The occipital lymph nodes are located on the back of the head close to the margin of the trapezius and resting on the insertion of the semispinalis capitis.
Their afferent vessels drain the occipital region of the scalp, while their efferents pass to the superior deep cervical glands.
Insulin-like growth factor 1 (IGF-1) , also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults. IGF-1 is a protein that in humans is encoded by the IGF1 gene. IGF-1 consists of 70 amino acids in a single chain with three intramolecular disulfide bridges. IGF-1 has a molecular weight of 7,649 Daltons. In dogs, an ancient mutation in IGF1 is the primary cause of the toy phenotype. IGF-1 is produced primarily by the liver. Production is stimulated by growth hormone (GH). Most of IGF-1 is bound to one of 6 binding proteins (IGF-BP). IGFBP-1 is regulated by insulin. IGF-1 is produced throughout life; the highest rates of IGF-1 production occur during the pubertal growth spurt. The lowest levels occur in infancy and old age. A synthetic analog of IGF-1, mecasermin, is used in children for the treatment of growth failure.