Human Skull Bones Anatomy

Stages in the Healing of a Bone Fracture

• Bone fracture healing involves several stages, including fracture, repair, and remodeling
• Types of fractures include open (compound), comminuted, greenstick, impacted, Pott, and Colles

Bone's Role in Calcium Homeostasis

• Bones store 99% of the body's calcium
• Parathyroid hormone (PTH) is secreted when calcium levels drop, stimulating osteoclasts to release calcium into the bloodstream
• PTH also stimulates the production of calcitriol, increasing calcium absorption in the intestines

Ageing and Bone Tissue

• From birth to adolescence, bone production exceeds resorption
• In adults, bone production and resorption are balanced
• In older individuals, especially postmenopausal women, bone resorption exceeds production, leading to decreased bone mass

The Axial Skeleton

• The axial skeleton consists of 80 bones that form the longitudinal part of the body
• It is divided into three parts: skull, vertebral column, and bony thorax

The Skull

• The skull is part of the axial skeleton
• It consists of 22 bones that fuse together
• The sphenoid bone is a butterfly-shaped bone that forms part of the cranial cavity
• The ethmoid bone is irregularly shaped and contains the crista galli and cribriform plates
• The nasal conchae are extensions of the ethmoid bone that form the lateral walls of the nasal cavity

Facial Bones

• The facial bones consist of 14 bones that form the face
• The maxillae bones form the upper jaw and contain the upper teeth
• The palatine bone forms the posterior part of the hard palate
• The zygomatic bone forms the lateral walls of the orbits
• The lacrimal bone forms the medial walls of the orbits

Paranasal Sinuses

• Paranasal sinuses are hollow portions of bones surrounding the nasal cavity
• They lighten the skull and give resonance and amplification to the voice

The Hyoid Bone

• The hyoid bone is a horseshoe-shaped bone that does not articulate with another bone
• It serves as a movable base for the tongue and is situated at the top of the larynx

The Fetal Skull

• The fetal skull is large compared to the infant's total body length
• Fontanelles are fibrous membranes that connect the cranial bones, allowing the brain to grow
• Fontanelles convert to bone within 24 months after birth

The Vertebral Column

• The vertebral column is the axial support of the body
• It consists of 33 bones separated by intervertebral discs that protect the spinal cord
• Each vertebra is given a name according to its location

Regional Characteristics of Vertebrae

• Cervical vertebrae (C1 to C7) allow for forward, backward, and twisting motions of the neck
• Thoracic vertebrae support the rib
• Lumbar vertebrae support the body's weight
• Sacrum and coccyx are triangular-shaped bones composed of fused vertebrae

The Bony Thorax

• The bony thorax forms a protective, cone-shaped cage around the heart, lungs, and major blood vessels
• It is made up of the sternum, ribs, and thoracic vertebrae
• The sternum is a flat bone divided into three segments: manubrium, body, and xiphoid process

Disorders

• Scoliosis, kyphosis, and lordosis are curve-related pathologies that affect the spinal column
• Herniated discs can occur due to trauma or aging, leading to the leakage of the nucleus pulposus into the annulus fibrosus