Unit 3: UE Lecture Notes

Unit 3: Upper Extremity (UE)

Lab Activity 1: Shoulder and Scapula Analysis (20 minutes)

  • Step 1: Watch one video of someone in your group.
  • Step 2: Create a list of movements observed during the occupation, focusing on both glenohumeral (shoulder) and scapular motions.
    • Document:
    • Time stamp of movements observed.
    • Muscles involved in each motion.
      • Example:
      • Shoulder flexion
        • Muscles: Anterior deltoid fibers, pectoralis major (clavicular fibers), biceps brachii
      • Shoulder abduction
        • Muscles: All fibers of the deltoid, supraspinatus
      • Internal rotation
        • Muscles: Anterior fibers of the deltoid, latissimus dorsi, subscapularis, teres major, pectoralis major (all fibers)
      • Scapular protraction
        • Muscles: Serratus anterior, pectoralis minor used at 10 seconds to pour sugar into coffee.
  • Step 3: Post findings on the discussion board under “Week 3: Shoulder and Scapula Analysis.” All individuals must post. Similar posts among individuals are acceptable for this step.

Anatomy of the Elbow

Bones Involved in Elbow Anatomy
  • Radius:
    • Head of radius
    • Radial tuberosity
    • Shaft of radius
    • Radial styloid process
  • Ulna:
    • Coronoid process
    • Olecranon process
    • Shaft of the ulna
    • Radial notch
Joints
  • Humeroulnar joint: True hinge joint (the primary joint of the elbow).
  • Humeroradial joint: Modified hinge joint.
  • Proximal radioulnar joint: Pivot joint allowing rotation.
Ligaments at the Elbow
  • Ulnar (medial) collateral ligament
  • Radial (lateral) collateral ligament
  • Annular ligament
  • Interosseous membrane
Cubital Fossa Anatomy
  • Contents (from lateral to medial):
    • Brachial artery
    • Radial artery
    • Ulnar artery

Motion in the Elbow and Forearm

  • Elbow flexion and extension are the primary motions.
  • Forearm rotation occurs at:
    • Proximal radioulnar joint (allows for pronation and supination).
  • Muscles responsible for elbow motion:
    • Biceps brachii (innervated by musculocutaneous nerve)
    • Triceps brachii (innervated by radial nerve)
    • Brachialis (innervated by musculocutaneous nerve)
    • Brachioradialis (innervated by radial nerve)
    • Supinator (innervated by radial nerve)
    • Pronator teres (innervated by median nerve)
    • Pronator quadratus (innervated by median nerve)

The Elbow Joint

  • Hinge Joint Composition:
    • Comprised of the humerus, radius, and ulna.
  • Key Components:
    • Humeroulnar joint:
    • “True elbow joint” characterized by the medial surface (trochlea) of the humerus articulating with the trochlear notch of the ulna, allowing for flexion and extension.
    • Humeroradial joint:
    • Modified hinge joint that involves the lateral surface (capitellum/capitulum) of humerus articulating with the head of the radius, allowing for flexion, extension, and some rotation.
  • Pivot Joint:
    • Located distal to the elbow joint at the proximal radioulnar joint, where the head of the radius pivots within the radial notch of the ulna allowing for pronation and supination.
  • Closed pack position:
    • Full elbow extension.
  • Open pack position:
    • 70 degrees of elbow flexion.

Elbow/Forearm Landmarks: Cubital Fossa

  • Borders:
    • Lateral: Brachioradialis.
    • Medial: Pronator Teres.
    • Superior: Imaginary line between the medial and lateral epicondyles.
  • Floor: Supinator and brachialis.
  • Contents (from lateral to medial): Distal biceps tendon, brachial artery, median nerve.

Elbow Joint Arthrokinematics

  • Humeroulnar joint:
    • Convex trochlea of the humerus articulating with concave trochlear notch on the ulna allows for roll and glide/slide motions:
    • Flexion: Anterior roll and anterior glide/slide.
    • Extension: Posterior roll and posterior glide/slide.
  • Humeroradial joint:
    • Convex capitulum articulating with concave radial head allows similar roll and glide/slide motion as above.

Elbow Ligaments

  • Ulnar (medial) collateral ligament:
    • Checks against valgus forces.
  • Radial (lateral) collateral ligament:
    • Along with lateral aspect of joint capsule, checks against varus forces.
  • Annular Ligament:
    • Provides stability to radioulnar articulation.
  • Interosseous membrane (IOM):
    • Contributes to stability of forearm by holding radial and ulnar shafts together.

Carrying Angle of the Elbow

  • Definition:
    • The angle formed by the longitudinal axis of the humerus and forearm.
  • Observation:
    • The trochlea (ulnar/medial) is positioned inferior to the capitulum (radial/lateral), creating the carrying angle.
  • Typical Angle Range:
    • 5-15 degrees of valgus, angled laterally from midline relative to the humerus.
  • Conditions:
    • Cubital Valgus: Excessive carrying angle (forearm positioned laterally).
    • Cubital Varus: Decreased carrying angle (forearm positioned medially).

Elbow/Forearm Landmarks

Bicipital Aponeurosis
  • Description:
    • Deep fascia along the anteromedial aspect of the forearm aiding in protection and may entrap the median nerve.
    • Acts as the “roof” of the cubital fossa.
Cubital Tunnel
  • Description:
    • Bony passage posterior to the medial epicondyle.
    • Roof: Ran ligament of Osborne.
    • Significance: Potential compression of the ulnar nerve, causing symptoms such as tingling in the ring and small fingers.
  • Risk Factors:
    • Frequent elbow flexion
    • Driving with arm bent
    • Sleeping with elbow flexed
    • Frequent use of phones or gaming devices.

Practice Questions

  • Question 1: Which of the following structures contributes to the carrying angle?

    • A. The trochlea sits inferior to the capitulum.
    • B. The capitulum sits inferior to the trochlea.
    • C. The distal humerus will extend farther in people with cubital valgus.
    • D. The radius is more proximal than the ulna.

  • Question 2: What is the position of active insufficiency at the biceps brachii?

    • A. Full elbow flexion.
    • B. Shoulder flexion, elbow flexion, forearm supination.
    • C. Shoulder extension, elbow extension, forearm pronation.
    • D. Elbow flexion, forearm supination.

Nerve Supply to the Elbow and Wrist

  • Anterior Interosseous Nerve:
    • Branch of the median nerve.
    • Innervates muscles necessary for flexing the tips of the thumb, index, and long fingers.
  • Posterior Interosseous Nerve:
    • Branch of the radial nerve.
    • Controls muscles responsible for extending the wrist and fingers; supports fine motor tasks like gripping, pointing, and spreading fingers.

Wrist Anatomy

Carpal Bones
  • Total Count: 8 carpal bones divided into proximal and distal rows (4 each).
  • List of Carpal Bones:
    • Scaphoid
    • Lunate
    • Triquetrum
    • Pisiform
    • Trapezium
    • Trapezoid
    • Capitate
    • Hamate
  • Anatomical Snuffbox:
    • Noted location for tenderness when scaphoid is fractured.
Wrist Articulations and Stability
  • Joints:
    • Distal Radioulnar Joint (pivot):
    • Responsible for pronation and supination.
    • Radiocarpal Joint (Ellipsoid/Condyloid):
    • Formed by the distal end of the radius and the radioulnar disk articulating with scaphoid, lunate, and triquetrum.
    • Mobility: Allows flexion, extension, radial deviation, ulnar deviation. Characterized by “Dart Thrower’s Plane” movement.
    • Force Transmission: 80% of compressive forces during weight-bearing in a neutral position occur at this joint.
    • Ulnocarpal Complex:
    • Comprised of the ulnar side of the wrist, explicitly referring to the ulna, lunate, triquetrum and Triangular Fibrocartilage Complex (TFCC).
    • The ulnocarpal complex does not have direct joint attachments.
    • Intercarpal Joints:
    • These joints are formed between adjacent carpal bones within the same row.
    • Midcarpal Joint:
    • The joint between the proximal and distal rows of carpal bones.
    • Carpometacarpal Joint:
    • Located between the distal row of carpal bones and the proximal end of the metacarpal bones.
Wrist Arthrokinematics
  • Radiocarpal Joint:
    • Convex on concave allows for roll and glide/slide movements:
    • Wrist Flexion: Anterior roll and posterior glide/slide.
    • Wrist Extension: Posterior roll and anterior glide/slide.
    • Wrist Radial Deviation: Lateral roll and medial glide/slide.
    • Wrist Ulnar Deviation: Medial roll and lateral glide/slide.

Muscles of the Wrist and Hand

  • Extensors (all innervated by radial nerve unless noted):
    • Extensor Carpi Radialis Brevis
    • Extensor Carpi Radialis Longus
    • Extensor Digitorum
    • Extensor Carpi Ulnaris
    • Extensor Pollicis Longus
    • Extensor Pollicis Brevis
    • Extensor Indicis
    • Extensor Digiti Minimi
    • Abductor Pollicis Longus
  • Flexors:
    • Flexor Carpi Ulnaris (innervated by ulnar nerve)
    • Flexor Carpi Radialis (innervated by median nerve)
    • Flexor Digitorum Superficialis (innervated by median nerve)
    • Flexor Digitorum Profundus (split innervation - median and ulnar nerve)
    • Opponens Pollicis (innervated by median nerve)
    • Flexor Digiti Minimi
    • Opponens Digiti Minimi (innervated by ulnar nerve)
  • Intrinsics:
    • Dorsal Interosseous (innervated by ulnar nerve)
    • Palmar Interosseous (innervated by ulnar nerve)
    • Adductor Pollicis (innervated by ulnar nerve)
    • Lumbricals (2nd and 3rd digits mediated by median nerve; 4th and 5th digits by ulnar nerve)
Carpal Tunnel Anatomy
  • Roof: Transverse carpal ligament (also known as flexor retinaculum).
  • Contents:
    • 4 Flexor Digitorum Superficialis (FDS) tendons
    • 4 Flexor Digitorum Profundus (FDP) tendons
    • 1 Flexor Pollicis Longus (FPL) tendon
    • Median nerve
  • Floor: Composed of carpal bones.
Ligaments of the Wrist
  • Extrinsic ligaments:
    • Example: Radioscapholunate ligament
  • Intrinsic ligaments:
    • Example: Pisohamate ligament
  • Triangular Fibrocartilage Complex (TFCC) includes:
    • TFCC disc
    • Palmar and dorsal radioulnar ligaments
    • Palmar ulnocarpal ligaments
    • Ulnar collateral ligament
    • ECU tendon sheath
Wrist Landmarks
  • Anatomical Snuffbox Components:
    • Scaphoid
    • Extensor Pollicis Longus (EPL)
    • Extensor Pollicis Brevis (EPB)
    • Abductor Pollicis Longus (APL)
    • Lister's tubercle (bony prominence serving as a pulley for the EPL).
  • Common Flexor Tendon:
    • Originates from the medial epicondyle of the humerus.
  • Common Extensor Tendon:
    • Originates from the lateral epicondyle of the humerus.
  • Dorsal Wrist Compartments:
    • The compartments are held together by the extensor retinaculum.
    • Compartment breakdown:
    • 1: APL, EPB
    • 2: ECRL, ECRB
    • 3: EPL
    • 4: EI, ED
    • 5: EDM
    • 6: ECU