The human torso skeleton has the spine and thorax . Spine The spine (diagram 25) - is the main axis of the body, a receptacle for the spinal cord. I

Torso skeleton (spine and chest) [human trunk]

The human torso skeleton has the spine and thorax.

Spine

The spine (diagram 25) — is the main axis of the body, a receptacle for the spinal cord. It has 33-34 vertebrae. All five parts of the spine — cervical, thoracic, lumbar, sacral and coccygeal — have more or less the same structure. In the middle of the spine there is a hole for the spinal cord.

The first cervical vertebra — atlas — has a special structure (diagram 25). On the upper surface is located glenoid fossa for connection with the occipital bone of the skull. A back and forth movement of the head performs due to this joint. The second cervical vertebra — epistrophe — has a tooth-like outgrowth, which enters in a special hole of the atlas (Fig 26.). The rotation of the head performs around this outgrowth.

In the spine transition from the cervical to the sacral, the vertebrae mass and area increase, and sacral even coalesce, forming a strong sacral bone or sacrum. Vertebrae end with 4-5 fused rudimentary vertebrae — the coccyx.

Diagram 25. The structure of the spine and vertebrae: 1 — neck; 2 — chest; 3 — lumbar; 4 — sacral; 5 — the coccyx; 6 — spinous outgrowth; 7 — transverse outgrowths; 8 — articular surface for connection with the rib; 9 — the body; 10 — arc; 11 — hole for the spinal cord
Diagram 26. Cervical vertebrae: a) connected by a spine (side view); b) connected by a spine (top view); c) atlas: 1 — upper glenoid fossa; 2 — anterior lobe; 3 — rear bump; 4 — lower articular surface; d) epistrophe: 5 — tooth axis; 6 — spinous outgrowth; 7 — upper articular surface; 8 — lower articular surface

Vertebrae are connected by cartilage and ligaments with each other (diagram 27), that, on the one hand, prevent their displacement relatively to each other, and on the other — provide a certain flexibility of the spine. Vertebrae have lip for the muscles attachment.

Human spine has four small bends (diagram 28), which allows the preservation of equilibrium, springs and soften shocks.

Thorax (chest)

Thorax (diagram 29) consists of the sternum and 12 ribs, which are attached to the sternum in front, and to the 12 thoracic vertebrae on the rear. Connection of ribs with the sternum and vertebrae is flexible enough, so the chest can increase its volume during inspiration and decrease as you exhale. In humans, it, unlike other mammals, is extended at the bottom. Taken from http://worldofschool.org

Diagram 27. The connection between the vertebrae: 1 — the cartilage between the vertebrae; 2 — ligaments between the vertebrae; 3 — vertebral body
Diagram 28. Formation of the curves of the spine begins in childhood
Diagram 29. The structure of the thorax: 1 — sternum; 2 — ribs; 3 — thoracic vertebrae
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Questions:
  • Describe the relationship of the human torso skeleton structure and functions.