The Ulna

The Ulna

The Ulna is one of two bones in the forearm

The Ulna lies medially

The Ulna

The Radius lies laterally

The Ulna

The Ulna is a long bone

It is divided into

thirds along its

length

It is divided into

thirds along its

length

It is divided into

thirds along its

length

Proximal third

It is divided into

thirds along its

length

Proximal third

Middle third

It is divided into

thirds along its

length

Proximal third

Middle third

Distal Third

The Proximal Ulna is expanded and has a number of interesting projections

Medial view Lateral view

Right Ulna

Anterior View Posterior View

The Proximal Ulna is expanded and has a number of interesting projections

Right Ulna

Proximal Ulna

Lateral View

Radial Notch

The Ulna articulates with the Radial Head at the Proximal Radioulnar Joint

Right Ulna

The Ulna

Proximal Radio-Ulnar Joint

The Ulna articulates with the Radial Head at the Proximal Radioulnar Joint

The Ulna articulates with the Humerus at the Elbow Joint

Lateral View

Trochlear Notch

Right Ulna

Distal HumerusPosterior view

Trochlea

The Trochlear Notch of the Ulna articulates with the

Trochlea of the Humerus

This joint permits flexion and extension

Lateral View

Olecranon

The Triceps Muscle inserts here

Right Ulna

Distal HumerusPosterior view

Olecranon Fossa

In extension the Olecranon Process of the Ulna engages with the Olecranon Fossa of

the Distal Humerus

Medial View

Coronoid Process

Distal HumerusAnterior View

Coronoid Process

In Elbow Flexion the

Coronoid Process of the Ulna

articulates with the

Coronoid Fossa of the distal Humerus

In Elbow Flexion the

Coronoid Process of the Ulna

articulates with the

Coronoid Fossa of the distal Humerus

The distal end of the Ulna is much smaller than the proximal end

It helps form the wrist joint

The Ulna articulates at both ends with the Radius

Proximal Radio-Ulnar Joint

Distal Radio-Ulnar Joint

The Distal Ulna has a

Rounded Head

The Distal Ulna has a

Rounded Head

and a small

Styloid Process

Muscles attaching to the Ulna

Proximal UlnaVolar Aspect

Flexor Digitorum SuperficialisUlnar Head

Pronator Teres

Proximal UlnaVolar Aspect

The Ulnar head attaches to the

medial border of the Coronoid Process

Pronates the forearm and flexes the elbow

Volar Aspect Forearm

Brachialis

Volar Aspect ForearmAttaches to

Coronoid Process and Tuberosity of the

Ulna

Flexes Elbow

Brachialis

Supinator

Proximal UlnaLateral View

Posterior View Forearm

Supinator

Deep part attaches to the supinator crest and ulna

tuberosity

Supinates the forearm

Proximal UlnaLateral View

Posterior View Forearm

Proximal UlnaLateral View

Supinator Crest

Ulna Tuberosity

Flexor Digitorum Profundus

Volar Aspect Forearm

Flexor Digitorum Profundus

Arises from the medial aspect of olecranon and

proximal 3/4 of medial and anterior surfaces of ulna

Flexes distal interphalangeal joints,

proximal interphalangeal joints,

metacarpophalangeal joint of digits 2-5; flexes wrist

Volar Aspect Forearm

Pronator Quadratus

Volar Aspect Forearm

Pronator Quadratus

Volar Aspect Forearm

Distal 1/4 of anterior surface of ulna

Pronates forearm

Triceps

Triceps

Attaches to olecranon process of ulna

Extends elbow joint

Anconeus

Anconeus

Attaches to postero-lateral aspect of

olecranon process of the ulna

Extends the elbow joint, abducts ulna in

pronation

Flexor Digitorum Profundus

Posterior View

Anterior View

Flexor Digitorum Profundus

Posterior View

Anterior View

Arises from medial olecranon, proximal 3/4 of medial and anterior surfaces of ulna

Flexes distal interphalangeal, proximal interphalangeal,

metacarpophalangeal joints of digits 2-5; flexes wrist

Aponeurotic attachment of

Flexor Digitorum ProfundusFlexor Carpi UlnarisExtensor Carpi Ulnaris

Dorsal aspect of right forearm

Abductor Pollicis Longus

Abductor Pollicis Longus

Arises from posterior surface of proximal

shaft of ulna

Abducts thumb, extends thumb at

carpometacarpal joint

Extensor Pollicis Longus

Extensor Pollicis Longus

Posterior surface of middle 1/3 of ulna

Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints

Extensor Indicis

Extensor Indicis

Distal aspect posterior surface of ulna

Extends index finger and hand

Abductor Pollicis Longus

Anconeus

Brachialis

Extensor Carpi Ulnaris

Extensor Indicis

Extensor Pollicis Longus

Flexor Carpi Ulnaris

Flexor Digitorum Profundus

Flexor Digitorum Superficialis

Pronator Quadratus

Pronator Teres

Supinator

Triceps

Summary of Muscles attaching to the Ulna

Posterior Forearm

Abductor Pollicis LongusOrigin Posterior surfaces of proximal

shaft of ulna and middle third radius and intervening interosseous membrane

Insertion Dorsal aspect base of 1st metacarpal, trapezium

Action Abducts thumb, extends thumb at carpometacarpal joint

Nerve Supply Posterior interosseous nerve (deep branch of radial nerve C7, C8)

Blood Supply Posterior interosseous artery

Posterior Forearm

AnconeusOrigin Distal and posterior aspect

lateral epicondyle of humerusInsertion Postero-lateral aspect olecranon

process of the ulnaAction Extends the elbow joint, abducts

ulna in pronationNerve Supply Posterior interosseous nerve

(deep branch radial nerve C7, C8)Blood Supply Posterior interosseous artery

Anterior ArmBrachialis

Origin Distal half of anterior surface of humerus

Insertion Coronoid process and tuberosity of ulna

Action Flexes elbowNerve Supply Musculocutaneous nerve (C5,

C6) Blood Supply Muscular branches of brachial

artery, recurrent radial artery

Posterior Forearm

Extensor Carpi UlnarisOrigin Common extensor origin on

anterior aspect lateral epicondyle of humerus

Insertion Base of 5th metacarpal via groove in ulnar styloid

Action Extends and adducts hand at wrist joint

Nerve Supply Posterior interosseous nerve, (deep branch of radial nerve C7, C8)

Blood Supply Ulnar artery

Posterior Forearm

Extensor IndicisOrigin Distal aspect posterior surface

of ulna and interosseous membrane

Insertion Extensor expansion of index finger

Action Extends index finger and handNerve Supply Posterior interosseous nerve

(deep branch radial nerve C7, C8)

Blood Supply Posterior interosseous artery

Posterior Forearm

Extensor Pollicis LongusOrigin Posterior surface of middle 1/3

of ulna and interosseous membrane

Insertion Base of distal phalanx of thumb

Action Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints

Nerve Supply Posterior interosseous nerve (deep branch of radial nerve C7, C8)

Blood Supply Posterior interosseous artery

Anterior Forearm

Flexor Carpi UlnarisOrigin Humeral head: common flexor

origin, medial epicondyle of humerusUlnar head: olecranon and upper 2/3rds posterior border of ulna

Insertion Pisiform, hook of hamate, 5th metacarpal

Action Flexes and adducts hand (at wrist)

Nerve Supply Ulnar nerve (C7 and C8)Blood Supply Ulnar artery

Anterior Forearm

Flexor Digitorum ProfundusOrigin Medial olecranon, proximal 3/4 of

medial and anterior surfaces of ulna and interosseous membrane

Insertion Base of the distal phalanx of digits 2 - 5

Action Flexes distal interphalangeal joints, proximal interphalangeal joints, metacarpophalangeal joint of digits 2-5; flexes wrist

Nerve Supply Medial part: ulnar nerveLateral part: anterior interosseous branch of median nerve (C8 and T1)

Blood Supply Ulnar and anterior interosseous arteries

Anterior ForearmFlexor Digitorum Superficilais

Origin Humeral head: common flexor origin, medial epicondyle of humerusUlnar head: ulnar collateral ligament, and coronoid process of ulnaRadial head: superior half of anterior border of radius, anterior oblique line

Insertion Tendons split and insert of either side of middle phalanges digits 2 –5

Action Flexes middle phalanges at proximal interphalangeal joints of 2-5 digits; flexes proximal phalanges at metacarpophalangeal joints and hand

Nerve Supply Median nerve (C7, C8 and T1)Blood Supply Ulnar artery

Pronator QuadratusOrigin Distal 1/4 of anterior surface

of ulnaInsertion Distal 1/4 of anterior surface

of radiusAction Pronates forearmNerve Supply Anterior interosseous nerve

from median nerve (C8 and T1Blood Supply Anterior interosseous artery

Anterior Forearm

Anterior Forearm

Pronator TeresOrigin Humeral head: medial

epicondyle, supracondylar ridge of humerusUlnar head: medial border coronoid process of ulna

Insertion Middle of lateral surface of radius

Action Pronates forearm, flexes elbowNerve Supply Median nerve (C6 and C7)Blood Supply Ulnar artery, anterior recurrent

ulnar artery

Posterior ForearmSupinator

Origin Superficial part (downwards): Lateral epicondyle of humerus, radial collateral and annular ligamentsDeep part (horizontal): supinator fossa and crest of ulna

Insertion Lateral, posterior and anterior surfaces of proximal 1/3 of radius

Action Supinates forearm Nerve Supply Posterior Interosseous nerve

(C5 and C6) Blood Supply Recurrent interosseous artery

TricepsOrigin Long head: infraglenoid

tubercle of scapula; Lateral head: posterior surface of humerus, superior to radial grooveMedial head: posterior surface of humerus, inferior to radial groove

Insertion Olecranon process of ulna, fascia of forearm

Action Extends elbow jointNerve Supply Radial nerve (C6, C7 and C8) Blood Supply Branches of deep brachial

artery

Posterior Arm