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SKELETAL SYSTEM • The bodily system that consists of the bones, their associated tendons, ligaments, and cartilages. Teeth are also considered part of the skeletal system. • 206 BONES IN HUMAN BODY FUNCTIONS OF BONES SUPPORTS THE BODY PROTECTS THE BODY PRODUCES BLOOD CELLS STORES MINERALS SKULL 28 skull bones (8 cranial, 14 facial, and 6 ear bones) the horseshoe-shaped hyoid bone of the neck VERTEBRAL (spinal) COLUMN The spinal column (or vertebral column) extends from the skull to the pelvis and is made up of 26 individual bones termed vertebrae. The vertebrae are stacked on top of each other group into four regions: Cervical Vertebrae : 7 Vertebrae nearest neck. Atlas (C1) supports the skull and Axis (C2) Thoracic Vertebrae : 12 Vertebrae nearest chest – Ribcage is attached to thoracic vertebrae Lumbar Vertebrae : 5 Vertebrae – responsible for most weight bearing and biomechanical stress. Sacral Spine : Sacrum – 1 (5 fused bones) Coccyx – 1 (5 fused bones) Cervical Vertebrae (C1 – C7) The cervical spine is further divided into two parts; the upper cervical region (C1 and C2), and the lower cervical region (C3 through C7). C1 is termed the Atlas and C2 the Axis. Atlas (C1) The Atlas is the first cervical vertebra and therefore abbreviated C1. This vertebra supports the skull. Its appearance is different from the other spinal vertebrae. The atlas is a ring of bone made up of two lateral masses joined at the front and back by the anterior arch and the posterior arch. Axis (C2) The Axis is the second cervical vertebra or C2. It is a blunt tooth–like process that projects upward. It is also referred to as the ‘dens’ (Latin for ‘tooth’) or odontoid process. The dens provides a type of pivot and collar allowing the head and atlas to rotate around the dens. Thoracic Vertebrae (T1 – T12) The thoracic vertebrae increase in size from T1 through T12 The rib cage is joined to the thoracic vertebrae. At T11 and T12, the ribs do not attach and are so are called "floating ribs." The thoracic spine's range of motion is limited due to the many rib/vertebrae connections Lumbar Vertebrae (L1 – L5) The lumbar vertebrae graduate in size from L1 through L5. These vertebrae bear much of the body's weight and related biomechanical stress Sacral Spine The Sacrum is located behind the pelvis. Five bones (abbreviated S1 through S5) fused into a triangular shape, form the sacrum. The sacrum fits between the two hipbones connecting the spine to the pelvis. The last lumbar vertebra (L5) articulates (moves) with the sacrum. Immediately below the sacrum are five additional bones, fused together to form the Coccyx (tailbone). RIBS A bony framework that protects the heart, lungs, and other underlying organs. The rib-cage is made up of three groups of bones – the sternum (breastbone), 12 pairs of ribs, and 12 thoracic vertebrae. All of the ribs are attached to the spinal column, but only the top seven pairs connect to the sternum. These are called true ribs and are joined to the sternum by strips of cartilage known as costal cartilage. The next three pairs of ribs are known as false ribs. Instead of attaching directly to the sternum, they all attach to the lowest true rib. The last two pairs of ribs are called floating ribs and attach only to the spine. CLAVICLE AND SCAPULA (pectoral girdle) The pectoral girdle is the set of bones which connect the upper limb to the axial skeleton on each side. It consists of the clavicle and scapula in humans CLAVICLE – “collarbone” SCAPULA – “shoulder blade” HUMERUS, RADIUS, ULNA • The humerus is the (upper) arm bone. It joins with the scapula above at the shoulder joint (or glenohumeral joint) and with the ulna and radius below at the elbow joint. **The ULNA is the bone that runs from the point of elbow to point outside of wrist. CARPALS, METACARPALS, AND PHALANGES • The hand has 27 bones PELVIS • The pelvis is a basin shaped cavity bordered by the pelvic girdle and sacrum, containing and protecting the bladder, rectum and reproductive organs. Pelvic, as pertains to the pelvis. The structure of the vertebrate skeleton supporting the lower limbs in humans and the hind limbs or corresponding parts in other vertebrates. FEMUR, TIBIA, FIBULA • Femur – Largest Bone in Body (Weight Bearing) • Tibia – “Shin Bone” (Weight Bearing) • Fibula – Helps muscles and tendons attach – non-weight bearing • Patella – “knee cap” TARSALS, METATARSALS, PHALANGES • The foot has 26 bones THE WHOLE PICTURE INTERESTING FACTS The hand has 27 bones, the foot has 26 and the face has 14. The longest bone in your body, the femur (thigh bone), is about 1/4 of your height. The smallest is the stapes (or stirrup) in the ear which is about 1/10 of an inch. Humans and giraffes have the same number of bones in their necks. Most of the bones in the body are in the hands.