Bone Types and Long Bone Anatomy

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Questions and Answers

What is the main structural characteristic of long bones like the femur?

They are longer than they are wide. (correct)

They are mostly spongy bone.

They consist of two layers of thin compact bone.

They have irregular shapes.

What type of cartilage covers the epiphyseal surface of a long bone?

Elastic cartilage

Dense regular cartilage

Hyaline cartilage (correct)

Fibrocartilage

What is the primary function of osteoclasts?

To destroy bone tissue (correct)

To facilitate bone growth

To cover the bone surface

To form new bone tissue

Which structure serves as a covering for the outer surface of a long bone?

Periosteum Signup and view all the answers

What characterizes short bones such as the tarsals?

They are cube-shaped with more spongy bone. Signup and view all the answers

What is the primary role of the epiphyseal plate?

To allow for bone growth Signup and view all the answers

Which of the following is NOT considered a type of bone?

Consolidated bones Signup and view all the answers

What is the structure within the shaft of a long bone that stores fat?

Medullary cavity Signup and view all the answers

What is the primary function of ear cartilage?

To support the external ear Signup and view all the answers

Which of the following bones is NOT part of the cranium?

Zygomatic bone Signup and view all the answers

Which structure of the temporal bone is associated with articulating the mandible?

Mandibular fossa Signup and view all the answers

What are the three concavities of the cranial floor called?

Anterior, Middle, Posterior fossa Signup and view all the answers

What is the shape of the suture that articulates the parietal bones?

Saggital Suture Signup and view all the answers

What condition results from an infection in the mastoid process?

Mastoiditis Signup and view all the answers

Which cranial nerve passes through the Stylomastoid foramen?

Cranial Nerve VII Signup and view all the answers

What is the role of the jugular foramen?

Opening for the internal jugular vein Signup and view all the answers

Which of these bones is NOT paired?

Frontal bone Signup and view all the answers

Which deficiency is a known cause of osteoporosis?

Calcium deficiency Signup and view all the answers

Which cranial opening serves as the passageway for cranial nerves VII and VIII?

Internal acoustic meatus Signup and view all the answers

Which structure articulates with the bony projection of the occipital bone?

C1 (Atlas) Signup and view all the answers

What is the main function of the superior and middle nasal conchae?

Warm and humidify incoming air Signup and view all the answers

Which feature of the sphenoid bone is responsible for holding the pituitary gland?

Hypophyseal fossa Signup and view all the answers

Which of the following structures is considered part of the ethmoid bone?

Crista Galli Signup and view all the answers

What is the key role of the foramen lacerum?

Passage for the internal carotid artery and small nerves Signup and view all the answers

Which paired bones belong to the facial bones?

Lacrimal bones Signup and view all the answers

Where does the perpendicular plate of the ethmoid bone primarily contribute?

Upper nasal septum Signup and view all the answers

The optic canals allow for the passage of which structures?

Optic nerves Signup and view all the answers

Which bone is located anterior to the sphenoid bone?

Ethmoid bone Signup and view all the answers

What is the primary function of fontanels in the fetal skull?

To permit compression during childbirth and enable brain growth Signup and view all the answers

Which structure serves as the point of articulation between the frontal and parietal bones?

Coronal suture Signup and view all the answers

Where is the stylomastoid foramen located and what is its significance?

It allows passage for cranial nerve VII. Signup and view all the answers

Which foramen provides passage for the internal jugular vein and cranial nerves IX, X, and XI?

Jugular foramen Signup and view all the answers

What are the floating or vertebral ribs characterized by?

Their lack of attachment to the sternum Signup and view all the answers

What is the primary function of the intervertebral discs?

To cushion and absorb shock Signup and view all the answers

Which type of curvature is present at birth?

Primary Curvature Signup and view all the answers

What characterizes lordosis?

Excessive anterior curvature Signup and view all the answers

What structure connects the body of the vertebra to the laminae?

Pedicles Signup and view all the answers

How is the atlas (C1) distinct from other vertebrae?

It has no body Signup and view all the answers

What is the role of the superior and inferior articular processes?

To articulate between vertebrae Signup and view all the answers

What occurs when the nucleus pulposus herniates through the annulus fibrosus?

Compression of spinal nerves Signup and view all the answers

What type of vertebrae are found in the cervical region?

7 cervical vertebrae Signup and view all the answers

What is the function of the transverse process in vertebrae?

To provide attachment points for muscles Signup and view all the answers

Which condition is characterized by excessive lateral curvature of the spine?

Scoliosis Signup and view all the answers

Study Notes

Bone Types

Long bones are longer than wide, mostly compact bone. Examples include the femur.
Short bones are cube shaped, contain more spongy bone than compact bone. Example includes the tarsals.
Flat bones consist of two layers of thin compact bone with spongy bone between. These bones are curved. Examples include skull bones.
Irregular bones have unusual shapes. Examples include the vertebrae.
Sesamoid bones are found inside tendons. Example includes the patella.
Wormian/Sutural bones are small bones found between cranial bones.

Long Bone Anatomy

Shaft or Diaphysis is the long axis of the bone, consists mostly of compact bone.
Periosteum is a fibrous membrane covering the outside of the bone.
- Sharpey's fibers extend from the periosteum into the bone allowing blood vessels and nerves to enter.
Osteoblasts are bone forming cells found in the periosteum.
Osteoclasts are bone destroying cells found in the endosteum, the inner surface lining of the shaft.
Epiphysis is found at the end of long bones, consists mostly of spongy bone with a thin layer of compact bone.
Articular cartilage covers the epiphyseal surface of the long bone instead of periosteum.
- It is made of hyaline cartilage and provides a smooth surface to prevent friction at the joints.
Epiphyseal plate is an area of hyaline cartilage that allows for growth in growing animals.
- The Epiphyseal line is a remnant of the plate after bone growth is complete.
Central Cavity or Medullary cavity is found in the shaft and stores fat.
Ear cartilage is elastic cartilage that supports the external ear.

Osteoporosis

Osteoporosis is a gradual loss of bone mass resulting in weakened bones, making them more prone to breaks and fractures.
Causes include:
- Hormone deficiency
- Calcium and vitamin deficiency
- Physical inactivity
- Vices

Axial Skeleton

Consists of the skull, vertebral column, and bony thorax. It contains 80 bones.

Skull

The skull consists of two sets of bones:
- Cranium encloses the brain
- Facial bones support the eyes and provide structures for facial muscles.
Skull bones are connected by non-moving sutures except for the mandible, which articulates at a freely moving joint.

Cranium/Cranial Bones

The cranium is divided into the superior Cranial Vault or Calvaria and the inferior Cranial Floor or Base.
The cranial floor has three concavities that hold the brain: Anterior, Middle and Posterior fossa.
The cranium consists of eight bones:
- Frontal
- Paired Parietals
- Paired Temporals
- Occipital
- Spenoid
- Ethmoid

Frontal Bone

Forms the anterior portion of the cranium.
Contains the forehead, superior orbit, and floor of the Anterior Fossa.
Supraorbital foramens (notch) are openings above each orbit that allow blood vessels and nerves to pass.

Parietal Bones

Make up the superior sides of the cranium.
The Saggital Suture is the midline articulation point of the parietal bones.

Temporal Bones

Make up the inferior sides of the cranium.
The Squamous Suture is the point of articulation of the temporal and parietal bones.
The bridge-like Zygomatic process forms the cheekbone.
The Mandibular fossa is a rounded depression that articulates with the mandible.
The External Acoustic Meatus is a canal leading to the eardrum and middle ear.
The Styloid process is an attachment site for muscles and ligaments of the neck.
The Mastoid process is an attachment site for muscles.
- Mastoidistis is an infection of the mastoid process.
- Infections can spread to the meninges, causing Meningitis.
The Stylomastoid foramen is an opening for Cranial Nerve # VII.
The Jugular foramen is an opening for the internal jugular vein and cranial nerves IX, X, and XI.
The Carotid canal is an opening for the internal carotid artery.
The Internal acoustic meatus is a passageway for cranial nerves VII and VIII.
The Foramen Lacerum is an opening for the internal carotid artery and small nerves.

Occipital Bone

Makes up the posterior portion of the cranium.
Joins the Sphenoid bone anteriorly.
The Lamboid Suture is the point of articulation between the occipital and parietal bones.
The Foramen Magnum is the large opening for the spinal cord.
The Hypoglossal Canal is a passageway for the hypoglossal nerve (cranial nerve #XII).
Occipital Condyles articulate with C1 (the Atlas).

Sphenoid Bone

Bat-shaped bone forming the anterior plateau of the middle cranial fossa, spanning the width of the skull.
Greater wings form part of the orbital socket.
Superior Orbital Fissures are jagged openings that allow passage of cranial nerves III, IV, V and VI into the orbit to serve the eye.
Inferior Orbital Fissures allow passage of the infraorbital vessels and cranial nerve #V.
Sella Turcica (Turk's Saddle) lies in the central portion of the bone.
- The seat of the saddle, the Hypophyseal fossa, holds the pituitary gland.
Optic canals are openings for the optic nerves.
The Foramen Rotundum and Ovale are openings for branches of the fifth cranial nerve.
The Foramen Spinosum is an opening for the Middle Meningeal Artery.

Ethmoid Bone

Anterior to the sphenoid, forms the roof of the nasal cavity, the upper nasal septum, and part of the medial orbital wall.
Crista Galli is a vertical projection where the dura mater of the brain attaches, securing it to the skull.
Cribiform plates are bony plates lateral to the crista galli that hold the Olfactory foramina, which allow passage of olfactory fibers.
- The crista galli and the cribiform plates form the horizontal plate.
The Perpendicular plate forms the superior nasal septum.
The Lateral masses form part of the medial orbital walls.
The Superior and Middle Nasal Conchae are turbinates that help the mucosa in the nasal cavity warm and humidify incoming air.

Facial bones

Consists of 14 bones:
- 7 paired
- 2 single: Vomer and Mandible

Vertebral Column

Protects the spinal cord and allows nerves to issue from the cord via openings between the vertebrae.
Consists of 24 bones called vertebrae, plus the Sacrum and Coccyx.
The 7 bones of the neck are called Cervical vertebrae.
The 12 bones in the upper back are called Thoracic vertebrae.
The 5 bones in the lower back are called Lumbar vertebrae.
Each vertebra is separated from another by fibrocartilage called Intervertebral discs which cushion and absorb shock.
- Each disc has two parts:
  - an inner nucleus pulposus, a central gelatinous mass.
  - an outer ring of collagen fibers, the annulus fibrosus.
Ruptured discs occur when the nucleus pulposus herniates through the annulus fibrosus, compressing spinal nerves.
The s-shaped curve of the spine (vertebral column) prevents shock and allows for flexibility.
- Primary Curvature (Thoracic and Sacral) is present at birth.
- Secondary Curvature (Cervical and Lumbar) develops later.

Spinal Curvature Abnormalities

Scoliosis is an abnormal/excessive lateral curvature of the spine.
Kyphosis is an abnormal/excessive dorsal curvature of the spine.
Lordosis is an abnormal/excessive anterior curvature of the spine.

Structure of the Vertebrae

Body or Centrum is the rounded central portion facing anteriorly.
Vertebral arch is comprised of the Pedicles, Laminae, and a Spinous Process.
- Pedicles connect the body to the laminae.
- Laminae connect the spinous and transverse processes.
Vertebral foramen is an opening between the arch and the body, allowing for the spinal cord to pass.
Transverse process is the lateral projection of the arch.
Spinous process is the medial/posterior projection of the arch.
Superior and Inferior articular processes are paired projections lateral to the vertebral foramen that articulate between vertebrae.
- The superior process faces towards the spinous process and the inferior away.
Intervertebral Foramina are spaces in the pedicels that allow for spinal nerves to leave between the vertebrae.

Cervical Vertebrae

C1 and C2 have special functions and names.
- Atlas, C1, has no body and lateral processes with large depressions for the occipital condyles of the skull.
- Axis, C2, acts as a pivot for rotation of the atlas.
Pairs 11 and 12 are not attached to the sternum and are called Floating or Vertebral ribs.

Fetal Skeleton

Indentations between bones of the fetal skull are called fontanels, which are fibrous membranes. These ossify by 20-22 months after birth.
Fontanels allow for compression during birth and for the brain to grow.
There are four fontanels:
- Anterior
- Posterior
- Sphenoid
- Mastoid

Skull Depressions and Projections Summary

Supraorbital foramens (notch) are openings above each orbit that allow blood vessels and nerves to pass.
Coronal Suture is the point of articulation of the Frontal and Parietal Bones.
Sagittal Suture is the point of articulation of the Parietal bones.
Squamous Suture is the point of articulation of the temporal and parietal bones.
Zygomatic process forms the cheekbone.
Stylomastoid Foramen allows passage of CN VII (7).
Jugular Foramen allows passage of the Internal Jugular Vein and CN IX, X, XI (9, 10, 11).
Carotid Canal allows passage of the internal carotid artery.
Mandibular fossa is a rounded depression that articulates with the mandible.
The Styloid process is an attachment site for muscles and ligaments of the neck.

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Description

Explore the different types of bones including long, short, flat, irregular, sesamoid, and wormian bones. This quiz will also cover the anatomy of long bones, focusing on their structure and key features such as the diaphysis and periosteum.