Category Zoology

From the back you can clearly see the complex structure of the spinal column and paired ribs. Each wing-like shoulder blade forms part of the shoulder gridle, where the arm attaches to the axial skeleton.

Suture

Suture lines form where bones of the skull have joined (fused) together.  A tiny amount of movement is permitted at sutures, which contributes to the compliance and elasticity of the skull. These joints are synarthroses. It is normal for many of the bones of the skull to remain unfused at birth.

Parietal bones

A pair of bones makes up the sides of the skull. The parietal bones are marked internally by meningeal blood vessels and externally by the temporal muscles. They meet at the top of the head (sagittal suture) and form a roof for the cranium. 

Occipital bone

This flattish bone forms the back of the skull. The occipital is cupped like a saucer in order to house the back part of the brain. It is one of seven bones that fuse together to form the skull and is directly next to five of the cranium bones.

Atlas

The uppermost vertebra of the spine, this bone supports the head. The atlas does not look like a typical vertebra, with its ring-like structure and the absence of a body, which is actually fused to the axis. Other anatomical landmarks on the atlas include the anterior arch and tubercle, posterior arch and tubercle, vertebral notches, facets, and transverse processes.

Axis

The second bone of the vertebral column allows the head to move from side to side. The axis is somewhat analogous to the other cervical vertebrae in shape, but it differs slightly for two reasons: its spinous process isn’t as obviously bifid, and the presence of the dens. The spinous process serves as the attachment site for many muscles of the spine, particularly those close to the skull, as well as the nuchal ligament.

Cervical vertebrae

These seven bones form the upper part of the spine.  Among the vertebrae of the spinal column, the cervical vertebrae are the thinnest and most delicate bones. Yet, in spite of their size, the cervical vertebrae have the huge jobs of supporting the head, protecting the spinal cord, and providing mobility to the head and neck.

Acromion

This is the highest part of the shoulder blade. It is an important landmark of the skeletal system and a muscle attachment point essential to the function of the shoulder joint. The acromion also forms the acromioclavicular (AC) joint with the clavicle.

Clavicle

This long bone is called the collarbone. The clavicle (collarbone) extends between the manubrium of the sternum and the acromion of the scapula. It is classed as a long bone, and can be palpated along its length. In thin individuals, it is visible under the skin. 

Scapula

Also called the shoulder blade, it connects the arm to the shoulder. In humans they are triangular and lie on the upper back between the levels of the second and eighth ribs. A scapula’s posterior surface is crossed obliquely by a prominent ridge, the spine, which divides the bone into two concave areas, the supraspinous and infraspinous fossae.

Spinal column

Also called the backbone, it is made up of 24 small bones (vertebrae), which protect the nerves.  The Spinal Column is also called the vertebral column. The bones in the spine are called vertebrae (ver-ta-bray). The column starts at the base of the skull and continues to the pelvis. Alternate layers of bone (vertebrae) and cartilage (car-til-ledge, the intervertebral discs) stack vertically one on top of the other in the spinal column. The lattice-like structure of the cancellous bone (cancel-lus, the spongy interior) in a vertebra absorbs external pressure.

Rib

The 12 pairs of curved rib bones protect the heart and lungs. The ribs partially enclose and protect the chest cavity, where many vital organs (including the heart and the lungs) are located. The rib cage is collectively made up of long, curved individual bones with joint-connections to the spinal vertebrae. 

Humerus

This is the upper arm bone. It is located between the elbow joint and the shoulder. At the elbow, it connects primarily to the ulna, as the forearm’s radial bone connects to the wrist. 

Lumber vertebrae

These five bones form the lower part of the spinal column. These vertebrae carry all of the upper body’s weight while providing flexibility and movement to the trunk region. They also protect the delicate spinal cord and nerves within their vertebral canal.

Ulna

This is the inner bone of the forearm. The ulna is located on the opposite side of the forearm from the thumb. It joins with the humerus on its larger end to make the elbow joint, and joins with the carpal bones of the hand at its smaller end.

Ilium

The ilium is one of the bones that makes up the pelvis. In humans, it is divided into two sections: the body and the ala, indicated by a line on the surface of the bone. The other two bones that form the fused pelvis are the ischium and the pubis, which lie below the ilium.

Radius

This is the outer bone of the forearm. It lies laterally and parallel to ulna, the second of the forearm bones. The radius pivots around the ulna to produce movement at the proximal and distal radio-ulnar joints.

Sacrum

This is large, triangular bone that forms the base of the spine. It forms the solid base of the spinal column where it intersects with the hip bones to form the pelvis. The sacrum is a very strong bone that supports the weight of the upper body as it is spread across the pelvis and into the legs. 

Coccyx

Several tiny bones at the end of the spine fuse to form the coccyx.  It is composed of three to five coccygeal vertebrae or spinal bones. The vertebrae may be fused together to form a single bone; however, in some cases, the first vertebra is separate from the others.

Femur

The femur, or thigh bone, is the longest bone in the body. It functions in supporting the weight of the body and allowing motion of the leg. The femur articulates proximally with the acetabulum of the pelvis forming the hip joint, and distally with the tibia and patella to form the knee joint.

Femoral condyles

These rounded, knobbly ends of the femur form part of the knee joint. There are two condyles on each leg known as the medial and lateral femoral condyles. If there is a fracture (break) in part of the condyle, this is known as a fracture of the femoral condyle. Physiotherapy is very important during the rehabilitation following a femoral condyle fracture.

Tibia

The front of this bone is the shin. It forms the knee joint with the femur and the ankle joint with the fibula and tarsus. Many powerful muscles that move the foot and lower leg are anchored to the tibia. 

Fibula

The smaller bone of the lower leg, this is located alongside the tibia. It runs parallel to the tibia, or shin bone, and plays a significant role in stabilizing the ankle and supporting the muscles of the lower leg. Compared to the tibia, the fibula is about the same length, but is considerably thinner.

Heel bone

The largest bone in the foot, this is also called calcaneus. It is situated in the back of the foot, just below the talus, tibia, and fibula bones of the lower leg. Of all of the bones in the foot, the heel bone is the largest.

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The skeleton can be divided into two parts. The axial skeleton (red) forms a central core that supports the upper body and protects important organs. The appendicular skeleton (blue) consists of the arm and leg bones, and the bony gridles that connect them to the axial skeleton.

Axial skeleton

This is made of 80 bones of the skull, vertebrate column, ribs, and breastbone. The bones of the axial skeleton, along with ligaments and muscles, allow the human body to maintain its upright posture. The axial skeleton also transmits weight from the head, trunk, and upper extremities down the back to the lower extremities. In addition, the bones protect the brain and organs in the chest.

Appendicular skeleton

This consists of the 126 bones of the upper and lower limbs, and the shoulder and hip gridles. It includes the bones of the arms and legs, hands and feet, and shoulder and pelvic girdles. The bones of the appendicular skeleton make possible locomotion and other movements of the appendages. They also protect the major organs of digestion, excretion, and reproduction.

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The female skeleton is usually smaller and lighter than a male’s with a wider pelvis, which makes childbirth easier.

Cranium

This contains and protects the brain, eyes, ears, and nose. The interrelationships formed by neurons to create working memory, the plasticity demonstrated when adapting to injury, and the process of sorting through the wealth of visual and auditory stimuli contained in our world are all amazing feats unto themselves. The brain, which performs these various functions, is protected by a part of the skull called the cranium. We’ll turn our attention to the eight bones that form it: the ethmoid bone, the sphenoid bone, the frontal bone, the occipital bone, two parietal bones, and two temporal bones.

Lower jaw bone (mandible)

The only part of the skull that can move is the mandible. In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear).

Spinal column

A flexible series of bones holds the head and upper body upright. The Spinal Column is also called the vertebral column. The bones in the spine are called vertebrae (ver-ta-bray). The column starts at the base of the skull and continues to the pelvis. Alternate layers of bone (vertebrae) and cartilage (car-til-ledge, the intervertebral discs) stack vertically one on top of the other in the spinal column. The lattice-like structure of the cancellous bone (cancel-lus, the spongy interior) in a vertebra absorbs external pressure.

Clavicle

This long bone is also called the collarbone. The clavicle (collarbone) extends between the manubrium of the sternum and the acromion of the scapula. It is classed as a long bone, and can be palpated along its length. In thin individuals, it is visible under the skin. 

Scapula

Also called the shoulder blade, connects the arm to the shoulder. In humans they are triangular and lie on the upper back between the levels of the second and eighth ribs. A scapula’s posterior surface is crossed obliquely by a prominent ridge, the spine, which divides the bone into two concave areas, the supraspinous and infraspinous fossae.

Sternum

Also called the breastbone, it supports the ribs at the front of the body. The sternum (or breastbone) is a flat bone located at the anterior aspect of the thorax. It lies in the midline of the chest and has a ‘T’ shape.

As part of the bony thoracic wall, the sternum helps protect the internal thoracic viscera – such as the heart, lungs and oesophagus.

Humerus

This is the upper arm bone. It is located between the elbow joint and the shoulder. At the elbow, it connects primarily to the ulna, as the forearm’s radial bone connects to the wrist. 

Ribs

The 12 pairs of curved rib bones protect the heart and lungs. The ribs partially enclose and protect the chest cavity, where many vital organs (including the heart and the lungs) are located. The rib cage is collectively made up of long, curved individual bones with joint-connections to the spinal vertebrae. 

Ulna

This is the inner bone of the forearm. The ulna is located on the opposite side of the forearm from the thumb. It joins with the humerus on its larger end to make the elbow joint, and joins with the carpal bones of the hand at its smaller end.

Pelvis

These connected bones support the abdominal organs. The pelvis consists of four bones: the right and left hip bones, the sacrum, and the coccyx. The pelvis has several important functions. Its primary role is to support the weight of the upper body when sitting and to transfer this weight to the lower limbs when standing. 

Radius

This is the outer bone of the forearm. It lies laterally and parallel to ulna, the second of the forearm bones. The radius pivots around the ulna to produce movement at the proximal and distal radio-ulnar joints.

Carpal

There are eight of these small bones at the wrist. Carpal bone, any of several small angular bones that in humans make up the wrist (carpus), and in horses, cows, and other quadrupeds the “knee” of the foreleg. They correspond to the tarsal bones of the rear or lower limb.

Metacarpal

There are five of these bones in each hand, at the base of the fingers and thumb. The metacarpals together are referred to as the ‘metacarpus.’ The tops of the metacarpals form the knuckles where they join to the wrist. 

Phalanges

There are 14 phalanges in each hand, forming the fingers and thumb. The phalanges are the bones that make up the fingers of the hand and the toes of the foot. There are 56 phalanges in the human body, with fourteen on each hand and foot. Three phalanges are present on each finger and toe, with the exception of the thumb and large toe, which possess only two.

 Femur

The largest leg bone is also called the thighbone. It functions in supporting the weight of the body and allowing motion of the leg. The femur articulates proximally with the acetabulum of the pelvis forming the hip joint, and distally with the tibia and patella to form the knee joint.

 Patella

This bone is the kneecap. It is a small, freestanding, bone that rests between the femur (thighbone) and tibia (shinbone). The femur has a dedicated groove along which the kneecap slides. As a form of protection, both bones also contain cartilage — strong, flexible tissue — in the areas near the patella.

Tibia

The front of this bone is the shin. It forms the knee joint with the femur and the ankle joint with the fibula and tarsus. Many powerful muscles that move the foot and lower leg are anchored to the tibia. 

Fibula

The smaller bone of the lower leg, this is located alongside the tibia. It runs parallel to the tibia, or shin bone, and plays a significant role in stabilizing the ankle and supporting the muscles of the lower leg. Compared to the tibia, the fibula is about the same length, but is considerably thinner.

Tarsal

There are seven of these small bones at the ankle joint. The tarsus is a cluster of seven articulating bones in each foot situated between the lower end of the tibia and the fibula of the lower leg and the metatarsus. It is made up of the midfoot (cuboid, medial, intermediate, and lateral cuneiform, and navicular) and hindfoot (talus and calcaneus).

Metatarsal

These five long bones sit between the tarsals and phalanges. Metatarsals are part of the bones of the mid-foot and are tubular in shape. They are named by numbers and start from the medial side outward. The medial side is the same side as the big toe.

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The skeleton shapes and supports the body, allows it to move, and protects internal organs. It is constructed from 206 bones that, far from being dry and dusty, are moist, living body parts. Together, those bones create a framework that is strong but light.

Without a skeleton the body would collapse in a heap. Yet it is not a rigid structure. Flexible joints between bones allow the body to move when those bones are pulled by muscles. The skeleton has other roles. It protects delicate organs such as the brain and heart. Its bones also make blood cells and store calcium, a mineral that is essential for healthy teeth.

There are also some differences in the male and female skeleton. The male skeleton is usually longer and has a high bone mass. The female skeleton, on the other hand, has a broader pelvis to accommodate for pregnancy and child birth.

Regardless of age or sex, the skeletal system can be broken down into two parts, known as the axial skeleton and the appendicular skeleton.

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The type of hair you have depends on the shape and size of the follicle it grows from. Small follicles produce fine hair, while bigger follicles produce thick hair. Hair on the head can be straight, wavy, or curly. About 100 head hairs are lost every day and these are replaced by new growth.

Straight hair

If your hair has no curl or wave to the strand, you have straight hair. Women with straight hair are more likely to have more “oily” hair since the natural oils can easily coat the whole straight strand of hair.

Like all other types of hair, straight hair is beautiful but many straight haired women wish for curls and waves, and the only way to make this happen is with a curling iron or perm. While straight hair is relatively easy to care for, it can lack volume and be hard to style.

Wavy hair

If you have naturally wavy hair, your strands are completely curled, but they form more of an “S” shape than a coil. While many women with wavy hair struggle living in an in-between world of straight and curly hair, wavy hair is typically not too oily and not too dry.

Curly or coiled hair

Curly hair has more “true” curls than wavy hair. Women with curly hair can have loose ringlets or tight spirals. Like other textures of hair, there are different types of curly hair which are based on thickness and the size of the curl. Coily (or kinky) hair is a variation of curly hair and women with coily hair can have a mix of “Z” and “S” shaped curls. Women with curly hair often opt to keep their hair short or have dreads, to make coily hair more manageable, but there are a variety of styles that look great. 

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There are two main types of hair on the human body – vellus and terminal. Vellus hairs are the fine, soft hairs that are usually found covering the skin of children and woman. Terminal hairs are thicker, and are found on the head, in the armpits and public area, and on the other parts of the body, especially in men.

Vellus hair

Fine, short vellus hairs are pale-coloured or translucent and grow over most areas of the body.

Terminal hair

Thicker hair on top of the head provides warmth and gives cover from the sun.

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