Anatomy of the elbow and forearm

1. Anatomy of Elbow
and Forearm
Dr. Mohammad Taqi Ehsani
PGY1 of Orthopedics, FMIC

2. Elbow Joint
• a complex joint involving three
separate articulation, which share
a common synovial cavity

3. • the joint between ulna and humerus
and between radius and the capitulum
of the humerus are primarily involved
with hinge-like flexion and
extension of the forearm on the arm
and, together, are the principal
articulations of the elbow joint
• the joint between the head of radius
and radial notch of ulna, the proximal
radio-ulnar joint is involved with
pronation and supination of the
forearm

4. • Articular surfaces: covered with hyaline
cartilage
• The synovial membrane: originate from the
edges of the articular cartilage and lines the
radial fossa, the coronoid fossa, and
separated from the fibrous membrane of the
joint capsule by pads of fat
• The fibrous membrane: overlies the
synovial membrane, enclose the joint,
thickened medially and laterally to form
collateral ligaments

5. • Sacciform recess: a pocket of synovial
membrane protrudes from the inferior margins of
the joint capsule and facilitates rotation of the
radial head during pronation and supination
• Vascular supply: anastomotic network of
vessels derived from collateral and recurrent
branches of the brachialis, profunda brachii,
radial, and ulnar arteries;
• Innervation: Predominantly, branches of the
radial and musculocutaneous nerves, some
innervation by branches of the ulnar and median
nerves

6. CUBITAL FOSSA
• An important area of transition between arm
and forearm, located anterior to elbow and is a
triangular depression formed between
Brachioradialis and the pronator teres
• Base: imaginary horizontal line between
medial and lateral epicondyle, Bed or Floor:
brachialis muscle
• Major contents:
• The tendon of Biceps brachii muscle
• The brachial artery
• The median nerves

7. CUBITAL FOSSA
• Brachial Artery: Bifurcates into he Radial and
Ulnar arteries in the apex of the fossa
• Median Nerve: lies medial to the brachial
artery and leaves the fossa by passing
between the ulnar and humeral heads of the
pronator teres
• Radial Nerve: under the lip of brachioradialis,
divided into superficial and deep branches
• Ulnar Nerve: does not pass through cubital
fossa, it passes posterior to the medial
epicondyle
• Median Cubital Vein: passes diagonally
across the roof and connects cephalic vein and
basilic vein

8. CUBITAL FOSSA (Surface Anatomy)

9. FOREARM
• Extends between the elbow joint and wrist joint
• proximally most major structures pass
through, or in relation to the cubital fossa,
except the ulnar nerve, which passes
posterior to the medial epicondyle of the
humerus
• Distally, structures pass through, or anterior to
the carpal tunnel, except the radial artery,
which passes dorsally around the wrist to enter
the hand posteriorly.

10. FOREARM
• The bone framework consists
of two parallel bones, the
radius and the ulna

11. FOREARM
Divided in to anterior and posterior
compartments, which separated by:
• A lateral intermuscular septum, which
passes from the anterior border of the
radius to deep fascia surrounding the
limb
• An interosseous membrane, which links
adjacent borders of the radius and ulna
along most of their length
• The attachment of deep fascia along the
posterior border of the ulna

12. FOREARM
Interosseous membrane:
• Thin fibrous sheet that connects the
medial and lateral borders of the radius
and ulna, collagen fibers pass inferiorly
from the radius to the ulna
• Free upper margins, circular aperture

13. FOREARM
Pronation and supination:
Two muscles pronate and two
muscles supinate the hand
Pronation:
• Pronator teres
• Pronator quadratus
Supination:
• Biceps brachii
• Supinator

14. Anterior Compartment
Muscles:
• Muscles in the anterior (Flexor) compartment occur in three layers;
superficial, intermediate, and deep
• Generally these muscles are associated with:
• Movement of the wrist joint
• Flexion of the fingers including the thumb
• Pronation
• All muscles in the anterior compartment of the forearm are
innervated by the median nerve, except for the flexor carpi ulnaris
muscle and the medial half of the flexor digitorum profundus
muscle, which are innervated by the ulnar nerve

15. Anterior Compartment
Superficial Layer:
• All four muscles have a
common origin from the medial
epicondyle of the humerus
• Flexor carpi ulnaris
• Palmaris longus
• Flexor carpi radialis
• Pronator teres

16. Anterior Compartment
Superficial Layer:

17. Anterior Compartment
Intermediate Layer:
• Flexor digitorum
superficialis
• has two heads:
• The humero-ulnar head
• The radial head

18. Anterior Compartment
Deep Layer: Three deep muscles:
• Flexor digitorum profundus
• Flexor policis longus
• Pronator quadratus

19. Anterior Compartment
Arteries and veins
Arteries:
Brachial artery enters the forearm by
passing through the cubital fossa, at
the apex, it divides into two major
branches, the radial and ulnar
arteries
Veins:
Generally accompany the arteries and
ultimately drian into the brachial
viens associated with the brachial
artery in the cubital fossa

20. Anterior Compartment
Nerves
• Median
• Ulnar
• Superficial branches of Radial nerve

21. Median Nerve
• Course:
• Lies medial to brachial artery and enters to cubital
fossa
• Lies between flexor digitorum superficialis and flexor
digitorum profundus
• then it reaches down the region of wrist where it lies
deep and lateral to palmaris longus tenon
• Lastly passes deep to flexor retinaculum to enter the
palm
• Branches:
• Muscular branches
• Anterior interosseous branch
• Palmar cutaneous branch
• Articular branches
• Vascular branches
• Communicating branch

22. Ulnar Nerve
• Course:
• Palpable as it lies behind medial epicondyle of
humerus and is not a content of cubital fossa
• Enters the forearm by passing between heads of
flexor carpi ulnaris, to lie along the lateral border
of flexor carpi ulnaris
• In the last, it courses superficial to the flexor
retinaculum, covered by its superficial slip or
volar carpal ligament to enter the region of palm
• Branches:
• Muscular branches
• Palmar branches
• Dorsal cutaneous branch
• Articular branches

23. Radial Nerve
• Course:
• Divides into its two terminal branches in
the cubital fossa just below of the lateral
epicondyle of humerus
• Branches:
• The deep terminal branch (Posterior
Interosseous)
• The superficial terminal branch

24. Posterior Compartment
•Muscles: Two layers: Superficial Layer, Deep layer
• The muscles are associated with:
• Movement of the wrist joint
• Extension of the fingers, and thumb
• Supination
All muscles in the posterior compartment are innervated
by the radial nerve

25. Posterior Compartment
Superficial layer Seven muscles
• All have common origin, from the
supraepicondylar ridge and lateral
epicondyle of humerus, except for
the brachioradialis and anconeus
• Brachioradialis
• Extensor carpi radialis longus
• Extensor carpi radialis brevis
• Extenso digitorum
• Extensor digiti minimi
• Extenso carpi ulnaris
• anconeus

26. Posterior Compartment
presentation title

27. Posterior Compartment
Deep Layer:
• Five muscles
• Supinator
• Abductor pollicis longus
• Extensor pollicis brevis
• Extensor pollicis longus
• Extensor indicis
• Except the supinator muscle, all these muscles
originate from the posterior surfaces of the radius,
ulna, and interosseous membrane and pass into the
thumb and fingers

28. Posterior Compartment
Deep Layer:
• Five muscles
• Supinator
• Abductor pollicis longus
• Extensor pollicis brevis
• Extensor pollicis longus
• Extensor indicis

29. Deep Layer

30. Arteries and Veins
Arteries: Blood supply occurs
predominantly through branches
of the radial, posterior
interosseous, and anterior
interosseous arteries
Veins: Deep veins of the
posterior compartment generally
accompany the arteries, they
ultimately drains into brachial
veins associated with brachial
artery in the cubital fossa

31. Nerves
Radial nerve:
Most of the muscles are
innervated by the deep branch
(Post. Interosseous nerve)
In the lateral wall of the cubital
fossa, and before dividing into
superficial and deep
branches, the radial nerve
innervates the brachioradialis
and extensor carpi radialis
longus muscle

32. Surface Anatomy
presentation title 32

33. thank you