Human Skeleton Anatomy PDF

skeleton consists of the pelvic and pectoral Functions of bones girdles and the bones of the hands, feet, lower and upper extremity, shoulder girdle, and The 206 bones i...

skeleton consists of the pelvic and pectoral Functions of bones girdles and the bones of the hands, feet, lower and upper extremity, shoulder girdle, and The 206 bones in the human body perform the pelvic bones. following functions: Bones provide shape to the body. Skull Bones act as a protection to internal organs like brain, heart, lungs etc.. The human skull consists of cranium and Provides support to the body and facial bones. The function of the cranium is to anchors muscles. Bones serve as storage space for protect the brain. It is formed of 8 minerals like calcium and phosphate plate-shaped bones joined together at Bones helps in facilitating body movements. meeting points called sutures. Along with Bones serve as the birthplace for red cranium, the remaining 14 bones form the blood cells. facial bones. Mandible is the only movable Axial Skeleton bone in the human skull. Human skeletal has two major divisions: The main function of the skull is to render Axial skeleton protection and support. It does so along with Appendicular skeleton the surrounding meninges. Protection is Axial skeleton provided to the different parts of the brain – Cerebellum, Cerebrum and brainstem in The axial skeleton is made up of 80 bones addition to the orbits of the eyes. Structural and it constitutes the middle axis. It includes support is provided for attachments of the the following regions: muscles of the face and scalp. Additionally, it Skull protects different vessels and nerves Hyoid Auditory ossicles innervating the facial muscles, brain and other Vertebral column related parts. The skull hardens and fuses as Ribs Sternum it develops to safeguard its internal contents. Appendicular skeleton Hyoid Out of the 206 bones present in the adult It is a U-shaped bone located in the anterior human body, a total of 126 named bones form neck. It is an intermediary between the skull the appendicular skeleton. The appendicular and post cranial skeleton. The hyoid bone of approximately 33 bones called vertebrae aids tongue movement and swallowing. It has which are separated by intervertebral discs. It no articulation with other bones. is divided into 5 categories. They are Cervical, Thoracic, Lumbar, Sacrum, Coccyx. Auditory Ossicles Functions of the Vertebral column Auditory ossicles namely malleus, incus, stapes are three bones in the middle ear that The vertebral column protects the are the smallest bones in the human body. spinal cord. The functions of ossicles are to transmit Provides stiffening to the body. sound from the air to the cochlea. Provides structural support by balancing the bodyweight Ribs Provides attachment to pectoral and Ribs are the long curved bones which pelvic girdles and other muscles. constitute the rib cage. The ribs consist of 24 Cervical Vertebrae bones in 12 pairs which form the protective cage of the thorax. The ribs protect the The cervical is the most delicate and the thoracic internal organs. They articulate thinnest bones of the vertebral column. The posteriorly with the vertebral column and cervical vertebrae are formed of 7 vertebrae. terminates anteriorly as cartilage. The seven cervical vertebrae are arranged along the length of the neck. They are named Sternum according to its position from the skull to the Sternum or the breastbone is a long bone chest. The superior C1 or first cervical placed at the central part of the chest. The vertebrae to C7 or the seventh cervical sternum and ribs make up the rib cage. The vertebrae constitute the cervical vertebrae. sternum is attached to the first seven ribs and The C1 vertebrae are named as Atlas whose also to the Clavicle or collarbone. function is to hold up the skull. Also, C2 is named as Axis since it serves as the axis for Vertebral Column the skull and atlas to rotate while turning head from one side to another. The vertebral column is also a part of the axial skeletal system. The vertebral column is a set Thoracic Vertebrae It is placed at the mid-back of the human are also referred to as the tail bone. The body. The main function is to hold the rib cage coccyx serves as an attachment site for and to protect the heart and lungs. The twelve ligaments, tendons and muscles. The coccyx thoracic vertebrae are named T1 to T12. may be fractured when a person falls abruptly. Thoracic vertebrae are the unique one other than the remaining vertebrae as it supports Appendicular Skeleton the ribs. The appendicular skeleton is the part of the human skeletal system that supports the Lumbar Vertebrae appendages. It consists of 186 bones These are the largest in the vertebral column including the bones of the limbs as well as and comprises of 5 vertebrae bones between supporting the pelvic and pectoral girdles. the rib cage and pelvis. The lumbar vertebrae The appendicular skeleton is divided into 6 are named from L1 to L5. L1 is closest to the regions. thoracic vertebrae whereas L5 is adjacent to the pelvis. The lumbar vertebrae functions as 1. Shoulder girdle the load-bearing structure. 2. Arms and forearms 3. Hands Sacral Vertebrae 4. Pelvis The sacral vertebrae consist of 5 vertebrae 5. Thighs and legs bones which fuse together to form Sacrum. 6. Feet and ankles The sacrum is a long wedge-shaped vertebra at the inferior end of the spine. It is a very Shoulder Girdle strong bone which supports the weight of the The shoulder girdle or the pectoral girdle is a upper body as it spread across the pelvis into set of 4 bones which connects to the arm on the legs. each side. The pectoral girdle is part of the appendicular skeleton which are for the upper Coccyx Vertebrae limbs. In human beings, the pectoral girdle The coccyx vertebrae are formed by the consists of the scapula and the clavicle. fusion of three to five rudimentary bones to form a small triangular bone at the bottom of Arms and Forearms the vertebral column. The coccyx vertebrae The arm and forearm are constituted of 6 pelvic girdle consists of two bones sacrum bones. The large bones of the arm include: and the coccyx. The pelvic girdle is formed of paired hip bones each made up of ilium, Humerus – Humerus runs from the ischium and pubis. shoulder socket and joins the radius and ulna at the elbow. Functions of Pelvic Girdle Radius – Radius is a forearm which It transfers the weight of the body from runs from the elbow to the thumb side the axial skeleton to the appendicular of the wrist. components, especially during the Ulna – Ulna, a forearm which runs movement. from the elbow to the ‘pinky’ side of Provides attachment from a number of the elbow. muscles and ligaments enabling movement. Hands The hands consist of 54 bones which provide The majority of women have a gynaecoid support and flexibility to the soft tissues. The pelvis and males have an android pelvis. The bones of hands are categorised into three: differences in the structure creates a great pelvic outlet enabling the process of childbirth. 1. Carpals – Carpals are a set of 8 irregularly shaped bones located in Thighs and Legs the wrist area. The bones of the legs and thighs are part of 2. Metacarpals – Metacarpals are bones the appendicular skeletal system which which are related to each digit, there supports the muscles of the lower limbs. are 5 metacarpal bones. These muscles help in walking, running, 3. Phalanges – Phalanges are the bones standing and jumping. These bones should be of the fingers. There are 3 phalanges strong enough in order to support the body’s in each finger, except, for the thumb weight. which has two phalanges only. The Femur or thigh bone is the largest Pelvic Girdle and heaviest bone in the human body. The pelvic girdle is located in the lower part of At the proximal end of Femur, there is the trunk. It a ring-like bony structure. The  a rounded prominence which is called Ligaments as the Head of the Femur. Ligaments join two bones together. They are The Tibia and Fibula are the two long also a type of connective tissue. bones in the lower leg. They are two separate bones but are closely linked Cartilage at the knee and the ankle. Cartilage provides protection of bones at the The top of Tibia connects to the knee joints from wear and tear. They are firm yet joint and bottom connects to the ankle softer and flexible than bones. joint. Although Tibia carries all the body weight, it needs the support of It forms a structural framework of many parts Fibula. of the body, e.g. ear, nose, ribs, bronchial tubes, etc. Feet and Ankles The foot is a firm platform which supports the Diseases related to Skeletal weight of the body. It is formed of many bones System such as the tarsals, metatarsals and 1. Osteoporosis: Osteoporosis is a phalanges. bone-related disease in which the Tarsals: A set of 8 irregular bones bone density is reduced and increases situated proximally in the foot in the the risk of bone fracture. ankle area. 2. Paget’s Disease: It is a chronic bone Metatarsals: A set of 5 bones each disease which causes the affected one for a digit. These bones connect bones to large and misshapen. tarsals with the phalanges. 3. Arthritis: It is the inflammation caused Phalanges: Each toe has 3 phalanges to the joints causing difficulty and pain namely the proximal, intermediate and in movements and limiting the same. distal. Tendons Tendons joint bones to skeletal muscles. They are made up of connective tissues.