This is necessary so that no single muscle group becomes fatigued too quickly. If any one group fails to function, body posture will be compromised. There are four pairs of abdominal muscles that cover the anterior and lateral abdominal region and meet at the anterior midline. These muscles of the anterolateral abdominal wall can be divided into four groups: the external obliques, the internal obliques, the transversus abdominis, and the rectus abdominis Figure and Figure.
Muscles of the Abdomen Movement Target Target motion direction Prime mover Origin Insertion Twisting at waist; also bending to the side Vertebral column Supination; lateral flexion External obliques; internal obliques Ribs 5—12; ilium Ribs 7—10; linea alba; ilium Squeezing abdomen during forceful exhalations, defecation, urination, and childbirth Abdominal cavity Compression Transversus abdominus Ilium; ribs 5—10 Sternum; linea alba; pubis Sitting up Vertebral column Flexion Rectus abdominis Pubis Sternum; ribs 5 and 7 Bending to the side Vertebral column Lateral flexion Quadratus lumborum Ilium; ribs 5—10 Rib 12; vertebrae L1—L4 There are three flat skeletal muscles in the antero-lateral wall of the abdomen.
Perpendicular to it is the intermediate internal oblique , extending superiorly and medially, the direction the thumbs usually go when the other fingers are in the pants pocket. The deep muscle, the transversus abdominis , is arranged transversely around the abdomen, similar to the front of a belt on a pair of pants.
This arrangement of three bands of muscles in different orientations allows various movements and rotations of the trunk. The three layers of muscle also help to protect the internal abdominal organs in an area where there is no bone. The linea alba is a white, fibrous band that is made of the bilateral rectus sheaths that join at the anterior midline of the body. Each muscle is segmented by three transverse bands of collagen fibers called the tendinous intersections. The posterior abdominal wall is formed by the lumbar vertebrae, parts of the ilia of the hip bones, psoas major and iliacus muscles, and quadratus lumborum muscle.
This part of the core plays a key role in stabilizing the rest of the body and maintaining posture. Physical Therapists Those who have a muscle or joint injury will most likely be sent to a physical therapist PT after seeing their regular doctor. Many PTs also specialize in sports injuries.
If you injured your shoulder while you were kayaking, the first thing a physical therapist would do during your first visit is to assess the functionality of the joint. The range of motion of a particular joint refers to the normal movements the joint performs. The PT will ask you to abduct and adduct, circumduct, and flex and extend the arm. The first step in physical therapy will probably be applying a heat pack to the injured site, which acts much like a warm-up to draw blood to the area, to enhance healing.
You will be instructed to do a series of exercises to continue the therapy at home, followed by icing, to decrease inflammation and swelling, which will continue for several weeks.
When physical therapy is complete, the PT will do an exit exam and send a detailed report on the improved range of motion and return of normal limb function to your doctor.
Gradually, as the injury heals, the shoulder will begin to function correctly. A PT works closely with patients to help them get back to their normal level of physical activity. The muscles of the chest serve to facilitate breathing by changing the size of the thoracic cavity Figure. When you inhale, your chest rises because the cavity expands. Alternately, when you exhale, your chest falls because the thoracic cavity decreases in size. The change in volume of the thoracic cavity during breathing is due to the alternate contraction and relaxation of the diaphragm Figure.
It separates the thoracic and abdominal cavities, and is dome-shaped at rest. The superior surface of the diaphragm is convex, creating the elevated floor of the thoracic cavity. The inferior surface is concave, creating the curved roof of the abdominal cavity. You hold your breath by a steady contraction of the diaphragm; this stabilizes the volume and pressure of the peritoneal cavity.
When the abdominal muscles contract, the pressure cannot push the diaphragm up, so it increases pressure on the intestinal tract defecation , urinary tract urination , or reproductive tract childbirth. A body that is lying down is described as either prone or supine. Prone describes a face-down orientation, and supine describes a face up orientation.
These terms are sometimes used in describing the position of the body during specific physical examinations or surgical procedures. Certain directional anatomical terms appear throughout this and any other anatomy textbook Figure.
These terms are essential for describing the relative locations of different body structures. Commit these terms to memory to avoid confusion when you are studying or describing the locations of particular body parts. Body Planes A section is a two-dimensional surface of a three-dimensional structure that has been cut. We call these scans. Body sections and scans can be correctly interpreted, however, only if the viewer understands the plane along which the section was made.
A plane is an imaginary two-dimensional surface that passes through the body. There are three planes commonly referred to in anatomy and medicine, as illustrated in Figure. Body Cavities and Serous Membranes The body maintains its internal organization by means of membranes, sheaths, and other structures that separate compartments. The dorsal posterior cavity and the ventral anterior cavity are the largest body compartments Figure.
These cavities contain and protect delicate internal organs, and the ventral cavity allows for significant changes in the size and shape of the organs as they perform their functions. The lungs, heart, stomach, and intestines, for example, can expand and contract without distorting other tissues or disrupting the activity of nearby organs. Subdivisions of the Posterior Dorsal and Anterior Ventral Cavities The posterior dorsal and anterior ventral cavities are each subdivided into smaller cavities.
In the posterior dorsal cavity, the cranial cavity houses the brain, and the spinal cavity or vertebral cavity encloses the spinal cord. Just as the brain and spinal cord make up a continuous, uninterrupted structure, the cranial and spinal cavities that house them are also continuous. The brain and spinal cord are protected by the bones of the skull and vertebral column and by cerebrospinal fluid, a colorless fluid produced by the brain, which cushions the brain and spinal cord within the posterior dorsal cavity.
The anterior ventral cavity has two main subdivisions: the thoracic cavity and the abdominopelvic cavity see Figure. The thoracic cavity is the more superior subdivision of the anterior cavity, and it is enclosed by the rib cage. The thoracic cavity contains the lungs and the heart, which is located in the mediastinum.
The diaphragm forms the floor of the thoracic cavity and separates it from the more inferior abdominopelvic cavity. The abdominopelvic cavity is the largest cavity in the body. Although no membrane physically divides the abdominopelvic cavity, it can be useful to distinguish between the abdominal cavity, the division that houses the digestive organs, and the pelvic cavity, the division that houses the organs of reproduction.
The more detailed regional approach subdivides the cavity with one horizontal line immediately inferior to the ribs and one immediately superior to the pelvis, and two vertical lines drawn as if dropped from the midpoint of each clavicle collarbone. There are nine resulting regions. A serous membrane also referred to a serosa is one of the thin membranes that cover the walls and organs in the thoracic and abdominopelvic cavities. The parietal layers of the membranes line the walls of the body cavity pariet- refers to a cavity wall.
The visceral layer of the membrane covers the organs the viscera. Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity Figure. There are three serous cavities and their associated membranes. The pleura is the serous membrane that encloses the pleural cavity; the pleural cavity surrounds the lungs. The pericardium is the serous membrane that encloses the pericardial cavity; the pericardial cavity surrounds the heart.
The peritoneum is the serous membrane that encloses the peritoneal cavity; the peritoneal cavity surrounds several organs in the abdominopelvic cavity. The serous membranes form fluid-filled sacs, or cavities, that are meant to cushion and reduce friction on internal organs when they move, such as when the lungs inflate or the heart beats.
Both the parietal and visceral serosa secrete the thin, slippery serous fluid located within the serous cavities. These include the spinal cord, the meninges of the spinal cord, and the fluid-filled spaces between them. This is the most narrow of all body cavities, sometimes described as threadlike.
The ventral cavity, the interior space in the front of the body, contains many different organ systems. The organs within the ventral cavity are also called viscera. The ventral cavity has anterior and posterior portions divided by the diaphragm, a sheet of skeletal muscle found beneath the lungs.
The thoracic cavity is the anterior ventral body cavity found within the rib cage in the torso. It houses the primary organs of the cardiovascular and respiratory systems, such as the heart and lungs, but also includes organs from other systems, such as the esophagus and the thymus gland. The thoracic cavity is lined by two types of mesothelium, a type of membrane tissue that lines the ventral cavity: the pleura lining of the lungs, and the pericadium lining of the heart.
The abdominoplevic cavity is the posterior ventral body cavity found beneath the thoracic cavity and diaphragm. It is generally divided into the abdominal and pelvic cavities. The abdominal cavity is not contained within bone and houses many organs of the digestive and renal systems, as well as some organs of the endocrine system, such as the adrenal glands. The pelvic cavity is contained within the pelvis and houses the bladder and reproductive system.
0コメント