Chapter 11: Joints of the Skull (pelswick48)

Anterior Fontanelle

The largest of the fontanelles located at the junction of the coronal and sagittal sutures. In adults, this lies at the location of the bregma. Useful to the physician in determining: the position of the fetal head in utero, the extent of pathological ICP, and the development of the skull (unlike other fontanelles, which ossify within a few months, the anterior fontanelle becomes bony at 2 years old. Called the soft spot in babies).

Condyle

The round prominence at the end of a bone, most often part of a joint.

Lambdoid Suture

Articulation of the parietal bones with the occipital bone.

Fetal Skull

Bones are not completely ossified at birth. Six major unossified, membranous areas between the cranial bones are called fontanelles (French fontanelle = a little fountain)

Sutures

Classification: fibrous joints, suture in type. There are no ligaments or movements of these joints

Hinge Movements of the TMJ

Depression (inferior movement of the mandible AKA opening the mouth). Elevation (superior movement of the mandible AKA closing the mouth)

Inferior Compartment of the Articular Disc

Located between the articular disc and the mandible.

Superior Compartment of the Articular Disc

Located between the articular disc and the mandibular fossa.

Planar Movements of the TMJ

Protraction (anterior movement of the mandible in a horizontal plane) Retraction (posterior movement of the mandible in a horizontal plane) Lateral movement (side-to-side movement AKA grinding)

Anterolateral Fontanelles (Sphenoid Fontanelles)

Small irregular fontanelles located at the junction of the frontal, parietal, sphenoid, and temporal bones.

Posterolateral Fontanelles (Mastoid Fontanelles)

Small irregular fontanelles located at the junction of the occipital, parietal, and temporal bones.

Temporomandibular Joint

Synovial joint, combined hinge and plane in type. Bony surfaces are the mandibular fossa of the temporal bone and the head (condyloid process) of the mandible.

Squamous Suture

The articulation of the parietal and temporal bones.

Frontal (Coronal) Suture

The articulation of the parietal bones with the frontal bone.

Sagittal Suture

The articulation of the two parietal bones in the median plane of the skull.

Ligaments of the TMJ

There is one prominent intraarticular ligament called the articular disc. It is an oval plate of fibrous tissue that sometimes contains patches of fibrocartilage. The circumference of the disc attaches to the articular capsule. The articular disc divides the joint cavity into two separate compartments. The superior compartment

Posterior Fontanelle

Triangular, located at the junction of the lambdoid and sagittal sutures. In adults, this lies at the location of the lambda.