Pta 120 Chapter 5 Elbow

Front 1

Four Bones of elbow and forearm complex

Back 1

1. Scapula

2. Distal Humerus

3. Ulna

4. Radius

Front 2

Distal Humerus: Trochlea

Back 2

Spool shaped-medial side of distal humerus-articulates with the ulna-humeroulnar (elbow) joint

Front 3

Distal Humerus: Capitulum

Back 3

Lateral to the trochlea-articulates with the head of the radius to form the humeroradial joint

Front 4

Medial epicondyle

Back 4

Prominent projection of dista humerus-medial side-proximal attachment for most wrist flexor muscles, pronator teres and medial collateral ligament of the elbow

Front 5

Lateral epicondyle

Back 5

Proximal attachment for most wrist extensor muscles, supinator muscle and lateral collateral elbow ligament

Front 6

Medial & Lateral Supracondylar Ridges

Back 6

Immediately proximal to both epicondyles

Front 7

Olecranon Fossa

Back 7

Relatively deep, broad pit located on posterior side of the distal humerus

Front 8

Four joints in elbow/forearm complex

Back 8

1. Humeroradial joint

2. humeroulnar joint

3. proximal radioulnar joint

4. distal radioulnar joint

Front 9

Olecranon Process

Back 9

Large, blunt, proximal tip of the ulna, rough posterior surface is distal attachment for triceps muscle

Front 10

Trochlear Notch

Back 10

Large, jaw like curvature of proximal ulna articulating with trochlea: inferior tip comes to a point, forming the coronoid process.

Front 11

Coronoid Process

Back 11

Strengthens articulation of humeroulnar joint by firmly "grabbing" trochlea

Front 12

Radial Notch

Back 12

Slightly inferior and lateral to the trochlear notch. Articulates with radial head to form proximal radioulnar joint

Front 13

Styloid Process

Back 13

Pointed projection of bone that arises from ulnar head

Front 14

Radius: Radial Head

Back 14

Shaped like a wide disc on proximal end of radius. Superior surface consists of shallow, cup shaped depression called the fovea that articulated with humeral capitulum, forming the humeroradial joint

Front 15

Bicipital tuberosity / Radial Tuberosity

Back 15

Enlarged ridge of bone on anterior medial aspect of proximal radius. Primary distal attachment for biceps brachii

Front 16

Ulnar notch

Back 16

Small depression on medial side of distal radius that articulates with the ulnar head

Front 17

Humeroulnar Joint

Back 17

provides most of elbow's structural stability by trochlear notch interlocking with trochlea. Limits motion of elbow to flexion and extension

Front 18

Humeroradial Joint

Back 18

Formed by the capitulum articulating with the fovea. Permits continous contact between radial head and capitulum during supination, pronation, flexion and extension

Front 19

Cubitus Valgus orientation

Back 19

Natural outward angulation of the forearm within the frontal plane. Called the CARRYING ANGLE because of its function of keeping a carried object away from the body. Elbow trauma can result in either excessive cubitus valgus or cubitus varus

Front 20

Supporting structures of the elbow

Back 20

1. annular ligament

2. articular capsule

3. medial collateral ligament (MCL)

4. lateral collateral ligament (LCL)

Front 21

articular capsule

Back 21

thin, expansive band of connective tissue enclosing humeroulnar, humeroradial and radioulnar joints

Front 22

medial collateral ligament (MCL)

Back 22

attaches proximally to medial epicondyle and distally to medial aspects of coronoid and olecranon processes, provides stability by resisting cubitus valgus producing forces

Front 23

lateral collateral ligament (LCL)

Back 23

originates on the lateral epicondyle and splits into two fiber bundles known as the RADIAL COLLATERAL LIGAMENT, which attaches to the annular ligament and the LATERAL (ULNAR) COLLATERAL LIGAMENT which attaches to lateral aspect of the proximal ulna.

Provides elbow stability by resisting cubitus varus producing forces.

Front 24

Supporting structures of elbow joint

Back 24

Collateral ligaments limit excessive varus and valgus deformities of the elbow. Medial collateral ligament is most often injured during attempts to 'catch' oneself from a fall. Because these ligaments also become tight at the extremes of elbow flexion and extension, these motions can also damage the collateral ligaments, if very forceful

Front 25

Elbow joint kinematics

Back 25

Elbow flexion and extension occur in the sagittal plane around a medial lateral axis of rotation, which courses through both epicondyles.

Elbow range of motion normally spans from 5 degrees of hyperextension to 145 degrees of flexion.

Most activities use a more limited 100 degree arc of motion, between 30 and 130 degrees (Functional ROM)

Front 26

Arthrology of the forearm complex

Back 26

composed of the proximal and distal joints.

Pronation and supination occur as a result of motion at each of these two joints. Pronation and supination DO NOT OCCUR AT THE HAND.

Firm articulation between distal radius and carpal bones requires that the hand follows the rotation of the radius.

Front 27

Proximal and Distal Radioulnar Joint: ANNULAR LIGAMENT

Back 27

Thick, circular band of connective tissue that wraps around the radial head and attaches to either side of the radial notch of the ulna.

Holds the readial head firmly against the ulna, allowing it to spin freely during supination and pronation

Front 28

Distal Radioulnar Joint capsule

Back 28

Reinforced by palmar and dorsal capsular ligaments. Provides stability to the distal radioulnar joint

Front 29

Interosseous membrane

Back 29

helps bind radius to ulna

serves as a site for muscular attachments and a mechanism to transmit forces proximally through forearm

Front 30

Supination

Back 30

occurs in many functional activities that require the palm to be turned up. ex. holding a bowl of soup

Front 31

Pronation

Back 31

occurs with activites that require the palm turned down.

ex: pushing up from a chair

Front 32

Supination and Pronation

Back 32

occur as the radius rotates around an axis of rotation that travels from the radial head to the ulnar head

Front 33

0 degree or neutral position

Back 33

the thumb up position. From this position, normally 80-90 degrees of supination and 80-90 degrees of pronation

Front 34

Arthrokinematics of supination & pronation

Back 34

With humerus fixed and forearm free:

Radius moves...Ulna stationary

Radial head spins in place in direction of moving thumb

Distal radius rolls and slides in the same direction relative to the ulnar head. (Concave on Convex=Same direction)

Front 35

During supination

Back 35

the radial head spins in the direction of the thumb.

Spinning head of the radius also makes contact with the capitulumof the humerus.

At the distal radioulnar joint, the concave surface of the distal radius rolls and slides in the same direction across the stationary ulna

Front 36

Force transmission through the interosseous membrane

Back 36

Most introsseous membrane fibers are oriented 45 degrees from the long axis of the forearm, helping transmit compressive forces from the hand to the upper arm

Front 37

Push up actions

Back 37

create a compressive force passing through the hand to the wrist, 80% of which is transmitted through the radius at the radiocarpal joint

Front 38

Proxial directed force

Back 38

passes up radius and because of angulation of interosseous membrane, is transferred partly to ulna

Front 39

As a result

Back 39

compressive force that entersdistal forearm at radius exits proximal forearm through both humeroulnar and humeroradial joints and is transferred up to the shoulder

Front 40

Distally

Back 40

radius is more able to accept force

Front 41

proximally

Back 41

ulna is more able to accept force