Common Pediatric Orthopedic Nomenclature
Aristides I. Cruz, Jr
Joseph G. Khoury
• Nomenclature
Proper examination of the musculoskeletal system requires a fundamental knowledge of standard anatomic nomenclature. This understanding forms the basis of the physical examination and helps with developing a differential diagnosis. It also facilitates communication with other musculoskeletal caregivers when discussing pediatric orthopedic conditions.
Anatomic Descriptors
Terms such as proximal/distal and medial/lateral are relative terminologies with the core or midline of the body forming the basis of descriptive anatomic nomenclature (Figure 1.1). These descriptive terms are important when describing the extremities/appendages. Proximal structures are closer to the core of the body while distal structures are further away. Medial structures are closer to the midline and lateral
structures are located away from the midline. Often times, the body can be additionally described in three-dimensional (3D) planes and this nomenclature is very common in radiological descriptions (Figure 1.2).
structures are located away from the midline. Often times, the body can be additionally described in three-dimensional (3D) planes and this nomenclature is very common in radiological descriptions (Figure 1.2).
 FIGURE 1.1 Common terms used to describe anatomic relationships. |
 FIGURE 1.2 The representation of the human body demonstrates the three common planes often used to describe three-dimensional imaging. |
Joint or limb angulation can also be described in standard anatomic terms. Varus and valgus are terms that can be used to describe coronal plane limb alignment at the hindfoot and ankle, knee (Figure 1.3) and elbow. Typically, these terms are used to describe joint position in the coronal/frontal plane, varus is when the distal limb segment is pointed toward the midline and valgus is when it is pointed away from the midline. Normally, the hindfoot and ankle, knee and elbow are in some degree of valgus. Radiographically, these terms can also be used to describe deviations from normal alignment. For instance, the normal neck shaft angle of the proximal femur is about 135°. A hip can be said to be in relative valgus with a neck shaft angle greater than 145° and in relative varus with a neck shaft angle less than 130°.
Because the spine is itself a midline structure, it is divided into its anatomic segments when describing location—cervical, thoracic, lumbar, and sacral. Scoliosis is an abnormal curvature in the coronal/frontal
plane of greater than 10°. In the sagittal plane, the thoracic spine normally has a roundness of 20° to 40°, which is called kyphosis. In the lumbar spine, there is normally concavity of 30° to 50° and this is termed lordosis. In cases where the normal values are exceeded, the spine may be considered to be relatively kyphotic or lordotic (Figure 1.4).
plane of greater than 10°. In the sagittal plane, the thoracic spine normally has a roundness of 20° to 40°, which is called kyphosis. In the lumbar spine, there is normally concavity of 30° to 50° and this is termed lordosis. In cases where the normal values are exceeded, the spine may be considered to be relatively kyphotic or lordotic (Figure 1.4).
 FIGURE 1.3 Examples of pathologic valgus and varus at the knee. Remember that the mature knee is normally in slight valgus (5°-9°). Relatively speaking, a knee with more than this (>9° of valgus) can be considered to have abnormal valgus, while a knee with less than 5° of valgus is considered in relative varus. |
 FIGURE 1.4 The normal spine has some degree of thoracic kyphosis and lumbar lordosis. The spine is normally straight in the coronal plane and any curvature greater than 10° is considered scoliosis. |
The hands and feet also carry specific nomenclature conventions: volar and plantar refer to the palm of the hand and sole of the foot, respectively; the dorsum of the hand or foot refers to the opposite side of each.
Planes of Motion
It is useful to understand the planes of motion specific to each joint and illustrate common planes of motion for frequently examined appendages. Because different joints such as the shoulder can have multiple planes of motion, it is important to understand standard descriptors of joint motion relative to anatomic planes. Flexion/extension describes motion in the sagittal plane, abduction/adduction describes motion in the coronal plane, and internal rotation/external rotation describes motion in the transverse plane. For the forearm, rotation is termed supination/pronation and describes forearm rotation in the transverse plane. The same term can be used to describe forefoot position. One can quantitate the degree of joint movement with a measuring device such as a goniometer. Zero degrees is considered that point that the standing body is in in with hands at the sides. For example, a knee is fully extended at 0° and usually flexes to 140°; one would report knee motion of 0° to 140°. If the knee hyperextends 10° the motion is described as −10° to 140°.
Shoulder
Due to the extreme mobility of the shoulder, it can be difficult to quantify motion in the individual planes. In general, comparison to the contralateral side can illicit differences in abnormal motion.
Flexion/extension (Figure 1.5).
FIGURE 1.5 Shoulder flexion (left panel) and extension (right panel).
Abduction/adduction (Figure 1.6).
FIGURE 1.6 Shoulder abduction (coronal plane motion away from the midline; left panel) and adduction (coronal plane motion toward the midline; right panel).
Internal/external rotation (Figure 1.7).
 FIGURE 1.7 Shoulder internal rotation (left panel) and external rotation (right panel). |
Elbow
Flexion/extension (Figure 1.8). Normal motion is from full extension (0°) with flexion to around 160°.
 FIGURE 1.8 Elbow flexion (left panel) and extension (right panel). |
Forearm
Supination/pronation (Figure 1.9). Normal motion: ≥80° of pronation and supination from the neutral position.
 FIGURE 1.9 Forearm supination (“palm up,” left panel) and pronation (“palm down,” right panel). |
Wrist
Flexion/extension (Figure 1.10). Normal motion: 75° of flexion and extension from the neutral position.
FIGURE 1.10 Wrist flexion (left panel) and extension (right panel).
Ulnar deviation/radial deviation (Figure 1.11). Normal motion: 20° to 30° in each direction from the neutral position.
 FIGURE 1.11 Ulnar deviation (coronal plane motion toward ulna; left panel) and radial deviation (coronal plane motion toward radius; right panel). |
Finger
Flexion/extension (Figure 1.12). Normal finger motion at the distal interphalangeal (DIP) joint and the proximal interphalangeal (PIP) joint is from full extension (0°) with flexion to around 80°. Metacarpal phalangeal (MP) joint motion is from full extension (0°) with flexion to around 70°.
FIGURE 1.12 Finger flexion (left panel) and extension (right panel).
Adduction/abduction (Figure 1.13).
 FIGURE 1.13 Finger abduction (coronal plane motion away from the midline; left panel) and adduction (coronal plane motion toward the midline; right panel). |
Hip
Flexion/extension (Figure 1.14). Normal motion: 15° of extension to 120° of flexion.
FIGURE 1.14 Hip flexion (left panel) and extension (right panel).
Abduction/adduction (Figure 1.15). Normal motion: 30° of adduction to 50° of abduction from the neutral position.
FIGURE 1.15 Hip abduction (coronal plane motion away from the midline; left panel) and adduction (coronal plane motion toward the midline; right panel).
Internal/external rotation (Figure 1.16). Hip internal and external rotation can be measured in the prone or supine (as shown here) position. The supine position is less frightening for toddlers who will have less anxiety if they can see the examiner. Prone measures of hip internal and external rotation are more accurate as the hip is extended and the hip capsule is usually at its normal tension. Due to anatomic differences in the proximal femoral hip geometry; there is a wide range of normal hip
internal and external hip motion. Most normal children and adolescents have about 90° of total rotation. Thus if a child internally rotates 60°, one can expect about 30° of external rotation. Pathology is suspected if the measures are not symmetric from side to side.
 FIGURE 1.16 Hip internal rotation (right panel) and external rotation (left panel). |
Knee
Flexion/extension (Figure 1.17). Normal motion: full extension (0°) to 140° of flexion.
 FIGURE 1.17 Knee flexion (left panel) and extension (right panel). |
Ankle
Dorsiflexion/plantarflexion (Figure 1.18). Normal motion: 20° to 30° of dorsiflexion from neutral to 60° of plantar flexion from neutral.
 FIGURE 1.18 Ankle dorsiflexion (aka ankle extension; right panel) and plantar flexion (aka ankle flexion; left panel). |
Foot
The foot is a complicated structure and several terms can be used to describe the position of the entire foot or, in some cases, the relationship of the forefoot to the midfoot or the forefoot to the hindfoot. For instance, the
foot is considered inverted (inversion) when the entire foot is rotated with the sole turned in toward the midline and everted (eversion) when the foot is rotated with the sole out away from the midline (Figure 1.19). The adducted foot is deviated medially and the abducted foot is deviated laterally (Figure 1.20). In metatarsus adductus, the term adductus refers to forefoot adduction relative to the midfoot. When the forefoot is
rotated up relative to the hindfoot, it is considered supinated and when the forefoot is rotated down relative to the hindfoot, it is considered pronated (Figure 1.21). The normal foot has a slight arch (pes cavus). Excessive cavus usually implies some pathology. While some pathologic conditions can present with flat feet, many normal and asymptomatic children can be completely flat (pes planus) (Figure 1.22). Finally, the hindfoot and ankle is normally in slight valgus; varus positioning is abnormal and implies some pathology (Figure 1.23).
foot is considered inverted (inversion) when the entire foot is rotated with the sole turned in toward the midline and everted (eversion) when the foot is rotated with the sole out away from the midline (Figure 1.19). The adducted foot is deviated medially and the abducted foot is deviated laterally (Figure 1.20). In metatarsus adductus, the term adductus refers to forefoot adduction relative to the midfoot. When the forefoot is
rotated up relative to the hindfoot, it is considered supinated and when the forefoot is rotated down relative to the hindfoot, it is considered pronated (Figure 1.21). The normal foot has a slight arch (pes cavus). Excessive cavus usually implies some pathology. While some pathologic conditions can present with flat feet, many normal and asymptomatic children can be completely flat (pes planus) (Figure 1.22). Finally, the hindfoot and ankle is normally in slight valgus; varus positioning is abnormal and implies some pathology (Figure 1.23).
 FIGURE 1.19 Foot inversion (sole of foot rotated toward the midline; left panel) and eversion (sole of foot rotated away from the midline; right panel). |
 FIGURE 1.20 Foot adduction (deviation medially toward the midline; left panel) and abduction (deviation laterally away from the midline; right panel). |
 FIGURE 1.21 Forefoot supination (sole of foot rotated toward the midline; left panel) and pronation (sole of foot rotated way from the midline; right panel). |
 FIGURE 1.22 Normal longitudinal arch (pes cavus; left panel); “flat” longitudinal arch (pes planus; right panel). |
 FIGURE 1.23 Posterior view of left ankle showing hindfoot valgus (left panel); posterior view of right ankle showing hindfoot varus (right panel). |
• Imaging Nomenclature
Growing Bone
Physis, Epiphysis, Metaphysis, Diaphysis, and Apophysis
The anatomic nomenclature of the immature skeleton is centered around the physis or “growth plate” (Figure 1.24). Practitioners often interchange words to describe the growing cartilaginous disk; these include, the “growth plate,” the “physis” and the “epiphyseal plate”. There is no clear point on a long bone where metaphyseal bone transitions to diaphyseal bone; most practitioners speak of this area as the meta-diaphyseal junction. Growth plate or physeal fractures can be described according to the Salter-Harris classification. The classification is based on the location of the fracture’s “exit” as it traverses the physis (Figure 1.25).
Commonly Symptomatic Apophyses
Besides the physis, bone growth also occurs at various apophyses (singular: apophysis). The apophysis is the site of a tendinous attachment, and in patients who are skeletally immature, pain can occur at these sites, usually as the result of overuse and excessive tension (red arrow) of the offending tendon which attaches at the apophysis. Common sites and diagnoses of “apophysitis” include:
Tibial tubercle (Osgood-Schlatter disease) (Figure 1.26)
Calcaneus (Sever disease) (Figure 1.27)
Base fifth metatarsal (Iselin disease) (Figure 1.28)
 FIGURE 1.24 Anterior-posterior left knee radiograph. Schematic of different named portions of the distal femur and proximal tibia. |
 FIGURE 1.25 Schematic representation of end of long bone. Red dashed line represents the primary fracture line that involves the physis. By definition, this fracture line enters the physis and the Salter-Harris classification is based on where this primary fracture line exits. |
 FIGURE 1.26 Lateral radiograph of a skeletally immature knee. Schematic representation of the pathophysiology underlying the Osgood-Schlatter disease. |
 FIGURE 1.27 Lateral radiograph of a skeletally immature hindfoot. Schematic representation of the pathophysiology underlying the Sever disease. |
 FIGURE 1.28 Radiograph of base of fifth metatarsal. If the patient had pain at this apophysis he or she would be classified as having Iselin disease. |
Categories of Imaging
Plain radiography, are also referred to as “plain films”. This includes two-dimensional images obtained by shooting x-rays through a body part. Tissues with higher density (such as bone) absorb more of the radiation and show up white on the image.
“Weight-bearing” x-rays. Some body parts look very different if they are imaged when bearing weight. For example, someone with a flat foot may appear to have an arched foot on x-ray, unless it is taken when standing. Whenever possible, x-rays of the legs and spine should be ordered in the standing position.
“Orthogonal view” (Figure 1.29). This refers to obtaining two images at right angles to one another. In most situations, the two views obtained are anteroposterior (AP) which means front to back and
lateral which is taken from the side. In general, a good rule of thumb is to get orthogonal radiographs of the bone under question as well as the joint above and below the pathology. Oblique images may be ordered which are taken at a 45° angle to the other views.
FIGURE 1.29 Orthogonal anteroposterior (AP) and lateral radiographs of the forearm. This example illustrates the importance of obtaining orthogonal radiographs since the fracture angulation is appreciated on one view only.
FIGURE 1.30 CT image (left panel) and 3D printed model (right panel) of a subtalar tarsal coalition.
Cross-sectional imaging.
Cross-sectional imaging is generally displayed in three dimensions; the axial or transverse plane (straight across the body), the sagittal plane dividing right to left, and the coronal plane dividing front to back. Planes are coronal, sagittal, and axial (Figure 1.2).
Computed tomography (CT) is a cross-sectional study using radiation where the bones are whiter and show up best compared to soft tissues. Because CT uses ionizing radiation to obtain images, efforts are made to minimize its use in children. The images can be displayed in any plane of the body, but generally are displayed in the three planes described above. Today, CT data can be used to produce a virtual 3D model and can also be used to produce an actual model via 3D printers (Figure 1.30).Related posts:
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