Radius & Ulna Quiz: Anatomy Test – Forearm Bones

The human forearm, an anatomical region crucial for precise movements, features two long bones: the radius, known for its role in pronation and supination, and the ulna, pivotal for forming the elbow joint. Accurate assessment of knowledge in this area can be achieved through tools such as a radius and ulna quiz, designed to test one’s grasp of forearm bone anatomy. Medical students often utilize resources from organizations like Visible Body to enhance their learning experience and ensure proficiency with the concepts explained by renowned anatomists like Dr. Frank Netter. These quizzes serve as a valuable method for healthcare professionals to reinforce their understanding.

Unveiling the Forearm: A Foundation for Upper Limb Function

The forearm, that critical link between the elbow and wrist, is more than just a connecting segment. It is a dynamic region enabling complex movements and force transmission in the upper limb. Central to this functionality are the radius and ulna, two bones whose intricate anatomy and coordinated action underpin our ability to grasp, rotate, and manipulate objects.

Defining the Forearm

The forearm extends from the elbow joint proximally to the wrist joint distally. Encased within its fascial compartments are numerous muscles, nerves, and blood vessels that work in concert with the skeletal framework.

Functionally, the forearm serves as a critical component of the upper limb, facilitating movements such as:

• Flexion
• Extension
• Pronation
• Supination

These movements, made possible by the interplay of the radius and ulna, allow for a wide range of manipulative tasks.

Introducing the Radius

Located on the lateral (thumb) side of the forearm, the radius is characterized by its unique ability to rotate around the ulna. This rotation is pivotal for pronation and supination, movements that allow us to turn our palm downwards or upwards, respectively.

The radius articulates with the humerus at the elbow joint and with the carpal bones at the wrist. This articulation enables the wrist to move more freely in conjunction with the forearm.

The structure of the radius is designed to allow the forearm to transfer weight from the hand to the upper arm while maintaining control and range of motion.

Introducing the Ulna

The ulna, situated on the medial (pinky finger) side of the forearm, contributes significantly to the stability of the elbow joint. Its proximal end forms the olecranon process, the bony prominence felt at the back of the elbow.

Unlike the radius, the ulna does not directly articulate with the carpal bones of the wrist. Instead, it primarily articulates with the radius at both the proximal and distal radioulnar joints.

• This arrangement allows the ulna to provide a stable axis around which the radius can rotate.*

The ulna is essential for bearing weight and facilitating movements at the elbow, creating a stable base of support for forearm function.

Why Understanding the Radius and Ulna Matters

A thorough understanding of the radius and ulna is foundational to comprehending upper limb biomechanics. Their unique shapes, articulations, and muscle attachments dictate the range and precision of forearm movements.

Moreover, knowledge of these bones is crucial in clinical settings:

• Fractures of the radius and ulna are common injuries.
• Dislocations of the elbow and wrist often involve these bones.

A solid grasp of the radius and ulna is not merely an academic exercise. It’s a gateway to understanding the intricate mechanics of the upper limb and addressing related clinical conditions.

[Unveiling the Forearm: A Foundation for Upper Limb Function
The forearm, that critical link between the elbow and wrist, is more than just a connecting segment. It is a dynamic region enabling complex movements and force transmission in the upper limb. Central to this functionality are the radius and ulna, two bones whose intricate anatomy and coordinated function are paramount to comprehending the biomechanics of the entire upper extremity. Let’s begin our exploration with an in-depth examination of the radius.]

Radius: A Deep Dive into its Anatomy

The radius, positioned laterally in the forearm, is a cornerstone of upper limb mobility. Its unique structure, featuring distinct distal and proximal characteristics, facilitates a wide range of movements, from the subtle rotations of the wrist to the powerful flexing actions of the elbow. Understanding the radius’s anatomy is crucial for anyone studying or treating conditions affecting the arm.

Distal Radius: Form and Function at the Wrist

The distal radius plays a critical role in the articulation of the wrist joint.

Its shape and bony landmarks dictate the range of motion and stability of the wrist. Let’s explore its most salient features.

The Styloid Process: A Lateral Anchor

The styloid process of the radius is a bony projection located on the lateral side of the distal radius.

It serves as an attachment site for ligaments that stabilize the wrist joint.

This process also acts as a critical point of articulation with carpal bones.

Its prominence makes it a palpable landmark, useful in clinical assessments and diagnostic imaging.

Articulating Surfaces: Engaging the Carpus

The distal radius features several articulating surfaces that directly interface with the carpal bones to form the wrist joint.

Specifically, the scaphoid and lunate fossae articulate with their respective carpal bones.

This articulation allows for a wide range of wrist movements, including flexion, extension, abduction (radial deviation), and adduction (ulnar deviation).

The smooth, concave nature of these surfaces ensures fluid movement and distributes forces effectively across the wrist.

Proximal Radius: The Elbow Connection and Muscle Attachment

The proximal radius is essential for both elbow joint function and forearm rotation.

Its unique features allow for articulation with the humerus and ulna, as well as providing an attachment site for a major muscle of the arm.

The Radial Head: Pivotal Elbow Motion

The radial head, located at the proximal end of the radius, is a disc-shaped structure that articulates with the capitulum of the humerus.

This articulation forms part of the elbow joint.

The radial head’s ability to rotate freely against the capitulum is essential for pronation and supination of the forearm.

This rotational movement occurs at the radioulnar joints.

The Radial Tuberosity: Biceps Brachii Insertion

Just distal to the radial head lies the radial tuberosity, a prominent bony prominence.

This serves as the primary attachment site for the biceps brachii tendon.

When the biceps brachii muscle contracts, it pulls on the radial tuberosity, resulting in supination of the forearm and flexion of the elbow.

The strength of this attachment is critical for powerful movements, like lifting objects.

Ulna: Exploring its Distinct Features and Roles

Following our exploration of the radius, we now turn our attention to its counterpart in the forearm: the ulna. This bone, with its unique morphology, plays a pivotal role in the stability of the forearm and the formation of the elbow joint. Let’s delve into the distinct features and roles that define the ulna, examining its distal and proximal aspects, key processes, and crucial muscle attachments.

Distal Ulna: Anatomy and Articulation

The distal end of the ulna, though smaller than its proximal counterpart, possesses vital features for forearm and wrist function.

The Ulnar Head

The ulnar head is a rounded prominence located at the distal end of the ulna. It primarily articulates with the ulnar notch of the radius at the distal radioulnar joint.

This articulation allows for the pivotal movements of pronation and supination.

While it doesn’t directly articulate with the carpal bones to a significant extent, it contributes to the overall stability of the wrist joint.

The Ulnar Styloid Process

Extending from the posteromedial aspect of the ulnar head is the ulnar styloid process.

This small, conical projection serves as an attachment point for the ulnar collateral ligament of the wrist.

It also provides stability to the ulnocarpal space. Palpation of the ulnar styloid process is a common clinical practice when assessing wrist injuries.

Proximal Ulna: A Foundation for Elbow Function

The proximal ulna is characterized by its robust structure, which is essential for the formation and function of the elbow joint.

The Olecranon: Elbow Extension and Triceps Attachment

The olecranon is a large, prominent projection that forms the most proximal part of the ulna.

This process articulates with the olecranon fossa of the humerus during elbow extension.

It also serves as the attachment point for the powerful triceps brachii muscle, the primary elbow extensor. The olecranon is critical for transmitting the force of triceps contraction to extend the elbow joint.

The Coronoid Process: Joint Stability and Muscle Attachment

Positioned inferiorly to the olecranon is the coronoid process, a triangular eminence that projects anteriorly.

It articulates with the trochlea of the humerus, contributing significantly to the stability of the elbow joint.

The brachialis muscle, a major elbow flexor, attaches to the coronoid process, further emphasizing its role in upper limb function.

Muscle Attachments on the Ulna

Several muscles attach to the ulna, contributing to various forearm and wrist movements. Understanding these attachments is vital for comprehending upper limb biomechanics.

• Flexor Carpi Ulnaris: Originates from the medial epicondyle of the humerus and the olecranon and ulna. Action: Flexes and adducts the wrist.
• Flexor Digitorum Profundus: Arises from the upper three-quarters of the ulna and the interosseous membrane. Action: Flexes the distal interphalangeal joints of the fingers.
• Pronator Quadratus: Originates from the distal quarter of the ulna. Action: Pronates the forearm.
• Supinator: Originates from the lateral epicondyle of the humerus, the radial collateral ligament, and the ulna. Action: Supinates the forearm.
• Anconeus: Originates from the lateral epicondyle of the humerus and inserts onto the olecranon and upper ulna. Action: Assists in elbow extension.

Understanding these muscle attachments provides a comprehensive overview of the ulna’s role in upper limb movement.

Interosseous Membrane and Radioulnar Joints: Connecting the Forearm

Bridging the gap between the radius and ulna, the interosseous membrane and radioulnar joints are essential for forearm stability and movement. These structures work in concert to enable force transmission between the bones and facilitate the crucial rotational movements of pronation and supination. Understanding their anatomy and function is key to appreciating the biomechanics of the forearm.

Interosseous Membrane: The Forearm’s Unsung Hero

The interosseous membrane isn’t just a simple sheet of tissue; it’s a dynamic structure with a vital role in maintaining forearm integrity. Spanning the length of the radius and ulna, it acts as a resilient bridge connecting these two bones.

Structure and Composition

This fibrous membrane is primarily composed of strong, collagenous fibers that run obliquely between the radius and ulna. This oblique orientation is crucial for its primary function.

The fibers run distomedially from the radius to the ulna. This specific arrangement enables efficient force transfer.

Force Transmission and Stability

One of the interosseous membrane’s most important functions is force transmission. When the hand or wrist experiences impact, the membrane dissipates and distributes these forces along the length of the radius and ulna.

This reduces stress on any single point, preventing localized bone overload. It’s a remarkable feat of biomechanical engineering!

Beyond force transmission, the interosseous membrane also contributes significantly to forearm stability. By tightly binding the radius and ulna, it prevents excessive separation of the bones.

This is particularly important during weight-bearing activities or when gripping objects tightly.

Clinical Significance and Exam Preparation

The interosseous membrane’s role in preventing proximal migration of the radius following radial head excision is critical. Understanding the functional significance of the interosseous membrane is critical for excelling on anatomy quizzes and practical exams.

Specifically, questions on its role in force distribution and forearm stability are frequently tested.

Radioulnar Joints: Enabling Rotation

The radius and ulna articulate at two distinct locations, forming the radioulnar joints. These joints, proximal and distal, are essential for pronation and supination of the forearm.

Proximal Radioulnar Joint

Located near the elbow, the proximal radioulnar joint involves the articulation between the radial head and the radial notch of the ulna. This is a pivot joint, allowing the radius to rotate around the ulna.

The annular ligament stabilizes this joint. This ligament wraps around the radial head, maintaining its position against the ulna.

Distal Radioulnar Joint

Situated near the wrist, the distal radioulnar joint is formed by the articulation of the ulnar head with the ulnar notch of the radius. This joint is also crucial for forearm rotation.

The articular disc is an essential element. The disc cushions and stabilizes the joint, ensuring smooth movement.

Ligamentous Support and Joint Stability

Several ligaments contribute to the stability of the radioulnar joints. The anterior and posterior radioulnar ligaments reinforce the joint capsules, preventing excessive movement.

These ligaments, combined with the interosseous membrane, maintain the structural integrity of the forearm.

Pronation and Supination: The Radioulnar Joints in Action

The radioulnar joints are key players in pronation and supination. During pronation, the radius crosses over the ulna, turning the palm posteriorly. Supination reverses this movement, bringing the palm anteriorly.

These movements require the coordinated action of multiple muscles, including the biceps brachii, supinator, pronator teres, and pronator quadratus.

Understanding the interplay between the radioulnar joints and these muscles is essential for comprehending forearm biomechanics.

Joints and Articulations: The Elbow and Wrist Connections

Bridging the distal end of the humerus to the intricate structure of the hand, the elbow and wrist joints exemplify the crucial role of articulation in upper limb functionality. Understanding their formation, ligamentous support, and range of motion is paramount to grasping the biomechanics of the arm. These joints are not merely connections; they are complex systems that facilitate a wide array of movements, enabling us to interact with the world around us.

The Elbow Joint: A Hinge of Precision

The elbow joint, a marvel of engineering, is where the humerus meets the radius and ulna. This articulation is primarily a hinge joint, allowing for flexion and extension of the forearm. The trochlea of the humerus articulates with the trochlear notch of the ulna, forming the primary articulation responsible for these movements.

The head of the radius also articulates with the capitulum of the humerus, contributing to the overall stability and function of the elbow. Understanding the precise interaction of these bony elements is fundamental to appreciating the elbow’s range of motion.

Ligamentous Support and Stability

The elbow’s stability is heavily reliant on its intricate network of ligaments. The ulnar collateral ligament (UCL), on the medial side, and the radial collateral ligament (RCL), on the lateral side, provide crucial support against valgus and varus stresses, respectively. These ligaments prevent excessive side-to-side movement, ensuring the elbow remains a stable and reliable hinge.

Another significant structure is the annular ligament, which encircles the head of the radius and secures its articulation with the ulna. This ligament is vital for maintaining the integrity of the proximal radioulnar joint, allowing for smooth pronation and supination of the forearm.

Key Anatomical Features for Study

When studying the elbow joint, several anatomical features warrant close attention. The radial notch of the ulna, the coronoid process, and the olecranon fossa are all important landmarks. Consider their specific roles in joint mechanics and ligament attachments. Visualizing these structures in relation to each other is essential for understanding how the elbow functions as a whole.

The Wrist Joint: A Complex Condyloid Articulation

Moving distally, the wrist joint connects the forearm to the hand. This joint is formed by the articulation of the distal radius with the scaphoid and lunate carpal bones. While the ulna does not directly articulate with the carpal bones (it is separated by an articular disc), it contributes to the overall stability of the wrist.

Range of Motion and Stability

The wrist is a condyloid joint, allowing for a wide range of movements, including flexion, extension, abduction (radial deviation), and adduction (ulnar deviation). This versatility is essential for hand function, enabling us to perform intricate tasks.

The stability of the wrist joint is maintained by a complex network of ligaments. The radiocarpal ligaments and the ulnocarpal ligaments are key players, providing support and guiding movement. These ligaments, along with the intrinsic ligaments connecting the carpal bones, ensure that the wrist can withstand various forces and maintain its structural integrity.

Importance of Bone Articulations

The elbow and wrist joints underscore the fundamental importance of bone articulations in the human body. These joints are not isolated entities but rather integral components of a kinetic chain that extends from the shoulder to the fingertips. A thorough understanding of their anatomy and biomechanics is crucial for healthcare professionals. It allows them to diagnose and treat injuries effectively.

The intricate interplay of bones, ligaments, and muscles at the elbow and wrist enables a remarkable range of movements. These movements are essential for performing daily activities. By studying these joints in detail, we can gain a deeper appreciation for the complexity and elegance of the human musculoskeletal system.

Function and Movement: Pronation and Supination

Bridging the distal end of the humerus to the intricate structure of the hand, the elbow and wrist joints exemplify the crucial role of articulation in upper limb functionality. Understanding their formation, ligamentous support, and range of motion is paramount to grasping the biomechanics of pronation and supination.

These movements, unique to the forearm, dictate our ability to orient the hand in space, essential for countless daily activities. Let’s delve deeper.

Understanding Pronation: Turning the Palm Down

Pronation is the rotational movement of the forearm that turns the palm from an anterior-facing (supinated) position to a posterior-facing (pronated) position.

Visualize turning a doorknob counter-clockwise with your right hand. That action exemplifies pronation.

This motion isn’t just about flipping the hand; it represents a coordinated effort of the radius rotating around the ulna.

Understanding Supination: Turning the Palm Up

Conversely, supination is the opposite movement, rotating the forearm to turn the palm anteriorly, or upwards.

Think of holding a bowl of soup. That posture reflects supination.

Supination, in essence, restores the forearm to its anatomical neutral position. This allows for a wide range of functions.

The Muscles of Pronation and Supination: A Collaborative Effort

These movements are facilitated by a complex interplay of muscles that act synergistically to achieve forearm rotation.

Primary Pronators: Pronator Teres and Pronator Quadratus

The pronator teres, originating from the medial epicondyle of the humerus and inserting onto the radius, is a powerful pronator, particularly when speed and force are required.

The pronator quadratus, located near the wrist, stabilizes the distal radioulnar joint during pronation and assists in this movement, regardless of speed or force. Its consistent action makes it indispensable.

Primary Supinators: Biceps Brachii and Supinator

While primarily known for elbow flexion, the biceps brachii also plays a crucial role in supination, especially when the elbow is flexed.

Its unique insertion point on the radial tuberosity allows it to generate significant supination torque.

The supinator muscle, as its name suggests, is dedicated to supination. It works most effectively when pronation resistance is not present.

It originates from the lateral epicondyle of the humerus and inserts onto the radius.

The interplay of these muscles and the unique structure of the forearm bones is essential for the versatility of the hand in performing delicate and powerful movements. The biomechanical efficiency of the forearm makes the wide range of human activities possible.

Clinical Considerations: Fractures and Dislocations

Bridging the distal end of the humerus to the intricate structure of the hand, the elbow and wrist joints exemplify the crucial role of articulation in upper limb functionality. Understanding their formation, ligamentous support, and range of motion is paramount to grasping the biomechanics of pronation and supination. This anatomical comprehension becomes even more vital when considering the clinical implications of injuries affecting the radius and ulna.

The forearm, with its dual-bone architecture, is unfortunately susceptible to a variety of traumatic insults.

Fractures and dislocations not only disrupt the structural integrity of the limb but also significantly impair its functionality. A thorough understanding of common injury patterns, their mechanisms, and appropriate management strategies is crucial for healthcare professionals.

Common Fractures of the Radius and Ulna

The radius and ulna, while providing essential support and movement capabilities to the forearm, are not immune to fractures.

These fractures can result from a variety of mechanisms, including direct blows, falls onto an outstretched hand, or high-energy trauma.

Fracture Sites

Identifying common fracture sites is critical for accurate diagnosis and effective treatment planning.

The distal radius is particularly vulnerable, especially in older adults with decreased bone density.

Shaft fractures of both the radius and ulna are also frequently encountered, often resulting from direct trauma.

The ulnar styloid process is another common site of injury, frequently associated with distal radius fractures.

For exam preparation, be sure to emphasize understanding the precise anatomical locations most susceptible to fractures.

Colles’ Fracture and Other Forearm Fractures

Colles’ fracture, a distal radius fracture with dorsal displacement, is perhaps the most well-known forearm fracture.

It typically occurs when an individual attempts to break a fall with an outstretched hand.

Other relevant fractures include Smith’s fracture (distal radius with volar displacement) and Galeazzi fracture (distal radius fracture with dislocation of the distal radioulnar joint).

Monteggia fracture (ulnar shaft fracture with dislocation of the radial head) is also a clinically important injury.

These fractures often require surgical intervention to restore proper alignment and stability.

Dislocations of the Elbow and Wrist Joints

Beyond fractures, dislocations of the elbow and wrist joints represent another significant category of forearm injuries.

These occur when the bones that form the joint are displaced from their normal anatomical alignment.

Elbow Joint Dislocations

Elbow dislocations are relatively common injuries, often resulting from falls or direct trauma.

The ulnohumeral joint is the most frequently dislocated joint in the upper extremity.

These injuries can be associated with fractures of the radial head or coronoid process, complicating the clinical picture. Prompt reduction of the dislocated elbow is essential to minimize pain and prevent long-term complications. Rehabilitation protocols must be closely followed to restore stability and range of motion.

Wrist Joint Injuries and Treatments

The wrist joint, with its complex articulation of the radius, ulna, and carpal bones, is also prone to dislocations and ligamentous injuries.

Scaphoid fractures are among the most common wrist injuries, and can be difficult to detect on initial radiographs.

Ligament sprains are also frequently encountered, resulting from falls or repetitive stress. Carpal tunnel syndrome is another common wrist condition, resulting from compression of the median nerve.

Treatment options range from conservative measures, such as splinting and physical therapy, to surgical intervention for severe dislocations and fractures. A thorough understanding of wrist anatomy and biomechanics is crucial for accurate diagnosis and effective management of these injuries.

Learning and Assessment Tools: Anatomy, Osteology, and Quizzes

Bridging the distal end of the humerus to the intricate structure of the hand, the elbow and wrist joints exemplify the crucial role of articulation in upper limb functionality. Understanding their formation, ligamentous support, and range of motion is paramount to grasping the biomechanics of pronation, supination, and overall arm movement. To solidify this understanding and prepare for assessments, several learning and assessment tools can be invaluable.

Delving into Anatomy

Anatomy, at its core, is the study of the structure of living organisms. More specifically, it’s the science that deals with the identification and description of the body’s components.

Understanding anatomy provides a foundational knowledge base for any healthcare professional or student in the medical field.

It is the bedrock upon which clinical practices and diagnostic reasoning are built.

Exploring Osteology

Osteology is a specialized branch of anatomy focusing specifically on the study of bones. It delves into the intricate details of bone structure, function, and development.

Given the central role of the radius and ulna in forearm mechanics, a firm grasp of osteological principles is non-negotiable.

This includes understanding bone composition, growth patterns, and the significance of various bony landmarks.

Mastering Concepts Through Interactive Quizzes

Interactive online quizzes offer a powerful and engaging method for self-assessment. They enable learners to actively test their knowledge and identify areas that require further study.

Quizzes reinforce learning by prompting active recall. They can be used to identify gaps in understanding and track progress over time.

Regular engagement with quizzes can significantly improve retention and overall comprehension. Don’t be afraid to test yourself!

Effective Quiz Strategies

To maximize the benefits of interactive quizzes, focus on the reasoning behind each answer, not just the answer itself.

Analyze why certain options are correct and others are incorrect. This will deepen your understanding of the underlying concepts.

Actively seek explanations for any questions you struggle with.

Use quizzes as a diagnostic tool to guide your studies and ensure comprehensive mastery.

Focusing Your Quiz Preparation

When preparing for quizzes on the radius and ulna, prioritize key anatomical features and functions.

Here are some high-yield topics to focus on:

• Attachments of tendons: Pay close attention to the attachment point of the biceps brachii tendon on the radial tuberosity. This attachment is critical for supination and flexion of the forearm.

• Articulating Surfaces: Deeply understand the articulating surfaces of the distal radius, specifically their role in the wrist joint and articulation with the carpal bones.

• The Function of the Interosseous Membrane: Understand how the Interosseous Membrane’s primary function facilitates force transmission and binds the radius and ulna bones together to maintain relative bone positions.

By focusing your preparation on these key areas, you can confidently tackle quizzes and demonstrate a thorough understanding of the anatomy of the radius and ulna.

Medical Terminology: Understanding Bone-Related Terms

Bridging the distal end of the humerus to the intricate structure of the hand, the elbow and wrist joints exemplify the crucial role of articulation in upper limb functionality. Understanding their formation, ligamentous support, and range of motion is paramount to grasping the biomechanics of the upper limb. Building on this foundation, let’s explore the language that describes these intricate structures, focusing on medical terminology related to bone anatomy.

Decoding the Language of Bones

Understanding medical terminology is essential for anyone studying or working in healthcare. It allows for clear and precise communication, reducing ambiguity and preventing errors. This section focuses on breaking down the components of medical terms related to bone anatomy, specifically those relevant to the radius and ulna.

Prefixes: Modifying Meaning

Prefixes are word parts added to the beginning of a root word to modify its meaning.

For example, consider the prefix “sub-”, meaning “below” or “under.” In the context of bone anatomy, "subcapital" refers to something below the head of a bone, such as the radius or ulna.

Understanding prefixes allows you to decipher the meaning of unfamiliar terms by recognizing these common building blocks.

Suffixes: Indicating Conditions and Procedures

Suffixes are word parts added to the end of a root word to indicate a condition, procedure, or relationship.

For example, the suffix “-itis” denotes inflammation. Therefore, "osteitis" refers to inflammation of the bone. Recognizing common suffixes like this can help you quickly understand the nature of a described condition.

Root Words: The Core of the Term

The root word is the core component of a medical term, providing its fundamental meaning.

For instance, the root word “osteo-” refers to bone. Therefore, osteology is the study of bones. Similarly, "radial" and "ulnar" directly relate to the radius and ulna, respectively.

By mastering these root words, you establish a solid foundation for understanding more complex medical terms.

Radius and Ulna: Terminology in Action

Let’s apply these principles to terms directly related to the radius and ulna. Knowing the key terminology associated with these two forearm bones significantly improves your anatomical vocabulary.

• Radiocarpal: Pertaining to the radius and the carpus (wrist).
• Ulnohumeral: Pertaining to the ulna and the humerus.
• Interosseous: Located between bones (referring to the interosseous membrane).

Understanding these terms enhances your ability to comprehend clinical reports, research articles, and discussions about forearm anatomy.

So, how did you do? Hopefully, you now have a better grasp of those tricky forearm bones! If you aced the radius and ulna quiz, fantastic! If not, don’t sweat it – just keep practicing and reviewing the anatomy. Good luck with your studies!