Sistema esqueletal

Summary

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Takeaways

• 😀 The human skeleton is divided into two main parts: the axial skeleton (skull, spine, ribs, and sternum) and the appendicular skeleton (limbs and girdles).
• 😀 The axial skeleton provides structure and protection, consisting of vertebrae with distinct regions: cervical (7), thoracic (12), lumbar (5), sacral (5 fused), and coccyx (2-4 fused).
• 😀 The cervical vertebrae (C1 and C2) are special, with C1 (atlas) allowing head rotation and C2 (axis) acting as the pivot for this movement.
• 😀 Thoracic vertebrae are identified by facets for rib articulation, providing structural support for the ribs.
• 😀 Lumbar vertebrae are larger, more robust, and help support the weight of the upper body.
• 😀 The sacrum consists of fused sacral vertebrae, while the coccyx contains fused remnants of the tailbone.
• 😀 There are 12 pairs of ribs: 7 true ribs, 3 false ribs (which connect to the sternum via cartilage), and 2 floating ribs that do not connect to the sternum.
• 😀 The sternum consists of three parts: the manubrium, the body, and the xiphoid process.
• 😀 The appendicular skeleton includes the limbs and girdles, such as the scapula and clavicle in the upper limbs, and the pelvic girdle formed by the coxal bones, sacrum, and acetabulum.
• 😀 The joints in the human body can be categorized as synarthroses (immovable), amphiarthroses (slightly movable), and diarthroses (freely movable), with synovial joints being the most common type.

Q & A

What are the main components of the axial skeleton?

The axial skeleton consists of the vertebral column, ribs, sternum, and skull. It supports the central axis of the body and includes structures such as the cervical, thoracic, and lumbar vertebrae, as well as the sacrum and coccyx.

How is the vertebral column divided, and what are the characteristics of each part?

The vertebral column is divided into five regions: cervical (7 vertebrae), thoracic (12 vertebrae), lumbar (5 vertebrae), sacral (5 fused vertebrae), and coccygeal (2-4 fused vertebrae). The cervical region has small vertebrae with an opening for spinal nerves, the thoracic region articulates with the ribs, and the lumbar region is larger to support body weight.

What is the function of the atlas and axis vertebrae?

The atlas (C1) and axis (C2) allow for the movement of the head. The atlas supports the skull and allows for the nodding motion, while the axis enables rotation of the head, as it functions as the pivot for the atlas.

What are the differences between true, false, and floating ribs?

True ribs (1–7) directly connect to the sternum. False ribs (8–10) connect to the sternum via a shared cartilage. Floating ribs (11–12) do not connect to the sternum at all.

What are the key characteristics of the pelvis and its bones?

The pelvis consists of two coxal bones (ilium, ischium, pubis) and the sacrum. The coxal bones fuse around the age of 20 to form a structure that supports the weight of the body and allows for the attachment of the legs. The acetabulum, formed by the fusion of these bones, is the socket that receives the head of the femur for hip joint articulation.

What is the role of the clavicle in the shoulder girdle?

The clavicle, or collarbone, connects the arm to the body by articulating with the sternum and the acromion of the scapula. It helps stabilize the shoulder and supports arm movement.

How do the upper limb bones interact in movement?

The humerus connects to the scapula to form the shoulder joint. The radius and ulna connect to the humerus and each other to allow for the movements of flexion, extension, and pronation/supination at the elbow and wrist.

What makes the femur a crucial bone in the human body?

The femur is the longest bone in the body and supports the weight of the body during standing, walking, and running. It articulates with the pelvis at the hip joint and with the tibia and fibula at the knee joint.

What are the types of joints in the body, and how are they classified?

Joints are classified into three types based on mobility: synarthrosis (immovable), amphiarthrosis (slightly movable), and diarthrosis (freely movable). Examples include sutures in the skull (synarthrosis), intervertebral joints (amphiarthrosis), and shoulder or knee joints (diarthrosis).

How is the structure of the hand similar to that of the foot?

Both the hand and foot have a similar bone structure with metacarpals/metatarsals and phalanges. The foot has tarsal bones (like the hand's carpal bones) and an arrangement that supports walking and weight-bearing, while the hand is specialized for manipulation.