Anatomical Terminology
Regional Terms
A sound understanding of terms associated with the different body regions will enable you to communicate more effectively. Additionally, if you have a firm knowledge of these terms, you’ll be able to understand other anatomical terminology more quickly. For instance, knowing that the brachial region is the area of the upper arm will help you understand that the biceps brachii muscle, which contains the word stem brachii, is located within the brachial region.
Directional Terms
When referencing a location on the body in relation to other landmarks, it’s important to use directional terms. These terms ensure clear and standardized communication with others. However, it takes some practice to become comfortable with them. These terms will be used frequently throughout this text when providing instructions on how to locate and palpate a structure. Remember to always start from the anatomical position.
- Anatomical position: Standing tall, facing forward with palms also facing forward
- Anterior (ventral): The front side, or direction towards the front aspect.
- Posterior (dorsal): The back side, or direction towards the back aspect.
- Superior: Above or higher than another body part.
- Inferior: Below or lower than another body part.
- Medial: Towards the midline of the body with midline referring to an imaginary line that can be visualized in the middle of the person, from the most superior to inferior aspect
- Lateral: Away from the midline of the body.
- Proximal: Closer to the point of origin, or to the trunk of the body.
- Distal: Further away from the point of origin, or the trunk of the body.
- Superficial: Closer to the surface of the body.
- Deep: Further away from the surface of the body.
Anatomical Planes
An anatomical plane is an imaginary plane that travels through the body, dividing the body into two portions based on its orientation. Many of the pictures you see in anatomical texts show a certain view, or plane, of the structure or body part.
Anatomical planes are also used to describe the direction, or plane, in which movements occur.
- Flexion and extension occur along the sagittal plane.
- Abduction and adduction occur along the frontal plane.
- Rotation occurs along the transverse plane.
Body Positions
When discussing an area of the body, it is important to clearly communicate the exact position you are referencing. First, remember that when referencing the right or left side of the body or structure, the anatomical right or anatomical left refers to the patient’s (or person’s) right or left, not yours. Next, the starting position for a body’s orientation is anatomical position. This position involves the person standing straight and looking forward, with their palms also facing forward.
When working through the activities in this textbook, you will need to position your partner in different ways to make certain structures more accessible. The following are common body positions that will assist you.
- Supine: The person faces upward.
- Prone: The person faces downward.
- Side-lying: The person lies on their right or left side, possibly in a “hook-lying” position, where their hips and knees are bent.
- Long-sitting: The person sits upright with their legs extended in front of them.
- Short-sitting: The person sits up at the edge of a table or chair with their lower legs hanging off.
Skeletal Terminology: Bone Markings
All bones have similar projections, depressions, and tunnels on or within them. Learning the appropriate terms for these markings will be valuable when you begin to identify and palpate these skeletal landmarks. Below is a list of common markings that can be found on different bones throughout the body, categorized according to the type of marking.
- Projections
- Condyle: Rounded surface
- Crest: Ridge
- Process: Any prominence
- Spine: Sharp process
- Tuberosity: Rough surface created by a muscle pulling on the area of the bone
- Tubercle: Small rounded surface
- Depressions
- Fossa: Large depression
- Sulcus: Groove
- Fissure: Deep groove
- Openings
- Meatus: Opening into a canal
- Foramen: Hole
- Sinus: Air-filled cavity or space
Musculature Terminology
- Attachments
- Tendons vs. Aponeurosis: Skeletal muscles, which are the focus of this text, can indirectly attach to bones via two different structures: a tendon or an aponeurosis. A tendon is a cord-like structure composed of connective tissue, like what is seen at either end of the biceps brachii. An aponeurosis is also made of connective tissue; however, instead of a cord-like structure it is a flat sheet of tissue. There is an expansive example of this in the lower back called the thoracolumbar aponeurosis (also sometimes called the thoracolumbar fascia).
- Origin vs. Insertion: With muscles having two ends, or two attachment points, we use the language of origin and insertion to identify which end of the muscle we are referring to. An origin is the end of the muscle that is more fixed, typically where the muscle does not act to move a joint. Usually, this is the more proximal end of the muscle, so sometimes the term proximal attachment is used interchangeably with the term origin. The insertion is the end of the muscle where more motion occurs. Usually, this is the more distal end of the muscle, so sometimes the term distal attachment is used interchangeably with the term insertion.
Muscle Actions
- Agonist: A muscle that is an agonist is the prime mover of the joint action, meaning it produces the most force to enable the action to occur.
- Antagonist: A muscle that performs the opposite joint action of the one identified is labeled the antagonist. For example, if referring to the motion of shoulder extension, a muscle that flexes the shoulder would be an antagonist.
- Synergist: Often there are several muscles that help perform the same joint action. A muscle that aids the agonist is called a synergist.
Joint Actions
- Flexion: From anatomical position, bending a joint away from anatomical position
- Extension: Straightening a joint toward anatomical position
- Abduction: Moving away from the midline
- Adduction: Moving toward the midline
- Horizontal Abduction: Abduction of a limb within the transverse plane
- Horizontal Adduction: Adduction of a limb within the transverse plane
- Medial Rotation (internal rotation): When the long bone of the joint rotates by turning on its long axis toward the midline
- Lateral Rotation (external rotation): When the long bone of the joint rotates by turning on its long axis away from the midline
- Supination: Rotation of the forearm so that the palm of the hand turns upward
- Pronation: Rotation of the forearm so that the palm of the hand turns downward
- Dorsiflexion: Flexion of the dorsal surface of the foot
- Plantarflexion: Flexion of the plantar surface of the foot
- Inversion: Turning the plantar surface of the foot toward the midline
- Eversion: Turning the plantar surface of the foot away from the midline
- Protraction: Moving forward in the transverse plane
- Retraction: Moving backward in the transverse plane
Range of Motion
Range of motion (ROM) is defined as the extent of movement of a joint through a given motion. There are different ways to examine an individual’s capability to move a joint through a given motion. These methods can be applied to identify the ROM they have or what may be limiting the ROM. Complete ROM depends on the healthy articulation of skeletal surfaces of the joint, along with mobility of soft tissue surrounding the joint. A thorough range of motion assessment is one piece of the clinical picture of a patient.
- Range of Motion Assessment: Each movement of a joint can be assessed in three ways: actively, passively, and resistively.
- Active Range of Motion (AROM): Active range of motion is assessed by having the patient perform the action without any assistance through their entire range of motion. This assessment provides an idea of the individual’s willingness to move through the given range.
- Passive Range of Motion (PROM): Passive range of motion is assessed by having the clinician completely guide the patient through the range while the patient is totally relaxed. This assessment provides an idea of the individual’s available ROM, beyond their willingness to move, while also providing insight into the structural limitations at their end range.
- Resistive Range of Motion (RROM): Resistive range of motion is assessed by having the patient perform the action against resistance provided by the clinician. This range of motion provides insight into the strength an individual has throughout a range of motion.
- Factors affecting ROM
- Normal Ranges: With any assessment, it is first important to remember that variability exists among individuals. There are normative ranges for all joints and actions. However, a normal range for one individual may be less or greater than the normal range for another individual. To help identify if a range is normal for an individual, all measurements should be compared bilaterally to assess for symmetry. Furthermore, goniometry skills should be practiced and standard procedures should be followed to ensure accuracy.
- Abnormal Ranges: There are many possibilities as to why an individual may have excessive or limited range of motion at a given joint. When an individual presents with a limited range of motion, the origin may be related to a skeletal or soft tissue injury. For example, swelling, which can occur secondary to many types of injury, can cause limitations in movement due to the increased fluid volume within a given tissue surrounding a joint.
Why Palpate?
Palpation is a useful clinical tool for a variety of healthcare professionals. It is often utilized to assist in the differential diagnosis process during the physical examination. Palpation may also be required to orient intervention strategies, such as manual therapy and soft tissue mobilization. However, palpation is not without limitations. Numerous research studies have demonstrated findings that question the validity and reliability of palpation. As this text describes, clinical practice should not rely solely on palpation. Additional examination procedures, such as range of motion and manual muscle testing, should also be considered as part of the examination process. As with all clinical skills, efficiency and effectiveness of palpation benefits from routine practice.
Consent to Touch
Physical touch of another requires consent to touch. Consent must be obtained before placing your hands on your partner. With palpation of every body structure, particularly those adjacent to sensitive areas, the examiner should clearly explain what they plan to do and confirm permission to proceed.
The Skill of Palpating
Surface palpation skills are developed over time through practice and guided feedback. The following are tips on how to approach different structures and what to be mindful of along the way.
- Soft Hands: Proceed gently with your palpation, and if needed gradually increase the pressure of your touch. Always gauge your partner’s response to palpation by looking for visual cues such as grimacing in addition to asking for verbal feedback on how you are doing.
- One or Five Fingers? If you are having trouble locating a landmark, utilize multiple fingers simultaneously to expand your palpation area. This will increase the likelihood of locating the structure of interest. For smaller structures it may be necessary to navigate the area with only one finger.
- Use Your Anatomy Knowledge! When palpating be mindful of the spatial orientation of anatomical landmarks. These landmarks, such as a skeletal protuberance, can be used to navigate from one location to another. Using your knowledge will also help you understand the depth of structures relative to each other (e.g., the rhomboid muscles are deep to the trapezius muscle).
- Practice: Practicing with a wide variety of partners will give you a better appreciation for different body types and will help you master your skills.
- Seek Feedback: Ask for feedback from your partner and instructor on the accuracy and approach of your palpations. This is how we improve our skills!
The Importance of Anatomy
An understanding of human anatomy is a foundational cornerstone of clinical practice for healthcare professionals. To provide a clinical framework for this exploration of anatomy, a series of clinical correlations will be presented. The primary aim of clinical correlations is to demonstrate the relationship between functional anatomy and various diagnoses, examination procedures, and intervention strategies typically encountered in contemporary healthcare settings.
Variability of Anatomy
A great deal of variability exists between the surface anatomy of two individuals. As you attempt to identify body structures, it is important to consider that there may be slight differences from one partner to the next and that relevant instructions to assist in locating landmarks may not always be applicable. By appreciating these differences and understanding that there are many roads to the same destination, you will be able to navigate the same anatomical structure in different bodies.