third trochanter

A projection known as the third trochanter is larger in P. madagascariensis.

Structures analogous to the third trochanter are present in other mammals, including some primates.

It is called the third trochanter in reference to the greater and lesser trochanters that are always present on the femur.

The third trochanter is a bony projection occasionally present on the proximal femur near the superior border of the gluteal tuberosity.

A structure of minor importance in humans, the incidence of the third trochanter varies from 17-72% between ethnic groups and it is frequently reported as more common in females than in males.

The vertebra of the neck unite on nearly flat surfaces, the humerus had lost the foramen, or perforation, at the lower end, and the third trochanter to the femur may have also been wanting.

The third trochanter is associated with short, robust femora, and is frequently present and well developed in Neanderthals (that were shorter and more robust than anatomically modern humans) but generally absent in higher primates.

In primitive tetrapods, the main points of muscle attachment along the femur are the internal trochanter and third trochanter, and a ridge along the ventral surface of the femoral shaft referred to as the adductor crest.

Mechanical load from the gluteus maximus may, on the other hand, affect the morphology of the proximal femur, similar to how quadriceps determines the size and shape of the tibial tuberosity, and thereby the shape of the third trochanter.

It is termed the gluteal tuberosity, and gives attachment to part of the glutæus maximus: its upper part is often elongated into a roughened crest, on which a more or less well-marked, rounded tubercle, the third trochanter, is occasionally developed.

The most generalized type was Coryphodon, representing the family Coryphodontidae, from the lower Eocene of Europe and North America, in which there were 44 teeth and no horn-like excrescences on the long skull, while the femur had a third trochanter.

Adductor: originates from the ventral side of the pubis and ischium, inserts into the caudal side of the femur (near the third trochanter) and the medial epicondyle of the femur (including the medial ligament of the femoropatellar joint).

Studying fossils of Ardipithecus ramidus (a Chimpanzee-human last common ancestor candidate), noted that in this species - as well as in Proconsul, Nacholapithecus, and Dryopithecus (Miocene primates) - homologs to the third trochanter and the hypotrochanteric fossa are present while both traits are absent in extant apes.