Cranium Basics
How many bones make up the cranium (excluding teeth)
22 bones
What are fontanelles?
Fibrous membranes between cranial bones in infancy
Name one paranasal sinus
Frontal/ethmoidal/sphenoidal/maxillary
The TMJ is classified as what type of joint?
Modified synovial hinge joint
Typical cervical vertebrae are which levels?
C3-C7
what vertebra is known as the atlas?
C1
what two bones make up the pectoral girdle?
Clavicle and scapula
What portion of the cranium houses the brain?
The Neurocranium
which fontanelle is located between the frontal and parietal bones?
Anterior fontanelle
What is the function of mucus produced in the sinuses?
To drain debris and bacteria into the nasal cavity
What type of cartilage lines the TMJ articular surfaces?
Fibrocartilage
what joints are unique to the lower cervical spine?
Uncovertebral joints
Approximately what percentage of cervical rotation occurs at C1-C2?
About 50%
What joint connects the clavicle to the sternum?
Sternoclavicular joint
The clavaria (cranial vault or skull cap)
At approximately what age does the anterior fontanelle close?
around 18 months
what structure serves as a landmark for locating the TMJ?
The zygomatic arch
What movement initiates mandibular depression?
Rotation in the inferior articular cavity
what spinal motions are necessarily coupled in the lower cervical spine?
Lateral flexion and rotation to the same side
What ligament prevents excessive anterior translation of the atlas?
Transverse ligament of the atlas
What scapular motion is required for full overhead reaching?
What type of joints primarily connect the bones of the calvaria?
Fibrous suture joints
why are fontanelles important during childbirth?
They allow cranial compliance during passage through the birth canal
which muscle attaches to the mastoid process?
Sternocleidomastoid
which ligament acts as the primary passive support of the mandible?
Sphenomandibular ligament
what ligament replaces the supraspinous ligament in the cervical region?
The nuchal ligament
What is the normal adult atlanto-dental interval (ADI)?
Less than 3mm
What ligament primarily resists excessive elevation of the clavicle?
Costoclavicular ligament
By approximately what decade of life do many cranial sutures fuse?
By the third decade
what condition results from premature fusion of cranial sutures?
Synostotic plagiocephaly
What ligament attaches to the external occipital protuberance?
The nuchal ligament
what condition is characterized by reciprocal clicking during opening and closing?
Anterior disc displacement with reduction
which cervical joints can refer pain as high as the head?
C2-C3 zygapophyseal joints
Rupture of which ligament is associated with an ADI of 3-5mm?
The transverse ligament of the atlas
why is posterior sternoclavicular dislocation considered dangerous?
Risk to neurovascular and visceral structures