The abdominal cavity extends from the lower border of the ribs to the pelvis. The abdominal wall is made up of muscle, layers of connective tissue, and fat and is lined by a thin double layered membrane called the periosteum. The abdominal cavity contains all of the organs of the digestive system and the genitourinary system. Research Abdominal Cavity
The compact bone tissue serves as the outer shell of the bone and serves to protect the inner core of spongy bone (trebiculae, or substantia spongiosa). The compact bone shell is particularly thick in the middle of the shaft in long bones in order to protect the bone against bending. The compact bone is covered by the periosteum. Research Compact Bone
The diaphysis, or shaft, of a long bone features a shell of compact bone surrounded by the periosteum, a cartilaginous membrane which contains the blood vessels which provide nutrients to the bone. The diaphysis is separated from the epiphyses of the bone by the epiphyseal line. Research Diaphysis
Empyema thoracis is the condition of pusformation in the pleural space. The pleural effusion which accompanies infective conditions of the lung may itself become infected and form pus. A lung abscess may burst into the pleural space. Haemothorax may become infected. The symptoms which the condition produces depend on the amount of puspresent, and the degree of compression of, or disease in, the underlying lungs. There is some embarrassment of respiration, and 'swinging' fever, typically present whenever pus has accumulated in the body. Fever may sometimes be absent, especially if the patient is being treated with antibiotics. The patient with an empyema is severely toxic, looks ill, loses weight rapidly and becomes severely anaemic. If the pus is sufficiently thin to be removed through a needle, then the treatment is entirely by aspiration. Penicillin or other antibiotic solution may be injected into the pleural space after the withdrawal of the pus. Aspiration needs to be repeated daily until lung expansion is adequate. If the pus becomes too
thick for aspiration, the empyema is treated by one of two surgical methods: (a) A small intercostal incision is made and a large self- retaining catheter placed into the pleural space to allow the escape of pus. The catheter is connected to an under-water seal. This method of intercostal drainage is rarely used but it is sometimes suitable for children. (b) Rib resection and drainage by a wide-bore tube. Part of one rib is removed and the pleural space opened through its periosteum. This tube may be left open at its outer end or may be attached to an under-water seal. One type of tube is the 'Tudor- Edward' empyema tube which has an additional small rubber side tube through which the empyema cavity can be irrigated. Research Empyema Thoracis
The periosteum is the tough, vascular membrane which covers the surface of a bone, except for the articular cartilage. The periosteum contains the blood vessels which supply nutrients to the bones enabling them to regenerate. The bones of the skull feature no such periosteum, and so cannot regenerate themselves. The periosteum also facilitates the regeneration of bone by serving as a confining membrane for the deposition of new bone cells, insuring that any regeneration of osseous material is added to the pre-existing bone. Research Periosteum
The skull is one of the principle groups of bones in the human anatomy. The skull consists of twenty-six bones: eight bones form the skull, which houses the brain and ear ossicles, plus fourteen facial bones, which form the front of the face, jaw, nose, orbits, and the roof of the mouth, three more bones make up the inner ear ossicles, and one more, the hyoid bone, is in the neck and is attached to the temporal bone by ligaments and anchors the tongue. The skull also contains a dental arcade of teeth, which are technically not bones, though they do share some of the compositional characteristics of bonetissue. Children may grow twenty deciduousteeth, which will eventually fall out and be replaced by the permanent teeth.
The bones of the skull include the frontal bone, the occipital bone, two parietal bones, and two temporal bones. The lower rearmost part of each temporal bone is called the mastoid process, but because it is separated from the temporal bone, proper, by a suture, it is often considered a separate bone. The sphenoid bone forms the central base of the skull and spans the skull from side to side, the greater wings forming side plates of the skull. The sections of the ethmoid bone are positioned between the orbits, forming the walls and roof of the nasal cavity, while the three middle ear ossicles (stapes, malleus, and incus) are located within the temporal bones on each side of the skull. The U-shaped hyoid bone is found in the neck, and is attached by ligaments to the temporal bones. In the face, the two maxillary bones form much of the orbits, nose, upper jaw and roof of the mouth, while the zygomatic bones form the cheeks. The lachrymal bones are located on the inner sides of the orbits and are attached to the ethmoid bone and maxillary bones. Within the nasal cavity, the vomer is located in the low center and forms the thin flat bone of the nasalseptum, while two inferior urbinates form the lower sides of the cavity and two palate bones form the floor of the nasal cavity as well as the roof of the mouth.
The mandible is the only movable part of the skull, forming the lower jaw and mounting the teeth. The bones of the skull, with the exception of the mandible, are held together by very thin sutures, or seams, in which the periosteum of the individual bones interweave with each other, and are cemented by a fibrous, connective tissue. In the newborn, these sutures are not yet developed, with the bones being attached by cartilage which ossifies over time as the bones of the skull fuse together. The most evident external sutures of the skull include the coronal suture, joining the frontal bone and parietal bone, the sagittal suture, joining the parietal bones to each other, the lambdoid suture, joining the occipital and parietal bones, the squamous suture, joining the temporal and sphenoid bones to the parietal bone on each side of the skull.
The pterion is the short segment of the suture joining the squamous and parietal bones. The bones of the skull also feature a number of sinuses and foramina. Four pairs of sinuses flank the nasal cavity. Two are found in the maxillary bone, and are called maxillary sinuses. The sphenoid bone forms two paranasal sinuses called the sphenoids, and the ethmoid bone forms the two paranasal sinuses called ethmoids. Additionally, the frontal sinuses are located in the frontal bone just behind the roof of each orbit. The foramen magnum is a large, round opening in the base of the skull which admits the spinal cord, while at the base of each temporal bone is the external auditory meatus, which serve as the auditory canals. Just above each orbit in the frontal bone is a small notch or hole, called a supraorbital foramen, and just below each orbit, in the maxillary bone, is an infraorbital foramen. Two more openings, one on each side of the skull, can be found in the frontal processes of the zygomatic bones, and are called zygomatofacial foramina.
On each side of the mandible, just below the lower canines, are the mental foramina. These facial foramina serve to admit blood vessels and nerves through and into the bone. The teeth are mounted in the maxillary bone and the mandible, and are brought together for chewing by the hinge-like motion of the mandible. An average adult will have thirty-two teeth, evenly arrayed on the maxilla and mandible. Research Skull
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Abdominal Cavity
