Items tagged “anatomy rewrite”

79 results found

Middle ear

The middle ear (or tympanic cavity) is an-air filled chamber in the petrous part of the temporal bone that is split into two parts: the tympanic cavity proper (the space directly internal to the tympanic membrane) and the epitympanic recess or attic (the space superior to the membrane). It sits ...

Temporomandibular joint

The temporomandibular joint (TMJ) is an atypical synovial joint located between the condylar process of the mandible and the mandibular fossa and articular eminence of the temporal bone. It is divided into superior discotemporal space and inferior discomandibular space by the TMJ disc (or menisc...

Orbital spaces

The orbital spaces are important when considering different pathologies: globe subdivided into anterior and posterior segments by the lens optic nerve-sheath complex optic nerve  ophthalmic artery central retinal artery and vein surrounding sheath of meninges as an extension of the cerebr...


The spleen is an organ of the haematological system and has a role in immune response, storage of red blood cells and hematopoiesis. Gross anatomy The spleen is a wedge-shaped organ lying mainly in the left upper quadrant (left hypochondrium and partly in the epigastrium) and is protected by t...

Ophthalmic artery

The ophthalmic artery (OA) is a branch off the C6 segment of the internal carotid artery (ICA). Gross anatomy Origin OA arises medial to the anterior clinoid process as the ICA exits the cavernous sinus. It originates from the antero- or supero-medial surface of the ICA. Course OA passes in...

Intracranial arteries (variants)

Intracranial arterial variants, of which there are many, are collectively common. Their clinical significance may be variable but knowledge and recognition of these variants is fundamental, especially if surgical or endovascular treatments (e.g. for acute stroke, aneurysms or other vascular path...

Congenital absence of the internal carotid artery

Congenital absence of the internal carotid artery (ICA) is a rare anomaly that occurs in less than 0.01% of the population. It encompasses agenesis, aplasia, and hypoplasia 1. The most common type of collateral flow is through the circle of Willis, through the anterior communicating artery (ACO...

Persistent otic artery

The persistent otic artery is one of the persistent carotid-vertebrobasilar anastomoses, although there is considerable controversy in regards to its existence. It is said to arise from the internal carotid artery within the carotid canal, emerges from the internal acoustic meatus, and joins the...

Maxillary artery

The (internal) maxillary artery is the larger of the two terminal branches of the external carotid artery.  Origin and course The maxillary artery's origin is behind the neck of the mandible, at first, it is embedded in the substance of the parotid gland. From there it passes anterior between ...

Middle meningeal artery

The middle meningeal artery branches off the first part of the maxillary artery. It passes vertically through the roots of the auriculotemporal nerve and enters the middle cranial fossa via the foramen spinosum. Here it gives off two branches - superior tympanic branch and ganglionic branch - be...

Internal jugular vein

The internal jugular vein (IJV) is the major venous return from the brain, upper face and neck. Gross anatomy Origin and course It is formed by the union of inferior petrosal and sigmoid dural venous sinuses in or just distal to the jugular foramen (forming the jugular bulb). It descends in t...

Superior thyroid artery

The superior thyroid artery is a branch of the external carotid artery and supplies the larynx and thyroid gland. Summary origin: branch of the external carotid artery at the level of the hyoid bone branches hyoid artery sterncocleidomastoid branches superior laryngeal artery cricothyroid...


The jejunum is arbitrarily defined as the proximal two-fifths of the small intestine and is, on average, ~300 cm in length. Gross anatomy The primary method of evaluation of the small bowel is small bowel follow-through examination (SBFT). On SBFT, the jejunum has a delicate feathery appearanc...

Bouthillier classification of internal carotid artery segments

Bouthillier et al described (in 1996) 1 a seven segment internal carotid artery (ICA) classification system. It remains the most widely used system for describing ICA segments at the time of writing (mid-2016). There are a few other classifications systems including those proposed by Fisher (19...


The pons is the middle of the three parts of the brainstem, sitting above the medulla and below the midbrain. It acts as a relay between the cerebellum and cerebral hemispheres.  Gross anatomy The pons has a bulbous shape and has two main components - the ventral pons and the dorsal tegmentum....

Circle of Willis

The Circle of Willis is an arterial polygon formed as the internal carotid and vertebral systems anastomose around the optic chiasm and infundibulum of the pituitary stalk in the suprasellar cistern. This communicating pathway allows equalization of blood-flow between the two sides of the brain,...

Cerebral vascular territories

An understanding of cerebral vascular territories is important in understanding stroke and complications from surgery and endovascular procedures.  Although one could be excused for thinking that within the brain, such a carefully organised organ, blood supply would be constant, the truth is th...

Muscles of mastication

The muscles of mastication can be divided into primary and secondary groups according to whether they connect the mandible directly to the skull or if they attach to other structures in the neck, e.g. hyoid, thyroid cartilage. Primary temporalis muscle masseter muscle medial pterygoid muscle...

Temporalis muscle

The temporalis muscle is one of the muscles of mastication. It is responsible for both closing the mouth and retraction (posterior fibres). Summary origin: temporal fossa between the infratemporal crest and inferior temporal line insertion: coronoid process and ramus of mandible innervation:...

Lateral pterygoid muscle

The lateral pterygoid muscle, also known as pterygoideus externus or external pterygoid muscle, is one of the muscles of mastication.  Gross anatomy The lateral pterygoid is a short, thick muscle, somewhat conical in form, which extends almost horizontally, posteriorly and laterally between th...

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