Humans as Bipedal Primates Key Terms

Key vocabulary terms and definitions regarding the anatomical and biological features of humans as bipedal primates.

Habitual biped

Usually walks upright on two legs.

Knuckle-walking

A form of quadrupedal walking in which the body weight to presses down on the ground through the knuckles.

Mandible

The lower jaw or jawbone.

Nuchal crest

A bony ridge at the back of the skull. It is where the neck muscles and ligaments attached in order to supporting the head.

Obligate biped

Adapted for walking only on two legs, with no ability to walk on four.

Opposable

A thumb that can be placed opposite the fingers of the same hand.

Prehensile

Describes an animal's limb or tail that is capable of grasping.

Apes

Any of various tailless Old World primates, including the gibbons, orangutans, gorillas, chimpanzees and humans.

Arboreal

Active/living in trees.

Brachiating

Locomotion accomplished by swinging by the arms from one hold to another.

Broca's region

A region of the brain concerned with the production of speech, located in the cortex of the dominant frontal lobe.

Brow ridge

A bony ridge located above the eye sockets of all primates. In modern humans the eyebrows are located on their lower margin.

Cranium

The part of the skull that encloses the brain (also called braincase).

Foramen magnum

The large opening at the base of the skull through which the spinal cord passes.

Primate

Any of various mammals of the order Primates, consisting of the lemurs, lorises, tarsiers, New World monkeys, Old World monkeys and apes.

Prognathic

Literally "forward jaw". Describes the degree to which the maxilla and mandible (the muzzle) extend forward of the face.

Sagittal crest

A bony ridge on the top of the skull to which the jaw muscles are attached.

Sexually dimorphic

The differences in appearance between males and females of the same species.

Terrestrial

Of or related to the ground or earth, particularly describing animals that live on the ground.

Valgus angle

The angle the femur (upper leg bone) makes relative to the knee. Close to $90^{\circ}$ in non-human apes, less in bipedal humans.

Wernicke's area

A region of the brain concerned with the comprehension of language, located in the cortex of the dominant temporal lobe.

Zygomatic arch

The bony arch at the outer border of the eye socket, formed by the joining of the cheekbone and the zygomatic process of the temporal bone.