Musculoskeletal System and Anatomy - NCLEX-PN

The structural classification of joints divides them according to the form of tissue that connects bones to each other. The three structural divisions of joints are fibrous, cartilaginous, and synovial. In contrast, synarthrosis, amphiarthrosis, and diarthrosis are all classifications of a joint's movement.

Condyloid, gliding, and hinge joints are all types of synovial joints, while sutures, syndesmosis, and gomphosis are all types of fibrous joints.

Gomphosis joints are fibrous joints that attach the root of the tooth to the bony socket of the mandible or maxilla.

Both the tibio-fibular joint and the joint between the radius and ulna are syndesmoses, while the joints between the bones of the skull are sutures.

The majority of joints of the human body are synovial joints. These joints are diarthrotic and include a synovial joint capsule that allows for greater freedom of movement. Examples include the fingers and the elbows, the knees, the temporomandibular joint, and the hips.

Fibrous and cartilagenous joints, all of which are either synarthrotic or amphiarthrotic, are relatively less common.

The intervertebral disc articulate with the vertebrae via cartilaginous symphysis joints. These joints are amphiarthrotic, meaning that they allow for slight mobility.

Synovial joints are all diarthrotic and characterized by a flexible joint capsule filled with synovial fluid. Synarthrotic joints have no movement - examples include the skull bones and the joints of the teeth to the jaw.

The head of the femur articulates with the acetabulum, a concave surface on the pelvis formed by the union of three bones: the ilium, the ischium, and the pubis.

The obturator foramen is a large opening in the pelvis formed by the pubis and the ischium bilaterally. It does not form any joints but rather allows the passage of the obturator artery, nerve, and vein.

The glenoid fossa is the surface onto which the head of the humerus articulates in the shoulder, and the patella is a part of the knee.

Bursae are synovial fluid sac between bones and overlying tissues. They provide a cushion between the bone and tendons or musculature around them, allowing for reduced friction and painless movement.

A tendon is a connective tissue point of attachment of muscle to bone, while a ligament is a connective tissue attachment from bone to bone. A capsule is a fibrous, fluid filled structure surrounding a synovial joint.

Bruxism, or involuntary tooth grinding, can cause inflammation and damage in the temporomandibular joint, which is the articulation between the condyle of the mandible and the temporal bone.

The xiphisternal joint is between the xiphoid process and the body of the sternum. The intermetacarpal joints are formed between the metacarpal bones of the hand, and the pisotriquetral joint is between the pisiform and triquetrum of the wrist.

Movement along a sagittal plane that decreases the angle between bones is flexion. This is in contrast to extension, which is movement along a sagittal plane that increases the angle between bones. Adduction is movement that pulls a structure toward the midline of the body, while abduction moves a structure away from midline.

Circumduction is movement that produces a circular motion wth the distal end of a body part. True circumduction allows for a 360 degree range of movement. Of the joints listed, the only one capable of circumduction is the shoulder.

Condyloid joints are a form of synovial joint in which a condyle rests in an ovoid cavity. Of the joints listed, the only condyloid joint is the metacarpophalangeal joints (the joint of the most proximal knuckle).

The acromioclavicular joint is a plane joint, while the glenohumeral and humeroradial joints are both ball and socket joints.

The only bone that the patella, or kneecap, articulates with is the femur, at the patellofemoral joint. The patella is a sesamoid bone, meaning it is fully embedded within a tendon. The patellar ligament joins the patella to the tibial tuberosity (but not the fibula).

The most superior vertebra of the spine is the atlas, or C1. This bone sits on the axis, or C2, over a bony process called the dens. The coccyx, or "tailbone," is part of the sacrum.

There are 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae. The mnemonic for this is "breakfast at 7, lunch at 12, dinner at 5."

The bone that forms the lower part of the jaw is the mandible. It is the largest and most inferior bone in the face, and articulates with the temporal bones at the temporomandibular joints. The maxilla forms the upper jaw, while the zygomatic bone forms the cheek and part of the orbit.

The occiput is the inferior and posterior bone of the skull. It wraps under the bottom of the skull and forms the base on which the head articulates with the spine. The ethmoid bone and sphenoid bone are housed primarily within the skull, and the maxilla forms the upper jaw and part of the orbit.

The cheek bones are formed by the zygomatic arches, which are part of the temporal bones of the face. The mental protuberance forms the chin, the styloid processes are just under the ears and serve as an attachment point for several muscles of the mouth and throat, and the pterion is the suture where the frontal, parietal, temporal, and sphenoid bones come together.

The bony protuberance(s) at which the occipital bone articulates with the atlas (C1) are the occipital condyles. The external occipital protuberance, external occipital crest, and inion are all part of the occipital bone and serve as the attachment points for various muscles and ligaments.

The orbit is formed by the following bones: the maxilla, the zygomatic bone, the frontal bone, the lacrimal bone, the ethmoid, the sphenoid, and the palatine bone. The temporal bone meets the zygomatic and sphenoid but does not form part of the orbit.

The suture that joins the frontal bone to the parietal bones is the coronal suture. The sagittal suture joins the two parietal bones together along the sagittal plane of the skull. There are no sutures named after the frontal or parietal bones themselves.

The costal cartilage of the ribcage is joined to the sternum, which is made up of three bony structures: the most superior is the manubrium, which articulates not just with the costal cartilage of the first rib but also with the clavicles. The body of the sternum is inferior to the manubrium, and articulates with the second through fifth ribs. The xiphoid process is a small protuberance just below the body of the sternum, at the point where the bottom of the ribcage meets the sternum. It is an attachment point for several muscles, including the diaphragm, the rectus abdominis, and the transverse abdominis. This is a common location for referred pain from gallbladder disease, GERD, or pain due to musculoskeletal injury or irritation.