What Are Sternal Wires?

The bone that is curved in the shape of an arch at the front of the torso is a rib, whose proximal end is connected to the spine, and the distal end is free or connected to the sternum by rib cartilage to form the thorax.

Ribs and sternum

Right!

Chinese name: Ribs and sternum

Foreign name: Ribs and chest

Bowed at the front of the torso

Ribs and sternum mammals

The mammal's sternum consists of a series of bone fragments (6 in rabbits and 8 in cats and dogs) located in the center of the chest wall. The first section is the sternal stalk, the middle section is called the sternum body, and the last section is the sword sternum. The end is connected with a wide and flat cartilage called sword-shaped cartilage.
The thorax is composed of the thoracic spine, ribs, and sternum connected by joints and ligaments. Fishes do not have sternum, and tailless amphibians do not have ribs. Only amnion, reptiles, birds, mammals, sternum and ribs have been developed. They form the thorax with the thoracic spine. This is linked to the development of terrestrial animal lungs. In addition to protecting the heart and lungs, the rib cage can also change the volume of the chest cavity through its own activities, which directly affects lung breathing.
The mammalian thorax has a truncated cone shape. The front mouth is called the anterior chest, and the posterior mouth is called the posterior chest. It is closed by the diaphragm. The thoracic cavity is the bone cavity, which is formed by the intercostal muscles and diaphragm. Breathing in mammals is achieved by the expansion and contraction of the thorax. The expansion and contraction of the thorax depends on the contraction of the intercostal muscles to change the position of the ribs, and also depends on the elevation of the diaphragm. The enlargement of the thorax during inhalation is usually the result of the synergy of the lowering of the diaphragm (the diaphragm contraction) and the raising of the ribs (the contraction of the external intercostal muscles). Combined with rib traction downward (intercostal muscle contraction).

Ribs and sternum amphibian

Tailless amphibians begin to have more developed sternum. But there are no obvious ribs, so the sternum is not connected to the spine, but only to the shoulder strap.

Ribs and sternum reptiles

Vertebrates above vertebrates have sternum. The sternum of the lizard is a cartilage plate located in the midline of the abdomen. The sternum of the turtle's sternum participates in the formation of the bone plate. The snake has no sternum.

Ribs and sternum

Animals (such as the lamprey) have no ribs, which is related to their lack of vertebral bodies. Cartilaginous fish (such as sharks) begin to have ribs, but are very underdeveloped. From the cross-section of the trunk, we can see that on both sides of the ventral surface of the vertebra, there are small cartilage strips, which are ribs. The bones of a teleost fish are long and arc-shaped, and there is only one joint head at the proximal end of the ribs, which is called a single-headed rib. The earliest amphibians (fishstone salamanders) run from the atlas to the end of the vertebra, and each vertebra is connected to a pair of developed ribs. The ribs of modern amphibians have been degraded; the ribs are short, cannot connect to the sternum, and have no effect on breathing. The ribs of the tailed amphibian are double-headed, which is a typical type of tetrapod ribs. The ribs form a joint with the spine with two ends, one is called the rib head and connected to the vertebra, and the other is called the rib nodule, which is connected to the transverse process. The ribs of a tailless amphibian (such as a frog) are single-headed. The ribs are not visible in the adult frog, but the degenerate ribs are connected to the ends of the transverse processes during embryonic development. Reptiles have ribs on both sides of the cervical, thoracic, and lumbar spine. The neck ribs are generally double-headed, and the chest ribs are mostly single-headed. Except for the atlas and pivot, the snake's torso has developed ribs. The distal end of the ribs has ligaments connected to the abdominal scales. The activities of the ribs dominate the abdominal scales to complete the snake's crawling. Wedge-toothed lizards and crocodiles also have abdominal ribs on the ventral surface of the body, which are degenerative bone plates that belong to the membranous prosthesis and are ossified from the dermis.

Ribs and sternum turtles

The turtle's cervical spine has no ribs. Its 10 vertebrae have long, flat ribs, and its back is healing with the carapace. The sacrum also has ribs. The distal end of the sacrum is enlarged and connected to the sacrum of the belt. Birds have ribs in five areas of the spine. The ribs of the cervical spine mostly heal with the vertebrae at both ends, so a hole is formed in the middle, and the vertebral artery passes through. The front ribs of the vertebrae are connected to the sternum and are called true ribs; the back of the ribs are not connected to the sternum and are called false ribs. True ribs are divided into vertebrae and sternum. The vertebrae and sternum of a bird are hard bones (the mammal's sternum is cartilage).

Ribs and sternum birds

Most of the bird's vertebral ribs have hook-shaped processes protruding backwards, which are placed on the rear ribs to enhance the rigidity of the thorax. The ribs of the lumbar, sacral, and coccygeal vertebrae all heal in the comprehensive sacrum. The number of ribs in mammals varies widely, from 9 pairs (certain whales) to 24 pairs (scoters). The number of ribs corresponds to the number of thoracic vertebrae. There are real ribs, false ribs, and floating ribs at the ends of the ribs. Each rib is divided into vertebral end, rib body and sternum end. The vertebra ends have rib heads, rib necks, and rib nodules. The rib head forms a joint with the rib fossa between the two vertebral bodies of the thoracic spine, and the rib nodules and the thoracic vertebra process form a joint. The thinner part between the rib head and rib nodules is called the rib neck. Ornithians have well-developed sternum bones with towering keel protrusions in the center of the sternum to enlarge the attachment surface of the pectoral muscles. This kind of keel-like bird is classified into the group of thoracic birds, which are more good at flying and account for the vast majority of birds. The few birds that are not good at flying (such as ostriches) have flat sternum and no keel protrusion. It belongs to the class of flat breasted birds.

Ribs and sternum fish

Fishes do not have a sternum, and sternums have appeared since amphibians, but primitive amphibians, such as Apodoptera and Crustacea (such as cave salamanders, three-finger salamanders, etc.) do not have sternum. The structure of the sternum in caudal amphibians is only a simple cartilage plate. The sternum of the loach is just a few scattered cartilage centers on the muscle compartment of the shoulder belt.