Bone Identification - NCLEX-PN

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.

The bony ridge of the brow is formed by the superciliary processes (superciliary means super, or above, cilia, the lens of the eye). The orbit refers to the bony socket in which the eye sits. The glabella is the small depression between the eyebrows where the two superciliary arches meet. The coronoid process is part of the mandible, or jawbone, and unrelated to the brow.

The nasal cavity is formed by the following bones: the maxilla, the vomer, the nasal bone, the palatine bones, the lacrimal bone, and the ethmoid bone. It is also formed by the nasal conchae and the septal cartilage. The sphenoid forms part of the orbit and multiple sinuses but does not form any art of the nasal cavity directly.

The foramen that forms the ear canal is called the external auditory meatus. This travels through the temporal bone and joins the inner ear to the outer ear. The internal auditory meatus passes through the temporal bone between the posterior cranial fossa and the inner ear, and is the track through which the vestibulocochlear nerve, the facial nerve, and the labyrinthine artery travel from the inner ear toward the CNS. The foramen ovale and foramen rotundum are both openings in the sphenoid bones and have to connection to the ear.

The large opening in the occipital bone at the base of the skull through which the spinal cord exits the skull is called the foramen magnum, or "large hole." It is by far the largest foramen of the skull, and generally measures 1.5-3.5 centimeters in the normal adult. The foramen spinosum, foramen cecum, and jugular foramen are all smaller foramen of the skull that transmit various blood vessels and cranial nerves.

The superior orbital fissure, an opening in the back of the orbit formed by the lesser and greater wings of the sphenoid bone, has several important structures passing through it. These include the ophthalmic nerve (CN V1), the abducens nerve (CN VI), the trochlear nerve (CN IV), and the superior and inferior divisions of oculomotor nerve (CN III). It also transmits various blood vessels and the sympathetic fivers from the cavernous plexus. Injury to this area can cause a wide range of ocular pathologies including pain, diplopia, ptosis, exophthalmos, and vision impairment or vision loss.

The splenius capitis, the longissimus capitis, and the posterior belly of the digastric muscle all attach to the mastoid process, a bony protuberance on the inferior border of the temporal bone. This landmark is also an attachment point for the sternocleidomastoid muscle. The styloid process of the temporal bone is directly anterior to the mastoid process, and is an attachment point for multiple ligaments and the styloglossus muscle, the stylohyoid muscle, and the stylopharyngeus muscle. The mandibular condyle and coronoid process are both part of the mandible and do not form any attachments to the muscles of the neck.

The inferior alveolar nerve exits through the mental foramina of the chin. This nerve is a branch of the mandibular nerve and supplies sensory innervation to the lower teeth. The foramen rotundum transmits the maxillary nerve. The supraorbital foramina transmit the supraorbital artery, vein, and nerve. The greater palatine foramen is located in the palatine bone and transmits the greater palatine nerve, artery, and vein.

The falx cerebri, the dura that separates the two hemispheres of the brain, attaches to a bony projection of the ethmoid bone called the crista galli, or "crest of the rooster." This projection is a distinct landmark that arises from the cribiform plate. The ethmoidal labyrinth and orbital plate do not form any attachments to the dura of the brain.

The scapula has multiple fossa that serve as attachment points of various bones and muscles of the shoulder. Among these are the glenoid fossa, where the head of the humerus articulates with the scapula, the subscapular fossa, which is an attachment for the subscapularis muscle, the infraspinous fossa, to which the infraspinatus attaches, and the supraspinous fossa, to which the supraspinatus muscle attaches. There is no suprascapular fossa on the scapula.

The supraspinatus tendon passes under the acromion, a bony hook-like process at the end of the scapular spine. Inflammation of the supraspinatus muscle or tendon can quickly lead to entrapment of this muscle under the acromion, causing pain and reduced mobility. The coracoid process, another projection from the anterior scapula, is an attachment point for several muscles and ligaments, including the pectoralis minor and the short head of the biceps brachii.

The pelvis is formed by the sacrum and coccyx and the three bones that come together to form the innominate: the ilium, ischium, and the pubis. The ileum is a part of the small intestine.