Fossa navicularis magna (also known as pharyngeal fossa or phyaryngeal fovela) is a variant bony depression found at the midline of the occipital part of clivus. This fossa was first described by Tourtual. [1] Its prevalence ranges from 0.9 to 5.3%. [2]
Fossa navicularis magna is located on the anterior surface or pharyngeal surface of the clivus. Its position when present is between the spheno-occipital synchondrosis and the foramen magnum. Size of this fossa varies considerably and its depth ranges from 3.49 to 4.94 mm. [3] A histological study reported the presence of loose connective tissue containing collagen and elastic fibers within the fossa navicularis magna. [4]
Two theories have been proposed to explain the formation of fossa navicularis magna. It is believed that the fossa is formed as a remnant of the notochord or residue of the channels for emissary veins. [5]
Different pathologies were found associated with fossa navicularis magna including cancers, adenoid hypertrophy, ecchordosis physaliphora, Tornwaldt cyst and Rathke cleft cyst. [6]
In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch so it covers much of the temporal bone.Temporal refers to the head's temples.
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. The other two meningeal layers are the arachnoid mater and the pia mater. It envelops the arachnoid mater, which is responsible for keeping in the cerebrospinal fluid. It is derived primarily from the neural crest cell population, with postnatal contributions of the paraxial mesoderm.
The suprapineal recess is an anatomical structure in the ventricular system of the brain. It is located in the posterior part of the third ventricle, overlying the cerebral aqueduct.
The ileocecal valve is a sphincter muscle valve that separates the small intestine and the large intestine. Its critical function is to limit the reflux of colonic contents into the ileum. Approximately two liters of fluid enters the colon daily through the ileocecal valve.
The stylomastoid foramen is a foramen between the styloid and mastoid processes of the temporal bone of the skull. It is the termination of the facial canal, and transmits the facial nerve, and stylomastoid artery. Facial nerve inflammation in the stylomastoid foramen may cause Bell's palsy.
The temporoparietalis muscle is a distinct muscle of the head. It lies above the auricularis superior muscle. It lies just inferior to the epicranial aponeurosis of the occipitofrontalis muscle. The temporoparietalis muscle may be used in reconstructive ear surgery.
In human anatomy, the mandibular canal is a canal within the mandible that contains the inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein. It runs obliquely downward and forward in the ramus, and then horizontally forward in the body, where it is placed under the alveoli and communicates with them by small openings.
The occipital vein is a vein of the scalp. It originates from a plexus around the external occipital protuberance and superior nuchal line to the back part of the vertex of the skull. It usually drains into the internal jugular vein, but may also drain into the posterior auricular vein. It drains part of the scalp.
The pterygoid canal is a passage in the sphenoid bone of the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa.
The pharyngeal tubercle is a part of the occipital bone of the head and neck. It is located on the lower surface of the basilar part of occipital bone. It is the site of attachment of the pharyngeal raphe.
The anterior lacrimal crest is a bony projection on the frontal process of the maxilla. It creates the lateral margin of the lacrimal sac fossa and is continuous with the orbital margin. The medial palpebral ligament is attached to anterior lacrimal crest. It is an important structure to avoid damaging during rhinoplasty.
The infraorbital groove is located in the middle of the posterior part of the orbital surface of the maxilla. Its function is to act as the passage of the infraorbital artery, the infraorbital vein, and the infraorbital nerve.
The sternalismuscle is an anatomical variation that lies in front of the sternal end of the pectoralis major parallel to the margin of the sternum. The sternalis muscle may be a variation of the pectoralis major or of the rectus abdominis.
The clivus or Blumenbach clivus is a part of the occipital bone at the base of the skull. It is a shallow depression behind the dorsum sellae of the sphenoid bone. It slopes gradually to the anterior part of the basilar occipital bone at its junction with the sphenoid bone. It extends to the foramen magnum. It is related to the pons and the abducens nerve.
The lesser palatine arteries are arteries of the head. It is a branch of the descending palatine artery. They supply the palatine tonsils and the soft palate.
A mental spine is a small projection of bone on the posterior aspect of the mandible in the midline. There are usually four mental spines: two superior and two inferior. Collectively they are also known as the genial tubercle, genial apophysis and the Latin name spinae mentalis. The inferior mental spines are the points of origin of the geniohyoid muscle, one of the suprahyoid muscles, and the superior mental spines are the origin of the genioglossus muscle, one of the muscles of the tongue. Mental spines are important landmarks in clinical practice.
Extensor digitorum brevis manus is an extra or accessory muscle on the backside (dorsum) of the hand. It was first described by Albinus in 1758. The muscles lies in the fourth extensor compartment of the wrist, and is relatively rare. It has a prevalence of 4% in the general population according to a meta-analysis. This muscle is commonly misdiagnosed as a ganglion cyst, synovial nodule or cyst.
Ectopic thymus is a condition where thymus tissue is found in an abnormal location. It usually does not cause symptoms, but may leads to a mass in the neck that may compress the trachea and the esophagus. It is thought to be the result of either a failure of descent or a failure of involution of normal thymus tissue. It may be diagnosed with radiology, such as an ultrasound or magnetic resonance imaging. If it causes illness, surgery can be used to remove it. Recurrence after surgery is very unlikely.
The extensor indicis et medii communis is a rare anatomical variant in the extensor compartment of forearm. This additional muscle lies in the deep extensor layer next to the extensor indicis proprius and the extensor pollicis longus. The characteristics of this anomalous muscle resemble those of the extensor indicis proprius, with split tendons to the index and the middle finger. This muscle can also be considered as a variation of the aberrant extensor medii proprius.
The myodural bridge or miodural ligament is a bridge of connective tissue that extends between the suboccipital muscles and the cervical spinal dura mater, the outer membrane that envelops the spinal cord. It provides a physical connection between the musculoskeletal and nervous systems, and the circulation of cerebrospinal fluid. Its importance has been highlighted by various authors.