The aim of this essay is the presentation of 30 human bones associated with the skull, the vertebral column, the thoracic cage, the pectoral girdle and upper limb, the pelvic girdle and lower limb, and the joints. The review will be conducted in categories and will include a description of the function and their classification.
The bones of the skull can be divided into two categories: the cranial bones (the calvarium and the cranial base) and the facial bones. Three bones of the calvarium are the frontal bone, the occipital bone, and the parietal bone. The frontal bone forms the anterior part of the superior skull. It is formed by two portions; the vertical and the horizontal. It surrounds and protects the anterior part of the brain. The occipital bone is large and trapezoid and forms the posterior part of the skull and articulates with the parietal bones. Along its interior surfaces is the foramen magnum which allows the spinal cord to pass through the skull. The parietal bone articulates with the frontal bones anteriorly and the occipital bone posteriorly. It is a large, thin four-sided bone that forms the most of the top and sides of the skull. Furthermore, three bones of the cranial base are the sphenoid bone, the ethmoid bone, and the temporal bone. The sphenoid bone is formed in a butterfly shape. It participates in the formation of the lower part of the skull, the sides, the floor and sides of the orbits. The ethmoid has a cuboid shape, spongy construction which separates the nasal cavity from the brain. The temporal bone is comprised of four parts (the squamous, the tympanic, the mastoid, and petrous). Its function is to protect the base and side parts of the skull. Finally, the mandible bone is an irregular bone that belongs to the facial bones. The mandible forms the lower jaw and the lower teeth.
The vertebral column is comprised of 33 spinal bones. The atlas is the first cervical vertebra. Its role is to support the head. The axis is the second cervical vertebra. The atlas and the axis form a pivot joint. When the head rotates, it rotates around this formation. The lumbar vertebrae are five and they are located in the lower part of the back. These bones carry the weight of the upper body and offer flexibility to the trunk. The sacrum consists of 5 sacral vertebrae which link the spine to the hips. They also form the pelvic girdle along with the iliac bones. The coccyx is the lowest segment of the spinal column. Several muscles of the pelvic region are attached to it and bear the weight of the body in a sitting position.
The thoracic cage includes thoracic vertebrae, ribs, the sternum, and costal cartilage. The manubrium is the upper part of the sternum. At the upper corners, there are clavicular notches and they articulate with the clavicles in order to form the shoulder girdle. The corpus sterni is the longest part of the sterni. Its costal notches cater for the ribs. The xiphoid process serves as an attachment point for several muscles that form the ribcage floor and participate in respiration. The twelve thoracic vertebrae hold the rib cage and protect the heart and the lungs. There are twelve sets of ribs which form the ribcage. Their function is to protect the important organs and blood vessels and aid the breathing process.
The bones that attach the upper limbs to the axial skeleton form the pectoral girdle. The scapula attaches the arm to the trunk of the body and is a flat bone. It stabilizes the connection and offers the ability for movement. The clavicle is the bone where the scapula and the free arm are suspended from and provides the maximum ability of movement. The humerus is the bone which originates from the scapula and ends at the elbow, serving as a link for the two lower bones. The ulna extends from the elbow to the wrist. Many muscles allowing movements such as the throwing of a ball are attached to it. The radius is paired to the ulna and serves the same function. It extends from the elbow to the thumb side of the wrist. The eight carpal bones aid the movement of the wrist.
The pelvic girdle is formed by one bone, the coxal bone which serves as an attachment point for the lower limbs. It also surrounds and protects the bladder and the reproductive organs. The femur is the thigh bone. It supports the weight of the body and allows movement at the lower part of the leg. The patella is an irregular bone, also known as kneecap, which allows knee extension. It, also, increases the leverage that the tendon can exert on the femur. The tibia extends from the patella to the ankle. It supports the weight of the body and allows movement and locomotion. Finally, the fibula runs parallel to the tibia and stabilizes the ankle.
The talus is part of the ankle joint. It sits above the heel bone and creates the lower part of this joint. It transfers the weight from the ankle to the leg and allows us to walk with balance. The ischium is the lowest part of the pelvis and carries all the body weight in a sitting position. They are both irregular bones.
The bones of the human body are classified in four categories according to their shape: long, short, flat, and irregular. The long bones identified in this essay are the clavicle, the humerus, the ulna, the radius, the femur, the tibia, and the fibula. The carpal bones belong to the short bones. The flat bones include the frontal bone, the occipital bone, the parietal bone, the manubrium, the corpus sterni, the xiphoid process, the ribs, and the scapula. The irregular bones are the sphenoid, the ethmoid, the temporal, all the vertebrae, the coxal bone, the patella, the talus, and the ischium.
In terms of their basis of development the bones are classified as membranous, cartilaginous, and membrocartilaginous. In the membranous bones belong the described bones of the skull. In the second category belong the bones of the vertebral column, the thoracic cage, and the limbs. Furthermore, the bones of the skull, the vertebral column, and the thoracic cage belong to the bones of the axial skeleton while the bones of girdles and limbs belong to the bones of the appendicular skeleton. Last but not least, concerning the structure, all the long bones identified in this essay are spongy bones covered by a thin layer of compact bone. The short bones have a thin layer of compact bone surrounding a spongy bone and they are joined by multiple articulations. The structure of the flat bones has two parallel layers of compact bones pressuring a layer of spongy bone. The irregular bones consist of a thin layer of compact bone surrounding a spongy bone interior.
References
Anould-Taylor, W. (1998). A Textbook of Anatomy and Physiology. Oxford: Nelson Thornes.
Netter, F. (1989). Atlas of the Human Body. Collingwood: Saunders.
Moore, K. L. (2013). Clinically Oriented Anatomy. Philadelphia: Lippincott Williams & Wilkins.
Rohen, J. (2010). Color Atlas of Anatomy: A Photographic Study of the Human Body. Stuttgart: Schattauer Verlag.
