Austin Lawrence, PhD

@humanaustinology

Paleoanthropologist, anatomist. Trying to figure out the evolution of the human hip and pelvis. Assistant Professor of Anatomy at Western University of Health Sciences. I ride bikes, play drums, and do what my dog tells me. 🏳️‍🌈/Ace. he/they.

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Bluesky

¿Es tu perfil?Reclámalo y humanaustinology.dirty.social es tuyo.Reclamar perfil

Austin Lawrence, PhD@humanaustinology· 26d

Austin Lawrence, PhD@humanaustinology· Oct 13

Everything is awful, but at least there are dogs.

Black and white dog lying on floor, looking at camera while holding a chicken-shaped fluffy squeaky toy.

Austin Lawrence, PhD@humanaustinology· Mar 18

For something fun… There is a great horned owl in this picture. Can you find it?

Photo of a white adobe-style building under a night sky. There are palm trees around the building and an owl hidden somewhere in the picture.

Austin Lawrence, PhD@humanaustinology· Jan 8

There are a couple of notable exceptions to the pattern of human-like acetabular orientation in fossil hominins. Neanderthals, as represented by Kebara 2, and Australopithecus africanus, as represented by Sts 14, have more laterally oriented acetabula, more like other great apes.

Acetabular orientation of fossil hominins in our sample shown on polygonal models of pelves in approximately ventral view with the lumbosacral plane horizontal (top row), left lateral view (middle row), and superior/lumbosacral view with the orthogonal comparative plane horizontal (bottom row). Pelves shown are (A) KSD-VP-1/1 (Australopithecus afarensis, reconstruction by Ryan and Sukhdeo (2016)), (B) A.L. 288–1 (Australopithecus afarensis, reconstruction by Häusler and Schmid (1995)), (C) A.L. 288–1 (reconstruction by Lovejoy (1979), articulated model based on 3D surface scans of plaster casts of individual pelvic elements for visualization), (D) Sts 14 (Australopithecus africanus, reconstruction by Häusler and Schmid (1995)), (E) MH2 (Australopithecus sediba, reconstruction by Kibii et al. (2011), including only elements preserved in original fossil and inferred morphology of sacroiliac joint, right hemipelvis mirrored for visualization), (F) Kebara 2 (Homo neanderthalensis, reconstruction 1 from Adegboyega et al. (2020)), (G) Kebara 2 (Reconstruction 2 from Adegboyega et al. (2020)), (H) Kebara 2 (reconstruction from Rak and Arensburg (1987) based on a 3D surface scan of a cast with the right hemipelvis mirrored for visualization), (I) a modern human male, and (J) a modern chimpanzee (Pan troglodytes). The orientation of the acetabulum was measured as the 3D angle between a plane on the acetabular plane (purple) and three reference planes: the median plane (black solid lines), lumbosacral plane (teal dashed lines), and orthogonal comparative plane (orange dotted lines). Arrows show approximate acetabular orientation. All hominins included in this analysis had more ventrally oriented acetabula than our extant primate comparative sample, though all three reconstructions of Kebara 2 and the Sts 14 pelvis exhibit slightly more laterally facing acetabula than modern humans. Images not to scale.

Austin Lawrence, PhD@humanaustinology· Jan 8

Our results demonstrate that the acetabulum is indeed more ventrally oriented in humans than in other extant primates, and that the acetabulum is also more ventrally oriented in most fossil hominins.

3D acetabular orientation vectors (normal vectors to the acetabular plane) overlayed on a human pelvis and shown in views representing the median plane, lumbosacral plane, and orthogonal comparative plane. Colors of the vectors and colors and symbols for the data points represent their taxonomic group. Within each view, all vectors are the same length. The view in the orthogonal comparative plane (top left), which approximates an anterior/ventral view, and the view in the median plane (center right) show that humans and most fossil hominins have more ventrally oriented acetabula than other groups but that groups do not differ in their acetabular orientation relative to the lumbosacral plane. The view in the lumbosacral plane (bottom left) approximates a cranial view and shows that humans have more ventrally oriented acetabula than other extant anthropoids, which have predominantly laterally facing acetabula.

Austin Lawrence, PhD@humanaustinology· Jan 8

We used anatomical landmarks to define the median plane, a plane on the lumbosacral joint, and a third "orthogonal comparative" plane to establish a 3D reference system, then fit a plane to the acetabular rim.

Schematic demonstrating alignment of in silico models of ossa coxae to the median plane (A, modified from Hammond et al. (2016)), (B) establishment of the lumbosacral plane, (C) establishment of orthogonal comparative plane, and (D) establishment of acetabular plane, shown on a left os coxae of Pan in the anterolateral view. In B and C, landmarks on the superior surface of the S1 vertebral body for the establishment of the lumbosacral plane are indicated by black open circles. For a full description of methods for aligning scans to the median plane, see Hammond et al. (2016). Images not to scale.

Austin Lawrence, PhD@humanaustinology· Jan 8

In this paper, we use several different quantitative approaches to test the hypothesis that the acetabulum (pelvic component of the hip joint) is more forward facing in humans and in our extinct hominin relatives than in other living anthropoid primates.

Pelves of extant Papio (left), Pan (center), and Homo (right) in ventral (top), left lateral (middle) and superior/lumbosacral views showing acetabular orientation. Planes on the acetabular rim are shown in purple, with arrows illustrating the direction of opening of the acetabulum in each view. Acetabula of extant monkeys (Papio) and apes (Pan) open laterally, whereas acetabula of humans (Homo) open more ventrally and slightly more caudally.

Austin Lawrence, PhD@humanaustinology· Jan 8

I'm very excited to share a new paper out this week with co-authors Ashley Hammond and Carol Ward. doi.org/10.1016/j.jh...

Austin Lawrence, PhD@humanaustinology· Sep 26

I also ride bikes, play drums, drink too much coffee, and have an adorable dog named Otis, who basically runs my life.