Anatomical Dictionary

Jeff Poling

Last updated October 19, 1998. Updated every Monday and Thursday, as necessary.

acetebulum n., abbrev. ac the socket on the hip into which the head of the femur fits (see figures 1 and 2)

amphicoelous adj. describes vertebrae in which the front and back of the centrum are concave. A feature of dinosaur vertebrae that were not supposed to move very much relative to one another, such as posterior dorsals

analogy n. a similar character state present in two or more species of organisms that is derived from different characters in their common ancestor. The opposable digits of Pandas and humans are analogous as the Panda's digit is formed from bones in the wrist while the human's is formed from the first digit --analogous adj.

angular bone n., abbrev. an mandible bone (see figure 3)

anterior adj. forward of; closer to or in the direction of the skull, specifically the tip of the "snout." For example, the arms are anterior to the legs --cranial syn.

antorbital fenestra n., abbrev. aof fenestration in front of the orbit (see figure 3)

appendicular skeleton n. the forelimbs, shoulders, hindlimbs and hip bones

arctometatarsalian adj. describes the condition where the third metatarsal is pinched or compressed between the second and fourth metatarsals (shown clearly, in green, in figure 5). This condition is found in tyrannosaurids, ornithomimids, troodontids, elmisaurids/caenagnathids, Avimimus, Mononykus and their close relatives

astragalocalcaneum n. bone formed by the fusion of the of the anklebones astragalus (a) and calcaneum (c). This feature was developed convergently in birds and ceratosaurs (see figure 8)

axial skeleton n. the spine, including tail, and ribs

basicranium n. the underside of the skull not including the palate; the base of the braincase and the back of the throat. This region is made up of irregularly shaped bones whose names end in "sphenoid" and which are generally fused together into a solid unit

carpal adj., abbrev. cl describes a bone of the carpus (carpals are sometimes called "wrist bones") (see figure 15)

carpometacarpus n. in some animals, the section of the forefoot formed by the fusion of the bones of the carpus and metacarpus (see figure 17)

carpus n., abbrev. CS the section of the forefoot between the metacarpus and the wrist joint (see figure 15)

caudal adj. behind; of, or closer to or in the direction of, the tail. For example, the vertebrae of the tail are called caudal vertebrae, and the legs are caudal to the arms --posterior syn.

centrum n., pl. centra, abbrev. cent the large, round area of a vertebra (see figure 9)

cervical adj. of the neck. For example, the vertebrae of the neck are called cervical vertebrae

choana n., pl. chonae the opening between the nasal cavity and the pharynx

coracoid n., abbrev. co semicircular bone attached to the front of the scapula (see figure 7)

cranial adj. forward of; of, or closer to or in the direction of, the skull. For example, the arms are cranial to the legs --anterior syn.

dentary bone n., abbrev. d bone in the mandible (see figures 3 and 4)

distal adj. describes a feature anatomically located farther away from, or in the direction away from, the central part of the body or point of attachment or origin. Usually used in the description of limb bones. For example, the ankle is distal of the knee

dorsal adj. describes a feature anatomically located on, closer to, or in the direction of the back. For example, the scapula is dorsal of the manus

fenestra n., pl. fenestrae an opening, such as a hole --fenestration n.

foramen n., pl. foramina an opening, such as a hole, generally smaller than a fenestra

frontal bone n., abbrev. fr skull bone (see figures 3 and 4)

furcula n. pl. furculae the V-shaped bone in certain theropod groups, including birds, formed by the fusion of the clavicles at the sternum. Also called the "wishbone" (see figure 12)

gastralia n. abdominal, or belly, ribs, generally not attached to the spine or thoracic ribs (see figure 13, in red)

glenoid adj. describes the pocket formed by the scapula and coracoid into which the forearm inserts (see figure 7, in yellow)

hallux n. the first, or innermost, digit of the pes (labeled I in figure 5). This is the "big toe" in humans and the backward pointing toe in birds and most theropods

homology n. a similar character state present in two or more species of organisms that is derived from a single character in their common ancestor. The opposable digits in humans and monkeys are homologies as the digits in both animals are formed from digit I --homologous adj.

humerus n., abbrev. h the upper forearm or foreleg bone (see figure 7)

hyposphene n., abbrev. hypo joint on the arch of a vertebra

ilium n., abbrev. il top hip bone to which the sacral vertebrae attach (see figures 1 and 2)

inferior temporal fenestra n., abbrev. itf lower temporal fenestra in diapsids (see figures 3 and 4)

integument n. the skin and the structures associated with it, including nails, claws, hooves, scales and feathers

ischium n., abbrev. is rear hip bone (see figures 1 and 2)

lacrimal bone n., abbrev. l skull bone (see figures 3 and 4)

lateral adj. in the direction away from, or farther from, a midline bisecting the animal. For example, the hindleg is lateral of the pelvis

mandible n. all the bones of the lower jaw, collectively

mandibular fenestra n., abbrev. mdf lower jaw fenestration (see figure 3)

manus n. the forefoot or hand

maxillary bone n., abbrev. mx one of the upper jaw bones (see figures 3 and 4)

medial adj. in the direction of, or closer to, a midline bisecting the animal. For example, the pelvis is medial of the hindleg

metacarpal n., abbrev. mc describes a bone of the metacarpus (see figure 15)

metacarpus n., abbrev. MC the section of the forefoot between the phalanges and the carpus; in humans, the long bones of the hand (see figure 15)

metatarsal adj. abbrev. mt describes a bone of the metatarsus (see figure 5 or figure 16)

metatarsus n., abbrev. MT the section of the hindfoot between the phalanges and the tarsus; in humans, the long bones of the foot (see figure 16)

naris n. in paleontology, the external opening of the nasal cavity; in other disciplines, the soft-tissue structure around the external opening of the nasal cavity (i.e. in humans, the nostril)

nasal bone n., abbrev. na skull bone (see figures 3 and 4)

neural arch n., abbrev. na the opening in a vertebra through which the spinal cord passes (see figure 9)

neural spine n., abbrev. sp the large "spike" of bone that rises above the top of a vertebra to which the muscles and tendons for raising the neck attach (see figure 9)

obturator prong adj., abbrev. obp describes the flange of bone connecting the ischium to the pubis in Predentatans. Thyreophoroids (armored dinosaurs) lacked this prong (see figure 2)

opisthocoelous adj. describes vertebrae in which the front of the centrum is convex and the rear of the centrum is concave -- so that the front of the vertebra fits into the next vertebra forward like a ball-and-socket joint

opisthopubic adj. describes a condition where the pubis bones point backward, as in maniraptors and predentatans (see figure 2)

orbit n., abbrev. o eye socket (see figures 3 and 4)

osteoderm n. any bone imbedded in the skin . Osteoderms include the scutes of crocodiles, the keeled scutes, spines, and tail-club bones of ankylosaurs, and the plates, spines, and gular ossicles of stegosaurs. Their function is usually for protection and display

parietal bone n., abbrev. par skull bone (see figure 3)

pes n., pl. pedes the hind-foot

phalanx n., pl. phalanges, abbrev. phx a bone in a digit of a foot; in humans, a bone in a finger or toe (see figures 15 and 16)

pollex n. the first, or innermost, digit of the manus (labeled I in figure 6). This is the "thumb" in humans

postcranial skeleton n. all of the skeleton except the skull

posterior adj. behind; closer to or in the direction of the rear or tail. For example, the legs are posterior to the arms --caudal syn.

postorbital bone n., abbrev. po skull bone (see figures 3 and 4)

predentary bone n., abbrev. pd mandible bone, unique to Predentatans among the Dinosauria, just forward of the dentary bone in the lower jaw (see figure 4)

prefrontal bone n., abbrev. prf skull bone (see figures 3 and 4)

premaxillary bone n., abbrev. pmx skull bone just forward of the maxillary in the upper jaw (see figures 3 and 4)

prepubic process adj., abbrev. prp describes the extension of the pubis forward from the hip socket in later Predentatans (see figure 2)

procoelous adj. describes vertebrae in which the front of the centrum is concave and the rear of the centrum is convex -- so that the rear of the vertebra fits into the next vertebra behind like a ball-and-socket joint (see figure 10)

proximal adj. describes a feature anatomically located closer to, or in the direction of, the central part of the body or point of attachment or origin. Usually used in the description of limb bones. For example, the knee is proximal of the ankle

pubis n., abbrev. pu forward hip bone, reduced to a splint in some Predentatans (see figures 1 and 2)

quadrate bone n., abbrev. q skull bone (see figures 3 and 4)

quadratojugal bone n., abbrev. qj skull bone (see figures 3 and 4)

radius n. abbrev. ra the innermost bone of the foreleg/forearm (see figure 6)

retroarticular process n. a small projection on the articular bone forming part of the jaw joint system

rostral bone n., abbrev. r upper jaw bone on ceratopians, in front of the premaxillary bone, that forms the upper part of the beak

sacrum n., the part of the backbone that attaches the pelvis to the spine, usually formed by the fusion of two or more vertebrae --sacral adj. (see figure 11)

scapula n., abbrev. sc the shoulder blade (see figure 7)

scapulocoracoid n. bone formed by the fusion of the scapula and coracoid (see figure 7)

sclerotic plate n., abbrev. scl bone on the eyeball that provides a strong attachment point for muscles. Typical of animals that rely heavily on vision (see figure 3)

sclerotic ring n. ring of sclerotic plates

splenial bone n., abbrev. spl mandible bone (see figure 3)

squamosal bone n., abbrev. sq skull bone (see figures 3 and 4)

sternal plate n. one of the two halves of the sternum, or chest. These bones are usually imbedded in cartilage and are sometimes poorly ossified. In dinosaurs, they generally do not articulate directly with the shoulder girdle (at the coracoids) but "float free" in the chest cartilage. They serve to anchor the tips of the thoracic ribs and the front of the abdominal ribcage, and they act as braces and spacers for the lower shoulder bones (coracoids). In flying birds, the sternal plates are fused solidly together into a relatively huge, keeled breastbone that serves to anchor the pectoral muscles that work the wings

superior temporal fenestra n., abbrev. stf upper temporal fenestra in diapsids (see figure 3)

surangular bone n., abbrev. sa mandible bone (see figures 3 and 4)

tarsal adj., abbrev. tl describes a bone of the tarsus (tarsals are sometimes called "ankle bones") (see figure 16)

tarsometatarsus n. in some animals, the section of the hindfoot formed by the fusion of the bones of the tarsus and metatarsus

tarsus n., abbrev. TS the section of the hindfoot between the metatarsus and the ankle joint (see figure 16)

temporal fenestra n. opening in the skull in the temple area. Many vertebrates are classified by how many temporal fenestrae they have (see figures 3 and 4)

tibiotarsus n. in birds and some dinosaurs, the hind limb bone formed by the fusion of the bottom of the tibia, or calf bone, with the astragalus, the largest ankle bone of dinosaurs and birds. In most dinosaurs, the astragalus was firmly attached to the tibia but not fused with it

ulna n. abbrev. ul the outermost bone of the foreleg/forearm (see figure 6)

uncinate process n. a strutlike bone between adjacent ribs in birds, dromaeosaurs and some other theropods (see figure 14, in red)

ungual adj. describes the last, outermost bone of the manual or pedal digit. Often forms the core of a claw (see figure 5 or 6)

ventral adj. describes a feature anatomically located on, closer to, or in the direction of the belly. For example, the manus is ventral of the scapula

vertebra n., pl. vertebrae a bone of the spine (backbone) (see figures 9 and 10)

Fig. 1: Saurischian hip	Fig 2: Predentatan hip

Fig. 3: Dromaeosaurus skull	Fig 4: Edmontosaurus skull

Fig. 5: Left Struthiomimus pes	Fig. 6: Left Deinonychus manus

Fig. 7: Left Deinonychus forearm	Fig. 8: Syntarsus lower leg and astragalocalcaneum

Fig. 9: Sauropod vertebra	Fig 10: Procoelus vertebrae

Fig. 11: Triceratops sacrum

Fig. 12: Oviraptor furcula	Fig. 13: Ornitholestes gastralia	Fig. 14: Gallus uncinate processes

Fig. 15: Right Homo manus	Fig. 16: Right Homo pes	Fig. 17: Avian carpometacarpus

Figures 1-5, 7-8, 11-13:

Weishampel, David B., Peter Dodson and Halszka Osmolska, eds. The Dinosauria. Los Angeles: University of California Press, 1990.

Figure 6:

Bakker, Robert T. The Dinosaur Heresies. New York: Kensington Publishing Corp., 1986.

Figures 9-10:

Jacobs, Louis. Quest For The African Dinosaurs. New York: Villard Books, 1993.

Figure 14:

Wellnhofer, Peter. Pterosaurs: The Illustrated Encyclopedia of Prehistoric Flying Reptiles. New York: Barnes & Noble Books, 1996.

• Holtz, Thomas R. and M. K. Brett-Surman. 1997. The Osteology of the Dinosaurs. In The Complete Dinosaur, eds. James Farlow and M. K. Brett-Surman, 78-91. Bloomington: Indiana University Press.