| Intercostal space | |
|---|---|
 Intercostal spaces, viewed from the right. | |
 Sternocostal and interchondral articulations. Anterior view. | |
| Details | |
| Identifiers | |
| Latin | spatium intercostale |
| TA98 | A02.3.04.007 |
| TA2 | 1102 |
| FMA | 12243 |
| Anatomical terminology | |
The intercostal space (ICS) is the anatomic space between two ribs (Lat. costa). Since there are 12 ribs on each side, there are 11 intercostal spaces, each numbered for the rib superior to it. [1]
There are 3 muscular layers in each intercostal space, consisting of the external intercostal muscle, the internal intercostal muscle, and the thinner innermost intercostal muscle. [2] [3] These muscles help to move the ribs during breathing. [4]
Neurovascular bundles are located between the internal intercostal muscle and the innermost intercostal muscle. [3] The neurovascular bundle has a strict order of vein-artery-nerve (VAN), from top to bottom. [2] This neurovascular bundle runs high in the intercostal space, and the smaller collateral neurovascular bundle runs just superior to the lower rib of the space (in the order NAV from superior to inferior). Invasive procedures such as thoracentesis are performed with oblique entry of the instrument, directly above the upper margin of the relevant rib, to avoid damaging the neurovascular bundles. [2]
In reference to the muscles of the thoracic wall, the intercostal nerves and vessels run posterior to the internal intercostal muscles: therefore, they are generally covered on the inside by the parietal pleura, except when they are covered by the innermost intercostal muscles, innermost intercostal membrane, subcostal muscles or the transversus thoracis muscle.
The intercostal muscles comprise many different groups of muscles that run between the ribs, and help form and move the chest wall. The intercostal muscles are mainly involved in the mechanical aspect of breathing by helping expand and shrink the size of the chest cavity.
Pectoralis minor muscle is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major in the human body. It arises from ribs III-V; it inserts onto the coracoid process of the scapula. It is innervated by the medial pectoral nerve. Its function is to stabilise the scapula by holding it fast in position against the chest wall.
The rectus abdominis muscle, also known as the "abdominal muscle" or simply the "abs", is a pair of segmented skeletal muscle on the ventral aspect of a person's abdomen. The paired muscles are separated at the midline by a band of dense connective tissue called the linea alba, and the connective tissue defining each lateral margin of the rectus abdominus is the linea semilunaris. The muscle extends from the pubic symphysis, pubic crest and pubic tubercle inferiorly, to the xiphoid process and costal cartilages of the 5th–7th ribs superiorly.
The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis.
In human anatomy, the internal thoracic artery (ITA), previously commonly known as the internal mammary artery, is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with one running along each side of the sternum, to continue after its bifurcation as the superior epigastric and musculophrenic arteries.
The transversus thoracis muscle, also known as triangularis sterni, lies internal to the thoracic cage, anteriorly. It is usually a thin plane of muscular and tendinous fibers, however on athletic individuals it can be a thick 'slab of meat', situated upon the inner surface of the front wall of the chest. It is in the same layer as the subcostal muscles and the innermost intercostal muscles.
In human anatomy, the axillary vein is a large blood vessel that conveys blood from the lateral aspect of the thorax, axilla (armpit) and upper limb toward the heart. There is one axillary vein on each side of the body.
The facial artery is a branch of the external carotid artery that supplies structures of the superficial face.
The anterior superior iliac spine (ASIS) is a bony projection of the iliac bone, and an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis. It provides attachment for the inguinal ligament, and the sartorius muscle. The tensor fasciae latae muscle attaches to the lateral aspect of the superior anterior iliac spine, and also about 5 cm away at the iliac tubercle.
In human anatomy, the inferior epigastric artery is an artery that arises from the external iliac artery. It is accompanied by the inferior epigastric vein; inferiorly, these two inferior epigastric vessels together travel within the lateral umbilical fold The inferior epigastric artery then traverses the arcuate line of rectus sheath to enter the rectus sheath, then anastomoses with the superior epigastric artery within the rectus sheath.
In human anatomy, the superior epigastric artery is a terminal branch of the internal thoracic artery that provides arterial supply to the abdominal wall, and upper rectus abdominis muscle. It enters the rectus sheath to descend upon the inner surface of the rectus abdominis muscle. It ends by anastomosing with the inferior epigastric artery.
The lingual artery arises from the external carotid artery between the superior thyroid artery and facial artery. It can be located easily in the tongue.
The lateral sacral arteries is an artery in the pelvis that arises from the posterior division of the internal iliac artery. It later splits into two smaller branches, a superior and an inferior.
The inferior rectal artery is an artery that supplies blood to the lower third of the anal canal below the pectinate line.
The innermost intercostal muscle is a layer of intercostal muscles. It may also be called the intima of the internal intercostal muscles. It is the deepest muscular layer of the thorax, with muscle fibres running vertically. It is present only in the middle of each intercostal space, and often not present higher up the rib cage. It lies deep to the plane that contains the intercostal nerves and intercostal vessels, and the internal intercostal muscles. The diaphragm is continuous with the innermost intercostal muscle.
The right colic artery is an artery of the abdomen, a branch of the superior mesenteric artery supplying the ascending colon. It divides into two terminal branches - an ascending branch and a descending branch - which form anastomoses with the middle colic artery, and ileocolic artery (respectively).
The perineal nerve is a nerve of the pelvis. It arises from the pudendal nerve in the pudendal canal. It gives superficial branches to the skin, and a deep branch to muscles. It supplies the skin and muscles of the perineum. Its latency is tested with electrodes.
The superior rectal artery is an artery that descends into the pelvis to supply blood to the rectum.
The triangle of auscultation is a relative thinning of the musculature of the back, situated along the medial border of the scapula which allows for improved listening to the lungs.
The intercostal arteries are a group of arteries passing within an intercostal space. There are 9 anterior and 11 posterior intercostal arteries on each side of the body. The anterior intercostal arteries are branches of the internal thoracic artery and its terminal branch - the musculophrenic artery. The posterior intercostal arteries are branches of the supreme intercostal artery and thoracic aorta.
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