Anatomy of Bursae

Bursae

• Bursae are small, flattened sacs that contain synovial fluid, a lubricant that helps decrease friction and create gliding movement between structures.
• They are located in areas of friction in the body, such as where muscles or tendons have to glide over bony prominences.
• Major bursae are found around the shoulder, elbow, hip, and knee.
• Bursae are fibrous, soft, and pillow-like when palpated, but normally difficult to palpate because they reside between bones and large tendons.

Cartilage

• Cartilage is a type of supporting connective tissue that varies in consistency and function by the proportion of proteins distributed through its matrix.
• Because cartilage does not contain blood vessels or nerves, it has a limited ability to heal following injury.
• There are three types of cartilage in the body: elastic cartilage, hyaline cartilage, and fibrous cartilage.
• Elastic cartilage has the highest proportion of elastic fibers and is found in the nose and ears, where it creates a structure that is self-supporting but flexible.
• Hyaline cartilage is found in the voice box, between the ribs and the sternum, and on the surfaces of bones where they form joints.
• Hyaline cartilage is smooth and rubbery and helps reduce friction during movement.
• Damage to hyaline cartilage can result in chronic inflammation of the joint, commonly termed osteoarthritis.

Blood Vessels

• Blood vessels are part of the circulatory system, the pathway by which blood flows throughout the body.
• The circulation of blood is necessary to deliver oxygen and nutrients to the body's tissues and remove wastes.
• Blood vessels vary in size from large arteries and veins to smaller arterioles and venules to the smallest capillaries.
• The network of blood vessels is woven throughout the body, existing side by side with lymphatic structures, nerves, and the structures of movement.
• Use caution when palpating near these structures to avoid damaging them.

Lymphoid Organs

• Lymphoid organs include the lymph nodes, as well as larger organs such as the spleen, thymus gland, tonsils, and Peyer's patches of the intestine.
• All of these organs are critical to the body's immune system.
• The lymphatic system is not pressurized in the same way as the circulatory system, as it has no pump comparable to the heart.
• The circulation of lymph relies heavily on skeletal muscle contraction and body movement.
• Breathing and the pulsation of nearby arteries also help propel lymph along.
• When lymph does not circulate efficiently, the tissue develops edema, an abnormal accumulation of fluid.

Lymph Nodes

• Lymph nodes cluster in certain areas of the body, such as the cervical, axillary, and inguinal regions.
• Lymph nodes are usually small, shaped like a kidney bean, and pliable when healthy.
• Diseases such as viral or bacterial infections can prompt enlargement of the associated lymph nodes, making them feel swollen and full.

Structure of the Skin

• The skin is composed of three tissue layers: the epidermis, dermis, and hypodermis.
• The epidermis is epithelial tissue, containing several thin layers of cells, which produce a protective protein called keratin and a pigment protein called melanin.
• The epidermis also contains defensive cells that protect against foreign substances.
• Beneath the epidermis is an underlying dermis, which is mostly dense connective tissue.
• The dermis contains hair follicles, glands, nerves, blood vessels, and tiny muscles.
• The hypodermis lies beneath the dermis, containing adipose cells that cushion and protect underlying structures.

SPECIAL STRUCTURES

• Skin, blood vessels, lymphatic vessels and lymph nodes, nerves, cartilage, and bursae are all special structures that contribute to healthy and efficient movement.
• Each of these structures plays a critical role in supporting the mechanical function of bones, muscles, tendons, ligaments, and fascia.

Tendons

• The dense connective tissue that surrounds muscles converges to form a tendon, which connects the muscle to a bone.
• Tendons contain abundant collagen fibers, giving them strength and elasticity as they transmit the forces produced by muscles into joint movement.
• Tendons come in a variety of shapes and sizes depending on their function and location.
• Like muscles, tendons change shape as they stretch and contract, helping us differentiate them from bones and ligaments.
• They are also denser and smoother than muscles.

Connective Tissue

• Connective tissue is the most abundant type of tissue in the body, found in nearly all structures involved in human movement.
• Primary movement structures, such as bone, tendons, ligaments, and fascia, are considered connective tissues.
• Support tissues, such as cartilage, adipose tissue, and blood, are also classified as connective tissue.
• There are four types of connective tissue: loose, dense, fluid, and supporting connective tissue.
• Loose connective tissue has high levels of ground substance and fewer fibers.
• Dense connective tissue is thicker and stronger with more collagen fibers and less ground substance.
• Fluid connective tissue is watery because of the presence of plasma.
• Supporting connective tissue is strong and solid because of the additional calcium salts deposited in its ground substance.

Nerves

• Nerves are parts of the nervous system, including the central nervous system and the peripheral nervous system.
• Nerves carry impulses, such as sensory impulses and motor nerve impulses.
• The function of nerves is to conduct impulses from one part of the body to another part.
• The impulse will always travel in a single direction, from dendrite to axon.

Muscle

• Muscle is one of the four main types of body tissue.
• There are three types of muscle in the human body: smooth muscle, cardiac muscle, and skeletal muscle.
• Smooth muscle is present in the walls of hollow organs, vessels, and respiratory passageways, and functions in digestion, urinary excretion, reproduction, circulation, and breathing.
• Cardiac muscle makes up the wall of the heart and creates the pulsing action necessary to circulate blood through the body.
• Skeletal muscles are connected to bones and create movements at joints, and are under our conscious control.