BIOMECHANICS OF ELBOW COMPLEX

1. BIOMECHANICS OF ELBOW COMPLEX

2. INTRODUCTION  Elbow complex is designed to serve hand.  They provide MOBILITY for Hand in space by apparent shortening and Lengthening of upper extremity.  They provide Stability for skillful and forceful movements

3. ELBOW JOINT

4. HUMERO ULNAR JOINT  ARTICULATIONS OF HUMEROULNAR JOINT  The articulating surface on the Humerus is Hour glass shaped TROCHLEA  The articulating surface on Ulna is a semicircular shaped concave surface called TROCHLEAR NOTCH

5. HUMERO RADIAL JOINT  ARTICULATION OF HUMERORADIAL JOINT  The articulating surface on the Humerus is spherical – shaped CAPITULUM  The articulating surface on the RADIUS is the cup shaped Radial head surrounded by a rim

6. ARTICULATIONS OF JOINT  IN EXTENSION  The OLECRANON PROCESS enter the olecranon fossa in Humeroulnar Joint  There is no contact between the articulating surfaces in Humeroradial Joint.

7. ARTICULATIONS OF JOINT  IN FLEXION  The Trochlear ridge of Ulna slides along the Trochlear groove until the Coronoid process reaches the Coronoid fossa in Humeroulnar joint  The radial head slides over capitulum and reaches Radial fossa in Full Flexion.

8. JOINT CAPSULE  The Humeroulnar , Humeroradial and Superior Radioulnar Joint are enclosed in a single Joint capsule.The capsule is fairly loose .  Anteriorly, it is attached above coronoid and radial fossa  Posteriorly ,it is attached above Olecranon fossa.

10. Joints  Radioulnar joint  Trochoid or pivot-type joint  Radial head rotates around at proximal ulna  Distal radius rotates around distal ulna  Annular ligament maintains radial head in its joint © 2007 McGraw-Hill Higher Education. All rights reserved.6-10 From Seeley RR, Stephens TD, Tate P: Anatomy & physiology, ed 7, New York, 2006, McGraw-Hill; Shier D, Butler J, Lewis R: hole’s human anatomy & physiology, ed 9, New York, 2002, McGraw-Hill.

12. LIGAMENTS  MEDIAL COLLATERAL LIGAMENT Extends from Medial epicondyle of Humerus to Coronoid and Olecranon process of Ulna  LATERAL COLATERAL LIGAMENT Extends from Lateral Epicondyle of Humerus to Annular Ligament and Olecranon process.  ANNULAR LIGAMENT It encircles the head of Radius

13. LIGAMENTS OF ELBOW

14. Movements of Elbow Joint  FLEXION-EXTENSION ( 0-140 degree)  AXIS-------Medio Lateral Axis (Passess through Trochlea)  PLANE------Saggital plane  MUSCLES:  FLEXORS OF ELBOW  Biceps Brachi---Powerful flexor when elbow is in 90 degree Flexion.  Brachialis----Flexor of elbow in all position  Brachioradialis---Flexor of elbow in midprone position

15. BICEPS BRACHI

16. EXTENSORS OF ELBOW  TRICEPS is the powerful extensor of the Shoulder  Long head of Triceps depends on Shoulder Position  Medial head of Triceps is active in unresisted Elbow extension  All three Heads of Triceps are active when heavy resistance is given to Extension.

17. Movements © 2007 McGraw-Hill Higher Education. All rights reserved.6-17  Flexion  movement of forearm to shoulder by bending the elbow to decrease its angle  Extension  movement of forearm away from shoulder by straightening the elbow to increase its angle

18. Movements © 2007 McGraw-Hill Higher Education. All rights reserved.6-18  Pronation  internal rotary movement of radius on ulna that results in hand moving from palm-up to palm-down position  Supination  external rotary movement of radius on ulna that results in hand moving from palm- down to palm-up position

19. CARRYING ANGLE  The angle formed between the axis of Humerus and the Longitudinal axis of Forearm  Normal angle: In MEN=5 degree , In WOMEN=10 degree  The angle is more in Women due to Wider Pelvis  CUBITUS VALGUS: Increase in Carrying Angle  CUBITUS VARUS: Decrease in Carrying Angle

20. CARRYING ANGLE

21. SUPERIOR RADIOULNAR JOINT  ARTICULATION  The Radial notch on Ulna articulate with Head of Radius along with Annular Ligament & Capitulum.  LIGAMENTS  Annular Ligament-----circle the head of Radius and keeps the Ulna together.  Quadrate Ligament----extends from the Inferior edge of radial notch to Neck of Radius  Oblique cord------attached to inferior part of Radial notch on Ulna to just below Radial Tuberosity

22. INFERIOR RADIOULNAR JOINT  ARTICULATION  The Ulnar notch of Radius articulates with head of Ulna along with Articular Disc.  LIGAMENTS  Anterior Radio Ulnar Ligament----attached to anterior aspect just above the Ulnar head to above Ulnar notch.  Posterior Radio Ulnar Ligament---attached to posterior part of Ulnar head to above Ulnar notch.  Interosseous Membrane---binds the shaft of Radius and Ulna together.

23. MUSCLES  PRONATOR TERES----- helps in Pronation,it acts in all position of Elbow, helps in Stabilization of Superio Radio Ulnar Joint. Active during rapid and resisted Pronation.  PRONATOR QUADRATUS---- helps in Pronation in all position of Elbow  SUPINATOR---------helps in Supination in all position of Elbow  BICEPS BRACHI-------- helps in Supination when Elbow is flexed to 90 degree

24. MOVEMENTS  Pronation & Supination  Axis of movement extends from radial head to Ulnar head  Pronation and Supination movement is good when Elbow is Flexed to 90 degree  In Elbow extended position Pronation is limited due to passive tension in Biceps Brachi. Supination is limited due to passive tension in Interosseous Membrane.

26. Nerves © 2007 McGraw-Hill Higher Education. All rights reserved.6-26  Radial nerve - originates from C5, C6, C7, & C8  Triceps brachii  Brachioradialis  Supinator (posterior interosseous nerve)  Anconeus  Sensation to posterolateral arm, forearm, & hand

27. Nerves © 2007 McGraw-Hill Higher Education. All rights reserved.6-27  Median nerve - derived from C6 & C7  Pronator teres  Pronator quadratus (anterior interosseus nerve)  Sensation to palmar aspect of hand & first three phalanges, palmar aspect of radial side of fourth finger, dorsal aspect of index & long fingers

29. PROBLEMS OF ELBOW  TENNIS ELBOW or LATERAL EPICONDYLITIS:  Inflammation at origin of Extensors of Wrist at Lateral Epicondyle.  It is caused due to repeated forceful contraction of Wrist Extensors.  Extensor carpi radialis brevis is affected  GOLFER’S ELBOW or MEDIAL EPICONDYLITIS:  Inflammation at origin of Flexors of Wrist at Medial Epicondyle.  Repetitive contractions of Pronator Teres,Flexor Carpi Ulnaris

30. PROBLEMS OF ELBOW  NURSEMAID’S ELBOW or PULLED ELBOW  In small children the radial head is not fully developed ,lifting small child up in to by one hand may cause the RADIAL HEAD to slip out of Annular Ligament.  CUBITAL TUNNEL SYNDROME  Repetitive forceful contractions of Flexor carpi Ulnaris may compress Ulnar Nerve as it passess through the cubital tunnel between Medial Epicondyle of Humerus and Olecranon process of Ulna.