Head

Internal Carotid Artery

Internal Carotid Artery The structure indicated is the internal carotid artery. The internal carotid arteries arise from the common carotid arteries. The brachiocephalic artery arises from the arch of the aorta and divides into the right subclavian artery and the right common carotid artery. There is no left brachiocephalic artery however, and the left common carotid arises directly from the aortic arch. There are three branches which come off the aortic arch: Brachiocephalic artery Left common carotid Left subclavian The common carotid arteries then divide into the external carotid and internal carotid arteries. The internal carotid artery ascends to supply the …

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internal carotid artery

Foramen Spinosum

Foramen Spinosum The structure indicated is the foramen spinosum. The floor of the cranial cavity consists of three cranial fossae: Anterior cranial fossa Middle cranial fossa Posterior cranial fossa There are several holes in the floor of the cranial cavity which allow structures to enter and exit the skull, known as foramen. Foramen (foramina is plural), are holes in the human body which allow other structures to pass through. In the case of the skull, foramina permit the passage of arteries, veins and nerves. The middle cranial fossa consists of the following foramina: Superior orbital fissure Foramen rotundum Foramen ovale …

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Cribriform Plate

Cribriform Plate The structure indicated is the cribriform plate. The cribriform plate of the ethmoid bone sits lateral to the crista galli and has numerous foramen which permit the passage of the olfactory nerves which pass from the nasal mucosa to the olfactory bulb. Learn more about the bones of the skull in this tutorial.

cribriform plate

Foramen Lacerum

Foramen Lacerum The structure indicated is the foramen lacerum. The floor of the cranial cavity consists of three cranial fossae: Anterior cranial fossa Middle cranial fossa Posterior cranial fossa There are several holes in the floor of the cranial cavity which allow structures to enter and exit the skull, known as foramen. Foramen (foramina is plural), are holes in the human body which allow other structures to pass through. In the case of the skull, foramina permit the passage of arteries, veins and nerves. The middle cranial fossa consists of the following foramina: Superior orbital fissure Foramen rotundum Foramen ovale …

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foramen lacerum

Maxilla

Maxilla The structure indicated is the maxilla bone. The skull consists of the calvaria which contains the brain, and the facial skeleton, also known as the viscerocranium. The facial skeleton consists of the following bones: Nasal bones Lacrimal bones Palatine bones Zygomatic bones Maxillae Inferior nasal conchae Vomer The maxillae (plural) are paired bones which are located between the orbit and the upper teeth, forming the upper part of the jaw. The maxilla consists of four processes: Zygomatic process – sticks out laterally to articulate with zygomatic bone Frontal process – projects superiorly and articulates with frontal bone Alveolar process …

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Maxilla

Basilar Artery

Basilar Artery The structure indicated is the basilar artery. The basilar artery is formed from the union of the two vertebral arteries on either side. The vertebral arteries arise from the first part of the subclavian artery. Two other arteries are given off from the first part of the subclavian artery – the internal thoracic artery and the thyrocervical trunk. The vertebral and internal carotid arteries provide the arterial supply to the brain, forming the Circle of Willis at the base of the brain. After the vertebral artery is given off from the subclavian artery, it passes through the transverse …

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basilar artery

Inferior Oblique Muscle of the Eye

Inferior Oblique Muscle of the Eye The structure indicated is the inferior oblique muscle of the eye. This muscle is one of six muscles that are involved in the movements of the eye. The muscles which move the eye are referred to as the extraocular muscles, these include: Superior rectus Inferior rectus Lateral rectus Medial rectus Superior oblique Inferior oblique The oculomotor nerve innervates the superior, inferior and medial rectus muscles as well as the inferior oblique muscle. The trochlear nerve innervates the superior oblique muscle The abducent nerve innervates the lateral rectus muscle. When the inferior oblique muscle is …

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inferior oblique

Lateral Pterygoid

Lateral Pterygoid The structure indicated is the lateral pterygoid muscle. The lateral pterygoid muscle is one of four muscles of mastication: Masseter Temporalis Medial pterygoid Lateral pterygoid The muscles of mastication act on the temporomandibular joint (TMJ), which is the joint of the jaw formed between the mandible and temporal bone. The TMJ is a synovial joint, which differs in structure to other synovial joints in that it contains a fibrocartilagenous articular disc that divides the joint into two parts. The two joint compartments result in different movements at the TMJ. The lower joint compartment allows rotational movement, whilst the …

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lateral pterygoid

Facial Artery

Facial Artery The structure indicated is the facial artery. The facial artery is a branch of the external carotid artery. The external carotid artery gives rise to 8 branches: Superior thyroid artery Ascending pharyngeal artery Lingual artery Facial artery Occipital artery Posterior auricular artery Maxillary artery Superficial temporal artery The maxillary artery and the superficial temporal artery are terminal branches of the external carotid artery, with the latter being the smaller of the two branches. The facial artery provides the major arterial supply to the face, terminating as the angular artery medially at the corner of the eye. It consists …

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facial artery

Temporalis Muscle

Temporalis Muscle The structure indicated is the temporalis muscle. This muscle is one of the muscles of mastication. The muscles of mastication include: Masseter Temporalis Medial pterygoid Lateral pterygoid The temporalis muscle is a large fan-shaped muscle which lies in the temporal fossa above the zygomatic arch. Origin: temporal line of parietal bone. Temporal surface of sphenoid bone Insertion: coronoid process of mandible and ramus of mandible Innervation: mandibular branch of trigeminal nerve (cranial nerve V) Action: Elevation of the mandible and retraction of the mandible (via posterior horizontal fibres) To learn more about the muscles of mastication, check out …

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temporalis