A joint or articulation is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole. They are constructed to allow for different degrees and types of movement. Some joints, such as the knee, elbow, and shoulder, are self-lubricating, almost frictionless, and are able to withstand compression and maintain heavy loads while still executing smooth and precise movements. Other joints such as sutures between the bones of the skull permit very little movement in order to protect the brain and the sense organs. The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis. Joints are classified both structurally and functionally.
The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubic symphysis. In females, the pubic symphysis is close to the clitoris. In most adults it can be moved roughly 2 mm and with 1 degree rotation. This increases for women at the time of childbirth.
Fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its inflexibility and toughness to the former of these constituents, and its elasticity to the latter. It is the only type of cartilage that contains type I collagen in addition to the normal type II.
A symphysis is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint.
- A symphysis is an amphiarthrosis, a slightly movable joint.
- A growing together of parts or structures.
A syndesmosis is a type of fibrous joint in which two parallel bones are united to each other by fibrous connective tissue. The gap between the bones may be narrow, with the bones joined by ligaments, or the gap may be wide and filled in by a broad sheet of connective tissue called an interosseous membrane. The syndesmoses found in the forearm and leg serve to unite parallel bones and prevent their separation.
A synarthrosis is a type of joint which allows no movement under normal conditions. Sutures and gomphoses are both synarthroses. Joints which allow more movement are called amphiarthroses or diarthroses. Syndesmoses joints are considered to be amphiarthrotic, because they allow a small amount of movement.
The gracilis muscle is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.
The metacarpophalangeal joints (MCP) are situated between the metacarpal bones and the proximal phalanges of the fingers. These joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the proximal phalanges. Being condyloid, they allow the movements of flexion, extension, abduction, adduction and circumduction at the joint.
In vertebrates, the pubic region is the most forward-facing of the three main regions making up the coxal bone. The left and right pubic regions are each made up of three sections, a superior ramus, inferior ramus, and a body.
The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet. Its lower boundary is the pelvic floor.
The pubic tubercle is a prominent tubercle on the superior ramus of the pubis bone of the pelvis.
Medial to the pubic tubercle is the pubic crest, which extends from this process to the medial end of the pubic bone.
The sacrococcygeal symphysis is an amphiarthrodial joint, formed between the oval surface at the apex of the sacrum, and the base of the coccyx.
A plane joint is a synovial joint which, under physiological conditions, allows only gliding movement.
Cartilaginous joints are connected entirely by cartilage. Cartilaginous joints allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint. Cartilaginous joints also forms the growth regions of immature long bones and the intervertebral discs of the spinal column.
In human male anatomy, the radix or root of the penis is the internal and most proximal portion of the human penis that lies in the perineum. Unlike the pendulous body or corpus of the penis which is suspended from the pubic symphysis, the root is attached to the pubic arch of the pelvis and is not visible externally. It is triradiate in form, consisting of three masses of erectile tissue; the two diverging crura, one on either side, and the median bulb of the penis or urethral bulb. Approximately one third to one half of the penis is embedded in the pelvis and can be felt through the scrotum and in the perineum.
The hip bone is a large flat bone, constricted in the center and expanded above and below. In some vertebrates it is composed of three parts: the ilium, ischium, and the pubis.
The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.
Anatomical terminology is a form of scientific terminology used by anatomists, zoologists, and health professionals such as doctors, physicians, and pharmacists.
The spinal column, a defining synapomorphy shared by nearly all vertebrates, is a moderately flexible series of vertebrae, each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank, and on the other with phylogenetic differences among the vertebrate taxa.
