Third trochanter

Third trochanter
Human femoral bones featuring third trochanters
Human right femur. Posterior view, featuring third trochanter
Details
Identifiers
Latin	trochanter tertius
TA98	A02.5.04.008
TA2	1367
FMA	75824
Anatomical terms of bone [edit on Wikidata]

In human anatomy, the third trochanter is a bony projection occasionally present on the proximal femur near the superior border of the gluteal tuberosity. When present, it is oblong, rounded, or conical in shape and sometimes continuous with the gluteal ridge. It generally occurs bilaterally without significant side to side dimorphism. ^[1] A structure of minor importance in humans, the incidence of the third trochanter varies from 17 to 72% between ethnic groups and it is frequently reported as more common in females than in males. Structures analogous to the third trochanter are present in other mammals, including some primates. ^[2] It is called the third trochanter in reference to the greater and lesser trochanters that are always present on the femur.

Function

Its function is to provide an attachment for the ascending tendon of the

, and thereby the shape of the third trochanter. ^[1] However, no certain conclusions regarding the biomechanical role of the third trochanter can be made.^[3]

Anthropology

The third trochanter is associated with short, robust femora,

Studying fossils of

derived

contrary to what was previously thought. [5]

See also

• Fourth trochanter

Notes

1. ^ ^{a b c} Lozanoff, Sciulli & Schneider 1985
2. ^ ^{a b} Bolanowski et al. 2005
3. ^ Nikolova; et al. (2018). "Trochanter tertius incidence in a Bulgarian population" (PDF). Science & Technologies. 8: 112–115.
4. ^ In modern humans, the gluteal tuberosity is occasionally replaced by a shallow groove known as the hypotrochanteric fossa. In some cases, this fossa coexists with the third trochanter.
5. ^ Lovejoy et al. 2009

References

• Bolanowski, Wojciech; Śmiszkiewicz-Skwarska, Alicja; Polguj, Michał; Jędrzejewski, Kazimierz S (2005). "The occurrence of the third trochanter and its correlation to certain anthropometric parameters of the human femur" (PDF). Folia Morphol. 64 (3): 168–175.
• Lovejoy, C Owen; Suwa, Gen; Spurlock, Linda; Asfaw, Berhane; White, Tim D (October 2009). "The Pelvis and Femur of Ardipithecus ramidus: The Emergence of Upright Walking" (PDF). Science. 326 (5949): 71, 71e1–71e6.
  doi:10.1126/science.1175831
  .
• Lozanoff, Scott; Sciulli, Paul W; Schneider, Kim N (December 1985). "Third trochanter incidence and metric trait covariation in the human femur". J Anat. 143 (143): 149–159.
  PMID 3870721
  .