1. Anatomy Of Arm And Forearm
Dr. Fadel Naim
Orthopedic Surgeon
Faculty of Medicine
IUG

3. Muscles of the Arm 4 arm (brachial) muscles:
3 flexors in the anterior compartment
Supplied by the musculocutaneous nerve
Biceps brachii
Brachialis
Coracobrachialis
1 extensor in the posterior compartment
Triceps brachii
Supplied by the radial nerve.

4. BICEPS BRACHII ORIGIN INSERTION ACTION NERVE Long head: Short head:
supraglenoid tubercle of scapula.
Short head:
coracoid process of scapula with coracobrachialis
INSERTION
posterior border of bicipital tuberosity of radius (over bursa)
bicipital aponeurosis to deep fascia and subcutaneous ulna
ACTION
Supinator of the forearm
Flexion of the elbow
weakly flexes shoulder
NERVE
Musculocutaneous nerve (C5, 6) (from lateral cord)

5. When right-handed persons drive a screw into hard wood
When the elbow is extended
The biceps is a simple flexor of the forearm
When the elbow is flexed and more power is needed against resistance
The biceps is the primary (most powerful) supinator of the forearm
When right-handed persons drive a screw into hard wood
Inserting a corkscrew and pulling the cork from bottle.
The biceps barely operates during flexion of the prone forearm.

7. BRACHIALIS ORIGIN INSERTION ACTION NERVE
Anterior lower half of humerus
medial and lateral intermuscular septa
INSERTION
Coronoid process and tuberosity of ulna
ACTION
Flexes elbow
NERVE
Musculocutaneous nerve (C5, 6) ( from lateral cord).
Also small supply from radial nerve (C7)

8. (picking up and put down a teacup carefully)
The brachialis is the main flexor of the forearm
Flexes the forearm in all positions and during slow and quick movements.
When the forearm is extended slowly, the brachialis steadies the movement by slowly relaxing
(picking up and put down a teacup carefully)
The brachialis always contracts during flexion of the elbow joint and is primarily responsible for maintaining flexion
Because of its many functions, it is regarded as the workhorse of the elbow flexors

9. CORACOBRACHIALIS ORIGIN INSERTION ACTION NERVE
Coracoid process of scapula with biceps brachii
INSERTION
Upper half medial border of humerus
ACTION
Flexes and weakly adducts arm
NERVE
Musculocutaneous nerve (C5, 6, 7) (from lateral cord)

10. Long head
Biceps brachii
Coracobrachialis
Short head
Biceps tendon
Aponeurosis of biceps brachii

11. Acromion process
Coracoid process
Humerus
Coracobrachialis
Musculocutaneous n.
Brachialis
Radius
Ulna

12. TRICEPS ORIGIN INSERTION ACTION NERVE Long head: lateral head:
infraglenoid tubercle of scapula.
lateral head:
upper half posterior humerus (linear origin).
medial head:
lies deep on lower half posterior humerus inferomedial to spiral groove and both intermuscular septa
INSERTION
Posterior part of upper surface of olecranon process of ulna and posterior capsule
ACTION
Extends elbow
Long head stabilizes shoulder joint
medial head retracts capsule of elbow joint on extension
NERVE
Radial nerve (C7, 8) (from posterior cord ), four branches

13. Olecranon Deltoid (cut) Long head Triceps brachii Lateral head
Anconeus

14. Suprascapular nerve
Dorsal scapular nerve
Axillary nerve
Lateral head
Long head
Triceps brachii
Radial nerve
Medial head
Anconeus

15. Cubital Fossa
The cubital fossa is the triangular hollow area on the anterior aspect of the elbow
The boundaries of the cubital fossa are:
Superiorly
An imaginary line connecting the medial and lateral epicondyles
Medially
The pronator teres
Laterally
The brachioradialis 1 3 2

16. The contents of the cubital fossa
Median nerve
Terminal part of the brachial artery and bifurcation into
The radial artery
The ulnar artery
(Deep) accompanying veins of the arteries
Biceps brachii tendon
The deep and superficial branches of the radial nerve are within the floor of the fossa.
Median cubital vein, lying anterior to the brachial artery
Superficially, in the subcutaneous tissue overlying the fossa
Medial and lateral antebrachial cutaneous nerves related to the basilic and cephalic veins.

17. Articulation of the Elbow Joint
A hinge type of synovial joint
Articulation:
The humerus
The spool shaped trochlea
The spheroidal capitulum
The trochlear notch of the ulna
The slightly concave superior aspect of the head of the radius
Humeroulnar articulation
Humeroradial articulation

18. Articulation of the Elbow Joint
Fully congruent when the forearm is in a position midway between pronation and supination and is flexed to a right angle.

19. Ligaments of the Elbow Joint
The collateral ligaments of the elbow joint are strong triangular bands
Medial and lateral thickenings of the fibrous capsule

20. Ligaments of the Elbow Joint
The lateral, fanlike radial collateral ligament
Extends from the lateral epicondyle of the humerus and blends distally with the anular ligament of the radius

21. Ligaments of the Elbow Joint
The medial, triangular ulnar collateral ligament
Extends from the medial epicondyle of the humerus to the of the ulna
Consists of three bands:
The anterior cordlike band is the strongest
The posterior fanlike band is the weakest
The slender oblique band deepens the socket for the trochlea of the humerus

22. Muscles Moving the Elbow Joint
Several muscles cross the elbow and extend to the forearm and hand:
Chief flexors of the elbow joint
Brachialis
Biceps brachii
Brachioradialis
Chief extensors of the elbow joint
Triceps brachii

23. Bursae Around the Elbow Joint
The three olecranon bursae are the:
Intratendinous olecmnon bursa
Subtendinous olecranon bursa
Subcutaneous olecranon bursa

24. Proximal Radioulnar Joint
The proximal radioulnar joint is a pivot type of synovial joint
allows movement of the head of the radius on the ulna
The head of the radius articulates with the radial notch of the ulna.
The radial head is held in position by the anular ligament.

25. Movements of the Proximal Radioulnar Joint
During pronation and supination of the forearm, the head of the radius rotates within the ring formed by the anular ligament and the radial notch of the ulna.
The axis for these movements passes:
Proximally through the center of the head of the radius
Distally through the ulna.

26. Muscles Moving the Proximal Radioulnar Joint
Supination:
The supinator (when resistance is absent)
The biceps brachii (when power is required because of resistance)
With some assistance from the: EPL ( Extensor Policis Longus ) and ECRL ( Extensor Carpi Radialis Longus )
Pronation
The pronator quadratus (primarily)
Pronator teres (secondarily)
With some assistance from the FCR, PL, and brachioradialis
(when the forearm is in the midprone position)

27. Distal Radioulnar Joint
A pivot type of synovial joint.
The radius moves around the relatively fixed distal end of the ulna.
The head of the ulna articulates with the ulnar notch on the medial side of the distal end of the radius.
During pronation and supination,the distal end of the radius moves anteriorly and medially, crossing the ulna anteriorly.

28. Triangular Ligament
A fibrocartilaginous articular disc ("triangular ligament") binds the ends of the ulna and radius together
The main uniting structure of the joint
The base is attached to the medial edge of the ulnar notch of the radius,
The apex is attached to the lateral side of the base of the styloid process of the ulna.
The articular disc separates the cavity of the distal radioulnar joint from the cavity of the wrist joint.

29. Ligaments of the Distal Radioulnar Joint
Anterior and posterior ligaments.
These relatively weak transverse bands extend from the radius to the ulna across the anterior and posterior surfaces of the joint

30. Fascial Compartment Of The Forearm
4 compartments of the forearm
(1) superficial volar
(2) deep volar
(3) the dorsal
(4) Lateral containing the mobile wad of henry
Brachioradialis
Extensor carpi radialis longus (ECRL)
Extensor carpi radialis brevis (ECRB)

31. These fascial compartments are separated by an interosseous membrane connecting the radius and ulna.
The flexors and pronators of the forearm are in the anterior compartment and are served mainly by the median nerve;
The one and a half exceptions are innervated by the ulnar nerve.
The extensors and supinators of the forearm are in the posterior compartment and are all served by the radial nerve

32. A superficial group of five muscles
Flexor-Pronator Muscles of the Forearm
A superficial group of five muscles
Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
Flexor digitorum superficialis [FDS] (intermediate)
These muscles all attach, at least in part, by a common flexor tendon from the medial epicondyle of the humerus the common flexor attachment

33. Flexor-Pronator Muscles of the Forearm
A deep group of three muscles:
Flexor digitorum profundus [FDP]
Flexor pollicis longus
Pronator quadratus

34. 1. Pronator Teres Origin: Insertion:
Humeral head:
Medial epicondyle
Medial supracondylar ridge
Medial intermuscular septum
Ulnar head:
Medial border of coronoid process
Insertion:
Middle of lateral surface of radius
Just posterior to most prominent part of lateral convexity of radius
Innervatlon:
Median nerve (C6 and C7)
Action:
Pronator of the forearm and a flexor of the elbow joint.

35. 2. Flexor Carpi Radialis Origin: Medial epicondyle of humerus
Insertion:
Base of 2nd and 3rd metacarpal bone
Innervation:
Median nerve (C6 and C7)
Action:
Flexion (when acting with the flexor carpi ulnaris)
Abduction of the wrist (when acting with the extensors carpi radialis longus and brevis)
A combination of flexion and abduction at the wrist ( when acting alone )

36. 3. Palmaris Longus Origin: Insertion: Innervation: Action:
Medial epicondyle of humerus
Insertion:
Distal half of flexor retinaculum and palmar aponeurosis
Innervation:
Median nerve (C7 and C8)
Action:
Flexes hand (at wrist)
Tightens palmar aponeurosis

37. Palmaris Longus
This small fusiform muscle is absent on one or both sides (usually the left) in approximately 10% of people, but its actions are not missed.
The palmaris longus tendon is a useful guide to the median nerve at the wrist.
The tendon lies deep and slightly medial to this nerve before it passes deep to the flexor retinaculum.
To test the palmaris longus:
The wrist is flexed and the pads of the little finger and thumb are pinched together.
If present and acting normally, the tendon can be easily seen and palpated.

38. 4. Flexor Carpi Ulnaris Origin: Insertion: Innervation: Action:
Humeral head:
medial epicondyle of humerus
Ulnar head:
olecranon and posterior border of ulna
Insertion:
Pisiform bone
Hook of hamate bone
5th metacarpal bone
Innervation:
Ulnar nerve (C7 and C8)
Action:
Flexes and adducts the hand at the wrist simultaneously if acting alone.
Flexes the wrist when it acts with the flexor carpi radialis
Adducts it when acting with the extensor carpi ulnaris.

40. 1. Flexor Digitorum Superficialis
Origin:
Humeroulnar head:
Medial epicondyle of humerus
Ulnar collateral ligament,
Coronoid process of ulna
Radial head:
Superior half of anterior border of radius
Insertion:
Bodies of middle phalanges of medial four digits
Innervation:
Median nerve (C7, C8, and T1 )
Action:
Flexes middle phalanges at proximal interphalangeal joints of medial four digits
Acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints and hand

41. Flexor Digitorum Profundus
Origin:
Proximal three-fourths of medial and anterior surfaces of ulna
Interosseous membrane
Insertion:
Bases of distal phalanges of medial four digits
Innervation:
Medial part ( the muscle serving digits 4 and 5 )
Ulnar nerve (C8 and T1)
Lateral part: ( the muscle serving digits 2 and 3 )
Median nerve (C8 and T1 )
Action:
Flexes distal phalanges at distal interphalangeal joints of medial four digits
Assists with flexion of hand

43. Flexor Pollicis Longus
Origin
Anterior surface of radius and adjacent interosseous membrane
Insertion
Base of distal phalanx of thumb
Action
Flexes phalanges of 1st digit (thumb
Innervation
Anterior interosseous nerve from median nerve (C8 and T1)

44. Pronator Quadratus Origin Insertion Action Innervation
Distal 1/4 of anterior surface of ulna
Insertion
Distal 1/4 of anterior surface of radius
Action
Pronates forearm; deep fibers bind radius and ulna together
The prime mover in pronation.
Initiates pronation
Innervation
Anterior interosseous nerve from median nerve (C8 and T1)

45. Extensor Muscles of the Forearm
In the posterior (extensor-supinator) compartment of the forearm
All are innervated by the radial nerve
Three functional groups:
Muscles that extend and abduct or adduct the hand at the wrist joint
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris
Muscles that extend the medial four digits
Extensor digitorum
Extensor indicis
Extensor digiti minimi
Muscles that extend or abduct the thumb
Abductor pollicis longus [APL]
Extensor pollicis brevis [EPB]
Extensor pollicis longus [EPL]

46. Brachioradialis Origin Insertion Action Innervation Flexes forearm
Proximal two-thirds of lateral supracondylar ridge of humerus
Insertion
Lateral surface of distal end of radius
Action
Flexes forearm
Innervation
Radial nerve (C5, C6, and C7)

47. Extensor Carpi Radialis Longus
Origin
Lateral supracondyle ridge of humerus
Insertion
Base of 2nd metacarpal
Action
Extend and abduct hand at wrist joint
Innervation
Radial nerve (C6 and C7)

48. Extensor Carpi Radialis Brevis
Origin
Lateral epicondyle of humerus
Insertion
Base of 3rd metacarpal
Action
Extend and abduct hand at wrist joint
Innervation
Deep branch of radial nerve (C7 and C8)

49. The extensor carpi radialis brevis and longus act together to steady the wrist during flexion of the medial four digits.

50. Posterior compartment:
Superficial group
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Anconeus muscle
Attached by a common extensor tendon to the lateral epicondyle
Posterior compartment:
Deep group
Supinator
Abductor pollicis longus
Extensor pollicis brevis
Extensor indicis

51. Extensor Digitorum Origin Insertion Action Innervation
Lateral epicondyle of humerus
Insertion
Extensor expansions of medial four digits
Action
Extends medial four digits at metacarpophalangeal joints; Extends hand at wrist joint
Innervation
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve

52. Extensor Digitorum The principal extensor of the medial four digits
Adjacent tendons are linked by intertendinous connections.
Because of presence of the intertendinous connections extension of one finger is impossible
The index finger has greater freedom because its tendon is not connected to the other tendons

54. Extensor Digiti Minimi
Origin
Lateral epicondyle of humerus
Insertion
Extensor expansion of 5th digit
Action
Extends 5th digit at metacarpophalangeal and interphalangeal joints
Innervation
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve

55. Extensor Carpi Ulnaris
Origin
Lateral epicondyle of humerus and posterior border of ulna
Insertion
Base of 5th metacarpal
Action
Extends and adducts hand at wrist joint
Innervation
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve

56. Supinator Origin Insertion Action Innervation
Lateral epicondyle of humerus
radial collateral and annular ligaments
supinator fossa and crest of ulna
Insertion
surface of proximal 1/3 of radius
Lateral
Posterior
Anterior
Action
Supinates forearm
Innervation
Deep branch of radial nerve (C5 and C6)

57. Abductor pollicis Longus
Origin:
Posterior surfaces of
Ulna
Radius
Interosseous membrane
Insertion:
Base of 1st metacarpal
Action:
Abducts thumb
Extends it at carpometacarpal joint
Innervation:
Posterior interosseous nerve (C7 and C8), the continuation of deep branch of radial nerve

58. Extensor Pollicis Brevis
Origin
Posterior sufraces of radius and interosseous membrane
Insertion
Base of proximal phalanx of thumb
Action
Extends proximal phalanx of thumb at carpometacarpal joint
Innervation
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve

59. Extensor Pollicis Longus
Origin
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
Adducts the extended thumb and rotates it laterally
Innervation
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve

60. Extensor Indicis Origin Insertion Action Innervation
Posterior sufrace of ulna
interosseous membrane
Insertion
Extensor expansion of 2nd digit
Action
Extends 2nd digit and helps to extend hand
Innervation
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve