The elbow complex consists of the humeroradial and humeroulnar joints, which are modified hinge joints that allow a slight degree of axial rotation and side-to-side motion during flexion and extension. These joints are stabilized by ligaments like the medial and lateral collateral ligaments. Muscles like the biceps brachii, brachialis, and triceps act as dynamic stabilizers. The proximal and distal radioulnar joints form a pivot joint that produces supination and pronation of the forearm. Significant compressive and shear forces act across the elbow, distributed between the ulnohumeral and radiocapitellar joints, varying with elbow position. The elbow's static

1. Elbow Complex
Vaibhavi Rathod

2. INTRODUCTION
▪ The joints and muscles of the elbow complex are designed to serve
the hand.
▪ They provide mobility for the hand in space by shortening and
lengthening the upper extremity.
▪ Rotation at the elbow complex provides additional mobility for the
hand.
▪ The elbow complex structures also provide stability for skilled (or)
forceful movements of the hand when performing activities with
tools or implements

3. Humeroradial and Humeroulnar Joint
▪ Type- Synovial joint (diarthrodial ).
▪ Variety- Modified (or) Loose Hinge joint.
▪ Why it is called as modified or loose
hinge joint?
▪ A slight bit of axial rotation and side-to-
side motion of the ulna occurs during
Flexion and Extension.
▪ So it is not pure Hinge joint

4. STRUCTURE
Articulating surface on humerus

5. Articulating surface of radius

6. Articulating surface of ulna

7. HUMERORADIAL JOINT
▪ Articulating surface- radial head and the
capitulum of humerus.
▪ Joint involves sliding the shallow concave
radial head over the convex surface of the
capitulum.
▪ Joint surfaces INCONGRUENT- (because of
the humeral capitulum slightly smaller than
the corresponding radial fovea).
▪ In full flexion, no contact occurs between the
articulating surfaces.
▪ In flexion, the rim of the radial head slides in
the capitulotrochlear groove.
▪ And enters the radial fossa as the end of the
Flexion range is reached.

8. HUMEROULNAR JOINT
▪ Articulating surfaces- Humeral
trochlear on the ulnar
trochlear notch.
▪ In Flexion > Coronoid process
reaches the floor of the
coronoid fossa
▪ In Extension >Olecranon
process enters the olecranon
fossa

9. LIGAMENTS

10. MEDIAL COLLATERAL LIGAMENT
▪ 1. Anterior medial collateral ligament Attachment: • Anterior aspect of
humerus to coronoid process. Anterior and posterior band that tightening
reciprocal manner as the elbow flexes and extends. • FUNCTION:- Restraint
of valgus stress from 20 to 120 degree of elbow flexion.
▪ 2. Posterior medial collateral ligament Attachment: • It Extends from
Posterior aspect of medial epicondyle of the humerus to ulnar coronoid and
olecranon process. • FUNCTION:- It limits elbow extension, Plays a less role
in providing valgus stability for the elbow.
▪ Transverse collateral ligament Attachment: • It extended between the
Olecranon process to ulnar coronoind process. • FUNCTION:- It Provide
little valgus stability, It May help to keep the joint surfaces in
approximation.

11. LATERAL COLLATERAL LIGAMENT
▪ LATERAL (radial) COLLATERAL LIGAMENT Attachment: • it extends
from inferior aspect of lateral epicondyle of humerus to merge with
the Annular ligament. • FUNCTION:- it provides reinforcement for
the Humero-radial articulation. Some protection against varus stress.
▪ LATERAL ULNAR COLLATERAL LIGAMENT Attachment: • It extend
from inferior aspect of lateral Epicondyle of humerus to edge of
Annular ligament and lateral surface of Ulna. • FUNCTION:- It acts as
a Dynamic stabilizer together with related muscles. Providing lateral
support to the Elbow joint.

12. MUSCLES OF ELBOW JOINT
▪ Anteriorly: 1) Pronator teres 2) Flexor
carpi radialis 3) Palmaris longus 4)
Flexor carpi ulnaris 5) Flexor
digitorum superficialis 6) Brachio
radialis 7) Brachialis 8) Biceps brachii.
▪ Posteriorly: 1) Extensor carpi radialis
longus 2) Extensor carpi radialis
brevis 3) Extensor digitorum 4)
Extensor digiti minimi 5) Extensor
carpi ulnaris 6) Supinator 7)Triceps 8)
Anconeus.

13. PROXIMAL AND DISTAL
RADIOULNAR JOINT

14. ▪ TYPE:- synovial joint (Diarthrodial)
▪ VARIETY:- Pivot (trochoid) • Uniaxial-
the 2 joints acting together produce
supination and pronation of forearm
and have 1 degree of freedom of
motion (which occurs transverse pale
around a longitudinal axis)

15. STRUCTURE of PROXIMAL (superior) RADIO-
ULNAR JOINT
▪ Articulating surface:-
▪ Radial notch of ulna
▪ Annular ligament
▪ Head of radius
▪ Capitulum of humerus.

16. DISTAL(inferior) RADIO-ULNAR JOINT
▪ Articular surface:
▪ Ulnar notch of the radius
▪ Articular disc
▪ Head of ulna

17. ARTICULATIONS
▪ PROXIMAL RADIO-ULANR ARTICULATION:
▪ Bones taking part- Head of radius and radial
notch of the ulna.The head of radius is
attached to the radial notch of the ulna with
the help ofAnnular ligament.
▪ DISTAL RADIO-ULANR ARTICULATION:
▪ Bones taking part- Head of ulna and ulna
notch of radius.The Head of the ulna
attached to the ulna notch of radius and
Articular disc.

18. LIGAMENTS
▪ PROXIMAL RADIO-ULNAR JOINT: 1.
Annular ligament 2. Quadrate
ligament 3. Oblique cord.
▪ • DISTAL RADIO-ULNAR JOINT: 1.
Dorsal radio-ulnar ligament 2.
Palmar radio-ulnar ligament 3.
Interosseous membrane.

19. MUSCLES
▪ PRONATION: 1. Pronator teres 2. Pronator qudratus.
▪ •SUPINATION: 1. Biceps 2. supinator

20. Joint forces
▪ Significant compressive and shear forces at the elbow
▪ Loads across the elbow - distributed
▪ 43% across the ulnohumeral joint and 57% across the radiocapitellar joint
▪ Joint reaction forces vary with elbow position.
▪ Force transmission at the radiocapitellar joint is
▪ Greatest between 0 and 30 of flexion and is greater in pronation than in
supination.
▪ elbow - extended, the overall force on theulnohumeral joint is concentrated at
the coronoid
▪ elbow - flexed, the force moves toward the olecranon

22. Stability of elbow joint
▪ static and dynamic constraints
▪ 3 primary static constraints
▪ Ulnohumeral articulation, the anterior bundle of the MCL the
lateral collateral ligament (LCL) complex
▪ Secondary constraints Radiocapitellar articulation, the common
flexor tendon, the common extensor tendon, the capsule.
▪ Dynamic stabilizers - Muscles that cross the elbowjoint

23. Thank you