Related Concept Videos

Bones of the Upper Limb: Humerus01:19

Bones of the Upper Limb: Humerus

The upper limb consists of the arm, forearm, wrist, and hand bones. The humerus is the single bone of the upper arm region. Proximally, it has a large, spherical, smooth head that articulates with the glenoid cavity of the scapula to form the glenohumeral or shoulder joint. The margin of the head is the anatomical neck, a residual epiphyseal plate. Laterally it extends to form bony projections called the greater tubercle and the lesser tubercle. Next to the tubercles is the surgical neck, a...
Bones of the Upper Limb: Ulna01:15

Bones of the Upper Limb: Ulna

The ulna and radius are parallel bones of the antebrachium or the forearm. The ulna lies medially and consists of a bony tip called the olecranon process at its proximal end. This hook-like projection articulates with the olecranon fossa of the humerus and forms the "hinged" ulnohumeral part of the elbow joint. This joint facilitates forearm extension and flexion while preventing its hyperextension. Similarly, the coronoid process, another bony projection on the proximal/anterior side of the...
Knee Joint01:23

Knee Joint

The knee joint is the most complicated joint in the body. It consists of three articulations– two tibiofemoral and one patellofemoral. As is characteristic of synovial joints, the knee joint has a thin articular capsule that partially surrounds this joint cavity. Additionally, several ligaments, muscles, and cartilaginous structures support the movement of the knee.
A total of seven ligaments support the knee joint. The patellar ligament, which is also attached to the quadriceps femoris group...
Glycosaminoglycans01:23

Glycosaminoglycans

Glycosaminoglycans (GAGs), also known as mucopolysaccharides, are long and linear polymers comprising of specific repeating disaccharides - the amino sugar that can be N-acetylglucosamine or N-acetylgalactosamine, and a uronic acid that is usually glucuronic acid or iduronic acid.
GAGS are found in the extracellular matrix of vertebrates, invertebrates, and bacteria. Due to their polar nature they attract water, and serve as excellent lubricants or shock absorbers in an animal body.
Hyaluronic...
Structural Joints: Synovial Joints01:16

Structural Joints: Synovial Joints

Synovial joints are the most common type of joint in the body. A key structural characteristic for a synovial joint is the presence of a joint cavity. This fluid-filled space is where the articulating surfaces of the bones contact each other. Also, unlike fibrous or cartilaginous joints, the articulating bone surfaces at a synovial joint are not directly connected to each other with fibrous connective tissue or cartilage. This gives the bones of a synovial joint the ability to move smoothly...
Bone Markings01:26

Bone Markings

Bones have various surface features that help form joints and attach to other soft tissues. Depending on the function, bone markings are categorized into articulating projections, processes for attachment, depressions, and openings.
Articulating Projections
Articulating projections are found where two bones meet to form a joint. These structures are usually found at the ends of bones. The largest articulation is a rounded projection called the head, supported by a narrow neck at the ends of...