Anatomy of the

Forearm & Hand

By: Dr. Mohamed Galal
Edited by: Dr. Nora Helal
Department of human Anatomy and Embryology
Faculty of Medicine
Mansoura National University, Egypt
 The Forearm: Muscles
Anterior compartment

Posterior compartment
 Anterior Forearm Muscles
5 Superficial Muscles Share a
Find the common flexor Origin:
Biceps tendon FRONT of the medial
Pronator Teres epicondyle of the
Flexor Carpi Radialis humerus
Palmaris Longus Share a
Flexor Carpi Ulnaris common action:
Flexion of the elbow

Flexor Digitorum Superficialis All supplied by Median

nerve EXCEPT
Flexor Carpi Ulnaris
supplied by
Ulnar nerve
 Pronator Teres
Origin 2 Heads:
- Humeral head: common flexor origin
- Ulnar head: Medial border of the coronoid process of the ulna

Insertion
Pronator tuberosity

Action
1. Flexion of the elbow joint
2. Pronation of the forearm (radioulnar joints)
 Flexor Carpi Radialis
Origin common flexor origin

Insertion Bases of the 2nd & 3rd metacarpal bones

Action

1. Flexion of the elbow joint

2. Flexion of the wrist joint
3. Radial deviation (Abduction) of the hand.
 Palmaris Longus
Origin
common flexor origin

Insertion
Palmar Aponeurosis & Flexor retinaculum

Action
1. Flexion of the elbow joint
2. Flexion of the wrist joint
 Flexor Carpi Ulnaris
Origin 2 Heads: - Humeral head: common flexor origin
- Ulnar head: Medial border of olecranon process of ulna
and posterior border of ulna

Insertion
Pisiform, hamate & 5th metacarpal bones

Action

1. Flexion of the elbow joint

2. Flexion of the wrist joint
3. Ulnar deviation (adduction) of the hand
 Flexor Digitorum Superficialis
Origin 2 Heads:
- Humeroulnar head: common flexor origin & coronoid process of ulna
- Radial head: Anterior oblique line of the radius
Insertion
Middle Phalanges of the medial 4 fingers

Action
1. Flexion of the elbow joint
2. Flexion of the wrist joint
3. Flexion of the Carpometacarpal & the proximal
interphalangeal joints of the medial 4 fingers
 Deep Anterior Forearm Muscles
3 Deep Muscles
Are supplied by
Flexor Digitorum Profundus Anterior interosseous
branch of the median
Flexor Pollicis Longus nerve EXCEPT:
Ulnar (medial) half of
flexor digitorum
Pronator Quadratus profundus by
Ulnar nerve
 Flexor Digitorum Profundus
Origin Upper ¾ of the anterior & medial surfaces of the ulna &
Posterior border of the ulna & interosseous membrane

Insertion
Distal Phalanges of the medial 4 fingers

Action
1. Flexion of the wrist joint
2. Flexion of ALL joints of the medial 4 fingers
 Flexor Pollicis Longus
Origin Upper 2/3 of anterior surface of the radius
(below anterior oblique line) and interosseous membrane

Insertion
Base of the distal phalanx of the thumb

Action

1. Flexion of the wrist joint

2. Flexion of ALL joints of the thumb
 Pronator Quadratus
Origin

Lower ¼ of the front of the ulna

Insertion
Lower ¼ of the front of radius

Action

MAIN pronator of the forearm

Posterior Forearm Muscles
 Posterior Forearm Muscles
7 Superficial Muscles 5 Deep Muscles
Brachioradialis
Anconeus Supinator
Extensor Carpi Radialis
Longus (ECRL) Abductor
Pollicis Longus
Extensor Carpi Radialis
Brevis (ECRB) Extensor
Pollicis Brevis
Extensor Extensor Digitorum
Digiti Minimi Extensor
Pollicis Longus
Extensor
Extensor
Carpi Ulnaris
Indices
7 Superficial Muscles
 Anconeus
Origin Back of the lateral epicondyle

Insertion
Lateral part of olecranon process

Action

1. Assists the triceps in elbow extension

 Brachioradialis
Upper 2/3 of the lateral supracondylar ridge
Origin
& Lateral intermuscular septum

Insertion styloid process of the radius

Action
1. Initiation of both supination & pronation to
reach the mid-prone position
2. Flexion of the elbow when the forearm is in
the mid-prone position
 Extensor Carpi Radialis Longus
Lower 1/3 of the lateral supracondylar ridge
Origin
& Lateral intermuscular septum

Insertion Dorsum of the base of the 2nd metacarpal bone

Action
1. Extension of the elbow
2. Extension of the wrist
3. Abduction (Radial deviation) of the wrist
 Extensor Carpi Radialis Brevis
Origin Common Extensor Origin

Insertion Dorsum of the base of the 3rd metacarpal bone

Action

1. Extension of the elbow

2. Extension of the wrist
3. Abduction (Radial deviation) of the wrist
 Extensor Digitorum
Common Extensor Origin
Origin

Extensor expansions of the medial 4 fingers to the

Insertion
middle and distal phalanges

Action

1. Extension of the elbow

2. Extension of the wrist
3. Extension of all joints of the medial 4 fingers
 Extensor Digiti Minimi
Origin Common Extensor Origin

Insertion Extensor expansion of the little finger

Action

1. Extension of the elbow

2. Extension of the wrist
3. Extension of all joints of the little finger
 Extensor Carpi Ulnaris
Origin Common Extensor Origin & Posterior Border of the ulna

Insertion Dorsum of the base of the 5th metacarpal

Action

1. Extension of the elbow

2. Extension of the wrist
3. Adduction (ulnar deviation) of the wrist
 Posterior Forearm Muscles
5 Deep Muscles

Supinator All are supplied with posterior interosseus

branch of radial nerve
Abductor
Pollicis Longus
Extensor
Pollicis Brevis
Extensor
Pollicis Longus
Extensor
Indices
 Ex.P.B
Ex. indicis
Superficial
head

Ex.P.L
Deep head

supinator

Ab.P.L
 Supinator
- Superficial head: Lateral epicondyle, radial collateral and annular ligaments
Origin 2 heads - Deep head: Supinator crest and supinator fossa of ulna

Insertion
upper 1/3 of the radius.

Action
Supination of the forearm
 Abductor Pollicis Longus
- Upper 1/3 of the posterior surface of the ulna
Origin - Upper 1/3 of the posterior surface of the radius
- Interosseous membrane

Insertion Lateral side of base of the 1st metacarpal

Action Abduction of the thumb

 Extensor Pollicis Brevis
- Lower 1/3 of the posterior surface of the radius
Origin - Interosseous membrane

Insertion Base of the proximal phalanx of the thumb

Action

Extension of the thumb without extending the

interphalangeal joint
 Extensor Pollicis Longus
- Middle 1/3 of the posterior surface of the ulna
Origin - Interosseous membrane

Insertion Base of the distal phalanx of the thumb

Action

Extension of all joints of the thumb

 Extensor Indices
- Lower 1/3 of the posterior surface of the ulna
Origin - Interosseous membrane

Insertion Extensor expansion of the index finger

Action

Extension of all joints of the index finger

Anatomy of the Hand
 Flexor Retinaculum
Structures passing superficial to it:
MEDIAL TO LATERAL
• Ulnar nerve
• Ulnar artery (& vein)
• Palmar cutaneous branch of ulnar nerve
• Tendon of Palmaris Longus
• Palmar cutaneous branch of median nerve Palmar
cutaneous
branch of
ulnar nerve

Palmar cutaneous branch of median nerve

Ulnar nerve
Tendon of Palmaris Longus
Ulnar artery
 Flexor Retinaculum
Structures passing deep to it
(Through the Carpal Tunnel)
• Flexor Carpi Radialis Tendon
(In a special compartment)
• Flexor Pollicis Longus Tendon
• Median nerve compression Carpal Tunnel Syndrome
• Flexor Digitorum Superficialis &
Profundus tendons
• Synovial sheaths
Flexor Carpi
around tendons Radialis Tendon
Flexor Digitorum
Superficialis tendons Flexor Pollicis
Longus tendon
Median nerve
(in synovial sheath)
Flexor Digitorum Profundus tendons
 Extensor Retinaculum

Structures passing superficial to it:

MEDIAL TO LATERAL
• Dorsal cutaneous branches of ulnar nerve
• Beginning of basilic vein
• Beginning of cephalic vein Dorsal cutaneous
• Terminal branches of superficial branch branch of ulnar
of radial nerve nerve
Basilic vein
Superficial
radial nerve
Cephalic vein
Extensor
Retinaculum
 Extensor Retinaculum
Structures passing deep to it:
❑ 1st Compartment:
• Abductor Pollicis Longus (APL)
• Extensor Pollicis Brevis (EPB)
❑ 2nd Compartment:
• Extensor Carpi Radialis Longus (ECRL) EI
• Extensor Carpi Radialis Brevis (ECRB)
EPL
❑ 3rd Compartment: Extensor Pollicis Longus (EPL)
❑ 4th Compartment:
• Extensor Indices (EI)
• Extensor Digitorum (ED)
❑ 5th Compartment: Extensor Digiti Minimi (EDM)
❑ 6th Compartment: Extensor Carpi Ulnaris (ECU) 2 3 4 5
6
1
Radius Ulna
 Compartments of the hand

The lateral and medial palmar septa divide the

palm into 3 fascial compartments:
1. Lateral (thenar) compartment:
Contains the thenar muscles.
2. Medial (hypothenar) compartment: 1
Contains the hypothenar muscles.
3. Intermediate (central) compartment: 5
2
deep to the palmar aponeurosis. 4 3
 Muscles of the hand
20 Muscles

4 Lateral 4 Medial 4 Dorsal 4 Palmar 4

Muscles Muscles Interossei Interossei Lumbricals

1. Adductor Pollicis 1. Palmaris Brevis

2. Flexor Pollicis Brevis 2. Flexor Digiti Minimi
3. Opponens Pollicis 3. Opponens Digiti Minimi
4. Abductor Pollicis Brevis 4. Abductor Digiti Minimi

Form the Form the

DAB PAD Medial 2: Lateral 2:
Thenar Muscles Hypothenar Muscles
Ulnar Median
Supplied by Abduction Adduction nerve nerve
median nerve
 Palmaris Brevis
Nerve
Supply
Superficial branch of ulnar nerve

Action
Corrugates skin to improve grip of the hand
(Cupping of the hand)
 Muscles of the hand
Muscles All muscles of the hand are Medial
supplied with deep branch
of the of the ulnar nerve except 5
muscles of
thumb muscles supplied with the hand
median nerve :
• 3 Thenar muscles.
• Lateral 2 lumbricals.
 Lumbricals
Action

Flexion of the metacarpophalangeal joint

& Extension of interphalangeal joints of the
medial 4 fingers (Writing Position)
 Dorsal Interossei
DAB
Action
Abduction

- Abduct Fingers Away from the center (middle finger)

- Flexion of the MCP joint & Extension of IP joints of
the middle 3 fingers (Writing Position)
 Palmar Interossei
PAD
Action
Adduction

- Adduct the other 4 Fingers Towards the middle finger

- Flexion of the MCP joint & Extension of IP joints of
the index, ring & little finger (Writing Position)