Growth arrest lines, also known as Harris lines, are lines of increased

bone density Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although medicine#Clinical practice, clinically it is measured by ...

that represent the position of the

growth plate The epiphyseal plate, epiphysial plate, physis, or growth plate is a hyaline cartilage plate in the metaphysis at each end of a long bone. It is the part of a long bone where new bone growth takes place; that is, the whole bone is alive, with ma ...

at the time of

insult An insult is an expression, statement, or behavior that is often deliberately disrespectful, offensive, scornful, or derogatory towards an individual or a group. Insults can be intentional or unintentional, and they often aim to belittle, of ...

to the organism and formed on

long bones The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities a ...

due to

growth Growth may refer to: Biology *Auxology, the study of all aspects of human physical growth *Bacterial growth *Cell growth *Growth hormone, a peptide hormone that stimulates growth *Human development (biology) *Plant growth *Secondary growth, growt ...

arrest. They are only visible by

radiograph Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeu ...

or in cross-section. The age at which the lines were formed can be estimated from a radiograph. Harris lines are often discussed as a result of juvenile

malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is a deficiency, excess, or imbalance of energy, protein and other nutrients which adversely affects the body's tissues a ...

, disease or trauma. Other studies suggest a reconsideration of Harris lines as more of a result of normal growth and growth spurts, rather than a pure outcome of nutritional or pathologic stress. The lines are named after Henry Albert Harris (1886–1968), professor of anatomy at the

University of Cambridge The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

. Particularly, deficiencies in

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

and

vitamin Vitamins are Organic compound, organic molecules (or a set of closely related molecules called vitamer, vitamers) that are essential to an organism in small quantities for proper metabolism, metabolic function. Nutrient#Essential nutrients, ...

s, which lead to delayed longitudinal

bone growth Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the ...

, can result in the formation of Harris lines. During the process of

endochondral Endochondral ossification is one of the two essential pathways by which bone tissue is produced during fetal development and bone repair of the mammalian skeletal system, the other pathway being intramembranous ossification. Both endochondral an ...

bone growth, the cessation of osteoblastic activity results in the deposition of a thin layer of bone beneath the

cartilage Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...

cap, potentially forming Harris lines. Subsequent recovery, necessary for the restoration of

osteoblast Osteoblasts (from the Greek combining forms for " bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cells with a single nucleus that synthesize bone. However, in the process of bone formation, osteoblasts fu ...

ic activity, is also implicated in Harris line formation. When matured cartilage cells reactivate, bone growth resumes, causing a thickening of the bony stratum. Therefore, complete recovery from periods of chronic illness or

also manifests as transverse lines on radiographs. Lines tend to be thicker with prolonged and severe malnutrition. Harris line formation typically peaks in long bones around 2–3 years after birth and becomes rare until adulthood after the age of 5. Additionally, Harris lines occur more frequently in boys than in girls.

References

Further reading