Kinesiology: Elbow and Forearm Anatomy, Mechanics, and Pathologies

Comprehensive vocabulary flashcards covering elbow and forearm kinesiology, including joint articulations, osteokinematic and arthrokinematic motions, muscle origins, insertions, actions, innervations, and clinical pathologies.

Humeroulnar Joint

A uniaxial, synovial hinge joint formed by the articulation between the convex trochlea of the humerus and the concave trochlear notch of the ulna.

Humeroulnar Joint Arthrokinematics

Arthrokinematic motion consisting of mostly glide and a slight roll.

Humeroradial Joint

A uniaxial, synovial hinge joint formed by the articulation of the convex capitulum of the humerus with the concave proximal surface of the radial head.

Humeroradial Joint Arthrokinematics

Glides during flexion and extension; during pronation and supination, the head of the radius spins on the capitulum.

Proximal Radioulnar Joint

A uniaxial, synovial articulation between the concave radial notch of the ulna and the convex head of the radius.

Proximal Radioulnar Joint Arthrokinematics

Motion in which the radius spins on the ulna and capitulum.

Distal Radioulnar Joint

A uniaxial, synovial pivot joint between the distal ulna and radius where the radius rolls and glides over the ulna.

Elbow Flexion Range of Motion

Normal osteokinematic range of motion measuring $0\text{--}150\text{ degrees}$.

Elbow Extension Range of Motion

Normal osteokinematic range of motion of $0\text{ degrees}$, with some individuals exhibiting a few degrees of hyperextension.

Forearm Supination Range of Motion

Movement where the palm faces anteriorly, through a normal range of $0\text{--}80\text{ degrees}$.

Forearm Pronation Range of Motion

Movement where the palm faces posteriorly, through a normal range of $0\text{--}80\text{ degrees}$.

Humeroulnar Joint End Feels

Soft end feel in flexion and hard end feel in extension.

Radioulnar Joint End Feel

Firm end feel found at both the proximal and distal radioulnar joints.

Humeroulnar Joint Positions

Close-pack position is full extension and supination; loose-pack position is $70\text{ Flexion}$ and $10\text{ Supination}$.

Proximal Radioulnar Joint Positions

Close-pack position is $5\text{ Supination}$; loose-pack position is $70\text{ Flexion}$ and $35\text{ Supination}$.

Distal Radioulnar Joint Positions

Close-pack position is $5\text{ Supination}$; loose-pack position is $10\text{ Supination}$.

Capsular Patterns of the Elbow and Forearm

Flexion is more limited than extension ($\text{Flexion} > \text{Extension}$) at the humeroulnar joint; pronation and supination are equally restricted ($\text{Pronation} = \text{Supination}$) at both the proximal and distal radioulnar joints.

Distal Humerus Landmarks

Bony landmarks including the trochlea, capitulum, medial epicondyle, lateral epicondyle, and lateral supracondylar ridge.

Ulna Landmarks

Bony landmarks including the trochlear notch, radial notch, olecranon process, coronoid process, and ulnar tuberosity.

Radius Landmarks

Bony landmarks including the radial head, radial tuberosity, and radial styloid process.

Carrying Angle (Cubitus Valgus)

The angle formed between the arm and forearm in anatomical position by intersecting vertical lines along the humerus and radius/ulna; measures $10\text{--}15^\bullet$ in females and $5^\bullet$ in males due to the medial aspect of the elbow being longer.

Brachialis Muscle

Originates on the anterior surface of the distal half of the humerus, inserts on the ulnar tuberosity and coronoid process of the ulna, performs elbow flexion, and is innervated by the musculocutaneous nerve ($C5, C6$).

Biceps Brachii Muscle

Originates from the supraglenoid tubercle (long head) and coracoid process of the scapula (short head), inserts on the radial tuberosity of the radius, performs shoulder flexion, elbow flexion, and forearm supination, and is innervated by the musculocutaneous nerve ($C5, C6$).

Brachioradialis Muscle

Originates on the lateral supracondylar ridge on the humerus, inserts on the distal lateral aspect of the radius proximal to the styloid process, performs elbow flexion and forearm supination and pronation, and is innervated by the radial nerve ($C5, C6$).

Triceps Brachii Muscle

Originates from the infraglenoid tubercle (long head), inferior to the greater tubercle on the posterior humerus (lateral head), and posterior surface of the humerus (medial head); inserts on the olecranon process of the ulna; performs shoulder extension and elbow extension; innervated by the radial nerve ($C6, C7, C8$).

Anconeus Muscle

Originates on the lateral epicondyle of the humerus, inserts laterally and inferiorly to the triceps on the olecranon process and annular ligament, performs elbow extension and capsule retraction during extension, and is innervated by the radial nerve ($C6, C7, C8$).

Pronator Teres Muscle

Originates on the medial epicondyle of the humerus and coronoid process of the ulna, inserts on the lateral aspect of the radius at its midpoint, performs forearm pronation and elbow flexion, and is innervated by the median nerve ($C6, C7$).

Pronator Quadratus Muscle

Originates on the anterior distal one-fourth of the ulna, inserts on the anterior distal one-fourth of the radius, performs forearm pronation and stabilizes the distal radioulnar joint, and is innervated by the median nerve ($C8, T1$).

Supinator Muscle

Originates on the lateral epicondyle of the humerus and adjacent ulna, inserts on the anterior surface of the proximal radius, performs forearm supination and elbow flexion, and is innervated by the radial nerve ($C6$).

Determinants of Muscle Action

The five factors evaluated to determine which muscle performs an action: location, size, line of pull, fiber type, and amount of force needed for the task.

Lateral Epicondylitis (Tennis Elbow)

An overuse syndrome characterized by inflammation of the common extensor tendon located on the lateral epicondyle.

Medial Epicondylitis (Golfer's Elbow / Little League Elbow)

An overuse syndrome characterized by inflammation of the common flexor tendon located on the medial epicondyle.

Pulled Elbow (Nursemaid's Elbow)

Condition seen in children under about 5 years of age when a sudden jerk on the forearm causes the radial head to slip out of the annular ligament.

Elbow Dislocation

Injury resulting from high force applied to a slightly flexed elbow, causing the ulna to slide posterior to the distal end of the humerus.

Supracondylar Fracture

A fracture located just proximal to the humeral condyles typically caused by a fall on an outstretched arm, which can damage nerves and blood vessels if displaced.

Ulnar Nerve Compression

Compression occurring where the nerve spans the posterior medial aspect of the elbow between the olecranon process and the medial epicondyle.

Radial Nerve Injury Causes

Peripheral nerve damage commonly caused by a fracture of the humerus or pressure from a cast that is applied too tightly.