Chapter 11 Elbow Joint Kinesiology

Medial Collateral Ligament

- Triangular, spans the medial side of the elbow, and inserts on the ulna -attaches on medial epicondyle of the humerus and runs obliquely to the medial sides of the coronoid and olecranon processes of the ulna - Most important to provide stability against valgus (lateral) stress, especially in the range of 20 to 130 degrees of extension and flexion

Pronator Teres

-gets name from action (pronation) and from long shape (teres) -superficial muscle as it crosses elbow but is covered by brachioradialis at its distal attachment -assisting mover bc of its smaller size and diagonal line of pull O - Medial Epicondyle of humerus and coronoid process of ulna I - lateral aspect of radius at its midpoint A - Forearm pronation, assistive in elbow flexion N - Median Nerve (C6, C7)

Interosseous Membrane

-in addition to annular ligament, this also holds radioulnar articulations together -broad, flat membrane located btw radius and ulna for most of their length, keeping the 2 bones from separating and providing more surface area for attachment of forearm and wrist muscles

Triceps Brachii Muscle (3 heads)

-located posteriorly and makes up entire muscle mass of posterior arm -long head descends btw teres muscles to join other 2 -crosses elbow posteriorly to attach to olecranon process of ulna -bc of vertical pull, is very effective in elbow extension, but plays no role in pronation or supination

Pronator Quadratus (see teres pic for quad pic)

-name from action and from shape (pronate and quad) -small, flat, deep on anterior surface of distal forearm, cant be palpated O - distal 1/4 of ulna I - distal 1/4 of radius A - Forearm pronation N - Median (C8, T1)

Pronation and Supination

-palm facing down/palm facing up -radius moves around the ulna, as ulna is locked in place by olecranon process Transverse Plane -Vertical Axis -approx 90 degrees of supination, 80 degr of pronation

3. Stand with your right arm extended straight up toward the ceiling. Using your left hand, push your right hand down behind your head. A. What motion motion is occurring in the right elbow? B. What muscles are being stretched?

A. Elbow Flexion B. Triceps

2. Sit in a chair that has armrests and place your hands on them. Do a chair push up, lifting your buttocks off the seat. A. What joint motion is occurring in the right elbow? B. What type of contraction (isometric, concentric, or eccentric) is occurring? C. What muscles are being strengthened? D. Is this an open- or closed-chain activity?

A. Elbow extension B. Concentric contraction C. Triceps D. Closed

5. Stand with your right hand next to your right shoulder, and hold a small weight. Move your hand to anatomical position. A. What joint motion is occurring in the right elbow? B. What type of contraction (isometric, concentric, or eccentric) is occurring? C. What muscles are being strengthened? D. Is this an open- or closed-chain activity?

A. Extension B. Eccentric C. - Biceps - Brachialis - Brachioradialis D. Open

Elbow Extension

Straightening Elbow -Posterior movement in Sagittal Plane-Frontal Axis -no hyperextension bc blocked by olecranon process of the ulna fitting into humerus

1. In a sitting position, place your right forearm on the table palm down with your elbow flexed as necessary. Using your left hand, push against the radial side of the right forearm just proximal to the wrist until the right palm is facing up. The right forearm remains relaxed. A. What joint motion is occurring at the right forearm? B. What muscles are being stretched?

A. Forearm supination B. - Pronator teres - Pronator quadratus

Muscles of the Elbow and Forearm

Brachialis Brachioradialis Biceps Supinator Triceps Anconeus Pronator Teres Pronator Quadratus

Innervation of Elbow Joint Muscles

Brachialis= Musculocutaneous C5, C6 Biceps= Musculocutaneous C5, C6 Brachioradialis= Radial C5, C6 Triceps= Radial C5, C6 Anconeous= Radial C5, C6 Pronator Teres= Median C6, C7 Pronator Quadratus= Median C8, T1 Supinator= Radial C6

8. Which muscles connect the humerus and ulna?

anconeus, triceps, and brachialis muscles

Carrying Angle

angle formed in anatomical position by longitudinal axes of forearm and humerus -occurs bc humerus is not level, the medial side (trochlea) is lower than lateral side (capitulum), therefore as ulna and radius rotate around trochlea and capitulum, they do not rotate in a single line like a typical hinge joint - 5-10 degrees in men, 15 in women

9. The only parts of the triceps that crosses the shoulder joint is ____________.

long head of triceps

Supracondylar Fractures

most common fractures in children caused by falling on an outstretched hand -distal end of humerus fractures just above the condyles

Elbow Joint End Feels

- Flexion = soft tissue approx bc of muscle bulk -Extension = bony end, hard due to bone on bone contact

Brachioradialis

-2 attachments: 1 on humerus (brachii), 1 on Radius -proximally attached on supracondylar ridge, slightly above lateral epicondyle of humerus -crosses elbow anteriorly and laterally to attach distally near the styloid process of radius -superficial and easy to identify -most effective as elbow flexor in neutral position bc of lateral attachment -vertical line of pull and goes thru axis for pronation and supination so has no real effect despite attachment on radius

Radius Parts of Elbow (see other pic for parts)

-Head: proximal end, has cylinder shape w/depression in superior surface for articulation w/capitulum of humerus -Radial Tuberosity: located on medial side near proximal end, attachment for biceps muscle -Styloid Process: posterior lateral side near the proximal end, attachment for brachioradialis

Scapular Elbow Function Parts

-Infraglenoid Tubercle: raised portion on inferior lip of the glenoid fossa that provides attachment for long head of triceps muscle -Supraglenoid Fossa: raised portion on superior lip of the glenoid fossa that provides attachment for long head of biceps muscle -Coracoid Process: projection on anterior surface that provides attachment for the short head of the biceps muscle

Humerus Elbow Parts Cont

-Lateral Supracondylar Ridge: above lateral epicondyle, provides attachment for brachioradialis -Olecranon Fossa: posterior surface btw lateral and medial epicondyles, arts with olecranon process of ulna

Ulna Elbow Parts

-Olecranon Process: proximal end of ulna on posterior side & forms prominent point of elbow, Attachment for TRIceps -Trochear Notch: aka semilunar notch due to C shape, Makes up anterior surface on proximal end-articulates w/ trochlea of humerus -Coronoid Process: just below trochlear notch, with ulnar tuberosity, attachment for brachialis

Ulna Elbow Parts Con't

-Radial Notch: proximal end on lateral side just distal to trochlear notch, art point for head of the radius -Ulnar Tuberosity: below coronoid process, attachment for brachialis -Styloid Process: distal end of posterior medial surface, spiny part on back medial wrist in AP -Head: distal end of lateral surface, ulnar notch of radius pivots here at supination/pronation

Forearm End Feels

-Supination = soft tissue stretch, firm -Pronation = bony, hard due to contact btw radius & ulna

Points to remember:

-Synovial joints can be irregular (plane), hinge, pivot, condyloid, saddle, and ball & socket -can have 0-3 axis -when muscle has contracted (shortened) over all its joints as far as it can, it has become actively insufficient -when it has elongated (stretched) over all its joints as far as possible, it is passively insufficient -activity can be open or closed kinetic chain movement, depending on whether the distal segment is fixed -concave/convex rule has convex joint surface moving in a direction opposite to the movement of the body segment and the concave joint surfacing moving in the same direction as the body segment

Humerus Elbow Parts

-Trochlea: medial side of distal end, articulates with ulna -Capitulum: lateral side next to trochlea, articulates w/head of radius -Medial Epicondyle: located on medial side of distal end above the trochlea, larger and more prominent than lateral epicondyle, attachment point for pronator teres -Lateral Epicondyle: located on lateral distal side above capitulum, attachment point for anconeus and supinator muscles

Lateral collateral ligament

-also triangular, attaches proximally on lateral epicondyle of humerus and distally on the annular ligament and lateral side of ulna -provides much medial and lateral stability - Helps provide stability against varus (medial) stress

Radioulnar Joint

-articulation btw radius and ulna -Superior and Inferior are considered one joint -Uniaxial Pivot Joint,allowing only pronation & supination

Annular Ligament

-attaches anteriorly and posteriorly to radial notch of ulna, encompassing head of radius and holding it against the ulna

Joint Capsule

-attaches distal end of humerus and encompasses trochlea and capitulum, and the fossas located above them -attaches around proximal end of ulna, under radial notch and coronoid process, and around trochlear notch -attaches around radius just under the head -strengthened anteriorly and somewhat posteriorly by the annular ligament -collateral ligaments reinforce capsule on sides of joint

Supinator Muscle

-deep that wraps around elbow joint laterally from posterior surface to anterior surface -combines with biceps muscle as prime mover in forearm supination O - Lateral epicondyle of humerus an adjacent ulna I - anterior surface of proximal radius A - forearm supination N - Radial Nerve (C6)

Anconeus Muscle

-small muscle that attaches net to much larger triceps -plays no significant role in elbow extension -lies on top of annular ligament and attaches to part of it so when the ligament contracts, the anconeus pulls on it and keeps it from getting pinched in olecranon fossa during elbow extension O - lateral epicondyle of humerus I - lateral and inferior to olecranon process of ulna A - not a prime mover in any joint action, assist extension N - Radial Nerve (C7, C8)

Distal End of Humerus has 2 convex areas:

-trochlea articulating with ulna -capitulum articulating with radius

Biceps Brachii Muscle

2 heads (long & short), Bi - commonly called Bicep, both heads attach on scapula -Long head runs over humerus head and descends through joint capsule running through bicipital groove -biceps assist in shoulder flexion bu main function is at the elbow -After joining together, 2 heads form a common muscle belly that covers anterior surface of the arm, crossing elbow joint to attach on radial tuberosity -superficial muscle, bc it spans elbow joint anteriorly, it is a good elbow flexor, bc it attaches obliquely on the radius it contributes to supination of the forearm

1. In terms of the elbow and forearm joints, identify the following. A. Name of bones involved: Forearm__________ Elbow__________ B. Number of Axes Forearm__________ Elbow__________ C. Shape of Joint Forearm__________ Elbow__________ D. Joint Motion Allowed Forearm__________ Elbow__________

A. Forearm: radius, ulna Elbow: humerus, radius, ulna B. Forearm: 1 Elbow: 1 C. Forearm: pivot Elbow: hinge D. Forearm: supination/pronation Elbow: flexion/extension

12. A. If you put your hand on the anterior surface of your arm, you would be touching what muscle? B. Placing your hand on the posterior surface of the arm is over what muscle? C. Touching the lateral forearm is touching what muscle?

A. biceps B. triceps C. brachioradialis

4. In a sitting position, place your hands and forearms on the table. Push on the table as if your are trying to hold it down. A. What joint motion is occurring in the right elbow? B. What type of contraction (isometric, concentric, or eccentric) is occurring? C. What muscles are being strengthened?

A. elbow extension B. Isometric C. Triceps

3. Name the ligament that: A. stabilizes the lateral side of the elbow. B. the medial side of the elbow C. radius and allows it to rotate

A. lateral, or radial, collateral ligament B. medial, or ulnar, collateral ligament C. annular ligament

10. What positions would you put the upper extremity in to achieve A. active insufficiency of the biceps? B. passive insufficiency of the biceps?

A. shoulder flexion, elbow flexion, forearm supination B. shoulder hyperextension, elbow extension, forearm pronation

Elbow Flexion

Anatomical Position - Anterior movement in Sagittal Plane -Frontal Axis

Prime Movers of Elbow and Forearm

Elbow Flexion: Biceps, Brachialis, Brachioradialis Elbow Extension: Triceps Forearm Pronation: Pronator Teres and Quadratus Forearm Supination: Biceps, Supinator

5. With a hammer in your hand, pound on a nail that has been set in the wall. Elbow__________ Forearm_________

Elbow: extension Forearm: midposition

3. When answering the telephone (old school phone), reach for the receiver. Elbow__________ Forearm_________

Elbow: extension Forearm: pronation

1. Identify the elbow and forearm motion in the following activity. Place a dinner plate in an upper kitchen cabinet. Elbow__________ Forearm_________

Elbow: extension Forearm: supination

4. Put the phone to your ear. Elbow__________ Forearm_________

Elbow: flexion Forearm: supination

2. Identify the elbow and forearm motion in the following activity. Put a piece of chocolate in your mouth. Elbow__________ Forearm_________

Elbow: flexion Forearm: supination (or possibly mid position)

Valgus stress

Ensures that any kind of lateral stress (force on the lateral side of the elbow) doesn't effect the joint

Brachialis Muscle

Named for location, no attachment on radius therefore no role in pronation or supination, but very strong elbow flexor, "the workhorse" O- distal half of humerus, anterior surface I- Coronoid process & ulnar tuberosity of ulna A - elbow flexion N - musculocutaneous nerve (C5, C6)

Biceps Brachii Muscle Con't

O - Long Head: supraglenoid tubercle of scapula Short Head: coracoid process of scapula I - radial tuberosity of radius A - elbow flexion, forearm supination N - Musculocutaneous (C5, C6)

Brachioradialis Con't

O - Lateral Supracondylar ridge I - Styoid process of radius A - Elbow flexion N - Radial Nerve (C5, C6)

Triceps Brachii Muscle Con't

O - Long Head: infraglenoid tubercle of scapula Lateral Head - inferior to greater tubercle on posterior humerus Medial Head: posterior surface of humerus I - Olecranon process of ulna A - elbow extension N - Radial Nerve (C7, C8)

2. If you were handed an unattached model of an ulna, how could you orient landmarks to determine on which side of the body it belonged?

The trochlear notch at the superior end faces anteriorly, the radial notch at the same end faces laterally, and the styloid process at the inferior end is on the medial side.

Both Elbow dislocation and Supracondylar fractures

are very dangerous due to potential damage to the brachial artery because of its close proximity which can lead to Volkmann's Ischemic Contracture

Elbow Joint

articulation of the humerus with ulna and radius , comprised of 3 bones, 3 ligaments, 2 joints and 1 joint capsule -humerus the trochlea articulates with the trochlear notch of the ulna and the capitulum articulates with the head of the radius -Uniaxial joint allows only flexion and extension -approx 145 degrees of flexion

Superior or Proximal Radiolulnar joint

at proximal end, head of radius pivots within radial notch of ulna, forming the superior or proximal radiolulnar joint

Elbow Dislocation

caused when great deal of force is applied to an elbow that is in a slightly flexed position causing the ulna to slide posterior to the distal end of the humerus

Lateral Epicondylitis aka Tennis Elbow

common overuse condition that affects common extensor tendon where it inserts into lateral epicondyle of humerus, with the extensor carpi radialis brevis is particularly affected -seen in racquet sports and repetitive wrist extensions

Inferior or Distal Radioulnar Joint

distal end of the radius rotates around the distal end of the ulna

Medial Epicondylitis aka Golfer's Elbow

inflammation of common flexor tendon that inserts into medial epicondyle, overuse condition that results in tenderness over medial epicondyle and pain on resisted wrist flexion

Little League Elbow

overuse of medial epicondyle, usually caused by repetitive throwing motion, seen in young ball players who havent reached skeletal maturity. -throwing places valgus stress on elbow, causing lateral compression and medial distraction on the joint

5. To which bone must a muscle attach to do forearm supination or pronation?

radius, because it is the radius moving around the ulna that produces these motions

Volkmann's Ischemic Contracture

rare but devastating ischemic necrosis of the forearm muscles

11. In a closed-chain activity, does the humeral joint surface move in the same or opposite direction as the forearm?

same direction

Pulled Elbow aka Nursemaid's Elbow

seen in young children under the age of 5 who have experienced sudden strong traction force on the arm, often occurs when the child pulls away from an adult suddenly or the adult pulls on the arm -causes the radial head to sublux out from under the annular ligament

7. Which muscles connect the scapula to the ulna and/or radius?

the biceps (to radius) and long head of the triceps (to ulna) muscles

4. Which muscles of the elbow and/or forearm are two-joint muscles?

the biceps and long head of the triceps muscles

6. Which elbow or forearm muscles do not attach to the humerus?

the pronator quadratus, biceps, and long head of the triceps muscles