The Skeletal System

Summary

This script offers an in-depth exploration of the human skeleton, highlighting its two main parts: the axial skeleton, consisting of the skull, vertebral column, and thoracic cage, and the appendicular skeleton, comprising the limbs. It details the skull's 22 bones, the spine's 26 vertebrae, and the thoracic cage's ribs and sternum. The limbs are dissected, from the clavicle and scapula to the intricate bones of the hands and feet, emphasizing the skeleton's complexity and function in supporting and protecting the body.

Takeaways

• 🦴 The human skeleton consists of around 206 bones, cartilage, joints, and ligaments, making up approximately 20% of an adult's body mass.
• 💀 The skull is made of 22 different bones, divided into cranial bones that protect the brain and facial bones that structure the face.
• 🔒 The cranium's bones are connected by sutures, including the coronal, sagittal, lambdoid, squamous, and occipitomastoid sutures.
• 🕳️ The skull features foramina, such as the foramen magnum, which allows the passage of the spinal cord.
• 🦷 The mandible is the lower jawbone, and the maxillary bones form the upper jaw and part of the face.
• 📐 The vertebral column, or spine, is composed of 26 irregular bones, divided into cervical, thoracic, lumbar, sacral, and coccygeal sections.
• 🌈 The spine supports the body in an S-shape, with intervertebral discs acting as shock absorbers.
• 🏗️ The thoracic cage includes the sternum and ribs, with costal cartilage connecting them to the spine.
• 🦾 The appendicular skeleton includes the limbs, pectoral girdle, and pelvic girdle, providing attachment and mobility.
• 🤲 The upper limb has the humerus in the arm, radius and ulna in the forearm, and multiple bones in the wrist and hand.
• 🦵 The lower limb features the femur in the thigh, tibia and fibula in the leg, and tarsals, metatarsals, and phalanges in the foot.

Q & A

How many bones are there in the adult human skeleton?

There are around two hundred and six bones in the adult human skeleton.

What are the main components of the skeletal system besides bones?

Besides bones, the skeletal system also includes cartilage, joints, and ligaments, which together make up around twenty percent of a person’s body mass.

What are the two main sections of the human skeleton?

The two main sections of the human skeleton are the axial skeleton and the appendicular skeleton.

What are the functions of the cranial bones in the skull?

The cranial bones in the skull serve to protect the brain, while the facial bones provide structure to the face.

How many bones make up the cranium and what are some of their names?

The cranium is made up of eight bones: the frontal bone, two parietal bones, the occipital bone, two temporal bones, the sphenoid bone, and the ethmoid bone.

What is the function of the sutures in the skull?

Sutures are the lines where most of the bones in the skull are connected, allowing for growth and providing some flexibility.

What is the vertebral column made up of and what is its general shape?

The vertebral column, also known as the spine, is made up of twenty-six irregular bones that form a flexible, curvy S-shape structure.

How many sections can the spine be divided into and what are they?

The spine can be divided into five sections: cervical vertebrae (7), thoracic vertebrae (12), lumbar vertebrae (5), sacrum, and coccyx.

What is the function of the intervertebral discs in the spine?

The intervertebral discs act as shock absorbers between each vertebra, providing cushioning during movement.

What is the composition of the thoracic cage and its role?

The thoracic cage is composed of the sternum, ribs, and costal cartilage. It provides protection for the organs in the thorax and contributes to the respiratory process.

What are the two main components of the appendicular skeleton and their functions?

The appendicular skeleton is mainly composed of the limbs and the pectoral and pelvic girdles, which attach the limbs to the axial skeleton and provide support and mobility.

How many bones are there in each hand and foot, and what are their types?

Each hand has 27 bones: 8 carpals, 5 metacarpals, and 14 phalanges. Each foot has 26 bones: 7 tarsals, 5 metatarsals, and 14 phalanges.

What is the significance of the foramen magnum in the skull?

The foramen magnum is a large hole at the base of the skull through which the spinal cord passes to connect with the brain.

What are the main ligaments in the spine and their functions?

The main ligaments in the spine include the anterior and posterior longitudinal ligaments, which run down the front and back of the column, and shorter ligaments that connect adjacent vertebrae. They help to hold the vertebrae together and provide stability.

What is the difference between true ribs and false ribs in the thoracic cage?

True ribs are the first seven pairs that attach directly to the sternum via costal cartilage. False ribs are the remaining five pairs, with three attaching indirectly to the sternum and the last two, the floating ribs, not attaching to the sternum at all.