Upper and lower arm anatomy

Biceps brachii: where does it insert?

Radial tuberosity.

Biceps brachii: what are its two main actions?

Elbow flexion and forearm supination.

Brachialis: where does it originate?

Anterior distal half of the humerus.

Brachialis: where does it insert?

Coronoid process and ulnar tuberosity.

Brachialis: what is its main action?

Elbow flexion.

Triceps brachii: where does the long head originate?

Infraglenoid tubercle of the scapula.

Triceps brachii: where does the medial head originate?

Posterior surface of humerus, inferior to radial groove.

Triceps brachii: where does the lateral head originate?

Posterior surface of humerus, superior to radial groove.

Triceps brachii: where does it insert?

Olecranon of ulna and fascia of forearm.

Triceps brachii: what is its main action?

Elbow extension.

Triceps brachii long head: what additional movements does it perform?

Shoulder extension and adduction.

Anconeus: where does it originate?

Lateral epicondyle of humerus.

Anconeus: where does it insert?

Lateral surface of olecranon.

Anconeus: what are its actions?

Elbow extension and elbow joint stabilisation.

Supinator: where does it originate?

Lateral epicondyle of humerus and supinator crest of ulna.

Supinator: where does it insert?

Lateral, posterior and anterior surfaces of proximal third of radius.

Supinator: what is its action?

Forearm supination (turning the palm upwards).

Pronator teres: where does its humeral head originate?

Medial supracondylar ridge of humerus.

Pronator teres: where does its ulnar head originate?

Coronoid process of ulna.

Pronator teres: where does it insert?

Lateral surface of radius, distal to supinator.

Pronator teres: what is its action?

Forearm pronation (turning the palm downwards).

What is the main action of biceps brachii at the elbow?

Flexion.

What is the main action of triceps brachii at the elbow?

extension

Which muscle is the primary elbow flexor?

Brachialis.

Which two muscles help extend the elbow?

Triceps brachii and anconeus.

Which muscle turns the forearm palm-up?

Supinator.

Which muscle turns the forearm palm-down?

Pronator teres.

Where does the long head tendon of biceps brachii run?

Through the intertubercular fossa.

Which muscle lies deep to biceps brachii?

Brachialis.

What are the four main regions of the upper limb?

Shoulder region, arm (brachium), forearm (antebrachium), and hand.

What is the single bone of the upper arm?

Humerus.

What are the proximal landmarks of the humerus?

Head, anatomical neck, greater tubercle, and lesser tubercle.

What are the main shaft landmarks of the humerus?

Deltoid tuberosity and radial groove.

What are the distal landmarks of the humerus?

Medial and lateral epicondyles, trochlea, capitulum, and olecranon fossa.

Which forearm bone is located laterally in the anatomical position?

Radius (thumb side).

Which forearm bone is located medially in the anatomical position?

Ulna (little-finger side).

Which part of the radius articulates with the capitulum of the humerus?

Radial head.

What major muscle attaches to the radial tuberosity?

Biceps brachii.

Why is the radial tuberosity clinically and functionally important?

It provides the attachment site for the biceps brachii, which is essential for supination strength.

Which landmark of the ulna forms the bony point of the elbow?

Olecranon.

Which depression on the humerus does the olecranon articulate with?

Olecranon fossa.

What does the radial notch of the ulna articulate with?

Head of the radius.

What is the primary role of the ulna within the forearm?

Forearm stabilisation.

What are the primary functions of the interosseous membrane in the forearm?

Transmits load between the radius and ulna and provides attachment surfaces for muscles.

What type of joint is the humeroulnar joint, and what movements does it permit?

Hinge joint allowing elbow flexion and extension.

What are the functional roles of the humeroradial joint?

Elbow stability and load transfer.

What is the approximate maximum range of elbow flexion?

Approximately $150^\circ$.

What is the normal range of elbow extension?

Approximately $0^\circ$, with up to $5^\circ$ of hyperextension.

What is the functional range of elbow motion needed for daily activities?

Approximately $30^\circ$ to $130^\circ$.

Which two muscles are the primary elbow flexors?

Biceps brachii and brachialis.

Which muscle is primarily responsible for elbow extension?

Triceps brachii.

What movement defines forearm pronation?

Rotation of the forearm that turns the palm downwards.

What is the approximate range of forearm pronation?

Approximately $80^\circ$.

Which two muscles produce forearm pronation?

Pronator teres and pronator quadratus.

What movement defines forearm supination?

Rotation of the forearm that turns the palm upwards.

What is the approximate range of forearm supination?

Approximately $90^\circ$.

Which two muscles produce forearm supination?

Biceps brachii and supinator.

Which three muscles belong to the anterior compartment of the arm?

Biceps brachii, brachialis, and coracobrachialis.

Which two muscles belong to the posterior compartment of the arm?

Triceps brachii and anconeus.

What are the two heads of the biceps brachii?

Long head and short head.

What are the primary actions of coracobrachialis?

Assists shoulder flexion and adduction.

Through which bony groove does the long head tendon of biceps brachii travel?

Intertubercular groove (fossa) of the humerus.

What clinical condition frequently affects the long head tendon of biceps brachii?

Tendinitis (tendonitis).

Which anterior arm muscle lies deep to the biceps brachii?

Brachialis.

Which two muscles are responsible for elbow extension?

Triceps brachii and anconeus.

Which head of the triceps brachii originates from the infraglenoid tubercle of the scapula?

Long head.

Which head of the triceps brachii originates inferior to the radial groove on the posterior humerus?

Medial head.

Which head of the triceps brachii originates superior to the radial groove on the posterior humerus?

Lateral head.

Where does the supinator muscle insert?

Lateral, posterior, and anterior surfaces of the proximal third of the radius.

Where does the pronator teres muscle insert?

Lateral surface of the radius, distal to the supinator.

How do pronation and supination differ regarding palm orientation?

Pronation turns the palm down, whereas supination turns the palm up.

How do muscle origin and insertion differ conceptually?

The origin is the more fixed, stable proximal attachment, while the insertion is the more mobile attachment moved during contraction.

Which muscle flexes the elbow and supinates the forearm?

Biceps brachii.

Which muscle acts as the primary elbow flexor regardless of forearm pronation or supination?

Brachialis.

Which muscle extends the elbow and also produces shoulder extension and adduction?

Triceps brachii long head.

Which muscle assists in elbow extension while also stabilising the elbow joint?

Anconeus.

What are the two heads of the biceps brachii called?

Long head and short head.

What are the proximal landmarks of the humerus?

Head, anatomical neck, greater tubercle, and lesser tubercle.

What are the distal landmarks of the humerus?

Medial and lateral epicondyles, trochlea, capitulum, and olecranon fossa.

Which part of the radius articulates with the capitulum of the humerus?

Head of the radius.

What is the functional range of elbow movement needed for daily activities?

Approximately $30^\circ$ to $130^\circ$.

What is the approximate maximum range of elbow flexion?

Approximately $150^\circ$.

What is the approximate range of forearm pronation?

Approximately $80^\circ$.

What is the approximate range of forearm supination?

Approximately $90^\circ$.

What are the primary functions of the interosseous membrane in the forearm?

Transmits load between the radius and ulna and provides muscle attachments.

What type of joint is the humeroulnar joint, and what movements does it permit?

Hinge joint allowing flexion and extension.

What are the functional roles of the humeroradial joint?

Stability and load transfer.

What are the two primary actions of coracobrachialis?

Assists shoulder flexion and adduction.

What are the main consequences of force transmission in the arm?

Need for strong muscles to cope with load, load-related bone hypertrophy, and sites of injury or referred pain.

Biceps brachii: what are its two heads?

Long head and short head.

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