The extreme capsule is a series of white matter tracts in the brain that run between the claustrum and insular cortex.
The extrinsic muscles of the tongue are a group of 4 muscles of the tongue. They all arise outside the tongue, which is in comparison to the intrinsic muscles of the tongue which are entirely within the tongue with no external attachments. They act to alter the position of the tongue where as th...
The extrinsic muscles of the tongue can be remembered with the following mnemonic:
Paris St Germain's Hour
Paris St. Germain's Hour
Eye movements are a complex set of movements of the globe that are performed by the extra-ocular muscles that are grouped by the muscles that perform particular movements:
ocular internal rotators
ocular external rotators
The fabella is an accessory ossicle typically found in the lateral head of the gastrocnemius. It occurs in ~20% (range 10-30%) of the population 1.
The fabella can also be fibrocartilaginous in nature and is occasionally found in the medial head of the gastrocnemius. The fabella articulates wi...
A faceless kidney refers to one in which the normal appearance of the renal sinus on cross-sectional imaging is absent. It was initially described as a sign of duplication of the collecting system 1 (a slice obtained between the two collecting systems will not demonstrate the normal components o...
The facet (or apophyseal or zygapophyseal) joints are the articulations of the posterior arch of the vertebrae and form part of the posterior column.
They are synovial-lined joints that have a fibrous capsule and connect the articular facets of the vertebrae. The superior facet ...
Facet joint capsules are the fibrous capsule that surround the vertebral facet or zygapophyseal joints. They are particularly thin and loose, attached to the margins of articular facets on adjoining articular processes. The capsules merge medially with the ligamentum flavum.
In the cervical re...
The facial artery is one of the branches of the external carotid artery and supplies blood to the structures of the face.
origin: branch of the external carotid artery a little above the level of the lingual artery
course: ascends anteriorly through the cheek with a tortuous route tow...
The facial bones comprise a set of bones that make up the face:
inferior nasal concha
zygoma (zygomatic bone)
Where these bones join each other, sutures occur.
The facial-cavernous anastomoses are the communications of the facial and deep facial veins with the cavernous sinus.
At the medial canthus of the eye there is a communication with the ophthalmic veins, which drain into the cavernous sinus. Blood from the frontal scalp normally f...
The facial colliculus is an elevation on the floor of the fourth ventricle and is not formed by the facial nerve nucleus, but by the fibres of the facial nerve arching backwards around the abducens nerve (CN VI) nucleus before turning forwards once more in the caudal pons.
The facial muscles enable facial expression and serve as sphincters and dilators of the orifices of the face. These muscles differ from those of other regions in the body as there is no fascia deep to the skin of the face; many of the facial muscles insert directly into the skin 1.
The facial nerve is one of the key cranial nerves with a complex and broad range of functions.
Although at first glance it is the motor nerve of facial expression which begins as a trunk and emerges from the parotid gland as five branches (see facial nerve branches mnemonic), it has taste and p...
There are many mnemonics to recall the branches of the facial nerve (superior to inferior) as they exit the anterior border of the parotid gland. Examples include:
Tall Zulus Bear Many Children
Two Zulus Bit My Cat
Two Zebras Bit My Coccyx
Ten Zebras Buggered My Car
To Zanzibar By Motor Car...
Helpful mnemonics for remembering the segments of the facial nerve include:
I Love Going To Makeover Parties 1
I Love Grinning, Then Making Pouts
both grinning and pouting are performed by muscles which are innervated by the facial nerve
I Must Learn To Make (facial) Expressions
The facial vein (previously known as the anterior facial vein) is the continuation of the angular vein and joins the anterior branch of the retromandibular vein to form the common facial vein 1-3.
At the level of the lower margin of the orbit, the angular vein becomes the facial ...
The falciform ligament is a broad and thin peritoneal ligament. It is sickle-shaped (Latin: "falciform") and a remnant of the ventral mesentery of the fetus.
It is situated in an anteroposterior plane but lies obliquely so that one surface faces forward and is in contact with the peritoneum beh...
The Fallopian (facial) canal refers to a bony canal through which the facial nerve traverses the petrous temporal bone, from the internal acoustic meatus to the stylomastoid foramen.
It is, for those of you fond of trivia, the longest bony canal through which a nerve passes. It is also responsi...
The false vocal cords (vestibular folds, ventricular folds) are paired shelf-like structures located within the supraglottic larynx that divide the vestibule above from the ventricle below.
The vestibular ligaments are the ligamentous component of the false vocal cords and const...
The falx cerebelli is a small infolding of the dura in the sagittal plane over the floor of the posterior cranial fossa. It partially separates the two cerebellar hemispheres 1.
The falx cerebelli is attached posteriorly in the midline to the internal occipital crest of the occip...
The falx cerebri is the largest of the four main folds (or septa) of the intracranial dura mater, separating the cerebral hemispheres 1.
The falx cerebri is a double-fold of dura mater that descends through the interhemispheric fissure in the midline of the brain to separate the...
The female reproductive system (or tract) comprises of the vagina, uterus, uterine tubes and ovaries.
It can be imaged using almost the entire range of modalities but ultrasound and MRI are most useful.
The female urethra is a simple tube that extends from the internal urethral orifice of the bladder to the external urethral orifice in the vestibule of the vagina.
The female urethra measures approximately 4 cm in length. It is embedded in the anterior vaginal wall and runs with...
The femoral canal, or the medial compartment of the femoral sheath, is the inverted cone-shaped fascial space medial to the femoral vein within the upper femoral triangle. It is only 1-2 cm long and opens superiorly as the femoral ring. It serves two purposes:
allows the femoral vein to expand ...
The femoral nerve is a large nerve arising from the lumbar plexus and one of two major nerves supplying the lower limb.
It arises from posterior divisions of L2-L4 roots of the lumbar plexus.
emerges from the lateral border of the psoas muscle to descend between ...
The femoral ring is the superior opening of the femoral canal. Its boundaries are:
medial: lacunar ligament
anterior: medial part of the inguinal ligament
lateral: femoral vein within the intermediate compartment of the femoral sheath
posterior: pectineal ligament overlying the pectineus and...
The femoral sheath is the funnel-shaped fascial space that extends from the abdomen, inferior to the inguinal ligament, into the femoral triangle. It has variable length and terminates by blending in with the adventitia of the femoral vessels. It is formed from the transversalis and psoas fascia...
The femoral triangle is found in the anterior upper thigh.
The major boundaries can be recalled with the mnemonic SAIL 1,2:
lateral border: medial border of sartorius
medial border: medial border of adductor longus
superior border: inguinal ligament
A mnemonic for the boundaries of the femoral triangle is:
This should be easy to remember because the femoral triangle is shaped like a sail.
A: adductor longus
IL: inguinal ligament
The femoral vein is the main deep vein of the lower limb, and accompanies the superficial femoral artery and common femoral artery. The term 'superficial femoral vein or its abbreviation, SFV' should not be used as it is a misnomer (i.e. it is not a superficial vein), this is formally stated in ...
The femoroacetabular or hip joint is a large ball-and-socket synovial joint between the femoral head and the acetabulum.
articulation: ball and socket joint between the head of the femur and the acetabulum
ligaments: ischiofemoral, iliofemoral, pubofemoral and transverse acetabular li...
The femur (plural: femora) is the longest, most voluminous and strongest bone in the human body.
It is composed of the upper extremity, body and lower extremity and provides several muscular origins and insertions.
The upper extremity is composed of the head, neck, greater tr...
Fetal circulation differs from the adult circulation due to the presence of certain vessels and shunts.
These shunts will close after birth, and most of these fetal vessels will be seen as remnants in the adult circulation. The function of these shunts is to direct oxygen-rich venous blood to ...
Fibrous joints are a type of joint where the bones are joined by strong fibrous tissue rich in collagen. These joints allow for very little movement (if any) and are often referred to as synarthroses.
cranial sutures between bones of the skull
gomphosis joints between teeth and alveo...
The fibula (plural: fibulae) is the smaller of the two bones of the leg. It is not directly involved in the transmission of weight but is important for ankle stability and acts as a source for numerous muscle attachments. It is commonly raised as a flap for reconstructive surgery.
The fibular or peroneal artery is one of the three arteries of the leg, along with the anterior and posterior tibial arteries.
Origin and course
arises from the tibioperoneal trunk approximately 2.5 cm distal to popliteus and passes obliquely to the fibula, descending along its ...
The fifth lumbar vertebra (L5) is the largest of the five lumbar vertebrae and is considered an atypical vertebra due to its shape.
L5 is the largest, most inferior lumbar discovertebral unit in the vertebral column, and participates in forming the lumbar lordosis (from L1 to L5...
The filum terminale is a filament of connective tissue that extends inferiorly from the apex of the conus medullaris.
The filum terminale is continuous with the pia mater and is described as having two sections:
filum terminale internum: upper three quarters of the filum; covere...
The first rib is the most superior of the twelve ribs. It is an atypical rib and is an important anatomical landmark and is one of the borders of the superior thoracic aperture.
Compared to a typical rib, the first rib is short and thick and it has a single articular f...
The fissula ante fenestram (FAF), also known as the cochlear cleft, is a small connective tissue-filled cleft located where the tendon of the tensor tympani muscle turns laterally toward the malleus. It is situated immediately anterior to the oval window, and posterior to the cochleariform proce...
Flat bones are 1 of the 5 types of bones in the body and represent a group of bones (predominantly of the cranium) that have a relatively flat shape and form from intramembranous ossification.
Flexor carpi radialis (FCR) is a muscle found in the first layer of the anterior compartment of the forearm. It does not pass through the carpal tunnel, but rather by itself in a small separate tunnel between the superficial and deep layers of the flexor retinaculum along the scaphoid and trapez...
Flexor carpi ulnaris (FCU) is a muscle of the first layer of the anterior compartment of the forearm.
humeral head: medial epicondyle of the humerus
ulnar head: medial border of olecranon and posterior border of ulna
insertion: base of 5th metacarpal; hook of hamate, pisiform...
The flexor digiti minimi brevis muscle lies lateral to the abductor digiti minimi.
origin: hook of the hamate and flexor retinaculum
insertion: proximal phalanx of 5th digit
action: flexes 5th finger at metacarpophalangeal joint
arterial supply: ulnar artery
innervation: deep branc...
The flexor digiti minimi brevis muscle lies under the 5th metatarsal bone.
origin: base of metatarsal V and related sheath of fibularis longus tendon
insertion: lateral side of base of proximal phalanx of 5th toe
action: flexes 5th toe at metatarsophalangeal joint
arterial supply: l...
The flexor digitorum brevis muscle lies immediately superior to the plantar aponeurosis and inferior to the tendons of the flexor digitorum longus in the sole of the foot.
origin: medial process of calcaneal tuberosity and plantar aponeurosis
insertion: sides of plantar surface of mid...
The flexor digitorum longus (FDL) muscle is located on the tibial side of the leg within the deep posterior compartment of the leg. At its origin it is thin but as it descends, the muscle increases in size.
origin: medial side of posterior surface of the tibia
insertion: plantar surfa...
Flexor digitorum profundus (FDP) makes up the third layer of the anterior compartment of the forearm along with flexor pollicis longus. It passes through the carpal tunnel.
origin: proximal, anterior surface of ulna and adjacent interosseous membrane
insertion: volar surface of distal...
Flexor digitorum superficialis (FDS) is a muscle in the second (intermediate) layer of the anterior compartment of the forearm that splits into four tendons, passes under the flexor retinaculum and through the carpal tunnel, to insert into the middle phalanx of the 2nd-4th digits.
The flexor hallucis brevis muscle is one of the small muscles of the foot that is involved in flexion of the 1st toe. The hallux sesamoid bones are embedded within its tendon.
origin: plantar surface of cuboid
insertion: medial and lateral sesamoid bones of first metatarsal
The flexor hallucis longus (FHL) muscle is one of the muscles of the posterior deep compartment of the leg and along with flexor hallucis brevis, is involved in flexion of the great toe. Its tendon passes between the medial and lateral tubercles of the talus. It's tendon sheath may communicate w...
The flexor pollicis brevis muscle is distal to the abductor pollicis brevis.
origin: tubercle of the trapezium and flexor retinaculum
insertion: proximal phalanx of the thumb
action: flexes thumb at metacarpophalangeal joint
arterial supply: superficial palmar arch
Flexor pollicis longus (FPL) is one of the two muscles that make up the third layer of the anterior compartment of the forearm along with the flexor digitorum profundus. It is a deep muscle under abductor pollicis brevis muscle. It passes through the carpal tunnel.
The flexor retinaculum (also known as the transverse carpal ligament) is a rectangular-shaped fibrous band located at the ventral aspect of the wrist.
On the radial side, it attaches to the scaphoid tubercle and the ridge of the trapezium. On the ulnar side, it attaches to the pi...
Flexor retinaculum at the ankle is formed by reinforcement of the deep fascia of the leg by transverse collagen bundles and functions to prevent 'bowstringing' of tendons as they pass the tibiotalar joint. It forms the roof of the tarsal tunnel 1, 2.
medial malleolus of the tibia
The floor of mouth is an oral cavity subsite and is a common location of oral cavity squamous cell carcinoma.
The floor of mouth is a U-shaped space extends (and includes) from the oral cavity mucosa superiorly, and the mylohyoid muscle sling 2,3.
superiorly: oral ...
Focal fatty deposits/replacement in spinal bone marrow are well-defined focal fat islands within the bone marrow of spine or other parts of axial skeleton.
Common in older individuals, related to age and not related to sex.
This process is a normal variant. Histologica...
The foramen caecum is located in the anterior cranial fossa, anterior to the cribriform plate of the ethmoid bone and posterior to the frontal bone, within the frontoethmoidal suture. It lies at a variable distance from the crista galli.
The foramen caecum is frequently found in infants, uncomm...
Foramen caecum can refer to a number of different anatomical structures:
foramen caecum (tongue)
foramen caecum (anterior cranial fossa)
The foramen lacerum is a triangular opening located in the middle cranial fossa anterior to the petrous apex, which forms its posterior border. Its anterior border is formed by the body of the sphenoid bone at the junction of greater wing and pterygoid process and medial border is formed by the ...
The foramen magnum is the largest foramen of the skull and is part of the occipital bone 1. It is oval in shape with a large antero-posterior diameter 2.
The foramen magnum is found in the most inferior part of the posterior cranial fossa 3. It is traversed by vital structures in...
The foramen of Langer is a defect in the deep pectoralis fascia. It is a defect at the level of the third intercostal space, through which the upper lateral portion of the breast extends into the axilla forming the axillary tail of Spence.
The foramen of Magendie (also called median aperture) is one of the foramina in the ventricular system and links the fourth ventricle and the cisterna magna. It is one of the three ways that cerebrospinal fluid (CSF) can leave the fourth ventricle and enter the subarachnoid space. The two other ...
The foramina of Morgagni, also known as the sternocostal triangles, are small defects in the posterior aspect of the anterior thoracic wall between the sternal and costal attachments of the diaphragm. The internal thoracic vessels descend through these foramina to become the superior epigastric ...
The foramen of Rouviere is a rarely seen space in the shoulder joint capsule between middle and inferior glenohumeral ligaments and it may communicate with the subcoracoid recess (inferior subscapularis recess). It should not be confused with an acquired defect.
The foramen of Weitbrecht is a small opening in the glenohumeral joint capsule between superior and middle glenohumeral ligaments and is seen communicating with the subtendinous bursa of the subscapularis muscle.
The foramen ovale (or ovalis) is the opening in the interatrial septum in the fetal heart that allows blood to bypass the right ventricle and non-ventilated lungs, shunted from the right atrium to the left atrium. Specifically it represents the opening between the upper and lower portions of the...
Foramen ovale can refer to a number of different anatomical structures:
foramen ovale (head)
foramen ovale (cardiac)
Foramen ovale is an oval shaped opening in the middle cranial fossa located at the posterior base of the greater wing of the sphenoid bone, lateral to the lingula. It transmits the mandibular division of the trigeminal nerve (CN Vc), accessory meningeal artery, emissary veins between the caverno...
The foramen rotundum is located in the middle cranial fossa, inferomedial to the superior orbital fissure at the base of greater wing of the sphenoid bone. Its medial border is formed by lateral wall of sphenoid sinus. It runs downwards and laterally in an oblique path and joins the middle crani...
The foramen spinosum is located in the posteromedial part of greater wing of sphenoid bone posterolateral to foramen ovale which connects the middle cranial fossa with the infratemporal fossa. It transmits the middle meningeal artery, middle meningeal vein, and (usually) the nervus spinosus.
The foramen tympanicum (also known as foramen of Huschke) is an anatomical variation in the external acoustic canal (EAC), where a bony defect connects the EAC to the temporomandibular joint (TMJ).
Various studies have reported on the occurrence of a foramen tympanicum in the asym...
The foramen Vesalii, also know as the foramen of Vesalius, sphenoidal emissary foramen, foramen venosus or canaliculus sphenoidal, is a tiny variably present foramen in the greater wing of the sphenoid bone, located between the foramen ovale and scaphoid fossa. It transmits a sphenoidal emissary...
The forceps major, also known as the posterior forceps, is a fibre bundle which connects the occipital lobes and crosses the midline via the splenium of the corpus callosum.
The forceps minor, also known as the anterior forceps, is a fibre bundle which connects the lateral and medial surfaces of the frontal lobes and crosses the midline via the genu of the corpus callosum.
The forearm is part of the upper limb below the (upper) arm and above the hand and wrist, comprising the radius and ulna bones. In the supinated anatomical position, the radius is lateral and the ulna is medial.
The elbow joint is superior and the wrist joint inferior. Forearm flexion and exten...
The forefoot is the portion of the foot distal to the midfoot and is composed of the metatarsals and the phalanges. The tarsometatarsal joints (TMTJ) joins the midfoot to the forefoot.
The fornix is the main efferent system of the hippocampus and an important part of the limbic system. It is one of the commissural fibres connecting the cerebral hemispheres.
Roughly C-shaped, the fornix extends from the hippocampus to the mammillary bodies of the hypothalamus an...
The term fornix (plural: fornices) is used for anatomical structures in multiple organ systems that all share an arch-like morphology:
History and etymology
Fornix is Latin for...
The fornix conjunctiva is loose soft tissue lying at the junction between the palpebral conjunctiva (covering the inner surface of the eyelid) and the bulbar conjunctiva (covering the globe). Each eye has two fornices, the superior and inferior fornices. The fornix permits freedom of movement of...
The fornices are superior recesses of the vagina formed by the protrusion of the cervix into the vaginal vault. There is a large posterior fornix and a smaller anterior fornix with two small lateral fornices.
History and etymology
Fornix is Latin for 'arch'.
The fossa navicularis refers to a normal mild dilatation of the urethra. It occurs at the most distal/downstream portion of the urethra.
It is more evident in males, where it occurs in the penile/pendulous urethra, near the urethral meatus. There is also a fossa navicularis in women: the more f...
The fossa of Rosenmüller, also known as the posterolateral or pharyngeal recess, is the most common site of origin for nasopharyngeal carcinoma.
It is located superior and posterior to the torus tubarius (the posterior projection of the cartilaginous portion of the eustachian tub...
The fossa ovale (or ovalis) is the small oval depression in the interatrial septum at the site of the closed foramen ovale, which closes once fetal circulation ceases in the first few minutes of postnatal life. It represents the overlapping primary and secondary septa of the interatrial septum. ...
The fourth ventricle is one of the components of the ventricular system in the brain, along with the lateral and third ventricles. It extends from the cerebral aqueduct (of Sylvius) to the obex and is filled with CSF.
CSF enters the ventricle via the cerebral aqueduct and leaves via one of four...
The fovea ethmoidalis is a portion of the ethmoid bone and represents its superior portion (part of the ethmoid roof) which is seen as a continuation of the superior orbital roof to the cribriform plate.
A foveola pharyngica recess is one of the variants of the inferior median clival canal, thought to represent a remnant of the notocord. It represents a blind ending recess in the anteroinferior surface (nasopharyngeal) surface of the clivus 1,2.
The frontal bone is a skull bone that contributes to the cranial vault. It contributes to form part of the anterior cranial fossa.
The frontal bone has two portions:
vertical portion (squama): has external/internal surfaces
horizontal portion (orbital): has superior/inferior su...
The frontal lobe is by far the largest of the four lobes of the cerebrum, and is responsible for many of the functions which produce voluntary and purposeful action.
The frontal lobe is the largest lobe accounting for 41% of the total neocortical volume 8. The frontal lobe resid...
The frontal nerve is a largest and main branch of the ophthalmic division of the trigeminal nerve. It divides off the ophthalmic division just before entering the orbit through the superior orbital fissure outside and superolateral to the tendinous ring, where it lies between the lacrimal nerve ...
The frontal pole is one of the three poles of the brain (along with the occipital pole and temporal pole), and corresponds to the anterior most rounded point of the frontal lobe.
It does not have easily defined boundaries, but is roughly equivalent to the frontopolar cortex, which in turn is co...
The frontal sinuses are the paranasal sinuses within the frontal bone. They are lined with mucosa and are most often two in number.
location: anterior frontal bones on either side of the midline behind the brow ridges
blood supply: supratrochlear, supraorbital and anterior ethmoidal a...