Special Sub-Topic: Anatomy of the Human Head Click Here To Play: Anatomy of the Human Head

What is the junction of the coronal suture and the sagittal suture called on the adult skull?

Bregma. In infants it's called the anterior fontanelle, the bones are separated to provide room for growth, and to allow more compression of the skull during delivery. When fused it's called the bregma. The lambda is the junction of the sagittal suture and the lamboidal suture, the site of the infantile posterior fontanelle.

How many separate bones comprise the skull? (including the jaw)

22. They are: Frontal, Sphenoid, Maxilla (x2)(fused), Zygomatic (x2), Nasal (x2), Ethmoid, Inferior Concha (x2), Parietal (x2), Temporal (x2), Lacrimal (x2), Occipital, Palatine(x2), Vomer and Mandible.

Which of these muscles is not supplied by the trigeminal nerve?

Buccinator. As a rule the trigeminal nerve (CN V) is sensory except for motor to the muscles of mastication. Although buccinator is involved in chewing (returning food from the vestibule) it is considered a muscle of expression as it is supplied by the facial nerve (CN VII)

What is the name of the venous sinus that lies adjacent to the pituitary gland?

Cavernous sinus. Part of the venous sinus system which drains the brain, there is one each side of the pituitary, they are joined by the intercavernous sinus. Sagittal and sigmoid venous sinuses also exist, but the frontal sinus is a bony sinus involved in filtering and moistening air.

What is the name given to the flap of dura mater which separates the two cerebral hemispheres?

Falx cerebri. The falx cerebri is formed by a double layer of the interior layer of dura. Lying inferiorly in the falx cerebri is the inferior saggital sinus, and superiorly is the superior saggital sinus.

The trochlear nerve (CN IV) innervates only one muscle, involved in eye movement, which is it?

Superior oblique. The superior oblique muscle runs through a pully or trochlea, hence the name of the supplying nerve.

Which of these nerves does not provide sensation to the tongue?

Hypoglossal nerve. The hypoglossal (CN XII) nerve provides the motor input to all the muscles of the tongue except {palatoglossus;} the glossopharyngeal (CN IX) nerve provides taste and general sensation to the posterior third of the tongue, the vagus (CN X) supplies a small area posteriorly via its internal laryngeal {branch;} and the chorda tympani, a branch of the facial nerve (CN VII) provide taste to the anterior two thirds of the tongue.

Which nerve (or branches thereof) would be vulnerable during surgery to remove a tumour of the parotid gland?

Facial nerve. The facial nerve (CN VII) exits the skull via the stylomastoid foramen and almost immediately splits into it's 5 terminal branches between the two layers of the parotid gland. The other three nerves are all branches of the trigeminal nerve (CN V).

The vagus nerve (CN X) exits the skull via which foramen?

Jugular foramen. CN IX, X, and XI all exit via the jugular foramen, unsurprisingly this is also where the sigmoid sinus becomes the jugular vein and exits the skull.

To where does the endolymph in the inner ear drain directly?

Cerebrospinal fluid. The cerebrospinal fluid is then reabsorbed at the arachnoid granulations into the superior saggital sinus, and hence into the systemic circulation.