Human Anatomy and Physiology - The Skeletal System

Frontal Bone

Frontal Bone

The bone of the cranium which forms the front or forehead of the skull and the upper parts of the eye sockets.

Parietal Bone

The bone which creates the central side and upper back of the cranium.

Temporal Bone

A pair of bones which form the lower part of the side of the cranium and enclose the middle and inner ear.

Occipital Bone

The bone of the cranium which forms the bottom, posterior side of the skull in which the vertebra of the vertebrae passes through.

Sphenoid Bone

A compound bone located in the middle of the skull. While it is visible on the lateral side, it extends inside of the skull behind the eyes and below the front of the brain. It has two broad sides, which look like wings and contains air-filled sinuses.

Ethmoid Bone

A square bone at the root of the nose, to the left and right of the nasal bone, forming part of the cranium, and having many perforations through which the olfactory nerves pass to the nose.

Maxilla

the upper jaw bone of the cranium of human beings and most vertebrates. It also forms parts of the nose and eye socket of humans.

Mandible

the lower jaw bone for mammals and fish

Palatine Bone

two bones within the skull forming parts of the eye socket, nasal cavity, and the hard palate.

Zygomatic

The bone that forms the outer part of the cheek and the outer side of the eye socket.

Nasal bone

two small, oblong bones, varying in size and form in different individuals. They are placed side by side at the middle and upper part of the face, and form "the bridge" of the nose.

Lacrimal Bone

A small bone forming part of the eye socket proximal to the external nose.

Vomer Bone

One of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with (comes in contact with) the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones.

Interior Nasal Conchae

One of the turbinates in the nose. It extends horizontally along the lateral wall of the nasal cavity and consists of a lamina of spongy bone, curled upon itself like a scroll.

Malleus

A small bone in the middle ear that transmits vibrations of the eardrum to the incus.

Incus

A small anvil-shaped bone in the middle ear, transmitting vibrations between the malleus and stapes.

Stapes

a small stirrup-shaped bone in the middle ear, transmitting vibrations from the incus to the inner ear.

Hyoid

A U-shaped bone in the neck that supports the tongue.

Cervical Vertebrae

Seven irregular bones or vertebral bodies (C1-C7) that provide support and structure for the cervical spine which connects to the head.

Axis

the second cervical vertebra (C2) of the spine. It produces a pivot joint by which the atlas, which carries the head, rotates.

Atlas

the first cervical vertebra (C1) of the spine which carries the head and permits it to rotate and pivot. It is named after the god in Greek mythology that carries the world on his shoulders.

Thoracic Vertebrae

The twelve irregular bones or vertebral bodies (T1-T12) by which the ribs attach through articular cartilage or facets.

Lumbar Vertebrae

The five irregular bones or vertebral bodies (L1-L5) which are situated between the thoracic vertebrae and the 5 fused sacral vertebrae.

Sacrum

A triangular bone in the lower back formed from fused sacral and coccygeal vertebrae. It is situated between the two hipbones of the pelvis.

Coccyx

a small, triangular bone at the base of the spinal column. Formed by 3-5 coccygeal vertebrae.

Ribs

Classified as flat bones, as they are flat and curved, these bones form a "cage" which surrounds and protects the heart, lungs, and other internal organs.

Sternum

A flat bone, or series of bones, which extends along the median line of the ventral portion of the body. It connects to the clavicles and true ribs.

Transverse plane

A plane which divides the body into superior and inferior or proximal and distal parts.

Sagittal/Median plane

A plane which divides the body into left and right (lateral) sections.

Coronal/frontal plane

A plane which divides the body into dorsal and ventral sections.

Clavicle

Two slender irregular/modified long bones which articulate with the sternum and form a part of the anterior shoulder.

Scapula

Two flat, triangular bones, each forming the posterior shoulder in humans known as the shoulder blade.

Humerus

The long bone of the upper arm or forelimb, forming joints at the shoulder and elbow. Articulates with the pectoral girdle (clavicles and scapula) at the shoulder and with the radius and ulna at the elbow.

Ulna

the thinner and longer of the two bones of the human forearm, on the side OPPOSITE to the thumb.

Radius

one of the two long bones of the forearm. It extends from the lateral side of the elbow to the thumb side of the wrist while running parallel to the ulna.

Carpal bones

the eight, short bones which makes up the human wrist and allow the hand to pivot at the forearm.

Metacarpal bones

the five, long bones which make up the palm of the human hand and are situated, and articulate, in-between the carpals and phalanges.

Phalanges

the fourteen, long bones which make up the fingers of the human hand and toes of the human foot. The thumb is made up of two phalanges while the rest of the digits are made up of three. They articulate with the metacarpals.

Pelvis

the large, funnel-shaped structure at the lower end of trunk of humans and other vertebrates by which the legs are attached.

Ischium

The curved, irregular bone at the base of each half of the pelvis. Articulates with the pubic arch and produces a hole on each side of the pelvis.

Pubis

two irregular bones, which articulate with the pubic arch, and define the two sides of the pelvis. Just above the ischium on both sides.

Ilium

the large, irregular bone which forms the upper section of each half of the pelvis.

Femur

the long bone of the upper hind limb which articulates with the tibia at the knee joint and the pubis at the pelvis.

Tibia

the larger one of the two long bones which articulates between the knee and the ankle and parallel with the fibula.

Fibula

the shorter one of the two long bones which articulates between the knee and the ankle, parallel with the tibia.

Patella

the sesamoid bone which resides underneath the patellar ligament which protects the knee joint between the fibula, tibia, and femur.

Tarsals

the short bones of the foot which make up the heel and articulate with the metatarsals, fibula, and tibia.

Metatarsal

the five, long bones which make up the middle of the foot and articulate with the tarsals and phalanges.

Calcaneus

the short bone that forms the foundation of the rear part of the foot and articulates with the talus and cuboid.

Talus

the short bone of the ankle that articulates with the tibia, calcaneum, and navicular.

Phalanges

the long bones of the foot, three for each toe except for the hallux (great toe), which articulate with the metatarsals and are distal to the body overall.

Cartilaginous/Amphiarthrosis Joints

joints that are connected entirely by cartilage which provide a descent range of motion; more than fibrous joints but less than synovial joints.

Fibrous/synarthrosis joint

joints which have no joint cavity (projections), but rather connect bones through connective tissue (cartilage). Often develop over time from childhood to adult.

Synchondrosis

an almost immovable joint between bones bound by a layer of cartilage - like the cartilage which connects the true ribs to the sternum.

Symphysis

a location where two bones are closely joined by fibrocartilage (collagen fibers), but where limited movement can still occur.

Suture

strongly united, immovable joints between adjacent cranial bones which protect the brain.

Syndesmosis

when two parallel bones are united by fibrous connective tissue.

Synovial/Diarthrosis joint

joint which provides the most range of motion. joins bones with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulating surfaces. Filled with synovial fluid.

Pivot joint

Rounded portion of a bone is enclosed within a ring formed partially by the articulation with another bone partially by a ligament. The bone rotates around this ring.

Hinge

type of joint which allows only for bending and straightening motions along a single axis. Convex end of one bone articulates with the concave end of another. Other known as a uniaxial joint.

Condyloid/Ellipsoidal Joint

an oval articular surface that is received into an elliptical cavity. This permits movement in two planes, allowing flexion, extension, adduction, abduction, and circumduction.

Saddle Joint

Both of the articulating surfaces for the bones have a saddle shape, which is concave in one direction and convex in the other.

Plane Joint

Articulating surfaces of the bones are flat or slightly curved and of approximately the same size, which allows the bones to slide against each other.

Ball and Socket

Joint with the greatest range of motion.

Rounded head of bone which fits into the concave articulation (socket) of the adjacent bone. Classified as multiaxial joints.

Flexion

Movements which occur in the sagittal (anterior and posterior) plane. Moving the head, or vertebral column, towards your anterior side.

Extension

Movements which occur in the sagittal (anterior and posterior) plane. Moving the head, or vertebral column, towards your posterior side.

Abduction

Involves the movement of limbs, hands, fingers, or toes in the coronal plane (medial-lateral).

Moving a limb, or hand, away from the lateral sides of the body.

Adduction

Involves the movement of limbs, hands, fingers, or toes in the coronal plane (medial-lateral). Moving a limb, or hand, towards the lateral sides of the body.

Circumduction

involves moving joints in a circular pattern via a combination of flexion, extension, abduction, adduction, and additional movements.

Lateral rotation

involves rotating the shoulder or hip to the lateral side.

Medial rotation

involves rotating the anterior side of the shoulder or hip towards the midline of the body.

Supination

Rotating the forearm so that the palm faces up.

Pronation

Rotating the forearm so that the palm faces down.

Dorsiflexion

when you lift the front of your foot.

Plantar Flexion

lifting the heel of the foot.

Inversion

Turning the bottom of the foot towards the midline.

Eversion

Turning the foots away from the midline.

Retraction

Moving the shoulders backward towards the posterior side.

Protraction

Moving the shoulders forwards towards the anterior side.

Elevation

Moving the shoulders up

Depression

Moving/lowering the shoulders down

Opposition

Moving the tip of your thumb so that it makes contact with the tip of another finger. This movement is possible due to the first carpometacarpal joint: the saddle joint between the trapezium carpal bone and the first metacarpal bone.