M6

• Skeletal system

  Composed of 206 bones, along with cartilage, tendons, and ligaments, that make up the framework or skeleton of the body
• Bones

  Composed of about 50% water and 50% a solid, calcified, rigid substance known as osseous (AH see us) tissue
• Parts of the skeleton

  • Axial skeleton
  • Appendicular skeleton
• Bones of the axial skeleton

  • Skull
  • Vertebral column
  • Thoracic cage
• Skull

  • Consists of 22 bones: 8 forming the braincase & 14 facial bones
  • The hyoid bone & 6 auditory ossicles are associated with the skull
• Temporal bone


  • Composed the side of the head
  • Contains the external auditory canal, mastoid process, styloid processes, carotid canal, and jugular foramen
• Occipital bone


  • Contains the occipital condyles and foramen magnum
• Sphenoid bone


  • Resembles a butterfly and extends completely across the skull
  • Contains the sella turcica, foramen rotundum, foramen ovale, and foramen spinosum
• Sutures


  Joints that unite bones of the skull
• Types of sutures

  • Squamous suture
  • Coronal suture
  • Lambdoid suture
  • Sagittal suture
• Facial bones


  • Form the structure of the face
  • All are paired bones, except mandible & vomer
• Maxilla


  • Jawbone that forms the upper jaw and contains the superior teeth
• Zygomatic bone


  • Also known as the cheekbone, located anterior to the sphenoid bone
  • Forms the zygomatic arch with the temporal bone
• Palatine bone


  • Forms the roof of the oral cavity, separating the nasal cavity and nasopharynx from the mouth
  • Consists of the hard palate and soft palate
• Nasal bone


  • Forms the bridge of the nose and mostly consists of cartilage
  • Contains the nasal cavity, nasal septum, nasal conchae, and paranasal sinuses
• Lacrimal bone


  • Small bone in the eye sockets, just above the opening of the nasolacrimal canal
  • Forms part of the orbits/eye sockets
• Mandible


  • Forms the lower jaw and contains the inferior teeth
• Auditory ossicles

  • Consist of 6 bones in total, 3 in each middle ear (malleus, incus, and stapes)
• Hyoid bone


  • Unpaired, U-shaped bone that does not articulate with any other bones
  • Provides attachment for some tongue and neck muscles
• Vertebral column


  The central axis of the skeleton, extending from the base of the skull to slightly past the end of the pelvis
• Regions of the vertebral column

  • 7 cervical vertebrae
  • 12 thoracic vertebrae
  • 5 lumbar vertebrae
  • 1 sacral bone
  • 1 coccyx bone
• Major vertebral column curvatures

  • Anterior curve of cervical & lumbar regions
  • Posterior curve of thoracic, sacral, and coccygeal regions
• Abnormal vertebral curvatures

  • Kyphosis
  • Lordosis
  • Scoliosis
• Structure of a vertebra

  • Consists of a body, an arch, and different processes
  • Vertebral arch surrounds the vertebral foramen which forms the vertebral canal to enclose and protect the spinal cord
  • Processes provide attachment sites for muscles that move the vertebral column
• Intervertebral foramina


  • Gaps between successive vertebrae that serve as an exit for spinal nerves from the spinal cord
• Thoracic cage (rib cage)


  • Protects the vital organs and prevents the collapse of the thorax during respiration
  • Consists of the thoracic vertebrae, the ribs with their associated cartilages, and the sternum
• Parts of the thoracic cage

  • True ribs 1-7
  • False ribs 8-10
  • Floating ribs 11-12
  • Sternum
• Sternum


  • Divided into 3 parts: manubrium, body, and xiphoid process
  • Contains the jugular notch and sternal angle
• Appendicular skeleton


  Consists of 126 bones, including the upper limb or pectoral girdle, pelvic girdle, and lower limb
• Pectoral girdle

  • Consists of the scapula and clavicle
• Scapula

  • A flat, triangular bone with 3 large fossae where muscles extending to the arm are attached
  • Contains the glenoid cavity, spine, acromion process, and coracoid process
• Clavicle


  • The first bone to begin ossification in the fetus and last to complete the process
  • Articulates with the scapula at the acromion process
• Upper limb


  • Consists of the arm (humerus), forearm (ulna & radius), wrist (8 carpal bones), and hand (5 metacarpal bones, 3 phalanges in each finger and 2 phalanges in the thumb)
• Humerus


  • Contains the head, anatomical neck, surgical neck, greater & lesser tubercles, deltoid tuberosity, and epicondyles
• Ulna


  • Contains the trochlear notch, olecranon process, coronoid process, and ulnar head
• Radius


  • Contains the radial head and radial tuberosity
• Carpal bones


  • Arranged in two rows of four bones each, forming a slight curvature that is concave anteriorly and convex posteriorly
• Forearm


  • Has two bones, the ulna on the medial side (little finger) and the radius on lateral side (thumb)
• Trochlear Notch


  Located at proximal end of ulna that fits tightly over the end of humerus, forming most of the elbow joint
• Olecranon Process


  Extension of ulna which can be felt as the point of elbow