Unit 8A - The Musculoskeletal System
The musculoskeletal system is a complex network of bones, muscles, and joints, along with
cartilage, tendons, ligaments, and connective tissue. This system gives the body its structure
and support and works together to allow the ability to move. The musculoskeletal system works
in harmony with other body systems, such as the nervous system and circulatory system, to
enable movement, support body weight, protect internal organs, and maintain posture. It plays
a crucial role in everyday activities as well as in more specialized movements like sports and
exercise. Additionally, the musculoskeletal system is essential for the production of blood cells
within the bone marrow and serves as a mineral reservoir for calcium and phosphorus.
The Skeleton
The adult human skeleton consists of 206 bones organized into the axial skeleton and the
appendicular skeleton. Overall, the skeleton forms a framework and support for the body and
allows it to move.
,https://as2.ftcdn.net/v2/jpg/00/38/27/47/500_F_38274711_akQrCPPlv5VtOAVEVXGAomnFkY7DEfZf.jpg
1) Cranial Portion 2) Facial Portion 3) Clavicle 4) Scapula 5) Sternum 6) Ribs 7) Humerus 8) Ulna
9) Radius 10) Carpals 11) Phalanges 12) Metacarpals 13) Femur 14) Patella 15) Tibia 16) Fibula
17) Calcaneus 18) Tarsals 19) Metatarsals 20) Phalanges 21) Vertebral Column 22) Pelvic Girdle
23) Sacrum 24) Pubic Symphysis 25) Ischium 26) Ilium 27) Coccyx
The Axial Skeleton
The axial skeleton consists of 80 bones in the centre of the body. It includes bones in the skull
(cranial portion and facial portion), the ossicles of the middle of the ear, the hyoid bone of the
neck, the vertebrae, and the thoracic cage. The axial skeleton primarily supports and protects
the heart, lungs and the central nervous system which is the brain and the spinal cord.
The skull is a complex structure of 22 bones that forms the head's framework, providing crucial
protection and support. It consists of the cranial bones and facial bones. The cranial bones
(eight in total) encase and safeguard the brain, one of the body's most vital organs, while also
providing attachment points for head and neck muscles. The facial bones (fourteen in total)
construct the face's architecture, housing the sensory organs for sight, smell, and taste, and
,facilitating essential functions such as breathing, eating, and speaking. The skull also contains
foramina and canals that allow the passage of nerves and blood vessels, ensuring proper
neurological and circulatory connections between the brain and other body parts. Overall, the
skull's primary functions are to protect the brain, support sensory structures, and provide a
foundation for facial expression and mastication.
The ear structures are classically divided into 3 parts: the external ear, the middle ear, and the
inner ear. The middle ear consists of the tympanic membrane and the bony ossicles called the
malleus, incus, and stapes. These 3 ossicles connect the tympanic membrane to the inner ear,
allowing sound wave transmission.
The vertebrae are the individual bones that compose the vertebral column, a pivotal structure
in the axial skeleton. There are 33 vertebrae in total, which are categorized into 5 regions: 7
cervical vertebrae in the neck, 12 thoracic vertebrae in the upper back, 5 lumbar vertebrae in
the lower back, 5 fused sacral vertebrae forming the sacrum, and 4 fused coccygeal vertebrae
making up the coccyx or tailbone. The primary function of the vertebrae is to protect the spinal
cord, a critical component of the central nervous system that transmits neural signals between
the brain and the rest of the body. Additionally, the vertebrae provide structural support,
allowing humans to maintain an upright posture and enabling a wide range of movements,
including bending, twisting, and rotating. Intervertebral discs between the vertebrae act as
shock absorbers, cushioning the impact during activities such as walking, running, and lifting.
The thoracic cage, also known as the rib cage, is a bony framework formed by the thoracic
vertebrae, ribs, and sternum. It consists of twelve pairs of ribs, each connected to the twelve
thoracic vertebrae at the back and most to the sternum at the front via costal cartilage.
Primarily, it protects the heart, lungs, and major blood vessels from physical damage but also
provides structural support for the upper body, enabling an upright posture. The flexible nature
of the rib attachments allows for the expansion and contraction of the chest cavity during
respiration, facilitating efficient breathing. The rib cage also serves as an anchor point for
muscles of the neck, back, and upper abdomen, contributing to the stability and movement of
these regions.
, https://s3-us-west-2.amazonaws.com/courses-
images/wp-content/uploads/sites/1223/2017/02/07233902/Figure_38_01_04.jpg
The musculoskeletal system is a complex network of bones, muscles, and joints, along with
cartilage, tendons, ligaments, and connective tissue. This system gives the body its structure
and support and works together to allow the ability to move. The musculoskeletal system works
in harmony with other body systems, such as the nervous system and circulatory system, to
enable movement, support body weight, protect internal organs, and maintain posture. It plays
a crucial role in everyday activities as well as in more specialized movements like sports and
exercise. Additionally, the musculoskeletal system is essential for the production of blood cells
within the bone marrow and serves as a mineral reservoir for calcium and phosphorus.
The Skeleton
The adult human skeleton consists of 206 bones organized into the axial skeleton and the
appendicular skeleton. Overall, the skeleton forms a framework and support for the body and
allows it to move.
,https://as2.ftcdn.net/v2/jpg/00/38/27/47/500_F_38274711_akQrCPPlv5VtOAVEVXGAomnFkY7DEfZf.jpg
1) Cranial Portion 2) Facial Portion 3) Clavicle 4) Scapula 5) Sternum 6) Ribs 7) Humerus 8) Ulna
9) Radius 10) Carpals 11) Phalanges 12) Metacarpals 13) Femur 14) Patella 15) Tibia 16) Fibula
17) Calcaneus 18) Tarsals 19) Metatarsals 20) Phalanges 21) Vertebral Column 22) Pelvic Girdle
23) Sacrum 24) Pubic Symphysis 25) Ischium 26) Ilium 27) Coccyx
The Axial Skeleton
The axial skeleton consists of 80 bones in the centre of the body. It includes bones in the skull
(cranial portion and facial portion), the ossicles of the middle of the ear, the hyoid bone of the
neck, the vertebrae, and the thoracic cage. The axial skeleton primarily supports and protects
the heart, lungs and the central nervous system which is the brain and the spinal cord.
The skull is a complex structure of 22 bones that forms the head's framework, providing crucial
protection and support. It consists of the cranial bones and facial bones. The cranial bones
(eight in total) encase and safeguard the brain, one of the body's most vital organs, while also
providing attachment points for head and neck muscles. The facial bones (fourteen in total)
construct the face's architecture, housing the sensory organs for sight, smell, and taste, and
,facilitating essential functions such as breathing, eating, and speaking. The skull also contains
foramina and canals that allow the passage of nerves and blood vessels, ensuring proper
neurological and circulatory connections between the brain and other body parts. Overall, the
skull's primary functions are to protect the brain, support sensory structures, and provide a
foundation for facial expression and mastication.
The ear structures are classically divided into 3 parts: the external ear, the middle ear, and the
inner ear. The middle ear consists of the tympanic membrane and the bony ossicles called the
malleus, incus, and stapes. These 3 ossicles connect the tympanic membrane to the inner ear,
allowing sound wave transmission.
The vertebrae are the individual bones that compose the vertebral column, a pivotal structure
in the axial skeleton. There are 33 vertebrae in total, which are categorized into 5 regions: 7
cervical vertebrae in the neck, 12 thoracic vertebrae in the upper back, 5 lumbar vertebrae in
the lower back, 5 fused sacral vertebrae forming the sacrum, and 4 fused coccygeal vertebrae
making up the coccyx or tailbone. The primary function of the vertebrae is to protect the spinal
cord, a critical component of the central nervous system that transmits neural signals between
the brain and the rest of the body. Additionally, the vertebrae provide structural support,
allowing humans to maintain an upright posture and enabling a wide range of movements,
including bending, twisting, and rotating. Intervertebral discs between the vertebrae act as
shock absorbers, cushioning the impact during activities such as walking, running, and lifting.
The thoracic cage, also known as the rib cage, is a bony framework formed by the thoracic
vertebrae, ribs, and sternum. It consists of twelve pairs of ribs, each connected to the twelve
thoracic vertebrae at the back and most to the sternum at the front via costal cartilage.
Primarily, it protects the heart, lungs, and major blood vessels from physical damage but also
provides structural support for the upper body, enabling an upright posture. The flexible nature
of the rib attachments allows for the expansion and contraction of the chest cavity during
respiration, facilitating efficient breathing. The rib cage also serves as an anchor point for
muscles of the neck, back, and upper abdomen, contributing to the stability and movement of
these regions.
, https://s3-us-west-2.amazonaws.com/courses-
images/wp-content/uploads/sites/1223/2017/02/07233902/Figure_38_01_04.jpg
