Unit 6 Readings PDF

Moore M, Dalley AF, Agur A. Moore’s Clinically Oriented Anatomy. 9th ed. Lippincott, Williams and Wilkins; 2018. Chapter 3: Osteologic p. 148–150 Chapter 3: Ligamentous: p. 277–283 Chapter 3: Articular: p. 277–283 1. (p.277-282) List what bones and joints make up the...

Moore M, Dalley AF, Agur A. Moore’s Clinically Oriented Anatomy. 9th ed. Lippincott, Williams and Wilkins; 2018. Chapter 3: Osteologic p. 148–150 Chapter 3: Ligamentous: p. 277–283 Chapter 3: Articular: p. 277–283 1. (p.277-282) List what bones and joints make up the elbow joint (hint... there should be 3 bones and 3 joints) a. Bones: i. Humerus ii. Ulna iii. Radius b. Joints: i. Humero-radial Joint ii. Humero-ulnar Joint iii. Proximal Radioulnar Joint 2. (p.277-282) List the ligaments of the elbow and identify what movements they would limit if they were shortened (what is the ligament couldn’t stretch as far). a. Ulnar Collateral Ligament (Anterior Fibers) i. Anterior Band (cord-like) *strongest and stiffest* ○ Limits Valgus (abduction), Extension, and Flexion b. Ulnar Collateral Ligament (Posterior Fibers) i. Posterior Band (fan-like) *less defined, weakest* ○ Resist Valgus -producing force ○ Becomes taut in the extremes of elbow flexion c. Ulnar Collateral Ligament (Transverse Fibers) i. Oblique Band *originate and insert on same bone* ○ Provides only limited articular stability d. Lateral (Ulnar) Collateral Ligament *attaches distally to the Supinator Crest of the Ulna* ○ Render fibers taut at full flexion ○ Resistance against excessive Varus movements ○ Prevents excessive External Rotation e. Radial Collateral Ligament *fans out to merge primarily with annular ligament, distally* ○ Resistance against Varus forces ○ Increases tension with External Rotation f. Annular Ligament *encircles and holds the head of the Radius in the radial notch of the Ulna (acts like a seatbelt) - permits pronation and supination* ○ Prevents distraction/subluxation of the Radius ★ (Nursemaid’s Elbow) ○ Increases tension with External Rotation 3. (p.277-282) Describe the osteokinematic (long bones moving on each other) and arthrokinematic (joint surfaces moving on each other) movements that occur at the elbow joint and the proximal radio-ulnar joint in both an open and closed pack position. a. Open Chain i. Elbow Flexion ○ Stationary Humerus. Ulna and Radius are free to move ○ Concave on Convex: Anterior Roll + Anterior Glide of Ulna and Radius on the Humerus ii. Elbow Extension ○ Stationary Humerus. Ulna and Radius are free to move ○ Concave on Convex: Posterior Roll + Posterior Glide of the Ulna and Radius on the Humerus iii. Pronation ○ Stationary Humerus. Ulna is the stationary pivot point. Radius rotates around / Crosses over the Ulna ○ Proximally: Radius Rotates Medially within the fibro-osseous ring formed by the Annular ligament and the Radial notch of the Ulna ○ Distally: Ulnar notch of the Radius Rolls and Slides (same direction), Medially on the head of the ulna iv. Supination ○ Stationary Humerus. Ulna is the stationary pivot point. Radius Returns to parallel with Ulna ○ Proximally: Radius Rotates Laterally within the fibro-osseous ring formed by the Annular ligament and the Radial notch of the Ulna ○ Distally (concave on convex): Ulnar notch of the Radius Rolls and Slides (same direction), Laterally on the head of the ulna b. Closed Chain i. Elbow Flexion ○ Stationary Ulna and Radius. Humerus is free to move ○ Convex on Concave: Anterior Roll + Posterior Glide of Humerus on the Ulna and Radius ii. Elbow Extension ○ Stationary Ulna and Radius. Humerus is free to move ○ Convex on Concave: Posterior Roll + Anterior Glide of Humerus on the Ulna and Radius  iii. Pronation (of the Ulna) ○ Radius is fixed (stationary) acting as pivot point. Humerus and Ulna are free to move ○ Proximally: External rotation of the Humerus and Ulna Annular ligament and the Radial notch of the Ulna rotate around the fixed Radial Head ○ Distally (convex on concave): Head of the Ulna rolls and slides in opposite directions on the fixed ulnar notch of the radius iv. Supination (of the Ulna) ○ Radius is fixed (stationary) acting as pivot point. Humerus and Ulna are free to move ○ Proximally: Internal rotation of the Humerus and Ulna Annular ligament and the Radial notch of the Ulna rotate around the fixed Radial Head ○ Distally (convex on concave): Head of the Ulna rolls and slides in opposite directions on the fixed ulnar notch of the radius Chapter 3: Neurological: p. 277–283; Neurological details p. 213–215 and 237–240 1. (p. 213-217) What is the relationship of the arteries and nerves of the arm to the humerus and the compartments of the arm? (Describe where they are positioned and how they travel into the forearm) a. Page 214. Figure 3.55 description answers the exact question. 2. (p. 213-217) What are the boundaries of the cubital fossa? (superiorly, medially, laterally, floor and roof). a. Superiorly: i. Imaginary line connecting the MEDIAL and LATERAL epicondyles b. Medially: i. Pronator Teres c. Laterally: i. Brachioradialis d. Floor: i. Brachialis and Supinator muscles of the arm and forearm, respectively e. Roof: i. Formed by the continuity of Brachial and Antebrachial (deep) fascia reinforced by the bicipital aponeurosis, subcutaneous tissue, and skin 3. Why is it necessary for a PT to know the boundaries of the cubital fossa? a. It helps identify injuries or conditions affecting nerves and blood vessels in the area Chapter 3: Vascular: p. 277–283; vascular details p. 212–213 and 234–237 1. (p.237-238 in Moore’s. p.196 of Neumann’s) What muscles receive their motor input by the Median nerve, Ulnar nerve, and Radial Nerve (respectively) around the elbow and forearm a. Median n. 1. Pronator Teres 2. Flexor Carpi Radialis 3. Palmaris Longus 4. Flexor Digitorum Superficialis i. Anterior Interosseous n. (Branch of Median n.) 1. Flexor Pollicis Longus 2. Flexor Digitorum Profundus (lateral ½ to digits 2 & 3) 3. Pronator Quadratus b. Ulnar n. 1. Flexor Carpi Ulnaris 2. Flexor Digitorum Profundus (medial ½ to digits 4 & 5) c. Radial n. (sensory) 1. Brachioradialis 2. Extensor Carpi Radialis Longus i. Deep Radial n. (Branch of Radial n.) (motor) 1. Extensor Carpi Radialis Brevis 2. Extensor Digitorum 3. Extensor Digiti Minimi 4. Extensor Carpi Ulnaris 5. Supinator ii. Posterior Interosseous n.) (Branch of Radial n.) 1. Abductor Pollicis Longus 2. Extensor Pollicis Brevis 3. Extensor Pollicis Longus 4. Extensor Indicis 2. (p.237 in Moore’s. Describe the cutaneous nerve distribution around the elbow and forearm (consider medial cutaneous, posterior cutaneous, lateral cutaneous nerve of the forearm). a. Lateral Cutaneous n. i. Continuation of the musculocutaneous nerve after its motor branches have all been given off to muscles of the anterior compartment of the arm. Supplying the area of the skin indicated by its name b. Medial Cutaneous n. i. Independent branch of the medial cord of the brachial plexus. Supplying the area of the skin indicated by its name c. Posterior Cutaneous n. i. Independent branch of the posterior cord (radial n.) of the brachial plexus. Supplying the area of the skin indicated by its name  Chapter 3: Muscular Anatomy: p. 277–283; mm details p. 207–212 and 221–226 (flexors of forearm) and 227-233 (extensors of forearm) 3. (p. 207-212) How do the biceps brachii, brachialis, coracobrachialis, triceps brachii, and anconeus influence the functional movement at the elbow both open (hand not in contact with surface) and closed chain (hand in contact with surface)? a. 4. (p. 225) List the muscles of the forearm and identify a functional movement/task that is performed with that muscle's activation. Example: pronator teres – pouring out a cup of water a. Chapter 3: Surface Anatomy: p. 215–217 and 241–242 Chapter 3: Compartments of Forearm (overview): p. 221 Neumann DA. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Mosby; 2016. Chapter 6: Osteology (p.175–179), Osteology (p.175–179), Arthrology (p.179–195), and Muscle & Joint Interaction (p.195–209) 1. List both muscular and nonmuscular tissues that are able to resist a distal pull (distraction) of the radius. a. Muscular Tissues: i. Biceps Brachii ii. Brachialis iii. Brachioradialis iv. Extensor Carpi Radialis Longus and Brevis b. Nonmuscular Tissues: i. Annular Ligament ii. Radial Collateral Ligament c. Joint Capsules d. Articular Cartilage in the elbow and wrist e. Fascia surrounding the muscles and joints 2. Describe how the different fibers of the medial collateral ligament of the elbow provide useful tension throughout the entire range of flexion and extension. a. Anterior Fibers i. Primary stabilizer of the elbow during extension and is taut when the elbow is fully extended. ii. As the elbow flexes, these fibers gradually slack, allowing for a smoother range of motion while still providing necessary support against valgus stress. b. Posterior Fibers i. More relaxed in full extension but becomes taut at greater degrees of flexion. ii. Helps stabilize the elbow during flexion, particularly when the forearm is subjected to valgus forces. c. Transverse Fibers i. Minor role compared to the anterior and posterior fibers ii. contributes to the overall integrity of the UCL by connecting the two other fibers and providing additional support. 3. Describe the arthrokinematics at the humeroradial joint during a combined motion of elbow flexion and supination of the forearm. a. Elbow Flexion: i. As the elbow flexes, the concave surface of the radial head moves within the convex surface of the humerus. The radial head rolls and glides in the same direction—posteriorly b. Supination i. Simultaneously, as the forearm undergoes supination, the radial head rotates around the stationary ulna. The radial head spins in the radial notch of the ulna. ii. This rotation occurs at the proximal radioulnar joint, but it is important to note that it influences the overall motion at the humeroradial joint. 4. What is the kinesiologic role of the anterior deltoid during a “pushing” motion that combines elbow extension and shoulder flexion? a. Elbow extends as the anterior deltoid flexes the shoulder b. Anterior deltoid must oppose and exceed the shoulder extensor torque produced by the long head of the triceps 5. What muscle is the most direct antagonist to the brachialis muscle? a. Triceps Brachii 6. A patient has a 20-degree elbow flexion contracture that is assumed to originate from muscular tightness. As the clinician applies an extension stretch (torque) to the elbow near the end range of motion, the forearm passively “drifts” rather strongly toward supination. What clue does this observation provide as to which muscle or muscles are most tight (stiff)? a. The observation that the patient's forearm "drifts" toward supination during an extension stretch near the end range of motion suggests that the biceps brachii is likely the tight/stiff muscle contributing to the elbow flexion contracture. b. Clue Explanation: i. The biceps brachii functions not only as an elbow flexor but also as a forearm supinator (due to its attachment to the radial tuberosity). ii. When the clinician applies an extension torque to stretch the elbow, if the biceps brachii is tight, it will resist the stretch and potentially cause the forearm to drift into supination as the muscle pulls on the radius. iii. This supination drift indicates that the biceps brachii is likely contributing to the restriction in elbow extension, as it acts strongly as a supinator when placed under tension near its end range. Other elbow flexors, like the brachialis and brachioradialis, do not have a similar supination action, further pointing to the biceps brachii as the stiff muscle. 7. What position of the upper extremity maximally elongates the biceps brachii muscle? a. Shoulder extension b. Elbow fully extended, c. Forearm fully pronated. 8. List some biomechanical benefits of the near-isometric behavior of the central band of the interosseous membrane during pronation and supination. a. Force Transmission: It efficiently transmits force between the radius and ulna, especially during weight-bearing activities, helping to distribute loads across the forearm bones. b. Stability: By maintaining near-constant length, it stabilizes the radius and ulna relative to each other during pronation and supination, ensuring smooth and coordinated movement. c. Energy Conservation: The isometric behavior minimizes energy expenditure by reducing the need for active muscle contraction to stabilize the radius and ulna during forearm motion. d. Protection of Joints: It helps protect the proximal and distal radioulnar joints from excessive stress or displacement during rotational movements. 9. In a weight-bearing position similar to that shown in Fig. 6.30 explain how, from a starting position of pronation, the latissimus dorsi could contribute to active supination of the forearm. Which tissues could restrict this active movement? a. In a weight-bearing position, the hand is fixed - the latissimus dorsi contracts to internally rotate the humerus b. Limiters i. Pronator teres and pronator quadratus: These muscles are primary forearm pronators and, if tight or contracted, could resist movement toward supination. ii. Interosseous Membrane: The central band of the interosseous membrane may limit Ulnar movement if it becomes excessively taut during forearm rotation. iii. Capsular Ligaments of the proximal and distal radioulnar joints: Tight ligaments at these joints could restrict the rotational movement required for full supination. iv. Tight wrist flexor muscles (ex. flexor carpi radialis): Since these muscles cross the forearm and wrist, they may resist the movement toward supination if they are stiff or overactive.