Elbow and Forearm

Question 1

Humeroradial Joint and Humeroulnar Joint

Answer 1

Part of the elbow complex. Interrelated joints where the humerus meets the radius or ulna. These joints are involved in flexion/extension.

Question 2

Proximal Radioulnar Joint

Answer 2

Part of the elbow complex. Where the radius meets the ulna and both rotate against the humerus. This joint is involved in forearm pronation/supination.

Question 3

Elbow Joint Type

Answer 3

Hinge or Synovial joint. Motions only in the sagittal plane: Flexion and Extension only.

Question 4

Stability of Elbow Joint

Answer 4

Joint is not very mobile (Flex/Ext only), and is therefore more stable.
• Withstands forces 1-3x the bodyweight.
• Less movements do make it more susceptible to repetitive stress injuries (RSI), however.

Question 5

Arc of Motion for the Elbow

Answer 5

0˚ extension to ~145˚ flexion (biceps stop the flexion range).

Can hyperextend ~10-15˚ due to laxity of ligaments or shortened olecranon process.

Motion needed for ADLs: 30˚ to 130˚.

Question 6

Motions of Forearm

Answer 6

Rotary motions of Supination and Pronation only. Also prone to repetitive stress injury (RSI).

Question 7

Interosseous Membrane

Answer 7

The tough, thin membrane that holds together the radius and ulna. Strengthens forearm against fractures from falls, etc.

Question 8

Rotation of Radius and Ulna in supination/pronation

Answer 8

Ulna is held stable while radius rotates around it.

REMEMBER: (R)ADIUS = (R)OTATES

Question 9

ROM norms for Supination/Pronation

Answer 9

0˚ to 80˚ for pronation and supination.

0˚-50˚ needed for ADLs (total Arc of Motion of 100˚).

Question 10

Carrying Angle

Answer 10

Angle formed by long axis of humerus and long axis of forearm. To accommodate anatomy and to help angle hand toward mouth. Seen in anatomical position. Women’s hands extend out to sides more than men due to hips.

Women: 10-15˚, Men: 5˚

Question 11

Cubital Varus vs. Cubital Valgus

Answer 11

Irregular carrying angles.

Cubital Varus = (inward) carrying angle less than 5˚. Also called “gun stock deformity.” Mal-alignment from supracondylar fractures.

Cubital Valgus = (outward) carrying angle greater than 15˚. Caused by fracture, Turner syndrome or Noonan syndrome. Can cause neuropathy and ulnar nerve palsy.

Question 12

Musculocutaneous Nerve

Answer 12

Terminal nerve of the lateral cord of brachial plexus (C5-C7).

Innervates:

• Biceps (flexion and supination)
• Brachialis (flexion)

Question 13

Radial Nerve

Answer 13

From posterior cord of brachial plexus; runs along radial side of arm (C5-C8).

Innervates:

• Triceps (extension)
• Anconeous (extension)
• Brachioradialis (flexion)

Question 14

Posterior Interosseous Radial Nerve

Answer 14

Runs along radial side of arm (C6). Innervates:

- Supinator (supination)

Question 15

Median Nerve

Answer 15

Has many “exits” along the arm. Runs along palmar side of arm. (C7-C8).

Innervates:
- Pronator Teres (pronation)

Question 16

Anterior Interosseous Median Nerve

Answer 16

(C7-T1). Innervates:

- Pronator Quadratus (pronation)

Question 17

Flexors of the Elbow

Answer 17

• Brachialis: **The only “true flexor” (it does not cause any other movement) and strongest flexor with forearm in any position.
• Brachioradialis: strongest flexor when forearm in neutral. Provides stabilization during rapid flexion (hammering a nail).
• Biceps: Strongest when combined with supination**, as it both flexes and supinates forearm.

**Keep pronation/supination in mind, as it may help someone use their arm more effectively depending on which muscles are injured.

Question 18

Extensors of Elbow

Answer 18

• Triceps (3 heads)-(No role in rotating forearm because no attachment to radius.)
• Anconeus: very small muscle on top of annular ligament; keeps ligament from getting pinched during extension.

Question 19

Pronators of Forearm

Answer 19

• Pronator Teres: pronates forearm and assists in elbow flexion. Position of elbow does not affect action of this muscle.
• Pronator Quadratus: deep muscle that pronates forearm.

**These muscles hold the arm in pronation during functional tasks like typing.

Question 20

Supinators of Forearm

Answer 20

• Biceps Brachii
• Supinator
(Work together as a “Force Couple” to produce supination.)

Question 21

MMT Positioning for Elbow Flexion

Answer 21

• Support hand placed on shoulder (since it’s a stronger muscle/movement).
• Testing hand proximal to wrist.
• Grades 5, 4, 3

Question 22

MMT Positioning for Supination/Pronation

Answer 22

• Supporting hand placed “cupping” 90˚ elbow (can palpate muscles firing, etc.)
• Testing hand in “handshake” position (for grades 4-5).
• Or, support elbow only for lower grades.

Question 23

ROM for Flexion/Extension of Elbow

Answer 23

• Arm hangs straight down along side, fulcrum of goni at elbow. Stationary arm of goni along upper arm; rotating arm goes with forearm during movement.
• Available ROM: 0-140˚ (flex) / 140˚-0 (ext)

Question 24

ROM for Pronation/Supination

Answer 24

• Arm at 90˚ to start.
• Hold “pencil” item in hand as guide.
• Align stationary arm of goni with line of upper arm (going below hand), fulcrum at 2nd knuckle of hand.
• Rotating arm, above hand, follows angle of pencil with movement.
• Available ROM: 0-80˚

Question 25

Ulnar Nerve Entrapment (Cubital Tunnel Syndrome)

Answer 25

Ulnar nerve injury most common after carpal tunnel syndrome in UE. Ulnar is most superficial nerve, passing through cubital tunnel on medial side of elbow joint. Entrapment caused by: pressure at the medial side of elbow over the nerve, frequent positioning of elbow in extreme flexion, and repetitive motion. • Causes inflammation and swelling that limit normal ulnar nerve gliding. • Tingling/numbness in ring/small fingers; worse at night. • Pain in medial elbow • Loss of grip, coordination, muscle atrophy in involved hand Treated with education, ergonomics, HEP, or ulnar nerve transposition surgery.

Question 26

Distal Biceps Tendon Rupture

Answer 26

(Davey Stribling's injury) Biceps tendon (attached at radial tuberosity) completely tears or ruptures. Caused by moving heavy object and elbow forcibly straightened. • Pop sound, pain, visible swelling/bruising, weakness, may be a bulge of recoiled muscle in upper arm. • Surgical repair, or 30% loss of elbow flexion/40% loss of supination strength. • Uses hinged brace to recover for up to 8 weeks. OT of light exercises/functional tasks starts then. • takes 3-6 months for full repair/normal activity.

Question 27

Lateral Epicondylitis (Tennis Elbow)

Answer 27

Inflammation and pain in elbow caused by overuse. Men develop it more than women. Pinpoint pain at lateral epicondyle of elbow that worsens over time. Not connected with a specific injury. • Pain caused by microscopic tears in extensor carpi radialis brevis (ECRB) tendon where it attaches to lateral epicondyle. • Causes weak grip, pain with gripping activities, and in lifting in pronation. • Treatment: Education, rest, ergonomics, bracing, cold/heat, stretching, scar mobilization. Friction massage at origin of tendon to decrease scar/increase bloodflow. • HEP of passive stretching by bending wrist into flexion with elbow extended, and gradual strengthening of forearm.

Question 28

Ulnar Collateral Ligament (UCL) Reconstruction (Tommy John Surgery)

Answer 28

Surgery first performed on Tommy John in 1974, pitcher for Dodgers. • UCL and lateral collateral ligament are most important in elbow. • UCL is also called medial collateral ligament (MCL) bc of its anterior and posterior bands passing through center of elbow. • Tear caused by overuse (athletes), mechanical faults, shoulder weakness or laxity • Pain in medial elbow, instability in elbow, irritation of ulnar nerve (tingling in ring/pinky); decreased ability to throw. • If tear is complete or large, surgery recommended. • Surgery requires tendon graft from palmaris longus or patellar tendon. Also usually ulnar nerve transposition, to avoid compression. • Athletes begin throwing again at 16 weeks; 80% of pitchers return to same level.

Question 29

Nerve roots that supply joints of elbow complex

Answer 29

C5-C8 and T1

Question 30

Damage to Radial Nerve in Humeral Region Weakens:

Answer 30

* Triceps * Wrist Extensors * Finger Extensors * Thumb Extensors

Question 31

Injuries to Tendons

Answer 31

Tendons have less blood supply compared to muscles, which increases risk of injury and slows healing. • Tears usually occur at musculotendinous junction, where tendon and muscle join (ie: distal biceps tendon rupture)

Question 32

Radial Head Subluxation (Nursemaid’s Elbow)

Answer 32

Also: “pulled elbow.” | Radial head pulled through underdeveloped, looser annular ligament of children under 6, causing dislocation.

Question 33

Little Leaguer’s Elbow

Answer 33

Repetitive stress to growth plate on inside of elbow, usually from throwing a ball. Pain in inner elbow when throwing; swelling, stiffness. • Requires exam for ROM, xray or MRI • Fully heals if treated early; can form deformity/disability if not. • Treatment: rest, icing, strengthening/endurance program, then correcting throwing mechanisms • Led to pitch counts on little league teams to avoid injury.

Question 34

Ulnar Nerve

Answer 34

• Runs along medial side of forearm and terminates in hand.