FOPC EXAM ONE

What are the three types of ultrasound probes and what are they used for?

What are the three types of ultrasound probes and what are they used for?

1. Phased Array

   1. Lowest frequency probe

   2. high resolution but poor penetration

2. Linear Array

3. Curvilinear Array

   1. Curvilinear transducers are used for evaluating deeper structures such as hip, piriformis muscle, and sciatic nerve.

   2. Best probe as it has a pretty even resolution to penetration ratio

What is ultrasound? How does it work?

Ultrasound, also known as ultrasonography, is a medical imaging technique that uses high-frequency sound waves to create images of the inside of the body. It's commonly used for visualizing internal structures, monitoring pregnancies, and diagnosing various medical conditions. Here's how ultrasound works:

1. Generating Sound Waves: An ultrasound machine consists of a transducer, which is a handheld device that emits and receives sound waves. The transducer contains piezoelectric crystals that can generate and detect sound waves. When an electrical current is applied to these crystals, they vibrate at a high frequency, creating sound waves in the ultrasound range (typically 2 to 18 megahertz).

2. Sending Sound Waves: The transducer is placed on the skin over the area of interest. It emits a focused beam of sound waves into the body. These sound waves are at a frequency that's too high for humans to hear, hence the name "ultrasound."

3. Sound Wave Interaction: The emitted sound waves travel through the body and encounter different tissues and structures. When the sound waves encounter a boundary between two different types of tissues (e.g., between fluid and soft tissue, or between soft tissue and bone), some of the waves are reflected back to the transducer while others continue deeper into the body.

4. Echo Reception: The transducer acts as both a sender and a receiver. When the reflected sound waves return to the transducer, the piezoelectric crystals in the transducer convert these echoes into electrical signals.

5. Signal Processing: The electrical signals containing information about the intensity and timing of the echoes are sent to a computer. The computer processes these signals and constructs a visual representation of the internal structures.

6. Image Formation: The computer uses the time it takes for the sound waves to travel to and from different structures to determine their distances and positions. It then generates a grayscale image that represents the density and composition of the tissues. Brighter areas in the image typically represent dense or reflective tissues, while darker areas represent less dense or absorptive tissues.

7. Real-Time Imaging: Modern ultrasound machines can generate real-time images by continuously emitting sound waves and updating the images as the transducer moves across the body. This is particularly useful for visualizing moving structures, such as a beating heart or a developing fetus during pregnancy.

8. Doppler Ultrasound: In addition to basic imaging, ultrasound can also be used to assess blood flow by utilizing the Doppler effect. This involves measuring the frequency shift of the sound waves reflected off moving blood cells. Doppler ultrasound is commonly used to evaluate blood flow in vessels and the heart.

Ultrasound is considered safe, non-invasive, and does not involve ionizing radiation like X-rays or CT scans. However, its effectiveness can be limited in certain cases, such as when imaging structures behind bone or air-filled organs.

Compare and contrast high and low frequency with ultrasound.

Ultrasound waves have frequencies above the range of human hearing, typically in the range of 2 to 18 megahertz (MHz). Higher-frequency waves provide better resolution but have reduced penetration capabilities. Lower-frequency waves penetrate deeper but may sacrifice resolution.

Depth & Gain in ultrasound

Depth in ultrasound refers to the distance from the transducer (the device that emits and receives ultrasound waves) to the point within the body where the ultrasound waves are being directed.

Gain in ultrasound refers to the amplification of the received echoes from tissues. It affects the brightness or intensity of the displayed echoes on the ultrasound image.

Anechoic

• Definition: Anechoic refers to an area or structure within the body that appears completely black or echo-free on an ultrasound image. Anechoic structures do not reflect any of the ultrasound waves and appear as voids.

• Example: Fluid-filled structures, such as cysts or blood vessels filled with non-clotted blood, often appear anechoic on ultrasound images.

Hypoechoic

• Definition: Hypoechoic describes a tissue or structure that reflects fewer ultrasound waves than the surrounding tissues. Hypoechoic areas appear darker than the surrounding tissues but are not completely echo-free.

• Example: Tumors or organs with a decreased density of cells, like a thyroid nodule with less dense tissue compared to normal thyroid tissue, may appear hypoechoic.

Hyperechoic

• Definition: Hyperechoic refers to a tissue or structure that reflects more ultrasound waves than the surrounding tissues. Hyperechoic areas appear brighter than the surrounding tissues.

• Example: Bone, calcifications, and other dense structures typically appear hyperechoic on ultrasound images due to their high ability to reflect ultrasound waves.

Isoechoic

• Definition: Isoechoic indicates that a tissue or structure has similar echogenicity to the surrounding tissues. In other words, it has the same level of reflectivity as the neighboring structures.

• Example: A tumor or lesion that has a similar appearance in terms of echogenicity to the surrounding normal tissue may be described as isoechoic.

Acoustic Shadow

• Definition: An acoustic shadow is an area on an ultrasound image that appears dark or black due to a reduction in the intensity of ultrasound waves reaching that particular region. This reduction in intensity occurs when the ultrasound waves encounter a highly reflective or attenuating structure that absorbs or scatters a significant portion of the waves.

• Cause: Acoustic shadows commonly occur when ultrasound waves encounter structures that strongly reflect or absorb the waves, preventing them from passing through to deeper tissues. These structures block the transmission of ultrasound waves, leading to a shadow that appears behind them on the image.

• Example: An example of an acoustic shadow is the shadow cast by a gallstone or kidney stone. These calcified structures strongly reflect ultrasound waves, causing a shadow behind them where the waves are unable to penetrate.

Acoustic enhancement

• Definition: Acoustic enhancement is an increased brightness or intensity of echoes seen on an ultrasound image that lies beneath or beyond a low-attenuating structure. In other words, the area beyond a less attenuating structure appears brighter than expected due to increased transmission of ultrasound waves.

• Cause: Acoustic enhancement occurs when an area of the body is filled with a substance that allows more ultrasound waves to pass through than the surrounding tissues. This can happen with fluids, such as cysts, which transmit ultrasound waves more effectively than soft tissues. As a result, the echoes from structures beyond the fluid-filled area appear brighter.

• Example: When imaging a cyst, the structures behind the cyst may appear brighter than expected due to the enhanced transmission of ultrasound waves through the fluid-filled cyst.

Reverberation

Reverberation is an ultrasound artifact that occurs when sound waves are reflected back and forth between two strong reflectors in the ultrasound beam's path. This results in the creation of multiple false echoes on the ultrasound image. Reverberation artifacts are characterized by closely spaced, parallel lines that appear at regular intervals, often resembling a ladder-like pattern.

Ring Down Artifact

The primary cause of a ring-down artifact is the presence of gas bubbles or air trapped within tissues or body cavities.

Edge Shadow Artifact

The "edge shadow artifact" is a type of ultrasound artifact that occurs when the ultrasound beam encounters a strong interface between two tissues with different acoustic properties. This artifact creates a shadow that appears as a dark area extending behind the interface on the ultrasound image. The edge shadow artifact can obscure structures located beyond the interface and may affect the interpretation of the image.

The artifact occurs when the ultrasound beam encounters a sharp boundary between two tissues with significantly different acoustic impedances. One side of the boundary reflects most of the ultrasound waves, while the other side allows the waves to pass through.

Mirror Artifact

\n The "mirror artifact" is a type of ultrasound artifact that occurs when an ultrasound beam encounters a strong reflector at a perpendicular angle. This artifact creates a mirrored or duplicated image on the ultrasound display, appearing as if the same structure is repeated on the opposite side of the actual structure. The mirror artifact can lead to confusion and misinterpretation of the image.

Here's how the mirror artifact occurs:

1. Strong Reflector: The mirror artifact occurs when the ultrasound beam encounters a strong reflector, often a smooth, flat surface or a large acoustic impedance mismatch.

What are some contraindications for MRI and CT?

MRI: Pacemakers, heavy metal

CT: Heavy metal, allergic to contrast

Pregnant woman and children are always sus.

What are the five main imaging modalities and what are they primary used to image?

1. XR/CT: Bone

2. MRI: Bone and soft tissue

3. NM: Bone

4. US: Soft tissue

What are some key points when describing fractures?

1. Location

   1. Specific location on bone

   2. Displaced or nondisplaced

      1. In a alignment?

   3. Extent—Complete or incomplete

   4. Simple or comminuted

   5. Intra-articular or extra-articular

   6. Open or closed

   7. Displacement

   8. Impaction or Distraction

   9. Avulsion

What are the eight types of fractures? Describe them.

Open Fracture Classification (Gustilo and Anderson)

• Grade 1: clean wound < 1 cm in length, simple fracture

• Grade 2: open wound 1–10 cm, no flaps or extensive tissue damage

• Grade 3: open segmental fracture with extensive soft tissue  injuries, also includes wounds more > 8 hours old

  • Grade 3a: adequate soft tissue  covering of the fracture despite extensive soft tissue  damage

  • Grade 3b: inadequate soft tissue  covering; periosteal stripping

  • Grade 3c: open fracture with a vascular injury that requires surgery for viability of the limb

What are two secondary signs of fracture?

Joint effusion and Periosteal reaction of callus formation

Colles Fracture. Fracture of both the distal radius and ulna. This has an ulnar styloid avulsion fracture for the ulnar fracture on these images. FOOSH with extended hand.

Smith’s Fracture. FOOSH with flexed hand. In contrast to a Colles' fracture, a Smith's fracture involves the distal radius bone breaking and the fractured fragment being displaced volarly (toward the palm of the hand). This leads to a deformity where the wrist and hand appear angulated and bent toward the palm side.

Anatomical Snuff Box Fracture. A "snuff box fracture" refers to a specific type of wrist fracture that involves the scaphoid bone and often occurs as a result of a fall on an outstretched hand.

A Hill-Sachs lesion, also known as a Hill-Sachs deformity, is a specific type of injury to the humerus bone (upper arm bone) that occurs in conjunction with certain shoulder dislocations. This injury is commonly associated with anterior shoulder dislocations, where the humeral head dislocates from the glenoid cavity of the scapula (shoulder blade). The Hill-Sachs lesion results from the impaction of the humeral head against the glenoid rim during the dislocation event.

A Bankart lesion is a specific type of shoulder injury that involves damage to the labrum of the glenoid cavity (the socket of the shoulder joint). This injury often occurs in conjunction with anterior shoulder dislocations or subluxations, where the humeral head (upper arm bone) partially or completely moves out of the glenoid cavity. The Bankart lesion is an important consideration in cases of recurrent shoulder instability.

Left humerus, distal, simple, displaced, darker area (lytic lesion)

Distal, left femur, osteoblastic lesion

Odontoid Fracture

Hangman’s fracture

A "hangman's fracture" is a specific type of cervical spine fracture that involves the second cervical vertebra, known as the axis (C2). This fracture is typically associated with traumatic injuries, such as high-impact accidents or falls, and is characterized by a break in a specific part of the C2 vertebra called the "pars interarticularis." Hangman's fractures can lead to instability of the cervical spine and potentially severe neurological complications.

Jefferson’s fx

Burst fracture of the atlas. Originally described as a four part fracture, but may only be a two or three part fracture.

Bennett Fracture

A Bennett fracture is a specific type of fracture that involves the base of the first metacarpal bone, which is the bone that connects the thumb to the wrist. This type of fracture often occurs as a result of a forceful impact to the thumb, such as during a fall or other traumatic event. Bennett fractures can result in pain, swelling, and instability of the thumb joint.

Rolando Fx

A Rolando fracture is a specific type of comminuted intra-articular fracture that involves the base of the first metacarpal bone, which connects the thumb to the wrist. Similar to a Bennett fracture, a Rolando fracture typically occurs as a result of a forceful impact to the thumb and is often seen in scenarios such as falls or direct trauma. However, a Rolando fracture is characterized by a more complex and three-part fracture pattern.

Salter-Harris Fracture Classification

Destroying the growth plate

S-slipped/separated

A-Away from joint

L-Lower (towards joint)

T-Through

R-Rammed

S-Slipped

M-Metaphysial

A-Articular

C-Complete

K-Krushed!

Type IV Salter-Harris fractice 2nd digit on the right hand, PIP

Monteggia: Ulnar fracture with proximal radial dislocation

Galeazzi:

Fracture of the radius with distal ulnar dislocation

Chance Fracture: A Chance fracture, also known as a seatbelt fracture, is a specific type of vertebral fracture that typically occurs in the thoracolumbar spine (the transition area between the thoracic and lumbar regions of the spine). This type of fracture is often associated with high-impact accidents, such as car accidents, and is characterized by a horizontal break extending across the vertebral body. Chance fractures are often caused by a combination of flexion and compression forces applied to the spine.

Disc Herniation

METS

Hip dislocation, most common is posterior

Types of hip fractures

Right subcapital Hip fx

METs, decreased lucency in left iliac crest

Paget’s Disease

AVN of left femur

Lipohemarthrosis is a medical term used to describe a specific type of joint effusion (accumulation of fluid) that contains a combination of blood and fat within a joint space. It often occurs as a result of significant trauma or injury, such as fractures or dislocations involving bones near the joint. Lipohemarthrosis is commonly seen in the knee joint and can provide valuable diagnostic information to healthcare professionals.

Arthritis

Tibia Plateau Fracture

Medial and lateral malleolus and intra-articular fracture of the tibial plafond

Tri-malleolar fracture

Jone’s Fracture

A Jones fracture is a specific type of fracture that occurs in the fifth metatarsal bone of the foot, which is the bone that connects to the pinky toe. This fracture is located at the base of the fifth metatarsal, and it is characterized by its unique location and potential for healing challenges. Jones fractures are commonly seen in athletes and individuals who engage in activities involving repetitive stress or twisting motions of the foot.

Navicular AVN, Köhler Disease

Bone Tumor

What are the four key features of a MSK complaint?

1. Articular or Extra-articular

2. Acute or chronic

3. Inflammatory or Non-inflammatory

4. Localized or Diffuse

Articular Structures vs Extra Articular structures

In summary, articular structures are the components within the joint itself, including the bone surfaces and articular cartilage, while extra-articular structures are the supporting elements located outside the joint capsule, such as ligaments, tendons, muscles, and bursae. Both types of structures are crucial for joint stability, movement, and overall function.

Intra-articular vs extra-articular

1. INTRA-ARTICULAR

   1. Definition: Intra-articular refers to structures or conditions that are located within the joint space itself.

   2. Components: Intra-articular structures include the articular cartilage, synovial membrane, synovial fluid, and any structures that are housed within the joint capsule, such as ligaments or menisci.

   3. Function: Intra-articular structures are directly involved in joint movement, lubrication, and protection. Articular cartilage provides a smooth surface for bone articulation, while the synovial membrane produces synovial fluid that nourishes and lubricates the joint.

   4. Location: Intra-articular structures are found within the joint cavity, which is the space enclosed by the joint capsule and containing the synovial fluid.

   5. Examples: Ligaments inside the joint capsule (intracapsular ligaments), joint surfaces, and any structures that move within the joint (e.g., menisci in the knee) are considered intra-articular.

   6. Significance: Injuries or conditions affecting intra-articular structures can directly impact joint function, leading to pain, instability, or limited range of motion.

2. EXTRA-ARTICULAR

   1. Definition: Extra-articular refers to structures or conditions that are located outside the joint space.

   2. Components: Extra-articular structures include ligaments, tendons, muscles, bursae, fascia, nerves, and blood vessels that are situated around the joint but do not directly reside within the joint capsule.

   3. Function: Extra-articular structures provide stability, support, and movement control to the joint. They help transmit forces generated by muscles and protect the joint from excessive stress or friction.

   4. Location: Extra-articular structures are found surrounding the joint but not within the joint cavity itself.

   5. Examples: Ligaments outside the joint capsule (extracapsular ligaments), tendons connecting muscles to bones near the joint, and bursae that reduce friction between structures are considered extra-articular.

   6. Significance: Injuries or conditions affecting extra-articular structures can also impact joint function and movement. For example, a torn ligament or inflamed bursa can cause pain and affect joint stability.

MSK Diagnosis Flow Chart

Septic Joint

Psoriasis

RA

What are the four signs of inflammation?

Pain, warmth, redness, swelling

What portion of the ROS is specific for MSK?

Joint pain, Joint swelling, Joint redness, Joint deformities, Neck pain, Back pain

What is the Nexus Criteria?

Normal alertness

No posterior midline cervical spine tenderness

No focal neurologic deficits

No evidence of intoxication

What are four tips for a successful MSK examination?

Look for symmetry of involvement

Assess surrounding tissues

Test ROM

Test Muscle Strength

When performing the examination, ALWAYS inspect ________________________, as well as the area itself

the joint above and below the area of complaint

Along with inspecting the joint what is also important to check with any MSK injury?

Distal pulses, capillary refill, ROM

What are important things to note about skin lesions?

• Color

• Size

• Shape and symmetry

• Border

• Texture/Consistency

• Configuration or arrangement

• Location/Distribution

• Symptoms: pruritus, pain, etc

Flexor Surfaces

These are areas of the body where the skin folds when a joint is bent. Examples include the inner elbows, inner wrists, and behind the knees.

Extensor Surfaces

These are areas of the body where the skin is stretched when a joint is extended. Examples include the outer elbows and the front of the knees.

Acral

This refers to the extremities of the body, including the hands, feet, fingers, and toes.

Palmar/Plantar Surfaces

"Palmar" refers to the palm side of the hand, and "plantar" refers to the sole of the foot.

Sun exposed Areas

These are parts of the body that are regularly exposed to sunlight, such as the face, neck, arms, and legs.

Symmetry (Skin Distribution)

In dermatology, symmetry refers to the balanced and equal distribution of skin conditions on both sides of the body. Asymmetrical presentations may raise concerns about skin diseases.

Hearing Bearing Areas

These are regions of the body covered by hair, such as the scalp, beard area in men, and underarm regions.

Intertriginous

This refers to areas where two skin surfaces come into contact, such as skin folds. Intertriginous areas are prone to moisture and friction and can be more susceptible to certain skin conditions like fungal infections.

Dermatomal

This term relates to the distribution of nerves in the body. Dermatomal areas are regions of skin supplied by a single spinal nerve. It's relevant when assessing neurological conditions that follow specific nerve patterns.

Macule

• L. macula, “spot”

• < 1 cm

• Completely flat

• Circumscribed alteration in skin color

• Macules may be of any color or shape

• Superficial

• Macular - having the form or structure of a macule

Macule

Patch

• Macule’s “big brother”

• Flat lesion

• Larger than 1 cm

• Superficial

• Any color

Patch

Papule

• Solid, well circumscribed, elevated lesion

• Less than 1 cm diameter

• Color may vary

• Superficial

• Papular - having the form or structure of a papule

Papule

Plaque

●Papule’s “older brother”

●Solid, well circumscribed, elevated lesion

●Typically flat-topped

●> 1 cm diameter

●Like papules, plaques are superficial

Plaque

Nodule

●L. nodulus, “small knot”

●Raised solid mass

●< 2 cm

●May be in the epidermis, dermis, or subcutaneous tissue

●Its depth helps distinguish it from a papule

tumor

●Nodule’s “older brother”

●Solid, firm lesion

●> 2 cm

●Can also be called a “mass” – pro tip: when talking to a patient, “mass” is better than tumor

tumor

Vesicle

●L. vesicula, “little bladder”

●Circumscribed elevation containing clear fluid

●< 0.5 cm

●“Blister”

●Superficial

●Vesicular - having the form or structure of a vesicle

Vesicle

Bulla

●L. bulla, “bubble”

●Vesicle’s “older brother”

●> 0.5 cm diameter

●Superficial

●Bullous - having the form or structure of a bulla

Bulla

Cyst

●Closed sac that contains liquid or semi-solid material

●Contents are not purulent

●Feels “fluctuant”

Olecranon Bursitis - used for cyst example

Pustule

●Circumscribed elevation of skin containing purulent material (i.e. fluid and leukocytes)

●< 1 cm

●Often surrounded by an erythematous base

Pustule

Abscess

●Localized collection of purulent material (“pus”)

●Vesicle’s big brother

●Located in the dermis or subcutaneous tissue

Abscess

More skin lesions

Cellulitis

●Bacterial skin infection of the dermal and subcutaneous tissue

●Presents with skin erythema, warmth, induration, and tenderness

●Group A strep or Staph aureus

Lymphangitis

•Inflammation of the lymphatic channels that occur as a result of infection at a site distal to the channel

•Streptococcus

(β-hemolytic)

Fissure

●Sharply defined, linear or wedge-shaped tear in the epidermis

●Generally deeper than wide