Dragon Anatomy and Physiology

Articulate

When two or more bones or processes form a joint, they are said to articulate with one another. [64] For example, the scapula articulates with the humerus.

Condyle

A process that helps to form a joint, is large and rounded. [62]

Crest

A process that aids in the attachment of muscle and ligaments shaped like a narrow ridge. [63]

Epicondyle

A process above a condyle that aids in the attachment of muscle and ligaments. [63]

Facet

A process that helps form a joint that has a smooth, flat surface. [62]

Fissure

Narrow opening in a bone that provides passageway for blood vessels or nerves. [63]

Fontanel

Membraned-covered areas that lie between skull bones. [63]

Foramen

Round opening in a bone that provides passageway for blood vessels or nerves. [63]

Fossa

Shallow depression in a bone that provides passageway for blood vessels or nerves. [63]

Fovea

Pitlike depression in a bone that provides passageway for blood vessels or nerves. [63]

Head

Term that indicates the enlarged portion at the end of a bone. [62]

Linea

Also called Line. A process shaped like a narrow ridge that aids in the attachment of muscle and ligaments; less prominent than a crest. [63]

Meatus

A tubelike passage in bone that might provide passageway for blood vessels or nerves. [63]

Process

A bone surface feature, also called a projection, which projects out from the bone. [62]

Ramus

A branch or extension of a bone that helps form a joint. [62]

Spinous Process

Also called Spine. A sharp or pointed process that aids in the attachment of muscle and ligaments. [63]

Sulcus

Also called Grove. A long, narrow depression in a bone that provides passageway for blood vessels or nerves. [63]

Tetrapod

In biological classification, Tetrapoda is a superclass that includes four-limbed vertebrates and descendant forms, which includes all amphibians, birds, mammals, and reptiles, including snakes and other animals that have lost some or all their limbs. [51]

Trochanter

A large, irregularly shaped process that aids in the attachment of muscle and ligaments. [63] Found only in the femur in vertebrates. [39]

Trochlea

A grooved structure similar to a pulley's wheel, usually used to form a hinged joint.

Tubercle

A small, knoblike process that aids in the attachment of muscle and ligaments. [63]

Tuberosity

A large, knoblike process that aids in the attachment of muscle and ligaments. [63]

Anterior

Positional term used to indicate the front or belly-side of a human. Paired with the term posterior; the term ventral is used in animal anatomy. [52]

Appendicular

Term used to indicate the appendages of a vertebrate, i.e. the arms and the legs. [57]

Axial

Term used to indicate the main axis, or trunk, of the body, usually including the neck and head. [57]

Contralateral

Relative positional term used to indicate that two objects are located on opposite sides in relation to an imaginary midline. [53] When no specific midline is defined, this indicates the midline of the body; meaning, the objects are on opposite sides of the body. [56] Paired with the term Ipsilateral.

Deep

Positional term that indicates within the body, closer to the internal area of the body, [53] or away from the surface of the body. [58] Paired with the term superficial.

Dermal

Relating to the dermis, which is the second major layer of the skin. [67] The dermis nourishes the epidermis and provides it with strength, [68] and usually contains glands for hair or other features above the epidermal layer.

Distal

Indicates that something is farther from the point of connection of a particular limb or area, i.e. the wrist is distal to the elbow. [58] When no specific limb or area is mentioned, it is assumed that that point of attachment is the trunk or midline of the body. [53]

Dorsal

Positional term that indicates the back area of the body; in vertebrates, this area is closet to the spine. Paired with the term ventral; the term posterior is used in human anatomy. [57]

Figure 1. The dorsal side of a lizard. Compare to Figure 2.
© Kylie 'drago' McCormick

Inferior

Term that defines a relative position that is toward the back, toward the tail, or toward the lowest part of the spine. Paired with the term superior. An alternative term is caudal. [53] For example, the wrist is inferior to the elbow.

Intermediate

Relational position term that indicates an object is between two elements. [58]

Ipsilateral

Relative positional term used to indicate that two objects are located on the same side in relation to an imaginary midline. [53] When no specific midline is defined, this indicates the midline of the body; meaning, the objects are on the same side of the body. [56] Paired with the term Contralateral.

Lateral

Positional term that indicates an area farther away from the midline of the body or toward the side of the body. [53] For example, the ears are lateral to the nose. [57]

Medial

Relative position term that indicates that an object is close to the imaginary midline of the body. [53] The midline divides the body into equal right and left sides. [57]

Posterior

Positional term used to describe the back area in human anatomy. Paired with the term anterior; the term dorsal is used in animal anatomy. [52]

Proximal

Positional term that indicates the area closer to the point of attachment of a limb to the trunk. [58] For example, because the arm, the limb in question, attaches to the trunk at the shoulder, the elbow is closer to the shoulder than the wrist. Thus, the elbow is proximal to the wrist. Alternatively, a positional term that indicates the area closer to the midline of the body. [53] For example, the sternum is proximal to the ribs.

Relative Position

Relative position indicates the location of one object in terms of another; it is particularly useful in anatomy when describing components of an area, like a joint or a limb. When describing elements of the body, positional terms establish the location and connection within the body, and using surrounding elements to describe anatomical structures can provide more specificity.

Superficial

Positional term that indicates the surface of the body [58] or toward the surface of the body. [53] For example, the skin is superficial to the muscles. [53] Paired with the term deep.

Superior

Term that defines a relative position, superior indicates something towards the head or uppermost part of the organism. Paired with the term inferior. Alternative terms include cephalic, cranial, and rostral. [52] For example, the elbow is superior to the wrist.

Thoracic

The thorax is commonly referred to as the chest; it is the area above the abdomen and below the neck, containing both dorsal and ventral sides. [69] Thoracic describes anything located in this area; for example, in humans, the thoracic cage includes the thoracic vertebrae, sternum, ribs, and costal cartilages. [65]

Ventral

Positional term used to indicate the front or belly-side of an animal. Paired with the term dorsal; the term anterior is used for human anatomy. [52]

Figure 2. The ventral side of a lizard. Compare to Figure 1.
© Kylie 'drago' McCormick

Acetabulum

Part of the pelvic girdle. The cup-like hollow where the femur fits into the hip girdle to form the hip joint. [1]

Angular

In reptiles and other early vertebrates, an angular bone lies on either side of the lower jaw. [44]

Atlas

The first vertebra in the vertebral column, modified to articulate with the skull. [42]

Axis

The second vertebra in the vertebral column, modified to support the head. [43]

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Calcaneus

The largest of the tarsal bones located in the lower rear part of the foot. Commonly referred to as the heel bone in humans. [45]

Carpal

Carpal bones are the proximal part of the vertebrate hand articulated with the radius and ulna proximally and with the metacarpals distally. [2] The human wrist has eight carpal bones; other species possess between ten and twelve carpal bones. [2]

Carpometacarpus

The fusion of a carpal and a metacarpal creates a carpometacarpus; this is common in avian species.

Caudal vertebra

The vertebrae of the tail run along the vertebral column. [3]

Coccyx

Bone created by the fused tail vertebrae; the number of fused bones varies by species. [4]

Columella or columella auris

Part of the nose in many species; it is a small and delicate rod of bone that has various positions in different species. [46]

Dentary

In vertebrates, one of the tooth-bearing membrane bones of the lower jaw. [5]

Digits

Commonly called fingers or toes in vertebrates. Part of a pentadactyl limb that contains the phalanges and may have associated claws, hooves, or nails. [6]

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Femur

In tetrapod vertebrates, the bone connected to the pelvic girdle by way of the acetabulum. [7]

Fibula

In tetrapods, the fibula is one of the two bones makes up the lower part of the hindlimb, the other bone being the tibia. [8]

Frontal Bone

Two of these membrane bones cover the forepart of the brain in vertebrates. [14]

Furcula

Formed by the fusion of the two clavicle bones; referred to colloquially as the wishbone in birds.

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Humerus

In tetrapods, the upper bone in the forelimb connected to the pectorial girdle and connected distally to the radius and ulna. [10]

Hypotarsus

A ridge or process located on the posterior side of the tarsometatarsus proximally; possibly related to the calcaneum. Found in Avian species. [70]

Ilium

In vertebrates, a bone that is paired to form part of the pelvic girdle, articulating with the sacral vertebrae. [11]

Ischium

Two of these ventral, back-projecting bones form the pelvic girdle. [12]

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Lumbar Vertebra

Bones of the lower back area of the vertebral column, lacking true ribs, located between thoracic and sacral vertebrae. [13]

Mandible

In vertebrates, the lower jaw bone. [14]

Maxilla

A term sometimes used for the entire upper jaw of a vertebrate; alternatively, one of the dermal bones of the upper jaw that carries the upper teeth. [15]

Metacarpal

In tetrapods, rod-like bones in the forefoot that articulate with carpals proximally and phalanges distally. Usually there is one metacarpal bone for each digit. [16]

Metatarsal

In tetrapods, rod-like bones in the hindfoot that articulate with tarsals proximally and phalanges distally. Usually there is one metatarsal bone for each digit. [17]

Nasal Cavity

In the tetrapod skull, a cavity that contains the olfactory organs for sense of smell. [18]

Olecranon Processes

A bone feature found in the ulna of the forelimb, located above the trochlea on the posterior surface of the ulna. It fits into the fossa of the humerus. [54]

Orbit

A depression or cavity in the skull that houses the eyeball. [19]

Palate

The roof of the mouth in most vertebrates; the exceptions being mammals and crocodiles. [20]

Palatine

In birds, a pair of large bones passing from the anterior ends of the pterygoids. [47]

Palatum

A structure that separates the nasal cavity from the oral cavity in some tetrapods.

Parietal

In the vertebrate skull, the parietal bone is under each orbit of the skull. [21]

Patella

Commonly called the kneecap. This bone sits over the front of the knee joint of a hindlimb. [22]

Pectorial Girdle

Commonly referred to as the shoulder girdle, supports the attachment of forelimbs in vertebrates. [23]

Pelvic Girdle

Commonly referred to as the hip girdle, supports the attachment of hindlimbs in vertebrates. [24]

Pelvis

Another term for the Pelvic Girdle. [24]

Pentadactyl Limb

Type of limb found in tetrapod vertebrates, commonly called forelimb. [24]

Phalanx, Phalanges

Phalanges (singular phalanx) are the bones of vertebrate digits. Each digit has between one to five phalanges articulating in a row, running end to end. [25]

Postorbital

A bony strut of the skull formed by combination of the frontal and jugal bones, surrounding the eye with a bony ring. [26]

Prefrontal

In lizards and some other reptiles, a small bone between the maxilla and orbit in the skull. [50]

Premaxilla

Dermal bone that forms the front part of the upper jaw in many vertebrates, [27] bearing teeth. In birds, this bone forms most of the upper break. [28]

Prootic, Prootic-exoccipital

A bone of the auditory capsule. In young birds, this bone alone forms the auditory capsule. [48] In lizards, the prootic articulates with the exoccipital on each side of the skull, forming part of the brain case as well as the auditory capsule. [49]

Pterygoid Process

Wing-like projections of the inferior part of the Sphenoid. [29]

Pygostyle

The structure formed from the last few caudal vertebrae fused into a single bone; it supports a bird's tail feathers and related musculature.

Quadrate

Cartilage bone of posterior end of the vertebrate upper jaw, in most cases it articulates with the lower jaw. [30]

Radius

In tetrapods, one of the two bones in the lower part of the forelimb, the other being the ulna. [31]

Rib

Vertebrae skeletal struts. True ribs connect ventrally with the sternum. [32]

Sacral Vertebra

In tetrapods, vertebrae of the lower back, articulating with the pelvic girdle. [33]

Sacrum

A group of fused sacral vertebrae, with the pelvic girdle connect to some or all of them. [33]

Scapula

Dorsal components of vertebrate; in mammals, this bone is commonly referred to as the shoulder blade. [34]

Sphenoid

A butterfly-shaped bone at the base of the skull. [29]

Spinal Column, Spine

See Vertebral Column.

Squamosal

Membrane bone of the skull that lies between the quadrate and dentary bones in mammals. [35]

Sternum

Commonly referred to as the breastbone. In tetrapods, the bone of the mid-chest to which the true ribs attach. [36]

Tarsals

The bones in the tetrapod hindfoot. Early species have ten to twelve tarsal bones are in each tarsus. Later species have fewer due to fusion or loss. The tarsal bones articulate proximally with the tibia and fibula, distally with the metatarsals. [37]

Tarsometatarsus

Structure formed from the a tarsus merged with a metatarsus; found in the hindlimb of some tetrapods.

Tarsus

In tetrapods, the region of the hindfoot that contains the tarsal bones. In humans, this is roughly the ankle area. [37]

Tibia

Commonly called the shinbone. In tetrapods, one of the two long bones below the knee in the hindlimb, the other being the fibula. [38]

Tibiotarsus

A bone in the hindlimb formed by the fusion of the tibia and one or more of the tarsal bones; found in avian species.

Ulna

In tetrapods, one of the bones in the forelimb, lateral to the radius. The ulna articulates distally with the carpus and proximally with humerus. In some species, the ulna forms the olecranon process (dubbed the "funny bone"), which protrudes over the humerus. In other species, the ulna can be fused with the radius or lost all together. [40]

Vertebra

The small bones that comprise the backbone or vertebral column. A typical vertebra has a centrum, a vertebral arch, and a vertebral foramen. [64] The centrum is the disc-shaped body of the vertebra; the vertebral arch is the bony ring behind the centrum. Pedicles and lamniae form the vertebral arch ventral and dorsal respectively. The spinal cord passes through the vertebral canal, which is a continuous passageway comprised of the successive vertebral foramen of each vertebrae. [64]

Vertebral Column

Also known as the backbone or spinal column; the number of vertebrae in the column depends on the species. Comprising the central element of a vertebrate's skeletal body, it articulates with the skull via the Atlas. [41]

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