the position of the flexor digiti minimi brevis relative to the other hypothenar muscles?
Lateral
What is the action of the flexor digiti minimi brevis?
Acts to flex the metacarpophalangeal joint of the little finger
What are the places of origination of the hypothenar muscles?
Hook of hamate, pisiform
What are the names of the two other muscles in the palm that do not fit into the hypothenar or thenar muscles?
Adductor pollicis, palmaris brevis
Describe the shape of the adductor pollicis. Which structure is of note?
Large, triangular, two heads; radial artery passes anteriorly between the two heads
What is the action of the adductor pollicis? What is its innervation?
Adduction of the thumb; ulnar nerve
Describe the structure and location of the palmaris brevis
Small, thin muscle, found very superficially in the subcutaneous tissue of the hypothenar eminence
What is the action of the palmaris brevis? What is its innervation?
Acts to wrinkle the skin of the hypothenar eminence, deepening the curvature of the hand, imporving grip; ulnar nerve
What are the lumbricals?
Four muscles, each associated with a finger, that link the extensor tendons to the flexor tendons; crucial for hand movement
What is the denervation of the lumbricals the basis for?
The ulnar claw and the hand of Benediction
What does each lumbical originate from?
A tendon of the flexor digitorum profundus
How do the lumbrical muscles pass along the finger?
Dorsally and laterally, they insert into the extensor hood
What is the action of the lumbricals?
They act to flex at the metacarpophalangeal joint of each finger, and extend at the interphalangeal joints of each finger
What is the innervation of the lumbricals?
The ulnar nerve innervates the medial two, and the median nerve innervates the lateral two
Where are the inerossei muscles found in the hand? What are the two groups?
Between the metacarpals; dorsal and palmar
Which muscles are most superficial on the dorsal side of the hand?
The dorsal interossei muscles
What is the specific action of the dorsal interossei muscles? What is their innervation?
Act to abduct the fingers at the metacarpophalangeal joint; ulnar nerve
How many palmar and dorsal interossei muscles are there?
3 palmar, 4 dorsal
What is the action of the palmar interossei muscles? What is their innervation?
Adduction of the fingers; the ulnar nerve
What is the general action of all interossei muscles of the hand?
Assist the lumbricals in flexion at the metacarpophalangeal joints, and extension at the interphalangeal joints
Which bones and what else form the carpal tunnel?
Pisiform, triquetrum, lunate, capitate, trapezoid trapezium, flexor retinaculum
Which structures are of importance within the carpal tunnel?
Median nerve, tendons of the flexor digitorum superficialis, flexor digitorum profundus and flexor pollicis longus (9 tendons)
What is carpal tunnel syndrome?
Compression of the median nerve within the carpal tunnel; thought to be due to increased pressure/thickening of tendon sheaths
What are the typical signs of carpal tunnel syndrome?
Pins and needles in the sensory distribution of the median nerve and weakness of thenar muscles
Why is some median nerve function retained in carpal tunnel syndrome?
The palmar cutaneous branch of the median nerve travels superficial to the flexor retinaculum
Which muscles produce the characteristic shape of the shoulder?
Deltoid and trapezius
Which level of the vertebrae does the trapezius origination extend down to?
T12
What is the motor and sensory innervation of the trapezius muscle?
Motor: accessory nerve; Sensory: ventral rami of 3rd and 4th cervical nerves
What is the action of the trapezius?
Upper fibres: elevate the scapula and rotate it during abduction of the arm
Middle fibres: retract the scapula
Lower fibres: pull the scapula inferiorly
How can you test the accessory nerve?
Test how well the trapezius is functioning; get the patient to elevate the shoulder against resistance
Describe the latissimus dorsi muscle
Flat, wide, found laterally on the back of the trunk
What is the action of the latissimus dorsi?
It acts to extend the arm at the shoulder, adduction at the shoulder and medial rotation of the arm
What is the innervation of the latissimus dorsi?
Thoracodorsal nerve
Describe the location of the levator scapulae
Lies in the back and neck, deep to the trapezius and sternocleidomastoid muscles
What is the action of the levator scapulae?
Elevates the scapula, rotates the scapula, and tilts the glenohumeral joint inferiorly
What us the innervation of the levator scapulae?
Dorsal scapular nerve
What are the rhomboid muscles?
Pair of muscles, rhomboid major and rhomboid minor; they lie deep to the trapezius and have a rhomboid appearance
What is the difference in size between the rhomboids?
Major is twice the width of minor
What is the innervation of the rhomboid muscles?
Dorsal scapular nerve
What is the action of the rhomboids?
Retract the scapula, rotate the scapula to tilt the glenohumeral joint, and also fix the scapula to the thoracic wall
What are the divisions of the deltoid muscle?
Anterior, middle and posterior; each can act independently or together when required
What is the innervation of the deltoid?
Axillary nerve
What is the action of the anterior and posterior fibres of the deltoid?
Anterior fibres flex the arm at the shoulder, posterior fibres extend the arm at the shoulder
What is the action of the middle fibres of the deltoid?
Major abductor of the arm; they take over from the supraspinatus, which abducts the first 15 degrees
What is the quadrangular space?
A ‘gap’ that the axillary artery and posterior circumflex humeral artery pass through to reach the posterior scapular region
What is the relevance of the teres major in regard to the quadrangular space?
Forms the inferior border
What is the innervation of the teres major?
Lower subscapular nerve
What is the action of the teres major?
Adduction of the shoulder, and medial rotation of the arm
How would you test the deltoid muscle?
Examiner resists patient’s abduction of the limb by the deltoid; if the deltoid is acting normally, contraction of the middle part of the muscle can be palpated
Which border of the axilla is the pectoralis major part of?
Pectoralis major makes up most of the anterior wall
Which border of the axilla is the serratus anterior part of?
Medial wall
Describe the two heads of the pectoralis major
There is a clavicular head (attaches to the clavicle) and a sternocostal head (attaches to the sternum/ribs)
Where do the heads of the pectoralis major convene?
The edge of the intertubecular groove of the humerus
What is the action of the pectoralis major?
The two heads can work independently and synergistically; together, they act to adduct and medially rotate the humerus at the shoulder, the clavicular head also performs flexion
Where do the fibres of the pectoralis minor attach?
The corocoid process of the scapula; this attachment forms a ‘bridge’, which vessels passing into the upper limb must pass underneath
Compare the size and location of the pectoralis minor to the pectoralis major
Pectoralis minor is much smaller and lies posterior to the pectoralis major
What is the innervation of the pectoralis minor
Medial pectoral nerve
Which border of the axilla does the pectoralis minor contribute to?
Anterior wall
What is the action of the serratus anterior?
Main action is to rotate the scapula, allowing the arm to be raised over 90 degrees. It also holds the scapula against the ribcage
What is the innervation of the serratus anterior?
Long thoracic nerve
What causes winging of the scapula?
Damage to the long thoracic nerve, resulting in paralysis of the serratus anterior
Describe the structure and location of the pectoralis major
Large, fan shaped, most superficial in region. It makes up most of the anterior wall of the axilla.
What is the innervation of the pectoralis major?
Innervation is by the medial and lateral pectoral nerves, derived from the brachial plexus
What action is changed with winging of the scapula?
When pushing the affected limb, the scapula is no longer held against the rib cage (no serratus anterior action), and protrudes out of the back
How can damage to the long thoracic nerve occur?
Trauma to the shoulder, repetitive movements involving the shoulder or by structures becoming inflamed and pressing on the nerve
What is the anatomical position?
Person standing upright, facing forward, hands by side, feet parallel and toes pointing forward
What are the three anatomical planes?
Sagittal, Coronal, Transverse
Distinguish between medial and lateral
Lateral is away from the midline, medial is towards the midline (the midline being a line in sagittal plane, splitting the right and left halves evenly)
Distinguish between anterior and posterior
Anterior refers to the ‘front’ and posterior to the ‘back’
Distinguish between superior and inferior
Refers to the vertical axes; superior means ‘higher’, inferior means ‘lower’
Distinguish between proximal and distal
Used mainly to describe limbs; they describe the position of a structure with reference to its origin, proximal meaning closer to the origin and distal meaning further away
Distinguish between flexion and extension
Flexion refers to a movement that decreases the angle between two body parts, extension refers to a movement that increases the angle between two body parts
Distinguish between abduction and adduction
Abduction is a movement away from the midline, adduction is a movement towards the midline
Distinguish between elevation and depression
Elevation refers to a movement in a superior direction, depression refers to a movement in an inferior direction
Distinguish between pronation and supination
Occurs only when the fore-arm is semi-flexed; pronation moves the palm of the hand so that it is facing posteriorly, supination moves the palm of the hand so that it is facing anteriorly
Distinguish between dorsiflexion and plantarflexion
Both terms describe movement at the ankle. Dorsiflexion refers to extension so that the foot points more superiorly, plantarflexion is flexion at the ankle so that the foot points more inferiorly
Distinguish between opposition and reposition
Opposition brings the thumb and little finger together, reposition is a movement that places the thumb and the little finger away from each other
Which side of the scapula is termed the costal surface?
The side facing the ribcage (anterior)
Which muscle originates from the costal surface, and to what does it attach?
The subscapularis muscle, to the subscapular fossa
What is the name of the hook like projection originating from the superior and lateral aspect of the scapula?
The coracoid process
Name 3 features of the lateral border of the scapula
The glenoid fossa, the supraglenoid tubercle, the infraglenoid tubercle
What are the four prominent features of the posterior surface of the scapula?
The spine, the infraspinous fossa, the supraspinous fossa, and the acromion
How would a fracture of the scapula occur?
Severe chest trauma, such as in a high speed road collision or in a crushing injury
Why does a fracture of the scapula not require much intervention?
The muscle tone should hold the pieces together in order for healing to occur
What type of bone is the clavicle?
Long bone
Describe the medial and lateral attachments of the clavicle
Medial attachment to sternum, lateral attachment to acromion of the scapula
Where is the conoid tubercle? What function does it serve?
Found near the acromial end of the clavicle; it is the attachment point of the conoid ligament, the medial part of the coracoclavicular ligament
What is the lateral part of the coracoclavicular ligament and where does it attach?
Trapezoid ligament, attaches to the trapezoid line, near the acromial end of the clavicle
What is the impression at the sternal end of the clavicle for?
The binding of the costoclavicular ligament
What are the three functions of the clavicle?
Attaches limb to upper trunk, protects underlying neurovascular structures, transmits force from upper limb to axial skeleton
How do fractures of the clavicle occur? What structures are at risk?
Fall onto shoulder/outstretched hand. There can be some nervous damage, due to the close proximity of the supraclavicular nerves
What happens to the lateral end of the clavicle after a clavicular fracture?
It is displaced inferiorly by the weight of the arm, and medially by the pectoralis major
What happens to the medial end of the clavicle after a clavicular fracture?
The medial end is pulled superiorly by the sternocleidomastoid muscle
Why can a fracture of the clavicle result in ‘waiter’s tip’
There can be damage of the supraclavicular nerves; they innervate the lateral rotators of the upper limb; loss off function will result in unopposed medial rotation
What forms the apex of the axilla? What is its importance?
The clavicle, first rib and the scapula. Structures passing into the upper limb from the thorax usually do so through the apex of the axilla
What is thoracic outlet syndrome?
The space between the clavicle and the first rib can become narrowed, and the vessels and nerves that pass through may become compressed
What can cause thoracic outlet syndrome?
Trauma (fractured clavicle) and repetitive use (lifting occupations etc)
How does thoracic outlet syndrome present?
Pain in the affected limb (where the pain is depends on the nerves affected), tingling, muscle weakness and discolouration
Where is the greater tubercle on the humerus? What is its major purpose?
Located laterally, it has a posterior and anterior face; it serves as the attachment site for 3 rotator cuff muscles
What does the head of the humerus do?
How does it project?
Projects medially and superiorly to articulate with the glenoid cavity
What are the four rotator cuff muscles?
Supraspinatus, infraspinatus, teres minor, and subscapularis
Which rotator cuff muscle attaches to the lesser tubercle?
Subscapularis
What purpose does the intertubecular sulcus serve?
Tendons of the pectoralis major, teres minor and latissiumus dorsi attach to the lips of the sulcus
What is the name of the landmark of the humerus where the deltoid muscle attaches? Where is it located?
Deltoid tuberosity; lateral side
What lies in the radial groove? Describe its location
The radial nerve and profunda brachii artery; runs diagonally down posterior surface of humerus, parallel to the deltoid tuberosity
Why is the lateral supraepicondylar ridge roughened?
It is a place of attachment for many of the extensor muscles in the posterior forearm
Where can the ulnar nerve be palpated?
Posterior side of the medal epicondyle
What does the trochlea articulate with?
The ulna; the trochlea is located medially and extends onto the posterior of the bone
Which bony landmark is located laterally to the trochlea? What does it do?
The capitulum, which articulates with the radius
What are the three fossae of the humerus?
Coronoid, radial and olecranon
What structures are of concern with a fracture to the surgical neck of the humerus?
The axillary nerve and the posterior circumflex artery
What will damage to the axillary nerve result in?
Axillary nerve damage will result in paralysis of the deltoid and teres minor muscles- patient unable to abduct. It also innervates the skin of the regimental badge region (loss of sensation)
What structures are at risk with a mid-shaft fracture of the humerus? Why?
The radial nerve and profunda brachii artery; they are tightly bound in the radial groove
What will happen if there is damage to the radial nerve at the radial groove?
Wrist drop; (unopposed flexion), the radial nerve innervates the extensors. There will be some sensory loss over the dorsal (posterior) surface of the hand and the proximal ends of the lateral 3 and a half fingers dorsally
What is a supraepicondylar fracture? How does it occur?
Occurs by falling on a flexed elbow. It is a transverse fracture, spanning between the two epicondyles
Which vascular structure is at risk with a supraepicondylar fracture? What can interference of its supply cause?
Brachial artery; the resulting ischaemia can cause Volkmann’s ischaemic contracture - uncontrolled flexion of the hand, as flexors become fibrotic and short
Which nervous structures are at risk with a supraepicondylar fracture?
There can be damage to all 3 nerves (median, radial, ulnar)
Which nervous structure can a fracture to the medial epicondyle of the humerus damage? What will result?
Damage to the ulnar nerve, resulting in a deformity known as ulnar claw, and loss of sensation over the medial 1 and ½ fingers if the hand, on both the dorsal and palmar surfaces
What is the rotator cuff?
A group of 4 muscles, originating from the scapula which attach to the humeral head, pulling it into the glenoid fossa, providing extra stability
What is the action of the supraspinatus muscle? What is its innervation?
It is responsible for the first 15 degrees of abduction at the shoulder, assisting the deltoid for the rest; suprascapular nerve
What is the action of the infraspinatus muscle? What is its innervation?
Acts to laterally rotate the arm; suprascapular nerve
What is the action of the subscapularis muscle? What is its innervation?
Acts to medially rotate the arm; upper and lower subscapular nerves
What is the action of the teres minor? What is its innervation?
Acts to laterally rotate the arm; axillary nerve
What is the function of the subacromial bursa?
Reduces friction between the supraspinatus tendon and the coracoacromial arch during abduction of the arm
Which degenerative changes result in ‘painful arc’? What is ‘painful arc’?
Pain in the middle of abduction; under repetitive use, there are degenerative changes in the subacromial bursa and supraspinatus tendon
How is the coraco-acromial arch related to rotator cuff tendonitis?
Repetitive use of the rotator cuff muscles can cause the head of the humerus and the tendons of the muscles to irritate the coraco-acromial arch, which in turn causes greater inflammation of the rotator cuff tendons
What forms the lateral wall of the axilla?
The intertubecular groove of the humerus and tendon of the long head of the biceps
What forms the medial wall of the axilla?
The serratus anterior and thoracic wall (ribs and intercostal muscles)
What forms the anterior wall of the axilla?
The pectoralis major, underlying pectoralis minor and the subclavius muscle
What forms the posterior wall of the axilla?
The subscapularis, teres major and latissimus dorsi
Name the vascular, muscular and lymph contents of the axilla?
The axillary artery and axillary vein, biceps brachii and coracobrachialis tendons, and the axillary lymph nodes
What are the two largest tributaries of the axillary vein?
The cephalic and basilic veins
What are the three parts of the axillary artery? What are their positions?
One medial to the pectoralis minor, one posterior to the pectoralis minor, and one lateral to the pectoralis minor; the medial and posterior parts travel in the axilla
Where does the majority of the lymph from the breast drain?
Into the axillary lymph nodes; they can be biopsied if breast cancer is suspected
What is axillary clearance? What can be damaged during the procedure?
The removal of the axillary lymph nodes; this is may be performed in patients with breast cancer, to prevent its spread. The long thoracic nerve may be damaged
What articulations form the shoulder joint? What is its anatomical name?
The glenoid cavity of the scapula with the head of the humerus; the glenohumeral joint
Why does the glenohumeral joint have inherent stability?
The glenoid cavity is relatively shallow, and the humeral head is large, and it is this disproportion that gives the inherent instability
What reduces the disproportion in size between the glenoid cavity and the humeral head?
The glenoid fossa is deepened by a fibrocartilaginous rim, called the glenoid labrum
Which nerves supply the glenohumeral joint? Where are they derived from?
The axillary, suprascapular and subscapular nerves; they are derived from C5 and C6
What is the blood supply of the glenohumeral joint?
Circumflex humeral arteries and suprascapular arteries
Where does the joint capsule of the glenohumeral joint attach? What property of it adds to mobility at the joint?
To the anatomical neck of the humerus and the border of the glenoid fossa; it is lax, although this adds to instability
What is the function of the inner surface of the joint capsule of the shoulder?
Synovial membrane; produces synovial fluid to reduce friction between structures at the joint
What occurs at ‘holes’ in the joint capsule of the shoulder?
Synovial membrane protrudes to form bursae; they act to reduce rubbing between the structures around the joint during movement
What are the 3 clinically important bursae at the shoulder joint that do not form holes in the joint capsule?
Subacromial, subscapular, subdeltoid
What is the location of the subacromial bursa? What is its function?
Between the acromion of the scapula and the joint capsule and supraspinatus tendon; it allows relatively friction free movement of the tendon under the coracoacromial arch and deltoid
What is the location of the subscapular bursa?
Between the tendon of the subscapularis muscle and the joint capsule
What is the location of the subdeltoid bursa?
Between the deltoid and the joint capsule
What are the ligaments of the shoulder joint?
Superior, middle and inferior glenohumeral ligaments (they appear as one ligament), the coracohumeral ligament, and the transverse humeral ligament
Describe the location of the coracohumeral ligament
Between the base of the coracoid process and the greater tubercle of the humerus
Describe the location of the transverse humeral ligament
Between the two tubercles of the humerus, holding the tendon of the long head of the biceps in the intertubecular groove
Describe the location and function of the coracoacromial ligament
Joins the acromion and coracoid process of the scapula in a protective arch, that lies over the humeral head; this prevents superior displacement of the humeral head
Which muscles perform extension at the shoulder joint?
The posterior deltoid, latissimus dorsi, and teres major
Which muscles perform flexion at the shoulder joint?
Biceps brachii (both heads), pectoralis major, anterior deltoid and coracobrachialis
Which muscles perform abduction at the shoulder joint?
Initially, by the supraspinatus, then the middle fibres of the deltoid take over; past 90 degrees, the scapula is rotated by the trapezius and serratus anterior
Which muscles perform adduction at the shoulder joint?
Pectoralis major, latissimus dorsi, teres major and anterior deltoid
Which muscles perform medial rotation at the shoulder joint?
Subscapularis, pectoralis major, latissimus dorsi, teres major and anterior deltoid
Which muscles perform lateral rotation at the shoulder joint?
Infraspinatus and teres minor
What factors contribute to mobility at the shoulder joint?
It is a ball and socket joint; the disproportion of size between the glenoid cavity and humeral head
What factors contribute to stability at the shoulder joint?
Rotator cuff muscles (attach to tubercles of the humerus, pulling the humeral head into the glenoid cavity), the glenoid labrum (deepens cavity, reducing risk of dislocation), and the ligaments
How is an anterior dislocation of the shoulder joint usually caused?
Trauma to a fully abducted arm usually from a posterior direction
Which nerves may be damaged with an anterior dislocation of the shoulder?
Axillary nerve as it runs in close proximity to the joint (causes paralysis of deltoid, regimental badge), and radial nerve damage can also occur, as it is tightly bound in the radial groove
Which structures, other than nerves, may tear during an anterior dislocation of the shoulder?
Rotator cuff muscles and joint capsule
How many muscles are in the anatomical arm? What are they (anterior and posterior)?
4;
Anterior: biceps brachii, brachialis, coracobrachialis
Posterior: triceps brachii
What is the action of the biceps brachii?
Supination of the forearm; flexion of the arm at the shoulder and elbow
What is the innervation of the biceps brachii?
Musculotaneous nerve
Which spinal cord segment is tested by tapping the biceps tendon?
C6
What is the bicipital aponeurosis?
A connective tissue sheath given off the biceps tendon as it enters the forearm
What is the significance of the bicipital aponeurosis?
Forms the roof of the cubital fossa, blending with the deep fascia of the forearm
What is ‘popeye sign’? What is it suggestive of?
Bulge of upper arm during flexion at the elbow; rupture of the tendon of the long head of the biceps brachii
Why would a patient not notice much weakness in the upper limb with a rupture of the tendon of the long head of the biceps brachii?
Action of brachialis and supinator compensate
What is the action of the coracobrachialis? What is its innervation?
Flexion of the arm at the shoulder; musculotaneous nerve
What forms the base of the cubital fossa?
The brachialis muscle
Which muscle is the main flexor of the elbow?
The brachialis
What is the action of the brachialis muscle?
Flexion at the elbow
What is the innervation of the brachialis muscle?
Musculotaneous nerve (small lateral portion is innervated by the radial nerve)
What are the three heads of the triceps brachii? Which one lies deeper than the other two?
Medial, lateral, and long; the medial head is deeper than the other two
What is the action of the triceps brachii?
Perform extension of the arm at the elbow
What is the innervation of the triceps brachii?
Radial nerve
Which spinal segment does a tap on the triceps tendon test?
C7
What are the five parts of the brachial plexus?
Roots, trunks, divisions, cords, branches
Which rami form the roots of the brachial plexus?
Anterior rami of cervical nerves 5, 6, 7, and 8, and the first thoracic nerve, T1
What are the trunks of the brachial plexus? Which roots supply each trunk?
Superior (C5 and C6), middle (C7), and inferior (C8 and T1)
What are the three cords of the brachial plexus?
Lateral, posterior, and medial
Which divisions form the lateral cord of the brachial plexus?
Anterior superior, and anterior middle
Which divisions form the posterior cord of the brachial plexus?
Posterior superior, posterior middle, and posterior inferior
Which divisions form the medial cord of the brachial plexus?
Anterior inferior
What are the branches of the brachial plexus? Which cords do they originate from?
Musculotaneous (lateral cord) Axillary (posterior cord) Median (lateral and medial cords) Radial (posterior) Ulnar (medial)
How does Erb’s palsy usually occur?
Difficult birth or blow to the shoulder
Which nerves are affected with Erb’s Palsy?
Those derived from solely C5 or C6 roots; musculotaneous, axillary, suprascapular and nerve to subclavius
Which muscles are paralysed with Erb’s palsy?
Supraspinatus, infraspinatus, subclavius, biceps brachii, brachialis, corachobrachialis, deltoid and teres minor
Which movements are lost or greatly weakened in people with Erb’s palsy?
Abduction at the shoulder, lateral rotation of the arm, supination of the forearm, and flexion at the shoulder
Where is there sensation loss for people with Erb’s palsy?
The sensory areas that are supplied by the axillary and musculotaneous nerves; down the lateral side of the arm
What are the characteristic signs of Erb’s palsy?
Affected limb hangs limply medially rotated by unopposed action of the pectoralis major, forearm pronated due to loss of biceps brachii; known as waiter’s tip
How does Klumpke’s palsy commonly occur?
Excessive abduction of the arm e.g. a person catching a branch as they fall from a tree
Which nerves are affected in Klumpke’s palsy?
Those derived from T1; ulnar and median nerves
Which muscles are paralysed with Klumpke’s palsy?
All the small muscles in the hand (the flexor muscles in the arm are innervated by different roots)
Where is sensation loss with Klupke’s palsy?
Along the medial side of the arm
What are the characteristic signs of Klumpke’s palsy?
A clawed hand, hyperextension occurs at the metacarpophalangeal joints and flexion occurs at the interphalangeal joints
Which roots does the musculotaneous contain fibres of?
C5, C6, C7
Describe the course of the musculotaneous nerve after it leaves the axilla
Pierces the corachobrachialis muscle, near the point of insertion on the humerus; then passes down the arm, anterior to the brachialis muscle, posterior to the biceps brachii; it emerges laterally to the biceps tendon, and continues in the forearm as the lateral cutaneous nerve of the forearm
Which muscles does the musculotaneous nerve innervate? What actions does it hence control?
Biceps brachii, brachialis, coracobrachialis; flexion of the upper arm at the shoulder and elbow, and the biceps brachii also performs supination of the forearm
Does the musculotaneous nerve have any sensory function?
Lateral cutaneous nerve provides sensory function to the lateral side of the forearm
How would damage to the musculotaneous nerve likely occur?
It is uncommon as relatively protected, but a stab wound could damage it
Which muscles would be paralysed by a lesion to musculotaneous nerve?
Biceps brachii, brachialis, coracobrachialis
What actions would be compromised by a lesion to the musculotaneous nerve?
Flexion at shoulder weakened but still performed by the pectoralis major; flexion at the elbow affected but still performed by the brachioradialis; supination greatly weakened, but still produced by the supinator
Where would there be loss of sensation with a lesion of the musculotaneous nerve?
Lateral side of the forearm
Which roots of the brachial plexus is the axillary nerve derived from?
C5 and C6
Describe the course of the axillary nerve after formation in the brachial plexus
Travels inferiorly and laterally, exiting the axilla through the quadrangular space
Which muscles and hence which actions does the axillary nerve contribute to?
Deltoid; flexion and extension of the arm at the shoulder, major abductor of the arm past 15 degrees; Teres minor; lateral rotation of arm
What sensory function does the axillary nerve contribute to?
Gives rise to lateral cutaneous nerve of arm; innervates the skin over the posterior deltoid, the ‘regimental badge’ area
What is the quadrangular space?
Route for nerves and vessels to pass from the anterior to posterior arm (below glenohumeral joint)
Which structures pass through the quadrangular space?
Axillary nerve and posterior circumflex artery
What are the superior and lateral boundaries of the quadrangular space?
Superior: subscapularis muscle and teres minor
Lateral: surgical neck of humerus
What are the inferior and medial borders of the quadrangular space?
Inferior: teres major muscle
Medial: long head of triceps brachii
How is the axillary nerve commonly injured?
Anterior dislocation of the humerus at the glenohumeral joint, or a fracture of the surgical neck
What functional loss will occur with an injury to the axillary nerve?
Paralysis of the deltoid and teres minor; patient will be unable to abduct the affected limb
What sensory loss will occur with an injury to the axillary nerve?
If the lateral cutaneous nerve supply is interrupted, there will be loss of sensation over the regimental badge area
What can be palpated in long standing cases of axillary nerve damage? Why?
Greater tuberosity of the humerus; deltoid rapidly atrophies
Which roots of the brachial plexus does the radial nerve contain fibres of?
All 5; C5, C6, C7, C8, & T1
How does the radial nerve exit the axilla? What does it innervate just after leaving?
Posteriorly; supplies branches to long and medial heads of triceps brachii
Which artery does the radial nerve accompany as it travels in the radial groove? What branch of the nerve arises here?
Profunda brachii artery; branch to the lateral triceps brachii arises here
After leaving the radial groove, describe the course of the radial nerve
Anteriorly over the lateral epicondyle of the humerus, through the cubital fossa, and into the forearm, where it divides into motor and sensory branches
What are the motor innervations and hence functions of the radial nerve?
Triceps brachii muscle (extension at elbow), posterior compartment of forearm (extension of wrist, and hand joints, and supination)
What is the sensory innervation of the radial nerve?
Cutaneous branches of the radial nerve supply skin for most of the back the arm and hand
Describe how the radial nerve could be damaged in the axilla
Dislocation of humerus at glenohumeral joint, or fractures of proximal humerus; can also happen via excessive pressure on the axilla
What motor function loss occurs with damage to the radial nerve in the axilla?
Triceps and muscles in posterior compartment of forearm are paralysed; inability to extend at elbow, wrist, or fingers; unopposed flexion – wrist drop
Why can supination still occur when the radial nerve is damaged?
Action of biceps brachii, innervated by the musculotaneous nerve
What sensory loss will there be with damage to the radial nerve in the axilla?
Whole of cutaneous innervation of radial nerve; most of the back of the arm and hand
How is the radial nerve most commonly damaged in the radial groove?
Midshaft humeral fracture
Why is extension at the elbow still possible in patients with damage to the radial nerve in the radial groove?
Majority of branches have already arisen is the triceps brachii not paralysed with damage
What motor function is lost with damage to the radial nerve in the radial groove?
Extension at the wrist and hand (muscles in posterior compartment paralysed), wristdrop occurs
What sensory loss occurs with damage to the radial nerve in the radial groove?
Forearm cutaneous branches have already arisen, so there is only sensory loss on the dorsum of the hand
How is the deep branch of the radial nerve in the forearm damaged?
Fractures of the radial head, or posterior dislocation of the radius at the elbow joint
Which muscles of the posterior compartment are NOT damaged with damage to the deep branch of the radial nerve in the forearm?
Supinator and extensor carpi radialis longus; wristdrop will not occur (ECRL is a strong extensor)
What sensory loss occurs with damage to the deep branch of the radial nerve in the forearm?
None, it is a motor nerve
How is the superficial radial nerve commonly damaged in the forearm?
Stabbing/laceration
What motor loss occurs with damage to the superficial radial nerve in the forearm?
None, it is a sensory nerve
What sensory loss occurs with damage to the superficial radial nerve in the forearm?
There will be sensory loss in the dorsum of the hand
Which roots does the median nerve contain fibres of?
C5, C6, C7, C8, T1
Describe the position of the median nerve relative to the brachial artery after leaving the axilla
Initially lateral to brachial artery, then halfway down crosses over to become medial, continuing into the cubital fossa
Which to muscles does the median nerve travel in between as it passes through the forearm?
Flexor digitorum profundus and flexor digitorum superficialis
Describe two important branches of the median nerve as it passes through the forearm, and their functions
Anterior interosseous nerve, supplying deep flexor muscles, and palmar cutaneous nerve, which innervates skin on the palmar, lateral aspect of the hand
How does the median nerve enter the hand? Which muscles in the hand does it innervate?
Through the carpal tunnel; thenar muscles, and lateral to lumbricals
Which muscles does the median nerve innervate in the forearm?
Pronator teres, palmaris longus, flexor carpi radialis, flexor digitorum superficialis, lateral flexor digitorum profundus, flexor pollicis longus and pronator quadratus
What are the general actions of the muscles in the forearm innervated by the median nerve?
Flexion at the wrist and of digits of the hand, and pronation
What is the name of the branch of the median nerve that innervates the thenar muscles?
Recurrent branch
What are the two branches of the median nerve that innervate the skin? Where do they innervate?
Palmar cutaneous: skin of the hand
Digital cutaneous: lateral three and a half digits on palmar side and fingertips on dorsal side
How does damage to the median nerve commonly occur at the elbow? Which muscles are paralysed?
Supracondylar fracture of the humerus; flexors and pronators in forearm (except those with ulnar innervation), and thenar muscles and lateral 2 lumbricals in hand
What actions will be lost with damage to the median nerve at the elbow?
Pronation, flexion very weak (often accompanied by adduction), flexion at thumb prevented, and flexion of digits II and III at the MCP joints lost, and inability to extend at ICP joints of these digits
What are the characteristic signs of median nerve damage at the elbow?
Thenar wasting, full flexion of only the little and ring fingers; ‘hand of benediction’
How is the median nerve commonly damaged at the wrist? (not carpal tunnel) Which muscles are paralysed?
Laceration of flexor retinaculum; lateral lumbricals and thenar muscles = same signs as damage at elbow
Which roots does the ulnar nerve contain fibres from?
C8 and T1
Describe the course of the ulnar nerve down the arm?
Descends down medial side of the arm, passes posterior to the medial epicondyle, pierces the two heads of the flexor carpi ulnaris in the forearm, then passes down the forearm alongside the ulna; at the wrist it travels superficially to the flexor retinaculum in the ulnar canal
What muscles does the ulnar nerve supply? What actions does it hence control?
Forearm: flexor carpi ulnaris and medial half of flexor digitorum profundus (flexes hand and fingers and adduction at wrist)
Hand: hypothenar muscles, medial two lumbricals, adductor pollicis, interossei of the hand
What are the sensory functions of the ulnar nerve?
Palmar cutaneous and dorsal cutaneous branches innervate medial half of the hand and surfaces of medial 1 and a half fingers;
What is the ulnar tunnel?
Space between the pisiform and hamate, bridged by a piece of fibrous tissue from the flexor retinaculum
What is ulnar tunnel syndrome?
Entrapment of ulnar nerve as it passes through the ulnar tunnel; degree of motor and sensory impairment depends on location of nerve entrapment
Where is the ulnar nerve vulnerable to damage at the elbow?
Medial epicondyle; fracture of the medial epicondyle is the most common way of damaging the ulnar nerve
Which actions will be affected by damage to the ulnar nerve at the medial epicondyle?
Flexion of wrist occurs but is accompanied by abduction; abduction and adduction of the fingers cannot occur, movement of little and ring fingers greatly reduced
What is the characteristic sign of ulnar nerve damage?
Cannot grip paper placed between fingers
How does damage to the ulnar nerve commonly occur at the wrist?
Lacerations
What is the sensory loss of damage to the ulnar nerve just proximal the wrist?
Palmar branch usually severed; sensory loss over the palmar side of the ulnar nerve supply (medial palm and 1 and a half fingers), but not dorsal
What is the cubital fossa?
Area of transition between the anatomical arm and forearm, on the anterior surface if the elbow
What are the lateral, medial, and superior borders of the cubital fossa?
Lateral: medial border of the brachioradialis
Medial: lateral border of pronator teres
Superior: imaginary line between condyles of humerus
What is the floor and roof of the cubital fossa?
Floor: brachialis, and more distally the supinator
Roof: skin, fascia, reinforced by bicipital aponeurosis
What are the contents of the cubital fossa? (lateral to medial)
Radial nerve, biceps tendon, brachial artery, median nerve
Which pulse can be palpated in the cubital fossa?
Brachial pulse; palpate medial to biceps tendon
What important structure runs superficial to the cubital fossa?
Median cubital vein, common site for venepuncture
Where does the arterial supply to the upper limb begin?
Subclavian artery; right branches from brachiocephalic trunk, left directly from aorta
When are the subclavian arteries called the axillary arteries?
After crossing the 1st rib (into the axilla)
Describe the position of the axillary artery relative to the pectoralis minor?
Deep
Which arteries arise at the level of the humeral surgical neck from the axillary artery?
Posterior and anterior circumflex humeral arteries, and the subscapular artery
At what position does the axillary artery become the brachial artery?
Teres major muscle
What is the danger of an axillary aneurysm?
Could put pressure on brachial plexus, manifesting clinically as pain and loss of sensation in the cutaneous distribution of the affected nerves
What does the brachial artery give rise to immediately distal to the teres major?
Profunda brachii artery; runs in radial groove, supplies triceps brachii
Describe the location of the brachial artery relative to the median nerve as it descends down the arm
Immediately posterior
Where does the brachial artery bifurcate to give the radial and ulnar nerves?
As it crosses the cubital fossa, under the brachialis muscle
What is a possible clinical manifestation of an occluded brachial artery?
Volkmann’s contracture; necrosis and paralysis of muscles makes them fibrotic and contractious, causing the flexion deformity
What are the respective areas supplied by the radial and ulnar arteries?
Radial: posterior aspect, Ulnar: anterior aspect
How do the radial and ulnar arteries anastomose in the hand?
Two arches; the superficial palmar arch and the deep palmar arch
What structures does the radial artery supply in the hand?
Contributes to supply of the thumb and lateral side of the index finger
What structures does the ulnar artery supply in the hand?
Digits 3-5 and the medial side of the index finger
Describe the course of the ulnar artery as it moves into the hand
Anterior to the flexor retinaculum, lateral to the ulnar nerve
What are the names of the arteries supply the digits?
Common palmar digital arteries (arise from superficial palmar arch)
Describe the location of the superficial palmar arch in the hand
Anterior to the flexor tendons, just deep to the palmar aponeurosis
Describe the course of the radial artery as it enters the hand
Dorsally, crossing the floor of the anatomical snuffbox; it turns medially and moves between the heads of the adductor pollicus
What are then two main veins of the upper limb?
Cephalic (antero-lateral) and basilica (medial)
Which veins join to form the axillary vein at the teres major?
Basilic vein and brachial veins (venae comitantes)
Which vessel connects the basilic and cephalic veins, superficial to the cubital fossa?
The median cubital vein (venepuncture)
What type of joint is the elbow? Which actions can it perform?
Synovial hinge; extension and flexion
Which muscles perform extension at the elbow joint?
Triceps brachii and anconeus
Which muscles perform flexion at the elbow?
Brachialis, biceps brachii and brachioradialis
What are the thickenings at the medial and lateral sides of the joint capsule? What purpose do they serve?
Collateral ligaments; stabilise the joint
Describe the location of the radial collateral ligament of the elbow joint
Found on the lateral side, extending from the lateral epicondyle, and blending with the anular ligament
Describe the location of the ulnar collateral ligament of the elbow
Originates from the medial epicondyle, attaches to coronoid process and olecranon of ulna
Name the three important bursae of the elbow joint
Intratendinosus, subtendinous, subcutaneous
Where is the intratendinous bursa of the elbow joint formed?
Within the tendons of the triceps brachii
Where is the subtendinous bursa of the elbow joint found?
Between the olecranon and the tendon of the triceps brachii, reducing friction between the two structures during extension and flexion of the forearm
Where is the subcutaneous bursa of the elbow joint found?
Between the olecranon and overlying connective tissue
Describe subcutaneous bursitis of the elbow
Repeated friction and pressure causes the bursa to become inflamed; because it is relatively superficial it can also become infected and cause inflammation
Describe subtendinous bursitis of the elbow
Caused by repeated flexion and extension of the forearm, commonly seen in assembly line workers; usually flexion is more painful because more pressure is put on the bursa
How does dislocation of the elbow joint usually occur in young children?
Fall on hand with elbow flexed
Describe what happened during an elbow dislocation in a young child. Where does the humerus go? Which ligament is usually torn? Which nerve is at risk?
Distal end of humerus driven through weakest part of the joint capsule, the anterior side; the ulnar collateral ligament is usually torn, and the ulnar nerve can be involved
What is the most common direction of elbow dislocation?
Posterior (elbow dislocations named by position of ulna and radius, not humerus)
What is ‘tennis elbow’?
Pain and inflammation in and around the lateral epicondyle, from the common extensor tendinous origin; an overuse strain
What is ‘golfer’s elbow’?
Pain and inflammation in and around the medial epicondyle, from the common flexor tendinous origin; an overuse strain
Which muscles perform scapular retraction?
Both rhomboids, middle trapezius
Which muscles perform scapular protraction?
Serratus anterior, pectoralis minor
Which muscles perform scapular elevation?
Upper trapezius, levator scapulae
Which muscles perform scapular depression?
Lower trapezius, pectoralis minor, subclavius, latissimus dorsi
Which muscles perform scapular lateral rotation (upward)?
Lower and upper trapezius, serratus anterior
Which muscles perform medial scapular rotation? (downward)
Pectoralis minor, rhomboids, levator scapulae
What are some common risk factors for carpal tunnel syndrome?
TRAMP; trauma, rheumatoid arthritis, acromegaly, myxoedema, pregnancy
Which myotome performs abduction of the arm at the glenohumeral joint?
C5
Which myotome performs flexion of the forearm at the elbow joint?
Primarily C6 (some C5)
Which myotome performs extension of the forearm at the elbow joint?
Mainly C7 (some 6/8)
Which myotome performs flexion of the forearm of the fingers?
C8
Which myotome performs abduction and adduction of the index, middle and ring fingers?
T1
What type of bones are the carpals?
Irregular
What are the nerve roots of the pectoral nerves?
C7, C8, T1
Which structures does the coracoid process compress when the arm is abducted?
Anterior to posterior; subclavian vein, subclavian artery, cords of the brachial plexus
What is the action of the pectoralis minor?
Depresses the shoulder tip (infermedial rotation of the scapula)
Which structures are contained with the axillary sheath?
Axillary artery, axillary vein and cords and branches of the brachial plexus
Which muscles form the anterior axillary fold?
Mostly pectoralis major (pectoralis minor adds superiorly)
Which muscles form the posterior axillary fold?
Teres major and latissimus dorsi
In a female patient why would you be concerned about enlargement of lymph nodes in the axilla?
Axillary lymph receives from the breast; in breast carcinoma, malignant cells may enter the lymph and produce enlargement
Which important vein lies immediately posterior to the sternoclavicular joint?
Brachiocephalic vein
Which parts of the brachial plexus are most at risk to injury as a result of a clavicular fracture?
Trunks and divisions
How would you acutely assess motor function of a person with a clavicular fracture, with suspected nerve damage
Don’t! You’ll get sued…
What would be observable differences in determining whether an artery or vein is ruptured as a result of trauma?
Artery may show pulsatile release of blood from an open wound; if there was damage to a major artery the patient would most likely be unconscious and dying; vein rupture would be non-pulsatile, patient conscious, haematoma forming
Describe the location of the brachial artery in relation to the median nerve in the upper arm and cubital fossa
Upper arm it is medial to the median nerve; in the cubital fossa it lies lateral
What lies immediately anterior to the brachial artery and median nerve in the cubital fossa?
Bicipital aponeurosis; collagen from distal radial tendon, passing obliquely across cubital fossa and merging with fascia of flexors
What is the cubital tunnel?
Formed by tendinous arch joing humeral and ulnar heads of the attachment of flexor carpi ulnaris; the median nerve enters the forearm through it
What clinical term is given to describe numbness and tingling? What clinical term is used to describe loss of feeling or sensation?
Paraesthesia; anaesthesia is loss of feeling or sensation
What is the most common direction of humeral dislocation at the glenohumeral joint?
Weakest at inferior aspect, so dislocates in this direction but ends up anterior due to pull of muscles
What would be seen in clinical examination as a result or a torn supraspinatus tendon?
Failure of abduction in first 15 degrees, when lowering fully abducted arm slowly and smoothly, the limb suddenly drops
Why can the upper limb become swollen with lymphatic fluid following axillary clearance?
Excision of the axillary lymph and lymphatic vessels leads to disturbance of the normal lymphatic drainage of the upper limb; the lymph nodes in the axilla receive lymph from the whole of the upper limb
Which myotome performs adduction at the shoulder?
C6, C7, (C8)
Which myotome performs pronation?
C7, C8
Which myotome performs supination?
C6
Where is the axis of rotation in movements of pronation and supination
The axis passes longitudinally along the head of the radius (proximally) and through the distal radio-ulnar joint at the wrist
What is a ‘pulled’ elbow? Describe what happens
Subluxation or dislocation of the articulating surface of the bones forming the proximal radio-ulnar joint; the injury results when a person is lifted by the upper limb with the forearm in a pronated position; the pulling of the upper limb tears the distal attachment of the annular ligament (surrounding the radial head) where it is loosely attached to the neck of the radius; the radial head moves distally and out of the torn ligament
Why is a ‘pulled’ elbow more common in children?
The radial head an annular ligament have not fully formed
Why is supination more powerful than pronation?
Strength of the biceps brachii is greater than the pronators
What will avascular necrosis of the scaphoid (weeks after injury) look like on X-ray?
The proximal segment will look less opaque as it is being resorbed
Which bony structure can be palpated around the elbow?
Medial and lateral epicondyles, olecranon process of ulna and head of radius
Why would a superficial laceration at the wrist result in loss of sensory function of the palm only?
Damage to palmar cutaneous branch of median nerve (may also be ulnar nerve damage); digits supplied by digital branch that arises after passage through carpal tunnel
What is the common action of the lumbricals and interossei muscles?
Flexion at MCP and extension as IP joints
What is inflammation of a tendon and it’s synovial sheath known as?
Tenosynovitis
Why can swelling proximal to the wrist joint be linked to infection in the tip of the thumb or little finger?
The synovial tendon sheath of the thumb and 4th finger are continuous with the common flexor synovial sheath; the 1st, 2nd, and 3rd fingers normmaly have separate synovial sheaths
Where is the most reliable area for testing sensation of the radial nerve in the hand?
Small area on the first interdigital webspace, on the dorsum of the hand
What are the medial and lateral attachments of the flexor retinaculum?
Medially attached to the pisiform and hook of hamate; laterally attached to the tubercle of the scaphoid and trapezium bones
Give causes of carpal tunnel syndrome
Tenosynovitis (thickening of synovium), repetitive trauma (compression forces and stretching), oedema, fractures, dislocations, inherited small bone fractures
