Anatomy Axial Skeleton Flashcards

Axial Skeleton Overview

• Comprised of three main parts: skull, vertebral column, and thoracic cage

Skull

• Consists of the cranium and facial bones
• Frontal bone: Forms the forehead and parts of the orbit and anterior cranial fossa
• Supraorbital foramen: Allows passage of blood vessels and nerves above each orbit
• Glabella: The smooth area located between the eyes
• Parietal bone: Forms the sides of the cranium, located posterolateral to the frontal bone
• Key sutures:
  • Sagittal suture: Midline joint between the two parietal bones
  • Coronal suture: Articulation point between the frontal and parietal bones
• Temporal bone: Located beneath the parietal bone, has several parts:
  • Squamous part: Borders the parietals
  • Tympanic part: Surrounds the ear opening
  • Petrous part: Contains the mastoid process and forms skull base
• Zygomatic process: Connects the zygomatic bone to the temporal bone
• Mandibular fossa: Socket for the mandible's condylar process
• External acoustic meatus: Canal to the eardrum and middle ear
• Occipital bone: Forms the back and base of the skull, contains the foramen magnum for spinal cord passage
• Sphenoid bone: Keystone of the cranium, articulates with all cranial bones and forms part of the middle cranial fossa
• Ethmoid bone: Forms part of the medial orbit walls and roof of the nasal cavity, features crista galli for dura mater attachment

Mandible

• Lower jawbone, articulates with the temporal bones at the only movable joint of the skull
• Mandibular body: Horizontal portion forming the chin
• Condylar and coronoid processes: Points for articulation and muscle attachment respectively
• Mental foramen: Opening transmitting nerves and blood vessels to the lower jaw
• Mandibular foramen: Passage for nerve related to tooth sensation

Vertebral Column

• Made up of vertebrae, including the sacrum and coccyx
• Vertebrae feature:
  • Vertebral arch: Includes pedicles, laminae, and spinous process
  • Transverse processes: Lateral extensions from the vertebral arch
  • Intervertebral foramina: Openings allowing spinal nerves to exit
• Sacrum: Formed by fusion of five vertebrae, features a median sacral crest from fused spinous processes
• Coccyx: Known as the human tailbone

Thoracic Cage

• Composed of the sternum, ribs, thoracic vertebrae, and costal cartilages
• Sternum: Breastbone made of three fused sections: manubrium, body, and xiphoid process
• Manubrium: Superior part of the sternum, recognizable by its knot-like shape
• Xiphoid process: Inferior end of the sternum
• Sternal angle: Angle formed between manubrium and body of sternum, important landmark in anatomy