The transverse arch of the foot is an arch in the coronal plane formed by the three cuneiforms, the cuboid, and the bases of the five metatarsals. They are held together by the deep transverse metatarsal ligaments. The peroneus longus and tibialis posterior tendons assist in maintaining the curv...
The transverse cervical artery, also known as the cervicodorsal trunk, is 1 of the 4 branches of the thyrocervical trunk (off the first part of the subclavian artery).
It is a short artery that bifurcates into the superficial and deep branches, both which course superficially and laterally acro...
The transverse cervical nerve, also known as the superficial cervical nerve, cutaneous cervical nerve or anterior cutaneous cervical nerve of the neck, is a cutaneous branch of the cervical plexus that innervates the skin covering the anterior cervical region.
The transverse colon is the longest and most mobile part of the large intestine. It measures up to 45 cm in length.
The transverse colon is the continuation of the ascending colon from the right colic flexure. It passes from the right to left hypochondrium in a downward convex p...
The transverse fissure (of Bichat) is the cerebral fissure that extends laterally from the ambient cistern towards the hippocampus.
The transverse fissure is the lateral extension of the ambient cistern that connects with the choroidal fissure superolaterally and hippocampal fiss...
The transverse humeral ligament (also known as the Brodie ligament) is a small broad ligament that extends between the lesser and greater tubercles of the humerus superior to the epiphyseal line. It encloses the tendon of the long head of biceps brachii and its sheath in the bicipital groove, fo...
The transverse ligament of the hip bridges the acetabular notch (located anteroinferiorly along the margin of the acetabulum) and joins the two ends of the acetabular labrum, thus forming a complete ring. Beneath it (through the acetabular foramen) pass nutrient vessels which enter the ligamentu...
The transverse ligament of the knee, also called the transverse intermeniscal ligament attaches transversely across the anterior aspects of the convex margins of the medial and lateral menisci.
The transverse ligament is a variable band-like intracapsular knee ligament.
The transverse mesocolon is a broad, meso-fold of peritoneum, which connects the transverse colon to the posterior wall of the abdomen.
It is continuous with the two posterior layers of the greater omentum, which, after separating to surround the transverse colon, join behind it, and are contin...
The transverse muscle of the tongue is one of the four intrinsic muscles of the tongue which alters the shape of the tongue mass, being entirely confined to the tongue without an extraglossal attachment (cf. extrinsic muscles of the tongue).
The muscles fibers attach proximally t...
The transverse pancreatic artery, also known as the inferior pancreatic artery, is a branch of the splenic artery that supplies the pancreatic tail and body.
It arises from the proximal splenic artery and descends a short distance to run to the left along the posterior margin of the pancreas ne...
The transverse pericardial sinus is the transverse communication between the left and right parts of the pericardial space proper behind the two outflow arteries of the heart.
It is superior to the left atrium and posterior to the intrapericardial parts of the pulmonary trunk a...
The transverse perineal muscles are important for the stability of the pelvic and perineal structures via their intimate relationship with the perineal body. For many years, it was thought that these muscles directly inserted into the perineal body. It is now known that fibers from the muscles o...
The paired left and right transverse sinuses are major dural venous sinuses and arise from the confluence of the superior sagittal, occipital and straight sinuses at the torcular herophili (confluence of sinuses).
On each side, the transverse sinus then runs in the lateral border of the tentori...
The transverse tibiofibular ligament is part of the tibiofibular syndesmosis.
The transverse ligament is a thick round ligament, which takes a horizontal course between the posterior tibia and the edge of the lateral malleolar fossa distal to the posterior tibiofibular ligament a...
Transverse vaginal (transvaginal) septum (TVS) is a type of rare congenital uterovaginal anomaly (class II under the Rock and Adam classification).
It is rare with a frequency of 1 in 70,000 females.
In the case of a complete septum, patients commonly prese...
The transversospinalis muscle group is the deep layer of the intrinsic back muscles. These muscles lie between the transverse and spinous processes and are grouped by length of the fascicles, as well as region covered. The groups are rotatores, multifidus, and semispinalis.
The transversus abdominis muscle, named according to the direction of its muscle fibers, is one of the flat muscles that form the anterior abdominal wall. It is deep to the internal oblique muscle and ends in the anterior aponeurosis, which ultimately blends with the linea alba.
The transversus thoracis muscle is the innermost muscle of the anterior thoracic wall (deep to external intercostal and internal intercostal muscles).
The transversus thoracis is a thin band of muscle and tendon arising from the lower posterior surface of the sternum, posterior...
The trapezium (also known as the greater multangular) is one of the eight carpal bones of the hand. It is the most lateral (radial) bone of the distal row, located between the scaphoid and the first metacarpal bone. It articulates with the scaphoid proximally, the trapezoid medially, and the thu...
The trapezium secondarium (or trapezium secundarium or secondary trapezium) is an accessory ossicle of the wrist. It can be seen adjacent to the tubercle of the trapezium superomedially 1,2.
According to Pfitzner, the trapezium secondarium is one of four potential secondary ossifica...
The trapezius muscle is a large, broad superficial muscle of the posterior neck and back. It gains its name from its diamond shape. Along with sternocleidomastoid muscle, it is invested by the superficial layer of the deep cervical fascia, which splits around it.
origin: superior nuch...
The trapezoid bone (also known as the os trapezoideum or the lesser multangular) is the smallest carpal bone in the distal row, sitting lateral to the capitate. The trapezium and trapezoid are collectively known as the multangulars.
The trapezoid is an irregular, boot-...
The trapezoid ligament is one of two components forming the coracoclavicular (CC) ligament. The conoid ligament is the other component.
The trapezoid ligament is a broad quadrilateral ligament that is quite thin. Its positioned almost horizontally. It is the anterolateral part of...
The triangle of Guillain and Mollaret, also known as the dentatorubro-olivary pathway, has three corners 1:
inferior olivary nucleus
contralateral dentate nucleus
Rubro-olivary fibers descend from the parvocellular division of each red nucleus along the central tegmental tracts t...
The triangle of Koch or Koch’s triangle is an important landmark for atrioventricular catheter ablation procedures for the localization of the atrioventricular node.
From a right atrial viewpoint, the triangle of Koch is delineated by the hinge of the septal tricuspid valve leafl...
The triangle of safety is an anatomical region in the axilla that forms a guide as to the safe position for intercostal catheter (ICC) placement. With the arm abducted, the apex is the axilla, and the triangle is formed by the:
lateral border of the pectoralis major anteriorly
lateral border o...
The triangles of the neck are surgically focused divisions of the neck, first described from early dissection-based anatomical studies which predated cross-sectional anatomical description based on cross-sectional imaging (see deep spaces of the neck).
The neck can be divided into anterior and ...
The triangular fibrocartilage complex (TFCC) is a complex structure that is a major contributor to the stability of the wrist.
The TFCC is located on the ulnar aspect of the wrist joint between the ulna and the lunate and triquetrum of the proximal carpal row. It has an elongate...
The triangular ligaments grouped with the ulnar collateral ligament and meniscal homologue, comprise the ulnar-sided components of the triangular fibrocartilage complex (TFCC). The triangular ligament attaches triangular fibrocartilage to the ulnar tip and fovea.
The triangular ligament is comp...
The triangular space may refer to:
medial (upper) triangular space in the axilla
lateral (lower) triangular space in the axilla
Triangular space of cruciate ligaments (TSC) is defined as the potential extrasynovial space between anterior and posterior cruciate ligaments of the knee joint.
anteriorly: anterior cruciate ligament
posteriorly: posterior cruciate ligament
inferiorly: tibial plate...
A useful mnemonic to remember the tributaries of the inferior vena cava is:
I Like To Rise So High
I: common iliac veins
L: lumbar veins
T: right testicular (gonadal) vein
R: renal veins
S: suprarenal veins
H: hepatic veins
The triceps brachii muscle, often referred to simply as the triceps, is a three-headed muscle in the posterior compartment of the arm.
long head: infraglenoid tubercle of the scapula
medial head: posterior humerus inferior to the radial groove, both intermuscular septa
The triceps coxae is the tricipital (three headed) collection of 3 muscles in the posterior hip which act together on the hip, primarily to laterally rotate the extended thigh. It comprises (in order from superior to inferior) the superior gemellus, obturator internus and inferior gemellus muscl...
Triceps surae muscle is another term used for the calf muscles, more specifically two of the three muscles of the superficial posterior compartment of the leg:
medial and lateral heads of the gastrocnemius muscle
The group of muscles are innervated by the tibial nerve and form t...
The tricuspid valve (TV) is one of the four cardiac valves. It is one of the two atrioventricular valves (AVs) and allows blood to flow from the right atrium to the right ventricle. It opens during diastole and closes during systole. The valve has anterior, posterior and septal leaflets (cusps),...
The trigeminal ganglion, also known as the Gasser, Gasserian or semilunar ganglion, is the large crescent-shaped sensory ganglion of the trigeminal nerve located in the trigeminal cave (Meckel cave) surrounded by cerebrospinal fluid.
The ganglion contains the cell bodies of the sensory root of ...
The trigeminal nerve is the fifth cranial nerve and its primary role is relaying sensory information from the face and head, although it does provide motor control to the muscles of mastication. It is both large and complicated and has multiple brainstem nuclei (sensory and motor) as well as man...
A mnemonic for remembering the names of the skull foramina that the division of the trigeminal nerve (CN V) pass through is:
Standing Room Only
S: superior orbital fissure (ophthalmic division of trigeminal nerve)
R: foramen rotundum (maxillary division of trigeminal nerve)
The trigone of the lateral ventricle is an area of the lateral ventricle at the confluence of the occipital and temporal horns. It refers either to the three-dimensional space at the transition between the body of the lateral ventricle and the occipital and temporal horns, in which case it is al...
The triquetrum (also known as os triquetrum or - historically - as the triangular bone) is one of the carpal bones and forms part of the proximal carpal row.
The triquetrum is wedge-shaped carpal bone located between the lunate and the pisiform. It has an oval facet fo...
The triradiate cartilage is the Y- shaped epiphyseal plate that occurs at the junction where the ischium, ilium, and pubis meet in the skeletally immature skeleton.
The vertical component of the "Y" is the meeting of the ischium and pubic bone. The anterior arm is the junction of the ilium an...
The triscaphe joint is the shared joint between the scaphoid, trapezium and trapezoid bones in the wrist. This joint is also referred to by its much longer name, the scaphotrapeziotrapezoid (STT) joint.
This joint may be fused as an alternative to scapholunate fusion in treat...
The triticeal cartilage is a small cartilage located within the lateral aspect of the thyrohyoid membrane, that may be bilateral, unilateral or absent. It is considered a laryngeal anatomical variant.
It is found in 33% of an adult cadaver series 2.
The triticeal c...
The trochanteric bursa, also known as the greater trochanteric bursa or, more specifically, the subgluteus maximus bursa, is the hip bursa located deep to the gluteus maximus muscle that is usually implicated in trochanteric bursitis.
The trochanteric bursa is located deep to the...
Trochlea (sing., pl. trochleae) is a general term that refers to an anatomic structure that resembles the grooved part of a pulley system:
Trochlea have been described in:
trochlea of the superior oblique muscle
trochlear nerve (CN IV)
trochlea of ...
The trochlear nerve is the fourth cranial nerve and is the motor nerve of the superior oblique muscle of the eye. It can be divided into four parts:
nucleus and an intraparenchymal portion
cavernous sinus portion
Nucleus and intraparenchy...
The trochlear nucleus is a small motor nucleus in the midbrain for the trochlear nerve.
The nucleus is located in the midbrain at the level of the inferior colliculus ventral and medial periaqueductal grey and dorsal to the medial longitudinal fasciculus. It lies just caudal to ...
The true vocal cords are the thickened, free edge of the cricovocal membrane, the cricovocal ligament, lined by mucous membrane 1. Together they form part of the glottis, the V-shaped aperture through which air passes. Their primary role is in phonation where vibration of the adducted vocal cord...
Tuber cinereum is a hollow eminence of gray matter. It is a part of the hypothalamus.
It is located between mammillary bodies and optic chiasm. Devoid of the blood brain barrier, it normally enhances after contrast administration.
It is continuous:
laterally: with an...
The tuberculum sellae is the ridged process of the sphenoid bone which forms the anterior wall of the sella turcica.
The tuberculum sellae forms the anterior wall of the sella turcica, which houses the pituitary gland. It is an elongated ridge located immediately poste...
Tubulation is the adult-type appearance of long bones with a diaphyseal narrowing or constriction that forms due to periosteal bone resorption and endosteal bone formation at the metaphysis during longitudinal bone growth at the physis.
Numerous diseases can affect tubulatio...
The tunica albuginea (TA) forms the fibrous covering of the testis and is itself covered by the serous layer, the tunica vaginalis. The covering is total, except for at the point of attachment of the epididymis, and a small defect posteriorly where the spermatic cord vessels enter and leave the ...
Tunica is a word used in anatomy to refer to a type of covering.
tunica adventitia (also known as tunica externa)
tunica albuginea (clitoris)
tunica albuginea (ovary)
tunica albuginea (penis)
tunica albuginea (testis)
The tunica vaginalis (TV) represents the investing serosal covering of the testis. It forms as the embryological testis descends and passes out through the superficial inguinal ring carrying its abdominal peritoneal covering with it.
The tunica vaginalis is said to consist of two layers, the pa...
The twelfth rib is an atypical rib. It is the shortest rib, and one of two floating ribs.
The 12th rib has a single facet on its head for articulation with the T12 vertebra. It has a short neck and no tubercle. It also lacks a costal groove and angle. internal surface ...
Twig-like middle cerebral artery or rete mirabile anomaly describes a discontinuity of a single trunk of the middle cerebral artery with several small vessels reconstituting the artery and giving it a twig-like appearance. Distally, normal vascular anatomy of the MCA branches need to be present ...
The tympanic annulus is the thickened edge of the pars tensa of the tympanic membrane, anchoring it in the tympanic sulcus 3.
The tympanic annulus is formed by a fibrocartilaginous thickening of the edge of the pars tensa and has a horseshoe-shaped configuration. It is deficient ...
The tympanic membrane is a thin membrane that separates the external ear from the middle ear. It acts to transmit sound waves from air in the external auditory canal (EAC) to the ossicles of the middle ear.
The tympanic membrane is shaped like a flat cone pointing into the middle...
The tympanic part of the temporal bone is situated inferiorly to the squamous part and anteriorly to the mastoid part.
The tympanic part of the temporal bone is composed of anterior and posterior surfaces and superior, inferior and lateral borders.
The tympanomastoid fissure is one of the intrinsic fissures of the temporal bone, located parallel and posterior to the bony external auditory canal, dividing the tympanic part of the temporal bone and mastoid process. Its radiological significance is as a fracture mimic (pseudofracture) 1. Its ...
The tympanosquamous fissure separates the tympanic part of the temporal bone from the squamous part. It is parallel and anterior to the bony external auditory canal and divides medially into the petrotympanic fissure and petrosquamous fissure.
Of the seven cervical vertebrae, C3 through C6 have typical anatomy, while C7 looks very similar. C1 (atlas) and C2 (axis) have very distinct anatomical features. For a basic anatomic description of the structure a generic vertebra, see vertebrae.
small, oval-shaped vertebral bod...
Typical ribs are those numbered 2 to 10 with ribs 1, 11 and 12 considered atypical. Some authors however include ribs 2 and 10 also atypical.
A typical rib is long and flat. They contain a:
Ribs have a rounded, smooth superior border. The infe...
Given the twelve thoracic vertebrae are largely similar, most are considered typical thoracic vertebrae with the exceptions T1 and T9 to T12. For a basic anatomic description of the structure of typical vertebrae, see vertebrae.
In medical English, some doctors and texts refer to t...
The ulna (plural: ulnae) is one of the two long bones of the forearm, located medially in the supinated anatomic position. It has a larger proximal end and tapers to a smaller distal end (opposite to the radius).
Prominent features of the ulna include:
The ulnar artery is a terminal branch of the brachial artery, arising at the proximal aspect of the forearm. Along with the radial artery, it is one of the main arteries of the forearm.
origin: terminal branch of the brachial artery
location: inferior aspect of the cubital fossa
A useful mnemonic to remember the branches of the ulnar artery is:
Anatomical Pictures Can Definitely Deeply Please
Anatomical Pictures Can Definitely Deeply Please
A: anterior ulnar recurrent
P: posterior ulnar recurrent
C: common interosseous artery
D: dorsal carpal branch
The ulnar collateral ligament of the wrist is an extrinsic dorsal ulnocarpal ligament and functions as a part of the triangular fibrocartilage complex as an ulnar stabilizer of the wrist 1-3.
The ulnar collateral ligament connects the ulnar styloid al process with the triquetrum ...
The ulnar nerve is one of the terminal branches of the brachial plexus and has motor and sensory supply to the forearm and hand.
The ulnar nerve originates as a terminal branch of the medial cord of the brachial plexus with nerve root fibers from the ventral rami of C8-T1...
The ulnar vein is one of the two major deep veins of the forearm, along with the radial vein. As is usual in the upper and lower limbs, there are often two veins (venae comitantes) that run on either side of the ulnar artery and anastomose freely with each other.
It forms in the hand from the d...
The ulnocapitate ligament is the most superficial of the three extrinsic palmar ulnocarpal ligaments and a volar stabilizer of the ulnocarpal complex 1-3.
The ulnocapitate ligament is the only ulnocarpal ligament directly attaching to the ulnar head. It runs superficial to the ul...
The ulnolunate ligament is one of the intracapsular, extrinsic palmar ulnocarpal ligaments and a component of the ulnocarpal complex 1-4.
The ulnolunate ligament forms the anterior part of the ulnocarpal joint capsule together with the ulnotriquetral ligament, with which it share...
The ulnomeniscal homologue (UMH) is an obliquely oriented, fibrocartilaginous structure, that forms part of the ulnar collateral ligament complex (ULC) of the wrist.
The UMH is located between the ulnar styloid process and the triquetrum. It adheres to the ulnar joint capsule and...
The ulnotriquetral ligament is one of the intracapsular extrinsic palmar ulnocarpal ligaments and a component of the ulnocarpal complex 1-4.
The ulnotriquetral ligament forms the anterior and ulnar part of the ulnocarpal joint capsule together with the ulnolunate ligament, with w...
The umbilical artery gives rise to both a nonfunctional remnant of the fetal circulation and an active vessel giving supply to the bladder. In the adult, the obliterated area of the vessel is identifiable as the medial umbilical ligament and the patent segment is the superior vesical artery.
The umbilical cord is a fetal organ that connects the placenta to the developing fetus and is a vital passage for nutrients, oxygen and waste products to and from the fetus.
The umbilical cord inserts into the center of the placental bulk and into the fetus at the umbilicus. Vari...
The umbilical folds are a series of 5 folds of parietal peritoneum on the deep surface of the anterior abdominal wall and consist of:
a single midline median umbilical fold,
bilateral medial umbilical folds, and
bilateral lateral umbilical folds
The umbilical vein is the conduit for blood returning from the placenta to the fetus until it involutes soon after birth.
The umbilical vein arises from multiple tributaries within the placenta and enters the umbilical cord, along with the (usually) paired umbilical arteries. Once it enters the...
The umbilicus is the fibrous remnant of the fetal attachment of the umbilical cord after birth.
All layers of the anterior abdominal wall fuse at the umbilical ring, a small round defect in the linea alba located just inferior to the midpoint between the xiphoid process of the st...
The uncinate fasciculus is a white matter tract that connects the uncus (Brodmann area 35), the anterior temporal areas (temporal pole; Brodmann area 38), the amygdala and the hippocampal gyrus (Brodmann areas 36 and 30) with areas of the frontal lobe (polar and orbital cortex); runs - forming a...
The uncinate process of the ethmoid bone is a thin hook-like osseous structure of the wall of the lateral nasal cavity.
Together with the ethmoid bulla, it forms the boundaries of the hiatus semilunaris and ethmoid infundibulum.
The course of the free edge of the uncinate proces...
The uncinate process of the cervical spine is a hook-shaped process found bilaterally on the superolateral margin of the cervical vertebral bodies of C3-C7.
The uncinate processes are more anteriorly positioned in the upper cervical spine and more posteriorly location in the lower cervical spin...
Uncovertebral joints, also called Luschka’s joints, are seen bilaterally between adjacent cervical vertebrae, identified by the cat ear shaped uncinate processes of the C3-7 vertebrae (C1 and C2 have no uncinate processes).
The articulation forms between the uncina...
The uncus (plural: unci) is the innermost part of the anterior parahippocampal gyrus, part of the mesial temporal lobe.
The uncus is the most anterior portion of the medial parahippocampal gyrus. It belongs to the limbic system. Housing the primary olfactory cortex, it is part o...
Unfused spinous process, which is really failure of fusion of the neural arch, is a relatively common anatomical variant and is part of the spectrum of spina bifida occulta.
This should be differentiated from accessory ossicles of the spinous process, which appear after non-fusion of the secon...
Fusion of sternal body segments is usually complete by 25 years of age. But non-fusion of sternal body segments can be seen in older age group.
A unicornuate uterus or unicornis unicollis is a type of Müllerian duct anomaly (class II) characterized by a banana-shaped uterus usually draining into a single Fallopian tube.
This type can account for ~10% (range 6-13%) of uterine anomalies and infertility is seen in ~12.5% (ra...
Upper limb anatomy encompasses the anatomy of the shoulder, arm, elbow, forearm, wrist and hand.
This anatomy section promotes the use of the Terminologia Anatomica, the international standard of anatomical nomenclature.
The upper subscapular nerve, also known as the short or superior subscapular nerve, arises from the posterior cord of the brachial plexus and supplies the subscapularis muscle.
The upper subscapular nerve branches from the posterior cord of the brachial plexus with fibers...
The upper T sign is one of the features useful in identifying the central sulcus of the cerebral cortex on cross-sectional imaging.
It relies on identifying the superior frontal sulcus which intersects the precentral sulcus in a "T" junction, thus defining the precentral gyrus. The central sulc...
The urachus (plural: urachuses or urachi ref) is the fibrous vestigial remnant of the embryonic allantois.
The lumen of the urachus usually obliterates after birth and it becomes known as the median umbilical ligament, which is covered by a midline linear fibrous fold of parietal peritoneum (ca...