Skeletal System

• What are the two divisions of the skeletal system?

  The two divisions are the Axial and Appendicular skeletons.
• How can the terms axial and appendicular be described in relation to the human skeleton?

  Axial refers to the center-line or pivot-line, while appendicular refers to structures that are "hung on" to this central element.
• What bones are included in the axial skeleton?

  The axial skeleton includes the bones in the skull, vertebral column, and ribcage of the chest.
• What bones are included in the appendicular skeleton?

  The appendicular skeleton includes the bones of the pectoral girdle and pelvic girdle.
• What does the term appendicular derive from?


  The term appendicular comes from appendicula, meaning ‘small appendage’.
• How are the appendicular skeleton and axial skeleton connected?

  The appendicular skeleton is held onto the axial skeleton by girdles.
• What are the functions of the pectoral and pelvic girdles?

  • Pectoral girdle: connects upper limbs to the axial skeleton.
  • Pelvic girdle: connects lower limbs to the axial skeleton.
• What is the calvaria of the skull?

  The calvaria is the dome or roof of the skull, also known as the “skullcap”.
• What is the origin of the term calvaria?

  The term calvaria comes from the Latin word calvāria, meaning 'of the skull'.
• What bones make up the calvaria?

  The calvaria is made up of the superior portions of the frontal bone, occipital bone, and parietal bones.
• What are sutures in the skull?

  • Sutures are immoveable joints of the skull.
  • They create boundaries for where one bone ends and another begins.
• What is the coronal suture?

  The coronal suture is the suture between the frontal and parietal bones.
• What is the lambdoidal suture?

  The lambdoidal suture is the suture between the occipital and parietal bones.
• What is the sagittal suture?

  The sagittal suture is the suture between the two parietal bones.
• What is the squamosal suture?

  The squamosal suture is the suture between the temporal and parietal bones.
• What is the intermaxillary suture?

  The intermaxillary suture is the suture between the two halves of the maxillae bones.
• Why are sutures useful landmarks in the skull?

  Sutures create boundaries for where one bone ends and another begins, aiding in identification.
• What is the foramen magnum?

  The foramen magnum is a large passageway for the spinal cord to exit the cranium.
• What are occipital condyles responsible for?

  Occipital condyles articulate with the atlas (C1) and are responsible for the 'yes' gesture.
• What is the external occipital crest?

  The external occipital crest is a midline ridge from the external occipital protuberance to the foramen magnum.
• What is the function of the external occipital protuberance?

  The external occipital protuberance serves as a bony prominence for muscle attachment at the back of the head.
• What are nuchal lines?

  Nuchal lines are for muscle attachments for the nape of the neck.
• What is the jugular foramen?

  The jugular foramen is a passageway for nerves and the exit of the internal jugular vein from the cranium.
• What is the groove for the superior sagittal sinus?

  The groove for the superior sagittal sinus is a shallow groove located on the internal aspect of the calvaria.
• How does the term 'sinus' differ in the skeletal and cardiovascular systems?

  In the skeletal system, a sinus means a hollow cavity in bone, while in the cardiovascular system, it refers to a large vessel, usually a vein.
• What is the orbital surface of the frontal bone?

  The orbital surface of the frontal bone creates the roof of the orbital (eye socket).
• What are the supraorbital margins?

  The supraorbital margins create the rim of the orbit.
• What is the difference between a foramen and a notch in the context of the frontal bone?

  A foramen is a hole, while a notch is a hole that has breached the margin and is no longer a hole.
• What is the superciliary arch?

  The superciliary arch is a thickening prominence of the forehead just above the eyebrows.
• What is the lacrimal fossa?

  The lacrimal fossa is a shallow depression for the lacrimal gland on the orbital surface.
• What is the zygomatic process of the frontal bone?

  The zygomatic process is the portion of the frontal bone that meets the zygomatic bone of the cheek.
• What is the metopic suture?

  The metopic suture is a remnant of fusion between the two frontal bones of the fetal skull.
• What is the frontal sinus?

  The frontal sinus is one of four skull bones that have a hollow sinus in them.
• What is the squamous portion of the temporal bone?

  The squamous portion is the flat thin superior part of the temporal bone.
• What is the petrous portion of the temporal bone?

  The petrous portion is the hard portion found on the internal aspect of the skull.
• What is the mastoid process?

  The mastoid process is a rounded lump behind the ear.
• What is the zygomatic process of the temporal bone?

  The zygomatic process reaches toward the zygomatic bone and contributes to the zygomatic arch.
• What is the mandibular fossa?

  The mandibular fossa is the shallow depression that holds the articulation surface with the mandible.
• What is the external auditory canal?

  The external auditory canal is the outer entrance to the tympanic membrane (ear drum).
• What is the internal auditory canal?

  The internal auditory canal is the internal passageway within the petrous portion of the temporal bone.