2016

PRESENTED BY :

DR.ASER MOHAMED KAMAL

PHYSICAL THERAPY

KINESOLOGY OF ELBOW &WRIST JOINTS

The Elbow & Radioulnar Joints

• Most upper extremity movements involve the elbow & radioulnar joints

• Usually grouped together due to close anatomical relationship

• Elbow joint movements may be clearly distinguished from those of the radioulnar

joints

• Radioulnar joint movements may be distinguished from those of the wrist

Bones • Ulna is much larger proximally than radius

• Radius is much larger distally than ulna

• Scapula & humerus serve as proximal attachments for

muscles that flex & extend the elbow

• Ulna & radius serve as distal attachments for these same

muscles

• Scapula, humerus, & ulna serve as proximal attachments for muscles that pronate &

supinate the radioulnar joints

• Distal attachments of radioulnar joint muscles are located on radius

• Bony landmarks

1- Humerus:

Medial and lateral epicondyles

– Palpated on medial and

lateral sides, respectively, of

distal end of humerus (2

“bumps” on distal end).

Medial and lateral

supracondylar ridge – above the

medial and lateral epicondyles

on distal end of humerus.

Olecxranon fossa – indentation on posterior of

elbow

2- Radius:

Head – From lateral epicondyle of humerus move

distally about 1 inch.Head of radius palpated

easiest as you pronate and supinate.

Anterior border – Ridge just above wrist on lateral

aspect of lower forearm.

Styloid process – In the anatomic position, styloid

is lateral just above wrist joint.

Dorsal tubercle – On distal end of radius on

posterolateral aspect of wrist. Feels like asmall

longitudinal bony prominence or module.

3- Ulna:

Olecranon – “Funny bone” – long protuberance

on

posterior of elbow.

Styloid process – In the anatomic position, styloid

process is on medial aspect of wrist, also slightly

posterior. Is more proximal than radial styloid

process.

Head – On distal end of ulna. In supination, it can

be palpated on medial-anterior aspect of wrist

(just proximal to wrist). In pronation, head is the

projection on posterior aspect (ulnar side) of

wrist.

*Key bony landmarks for wrist & hand muscles

o medial epicondyle

o lateral epicondyle

o lateral supracondylar ridge

Joints

• hinge-type joint

• Allows only flexion & extension

• 2 interrelated joints

– humeroulnar joint

– radiohumeral joints

• Elbow motions

– primarily involve movement between articular surfaces of humerus & ulna

– specifically humeral trochlear fitting into ulna trochlear notch

– radial head has a relatively small amount of contact with capitulum of

humerus

– As elbow reaches full extension, olecranon process is received by olecranon

fossa

• increased joint stability when fully extended

• As elbow flexes 20 degrees or more, its bony stability is

unlocked, allowing for more side-to-side laxity

• Stability in flexion is more dependent on the lateral (radial

collateral ligament) & the medial or (ulnar collateral

ligament)

• Ulnar collateral ligament is critical in providing medial

support to prevent elbow from abducting when stressed in

physical activity

– Many contact sports & throwing activities place

stress on medial aspect of joint, resulting in

injury

• Radial collateral ligament provides lateral stability & is

rarely injured

• Annular ligament provides a sling effect around radial head for

stability

• Elbow moves from 0 degrees of extension to 145 to 150 degrees

of flexion

Radioulnar joint

– Trochoid or pivot-type joint

– Radial head rotates around at proximal ulna

– Distal radius rotates around distal ulna

– Annular ligament maintains radial head in its

joint

• Radioulnar joint

– Supinate 80 to 90 degrees from

neutral

– Pronate 70 to 90 degrees from

neutral

– Joint between shafts of radius & ulna held tightly together between

proximal & distal articulations by an interosseus membrane (syndesmosis)

• substantial rotary motion between the bones

• Synergy between glenohumeral, elbow, & radioulnar joint muscles

– As the radioulnar joint goes through its ROM, glenohumeral & elbow

muscles contract to stabilize or assist in the effectiveness of movement at

the radioulnar joints

– Ex. when tightening a screw with a screwdriver which involves radioulnar

supination, we tend to externally rotate & flex the glenohumeral & elbow

joints, respectfully

• Synergy between glenohumeral, elbow, & radioulnar joint muscles

– Conversely, when loosening a tight screw with pronation, we tend to

internally rotate & extend the elbow & glenohumeral joints, respectfully

– we depend on both the agonists and antagonists in the surrounding joints to

assist in an appropriate amount of stabilization & assistance with the

required task

Movements

• Flexion

– movement of forearm to shoulder by bending the

elbow to decrease its angle

• Extension

– movement of forearm away from shoulder by

straightening the elbow to increase its angle

• Pronation

– internal rotary movement of radius on ulna that

results in hand moving from palm-up to palm-down

position

• Supination

– external rotary movement of radius on ulna that

results in hand moving from palm-down to palm-up

position

Muscles

• Elbow flexors

– Biceps brachii:

Origin: Short head: tip of coracoid process of

scapula; Long head: supraglenoid tubercle of

scapula

Insertion: Tuberosity of radius and fascia of

forearm via bicipital aponeurosis

Action: Supinates forearm and, when it is

supine, flexes forearm

Innervation: Musculocutaneous nerve (C5 and C6 )

– Brachioradialis:

Origin: Upper lateral supracondylar ridge of the

humerus (between triceps brachii and brachialis

Insertion: Superior aspect of the styloid process of

the radius and the lateral side of the distal half to

one-third of the radius.

Action: Flexion of the forearm at the elbow

Innervation: Radial Nerve (C5, 6)

- Weak assistance from Pronator teres:

Origin: Humeral Head: Superior portion of the medial

epicondyle via the common flexor tendon of the ulna.

Ulnar Head: Coronoid process of the ulna

Insertion: Lateral aspect of the mid shaft of the radius

Action: Pronation of the forearm

Innervation: Median nerve (C6, 7 )

• Elbow extensor

– Triceps brachii:

Origin: Long head: infraglenoid tubercle of

scapula; Lateral head: posterior surface of

humerus, superior to radial groove; Medial

head: posterior surface of humerus, inferior

to radial groove

Insertion: Proximal end of olecranon

process of ulna and fascia of forearm

Action: Chief extensor of forearm; long

head steadies head of abducted humerus

Innervation: Radial nerve (C6, C7 and

C8)

– Anconeus provides assistance

• Origin: Posterior aspect of the lateral epicondyle of humerus.

Insertion: Lateral aspect the olecranon process extending to

the lateral surface of the ulna body.

Action: Extension of the elbow

Innervation: C7-8, Radial Nerve

• Radioulnar pronators

– Pronator teres

– Pronator quadratus

– Brachioradialis

• Radioulnar supinators

– Biceps brachii

– Supinator muscle

– Brachioradialis

• Anterior

– Primarily flexion & pronation

• Biceps brachii

• Brachialis

• Brachioradialis

• Pronator teres

• Pronator quadratus

• Posterior

– Primarily extension & supination

• Triceps brachii

• Anconeus

• Supinator

Wrist and Hand

Wrist is the most complex joints of the body due to the

numerous joints combined to create one.

Very complex

29 bones

25 joints

33 muscles

- 29 bones, including radius & ulna

- Carpals (8)

- Two rows of 4 bones

- Metacarpals (5)

- Numbered 1-5

- Phalanges (14)

- Three for each finger

- Two for the thumb

- Thumb has a sesamoid bone in its flexor tendon

- Other sesamoids may occur in joints of fingers

- Radiocarpal joint

o Biaxial ball and socket

- Intercarpal joints

o Gliding/nonaxial

- Carpometacarpal joints

o Fingers – Gliding/nonaxial

o Thumb – Biaxial saddle

- Metacarpophalangeal joints

o Fingers – Biaxial ball and socket

o Thumb – Uniaxial hinge

- Proximal interphalangeal joints

o Fingers – Uniaxial hinge

- Distal interphalangeal joints

o Fingers – Uniaxial hinge

- Interphalangeal joint

o Thumb – Uniaxial hinge

Carpal bones- Create a Mnemonic for them. S-L-T-P-T-T-C-H

Two rows of bones starting on the thumb side.

Scaphoid, lunate, triquetrum, pisiform

Second row of carpals bones, is more proximal

Trapezium, trapezoid, capitate, Hamate.

Medial and Lateral epicondyle are where many of the wrist and hand muscles

originate.

Styloid process- projection at distal end of radius and ulna where the collateral

ligaments attach.

Radiocarpal Joint- distal end of the radius and

scaphoid, lunate, and triquetrum. There is a

radioulnar disk in between the radius and other

bones. It is a condyloid joint.

Midcarpal joint- between the two rows

of carpal bones. Plane joints that allow

gliding motion, but assist with wrist

motions.

Carpometacarpal joint- between the

distal row of carpal bones and proximal

end of the metacarpal bones. Provide

more stability than mobility.

Carpals:

1. Pisiform – “Pea-shaped” bone on ulnar side of

hand (palmar surface)

2. Scaphoid – On radial side of wrist – easiest to

palpate in “floor” of anatomical snuffbox

(proximal to thumb) as you move hand into ulnar

deviation.

3. Trapezium – On radial side of wrist where it

articulates with 1stmetacarpal to form saddle joint.

Easiest to palpate as you flex and extend the

thumb.

4. Hamate (hook) – Located slightly distal and

radial to the pisiform.

5. Capitata – Proximal to the base of the third

metacarpal between the dorsal

tubercle of the radius and the third metacarpal.

Most easily palpated as you flex the wrist.

6. Triangular – Located just distal to the ulnar

styloid process. To palpate, radially deviate the

hand.

7. Base, body, head of metacarpals and phalanges.

Ligaments of hand

Palmar radiocarpal ligament-broad band attaches

anterior surface of distal radius and ulna to anterior

surface of the proximal carpal bones and the

capitate. Limits wrist extension. So repeated falls in

extension would injur it.

Muscles of forearm

MUSCLES IN THE ANTERIOR COMPARTMENT OF THE FOREARM There are many muscles in the forearm. In the anterior compartment, they are split into three categories; superficial, intermediate and deep.

In general, muscles in the anterior compartment of the forearm perform flexion at the wrist and fingers, and pronation.

Superficial Compartment The superficial muscles in the anterior compartment are the flexor carpi ulnaris, palmaris longus, flexor carpi radialis and pronator teres. They all originate from a common tendon, which arises from the medial epicondyle of the humerus. Flexor Carpi Ulnaris Attachments: Originates from the medial epicondyle with the other superficial

flexors. It also has a long origin from the ulna. It passes into the wrist, and attaches to the pisiform carpal bone.

Actions: Flexion and adduction at the wrist. Innervation: Ulnar nerve. Palmaris Longus This muscle is absent in about 15% of the population.Dissection Tip: Just distal to the wrist, if you reflect back the palmaris longus, you will find the median nerve immediately underneath it

Attachments: Originates from the medial epicondyle, attaches to the flexor retinaculum of the wrist.

Actions: Flexion at the wrist. Innervation: Median nerve.

Flexor Carpi Radialis Attachments: Originates from the medial epicondyle, attaches to the base of

metacarpals II and III. Actions: Flexion and abduction at the wrist. Innervation: Median nerve. Pronator Teres The lateral border of the pronator teres forms the medial border of the cubital fossa, an anatomical triangle located over the elbow. Attachments: It has two origins, one from the medial epicondyle, and the other

from the coronoid process of the ulna. It attaches laterally to the mid-shaft of the radius.

Actions: Pronation of the forearm. Innervation: Median nerve.

Intermediate Compartment

The flexor digitorum superficialis is the only muscle of the intermediate compartment. It can sometimes be classed as a superficial muscle, but in most cadavers it lies between the deep and superficial muscle layers. The muscle is a good anatomical landmark in the forearm – the median nerve and ulnar artery pass between its two heads, and then travel posteriorly. Attachments: It has two heads – one originates from the medial epicondyle of the

humerus, the other from the radius. The muscle splits into four tendons at the wrist, which travel through the carpal tunnel, and attaches to the middle phalanges of the four fingers.

Actions: Flexes the metacarpophalangeal joints and proximal interphalangeal joints at the 4 fingers, and flexes at the wrist.

Innervation: Median nerve.

Deep Compartment

There are three muscles in the deep anterior forearm; flexor digitorum profundus, flexor pollicis longus, and pronator quadratus.

Flexor Digitorum Profundus Attachments: Originates from the ulna and associated interosseous

membrane. At the wrist, it splits into four tendons, that pass through the carpal tunnel and attach to the distal phalanges of the four fingers.

Actions: It is the only muscle that can flex the distal interphalangeal joints of the fingers. It also flexes at metacarpophalangeal joints and at the wrist.

Innervation: The medial half (acts on the little and ring fingers) is innervated by the ulnar nerve. The lateral half (acts on the middle and index fingers) is innervated by the anterior interosseous branch of the median nerve.

Flexor Pollicis Longus This muscle lies laterally to the FDP.

Attachments: Originates from the anterior surface of the radius, and surrounding interosseous membrane. Attaches to the base of the distal phalanx of the thumb.

Actions: Flexes the interphalangeal joint and metacarpophalangeal joint of the thumb.

Innervation: Median nerve (anterior interosseous branch).

Pronator Quadratus A square shaped muscle, found deep to the tendons of the FDP and FPL.

Attachments: Originates from the anterior surface of the ulna, and attaches to the anterior surface of the radius.

Actions: Pronates the forearm. Innervation: Median nerve (anterior interosseous branch).

MUSCLES IN THE POSTERIOR COMPARTMENT OF THE FOREARM The muscles in the posterior compartment of the forearm are commonly known as theextensor muscles. The general function of these muscles is to produce extension at the wrist and fingers. They are all innervated by the radial nerve. Anatomically, the muscles in this compartment can be divided into two layers; deep andsuperficial. These two layers are separated by a layer of fascia. In this article, we shall look at the attachments, actions and clinical relevance of the muscles in the posterior compartment of the forearm.

Superficial Muscles

The superficial layer of the posterior forearm contains seven muscles. Four of these

muscles – extensor carpi radialis brevis, extensor digitorum, extensor carpi ulnaris

and extensor digiti minimi share a common tendinous origin at the lateral epicondyle.

Brachioradialis The brachioradialis is a paradoxical muscle. Its origin and innervation are characteristic of a extensor muscle, but it is actually a flexor at the elbow.

The muscle is most visible when the forearm is half pronated, and flexing at the elbow against resistance.

In the distal forearm, the radial artery and nerve are sandwiched between the brachioradialis and the deep flexor muscles.

Attachments: Originates from the proximal aspect of the lateral supracondylar ridge of humerus, and attaches to the distal end of the radius, just before the radial styloid process.

Actions: Flexes at the elbow. Innervation: Radial nerve.

Extensor Carpi Radialis Longus and Brevis The extensor carpi radialis muscles are situated on the lateral aspect of the posterior forearm. Due to their position, they are able to produce abduction as well as extension at the wrist.

Attachments: The ECRL originates from the supracondylar ridge, while the ECRB originates from the lateral epicondyle. Their tendons attach to metacarpal bones II and III.

Actions: Extends and abducts the wrist. Innervation: Radial nerve. Extensor Digitorum The extensor digitorum is the main extensor of the fingers. To test the function of the muscle, the forearm is pronated, and the fingers extended against resistance.

Attachments: Originates from the lateral epicondyle. The tendon continues into in the distal part of the forearm, where it splits into four, and inserts into the extensor hood of each finger.

Actions: Extends medial four fingers at the MCP and IP joints. Innervation: Radial nerve. Extensor Digiti Minimi The extensor digiti minimi is thought to originate from the extensor digitorum muscle. In some people, these two muscles are fused together. Anatomically, the extensor digiti minimi lies medially to the extensor digitorum.

Attachments: Originates from the lateral epicondyle of the humerus. It attaches, with the extensor digitorum tendon, into the extensor hood of the little finger.

Actions: Extends the little finger, and contributes to extension at the wrist. Innervation: Radial nerve. Extensor Carpi Ulnaris The extensor carpi ulnaris is located on the medial aspect of the posterior forearm. Due to its position, it is able to produce adduction as well as extension at the wrist.

Attachments: Originates from the lateral epicondyle of the humerus, and attaches to the base of metacarpal V.

Actions: Extension and adduction of wrist. Innervation: Radial nerve. Anconeus The aconeus is situated medially and superiorly in the extensor compartment of the forearm. It is blended with the fibres of the triceps brachii, and the two muscles can be indistinguishable.

Attachments: Originates from the lateral epicondyle, and attaches to the posterior and lateral part of the olecrannon.

Actions: Moves the ulna during pronation and extends at the elbow joint. Innervation: Radial nerve.

Deep Muscles There are five muscles in the deep compartment of the posterior forearm – the supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis.

With the exception of the supinator, these muscles act on the thumb and the index finger.

Supinator The supinator lies in the floor of the cubital fossa. It has two heads, which the

deep branch of the radial nerve passes between.

Attachments: It has two heads of origin. One originates from the lateral epicondyle of the humerus, the other from the posterior surface of the ulna. They insert together into the posterior surface of the radius.

Actions: Supinates the forearm. Innervation: Radial nerve. Abductor Pollicis Longus The abductor pollicis longus is situated immediately distal to the supinator muscle. In the hand, its tendon contributes to the lateral border of the anatomical snuffbox. Attachments: Originates from the interosseous membrane and the adjacent

posterior surfaces of the radius and ulna. It attaches to the lateral side of the base of metacarpal I.

Actions: Abducts the thumb. Innervation: Radial nerve.

Extensor Pollicis Brevis The extensor pollicis brevis can be found medially and deep to the abductor pollicis longus. In the hand, its tendon contributes to the lateral border of the anatomical snuffbox. Attachments: Originates from the posterior surface of the radius and

interosseous membrane. It attaches to the base of the proximal phalanx of the thumb.

Actions: Extends at the metacarpophalangeal and carpometacarpal joints of the thumb.

Innervation: Radial nerve.

Extensor Pollicis Longus The extensor pollicis longus muscle has a large muscle belly than the EPB. Its tendon travels medially to the dorsal tubercle at the wrist, using the tubercle as a ‘pulley’ to increase the force exerted.

The tendon of the extensor pollicis longus forms the medial border of the anatomical snuffboxin the hand. Attachments: Originates from the posterior surface of the ulna and interosseous

membrane. It attaches to the distal phalanx of the thumb. Actions: Extends all joints of the thumb: carpometacarpal, metacarpophalangeal

and interphalangeal. Innervation: Radial nerve.

Extensor Indicis Proprius This muscle allows the index finger to be independent of the other fingers during extension.

Attachments: Originates from the posterior surface of the ulna and interosseous membrane, distal to the extensor pollicis longus. Attaches to the extensor hood of the index finger.

Actions: Extends the index finger. Innervation: Radial nerve.