human anatomy Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross ...

, the lesser trochanter is a conical, posteromedial, bony projection from the shaft of the

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

. It serves as the principal insertion site of the iliopsoas muscle.

Structure

The lesser trochanter is a conical posteromedial projection of the shaft of the

, projecting from the posteroinferior aspect of its junction with the femoral neck. The summit and anterior surface of the lesser trochanter are rough, whereas its posterior surface is smooth. From its apex three well-marked borders extend: * two of these are above ** a medial continuous with the lower border of the femur neck ** a lateral with the intertrochanteric crest * the inferior border is continuous with the middle division of the

linea aspera The linea aspera () is a ridge of roughened surface on the posterior surface of the shaft of the femur. It is the site of attachments of muscles and the intermuscular septum. Its margins diverge above and below. The linea aspera is a prominent ...

Attachments

The summit of the lesser trochanter gives insertion to the tendon of the psoas major muscle and the iliacus muscle; the lesser trochanter represents the principal attachment of the iliopsoas.

Anatomical relations

The intertrochanteric crest (which demarcates the junction of the femoral shaft and neck posteriorly) extends between the lesser trochanter and the greater trochanter on the posterior surface of the femur.

Clinical significance

$Lesser trochanter avulsion fracture x-ray$ The lesser trochanter can be involved in an avulsion fracture.

Other animals

Paleontology

The position of the lesser trochanter close to the head of the

is one of the defining characteristics of the

Prozostrodontia Prozostrodontia is a clade of cynodonts including mammaliaforms and their closest relatives such as Tritheledontidae and Tritylodontidae. It was erected as a node-based taxon by Liu and Olsen (2010) and defined as the least inclusive clade contai ...

, which is the

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

cynodont Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extin ...

s including

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s and their closest non- mammaliform relatives. It was erected as a node-based taxon as the least inclusive clade containing ''

Prozostrodon brasiliensis ''Prozostrodon'' is an extinct genus of probainognathian cynodonts that was closely related to mammals. The remains were found in Brazil and are dated to the Carnian age of the Late Triassic. The holotype has an estimated skull length of , ind ...

'', '' Tritylodon langaevus'', ''

Pachygenelus monus ''Pachygenelus'' is a genus of extinct cynodont. Fossils have been found from the Karoo basin in South Africa and date back to the Early Jurassic. The genus was named in 1913 on the basis of a partial lower jaw found from South Africa, with the ...

'', and ''

Mus musculus The house mouse (''Mus musculus'') is a small mammal of the rodent family Muridae, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus ''Mus (genu ...

'' (the house mouse). All living mammals have a lesser trochanter, whose size, shape, and position is distinctive to their species.

Additional images

File:Gray245.png, Right femur. Posterior surface. File:Gray339.png, Right hip-joint from the front. File:Gray343.png, Capsule of hip-joint (distended). Posterior aspect. File:Slide2DAD.JPG, Hip joint. Lateral view. Lesser trochanter File:Slide1BIBI.JPG, Muscles of thigh. Anterior views.

References

External links

* * (, ) {{Authority control Bones of the lower limb Femur