The transversospinalis 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 most anterior muscle of the inner layer (external intercostal, internal intercostal and transversus thoracis) of the thoracic wall.
The transversus thoracis is a thin band of muscle and tendon arising from the lower posterior surface of th...
The trapezium (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 thumb and index meta...
Trapezium fractures are uncommon carpal bone injuries. They can either occur in isolation or combination with another carpal bony injury.
Isolated fractures of the trapezium are only thought to account for 3-5% of all carpal fractures 1-2.
They can be broadly classifie...
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 trapezoid is an irregular, boot-shaped bone. The dorsal surface is larger than the palmar surface and i...
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...
This is a basic article for medical students and other non-radiologists
Trauma films are ubiquitous in an orthopedic attachment and also in the Emergency Department.
In most cases, a trauma film will come with two views. It is important that you review both films because in some cases a fractu...
Traumatic neuromas may occur from acute or chronic injury to a nerve.
The patient presents with a focal area of pain and tenderness to palpation. There should be a history of injury to the area. Surgery is a common source of traumatic neuromas (e.g. ilioinguinal pain post...
The Trethowan sign is used to diagnose slipped capital femoral epiphysis (also called slipped upper femoral epiphysis). In this sign, the line of Klein passes above the femoral head.
It is best done on both AP and true lateralcit projections. On the AP view of a normal hip, the Klein line inter...
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...
Triangular fibrocartilage complex (TFCC) injuries may be traumatic or degenerative in nature. The TFCC is a complex structure consisting of the triangular fibrocartilage (TFC) disk proper, ulnomeniscal homologue and numerous ligaments and tendons.
Traumatic injuries are u...
The triangular ligaments grouped with the ulnar collateral ligament and meniscal homologue, comprising 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 co...
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...
Avulsion injury of the triceps tendon is an uncommon injury. It is one of the least common injuries to elbow but is nevertheless commoner than an intramuscular triceps tear.
Patients usually usually present with regional pain, swelling and inability to extend to the elbow...
The triceps brachii, which 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, medial intermuscular septum
The triceps coxae is the tricipital (three headed) collection of 3 of the 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 gemellu...
Triceps surae 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 the Achi...
Triceps tendinopathy is the least common tendon injury of the elbow, and most commonly presents as rupture.
There is a male predominance 1.
Triceps tendinopathy can range from tendinosis through to complete rupture 1,2.
Rupture most commonly occurs at the osteotendin...
Trichilemmomas are important due to their invariable association with Cowden syndrome.
They are a benign cutaneous neoplasm that usually present on the head or face as a smooth or verrucoid lesion, and may be single or multiple. They may be mistaken for a basal cell carcinoma.
Trident acetabulum is an appearance which can be seen in several skeletal dysplasias 1.
It is characterized by small bony spurs at the medial and lateral acetabular margins with a more subtle central spur, resembling a trident, the three-pronged spear of classical Greece 1. The trident is most ...
A trident hand is a description where the hands are short with stubby fingers, with a separation between the middle and ring fingers.
The appearance mimics a trident, the three-pronged spear of classical Greece. The trident is most commonly associated with the sea god Poseidon in Greek mytholo...
A trigger finger is a type of stenosing tenosynovitis. It develops due to repetitive microinjury from frequent flexion-extension movements of the fingers.
A patient with trigger finger finds it difficult to straighten or bend the affected finger. The finger transiently ge...
Trigger thumb (or flexor pollicis longus stenosing tenosynovitis) is a specific type of trigger finger involving the thumb.
May present as a transient locking of the thumb in flexion, followed by a painful snapping sensation during extension
A trigger toe (or hallux saltans if it involves the 1st toe) refers to a uncommon situation where active plantar flexion causes the toes to catch in flexion and the patient is then unable to extend them. It can arise from a number of pathologies and if it involves the great (1st) toe a common pa...
Trimalleolar fractures refer to a three-part fracture of the ankle. The fractures involve the medial malleolus, the posterior aspect of the tibial plafond (referred to as the posterior malleolus) and the lateral malleolus. Having three parts, this is a more unstable fracture and may be associate...
Triphalangeal thumb is considered a form of pre-axial polydactyly.
Triphalangeal thumbs have an incidence of 1 in 25,000 7.
A triphalangeal thumb, as the name implies, has three phalanges instead of the usual two. There is an autosomal dominant genetic transmission 8....
Triplane or triplanar fractures are of the distal tibia only occurring in adolescents. As the physiological closure of the physeal plate begins medially, the lateral (open) physis is prone to this type of fracture. The name is due to the fact of the fracture expanding both in frontal and lateral...
Triquetral fractures are carpal bone fractures generally occuring on the dorsal surface of the triquetrum. The triquetral may be fractured by means of impingement from the ulnar styloid, shear forces, or avulsion from strong ligamentous attachments. They are the second commonest carpal bone frac...
The triquetrum (os triquetrum) 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 for articulation with the pisiform.
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 and...
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...
Trochanteric bursitis results from the trochanteric bursa becoming irritated.
Previously trochanteric bursitis has been attributed as the major cause of lateral hip pain but now the term greater trochanteric pain syndrome is preferred because most commonly the cause of lateral hip ...
A trochanteric fracture is a fracture involving the greater and/or lesser trochanters of the femur.
Fractures in these regions can be classified as:
pertrochanteric: intertrochanteric, involving both trochanters
greater trochanteric avulsio...
The trough line sign is a sign of posterior shoulder dislocation on AP films.
In a posterior dislocation, the anterior aspect of the humeral head becomes impacted against the posterior glenoid rim. With sufficient force, this causes a compression fracture on the anterior aspect of the humeral ...
Musculoskeletal tuberculosis is always secondary to a primary lesion in the lung.
The prevalence of the disease is around 30 million globally and 1-3% of the 30 million have involvement of their bones and/or joints. Mycobacterium tuberculosis is responsible for almost all of the c...
Tuberculous arthropathy is a type of musculoskeletal manifestation of tuberculosis (TB) and a common cause of infectious arthritis in developing countries. Any pathological joint lesion where the exact diagnosis is equivocal should be considered tubercular in origin unless proven otherwise.
Tuberculous dactylitis, also known as spina ventosa, is a rare skeletal manifestation of tuberculosis where the short tubular bones (i.e. phalanges, metacarpals, metatarsals) are affected.
Tuberculous osteitis is one of the commonest bacterial osteitides. Typically the dactylitis ...
Tuberculous spondylitis, also known as Pott disease, refers to vertebral body osteomyelitis and intervertebral diskitis from tuberculosis (TB). The spine is the most frequent location of musculoskeletal tuberculosis, and commonly related symptoms are back pain and lower limb weakness/paraplegia....
Tuberculous spondylitis and pyogenic spondylitis are both common causes of spinal infection. Imaging findings of these 2 diseases can be challenging to distinguish, yet crucial because the treatments for these infections are particularly different 2.
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...
A tug lesion in musculoskeletal imaging is a term given to describe a bony traction reaction at a muscle attachment site likened to that of the "tug effect. They are benign and are placed as do not touch lesions.
Notable sites include:
distal femur: cortical desmoid
posterior tibia: soleal li...
Tumoral calcinosis is a rare familial condition characterized by painless, periarticular masses. The term should be strictly used to refer to a disease caused by a hereditary metabolic dysfunction of phosphate regulation associated with massive periarticular calcinosis and should not be used to ...
There are a number of tumors of muscular origin, which overall are relatively uncommon, representing only 1.7% of benign soft tissue tumors, and 10.3% of malignant soft tissue tumors1.
The tumors can be divided according to the type of muscle fiber:
Skeletal muscle origin
Tumors of the chest wall are varied, some of which are found most often in this region. They can be divided into benign and malignant tumors and into those which arise in the ribcage and those of soft tissue density.
Benign tumors include 1,3,4:
Tumors that metastasise to bone may be remembered using the mnemonic "lead kettle" spelled PBKTL (lead is Pb on the Periodic Table).
For females, breast and lung are the most common primary sites; nearly 80% of cancers th...
Turf toe is an extreme traumatic dorsiflexion (hyperextension) injury of the toe results in plantar plate injury from sprain to complete tear of the plantar plate capsuloligamentous complex and allows unrestricted range of motion of the first metatarsophalangeal (MTP) joint. It is common in prof...
Turner syndrome, also known as 45XO or 45X, is the most common of the sex chromosome abnormalities in females.
The incidence is estimated at 1:2000-5000 of live births, although the in utero rate is much higher (1-2% of conceptions) due to a significant proportion of fetuses with...
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 ...
The two-slice-touch rule is a sign on MRI of the knee used to increase the sensitivity of diagnosing meniscal tears.
This rule states a meniscal tear is present if abnormal findings are present on two or more images - these do not have to be contiguous, e.g. can occur on sagittal and coronal sl...
The tympanic part of the temporal bone is situated inferiorly to the squamous part and anteriorly to the mastoid part.
The tympanic part surrounds the external auditory meatus, forming the anterior wall, floor and some of the posterior wall of the bony external acoustic meatus. The lateral bord...
Type 1 pelvic resections are complex surgeries that involve removing part of the pelvis, usually to resect malignant tumor.
Type 1 pelvic resections remove a varying amount of the iliac bone, and are classified in general terms as "partial" or "complete", depending on how much of the iliac bone...
Type II collagenopathies are a group of conditions collectively characterized by abnormalities in synthesis of collagen type II. This usually occurs due to a mutation in the COL2A1 gene.
Entities that fall under this group include:
achondrogenesis type II
platyspondylic lethal skeletal dyspla...
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-sized vertebral bodi...
Typical ribs are those numbered 2 to 10 with ribs 1, 11 and 12 considered atypical.
A typical rib is long and flat. They contain a:
Ribs have a rounded, smooth superior border. The inferior border is thin and sharp.
The ulna (plural: ulnae) is one of the two long bones of the forearm. It is 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
Ulnar dimelia or mirror hand syndrome is a rare congenital anomaly of the upper limb characterized by absence of the radial ray (including thumb), duplication of the ulna and duplication of the ulnar halves of the carpals, metacarpals and phalanges 1.
The embryology of mi...
Ulnar hemimelia is a rare congenital upper limb anomaly characterized by complete or partial absence of the ulna bone.
Incidence is estimated at 1/100,000-150,000 live births, with a male to female ratio of 3:2.
Ulnar hemimelia may be associated with other skeletal ...
Ulnar impaction syndrome, also known as ulnar abutment or ulnocarpal loading, is a degenerative wrist condition caused by the ulnar head impacting upon the ulnar-sided carpus with the injury to the triangular fibrocartilage complex (TFCC).
Ulnar impaction syndrome most commonly pr...
Ulnar impingement syndrome is a wrist condition caused by a shortened distal ulna impinging on the distal radius proximal to the sigmoid notch. The syndrome is distinct from ulnar impaction syndrome, which typically occurs due to a long ulna (positive ulnar variance) impacting upon the triangula...
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 C8-T1.
Ulnar nerve dislocation is an uncommon cause of pain and paresthesias in the ulnar nerve distribution. It occurs if the ulnar nerve subluxates and then dislocates over the anterior aspect of the medial epicondyle during flexion and extension of the elbow.
Ulnar nerve dislocation occ...
There are several distinct ulnar-sided wrist impaction and impingement syndromes. Underlying anatomical causes exist for each syndrome, however, repetitive or excessive use of the forearm and wrist can also contribute.
ulnar impaction syndrome: positive ulnar variance
ulnar impingement syndrom...
Ulnar styloid fractures occur in association with ~60% of distal radius fractures. Most of these are small avulsion fractures involving the tip of the ulnar styloid.
Usually, this kind of fracture occurs as the result of a fall on an outstretched arm and is often associated with a di...
Ulnar styloid impaction syndrome refers to wrist pain due to a long ulnar styloid process impacting upon the triquetral bone.
An unlar styloid >6mm in length is commonly regarded as being long. Impaction results in chondromalacia of the opposing articular surfaces, i.e. the proximal ...
Ulnar variance (also known as Hulten variance) refers to the relative lengths of the distal articular surfaces of the radius and ulna.
Ulnar variance may be:
neutral (both the ulnar and radial articular surfaces at the same level)
positive (ulna projects more distally)
negative (ulna projec...
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...
Ultrasound-guided biopsy is one form of image-guided biopsy, typically performed by a radiologist. It is the most common form of image-guided biopsy, offering convenience and real-time dynamic observation with echogenic markers on cannulae allowing for precise placement.
It can potentially be u...
Ultrasound of the elbow allows high-resolution imaging of elbow anatomy while simultaneously allowing dynamic evaluation of the joint, tendons, and ligaments.
There are multiple possible approaches to imaging the elbow with ultrasound. A typical protocol is as follows 1:
There are several approaches to ultrasound examination of the adult hip.
supine with the hip in mild external rotation
sagittal oblique plane parallel to the long axis of the femoral neck to assess femoral head and neck and for any joint effusio...
Ultrasound of the knee allows high-resolution imaging of superficial knee anatomy while simultaneously allowing dynamic evaluation of some of the tendons and ligaments. Knee ultrasound is somewhat limited compared with ultrasound examinations of other joints because the cruciate ligaments and th...
Ultrasound of the shoulder is a fast, relatively cheap and dynamic way to examine the rotator cuff and is particularity useful in diagnosing:
rotator cuff disorders
The examination requires attention to technique and appropriate patient positioning. ...
Ultrasound is a useful imaging modality for evaluation of the wrist, allowing high-resolution imaging of anatomy while simultaneously allowing dynamic evaluation of the joint, tendons, and ligaments.
There are multiple possible approaches to imaging the wrist with ultrasound. The exam...
Umbilical hernias are the most common ventral hernia and occur in the midline.
Ten times more common in females 2 and represent ~5% of all abdominal hernias 4.
Umbilical hernias present in the midline as painless or painful mass.
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...
Undifferentiated spondyloarthritis (uSpA), also known as undifferentiated arthritis, is a non-specific mono- or polyarthropathy that lacks the clinical, serological and radiological features that would allow specific diagnosis. It often turns out to be an early presentation of a more well known ...
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.
Unicameral bone cysts (UBC), also known as simple bone cysts, are common benign non-neoplastic lucent bony lesions that are seen mainly in childhood and typically remain asymptomatic. They account for the S (simple bone cyst) in FEGNOMASHIC, the commonly used mnemonic for lytic bone lesions.
Unilateral facet dislocation is a relatively stable type of facet dislocation.
Flexion/distraction associated with rotation. The inferior articular facet of vertebral above moves over the superior facet of the vertebral below and becomes locked. It usually affects C4-C5 or...
Upper extremity dislocations are relatively common on account of the great range of motion the upper limb is capable of (a general principle is that the greater the range of motion of a joint, the more prone it is to dislocation). In many instances dislocations are associated with fractures eith...
The upper limb sustains a wide variety of fractures that range significantly in demographics, treatment and functional impact.
blade of scapula fracture
coracoid process fracture
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 global standard for correct gross anatomical nomenclature.
Upper limb radiography is the radiological investigation of the shoulder girdle, humerus, ulna, radius, carpals and metacarpals of the hand. It is often utilized in the context of trauma to rule out fractures and dislocations.
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...
Vacuum phenomenon in the shoulder refers to the presence of intra-articular gas in the shoulder joint. It is a very common occurrence, particularly in external rotation. This can cause circular or linear areas of low signal intensity on GRE MR images of the shoulder obtained with external rotati...
Valgus extension overload syndrome, also known as pitcher's elbow, refers to a constellation of symptoms and pathologies commonly seen in overhead throwing athletes secondary to high repetitive tensile, shear and compressive forces generated by the overhead throwing motion.
The syndrome may cor...
The terms valgus and varus refer to angulation (or bowing) within the shaft of a bone or at a joint.
It is determined by the distal part being more medial or lateral than it should be. Whenever the distal part is more lateral, it is called valgus. Whenever the distal part is more medial, it is ...
Van Buchem disease (VBD) is an extremely rare hereditary sclerosing bone dysplasia, also known as hyperostosis corticalis generalisata. This disease is characterized most notably by mandibular enlargement and thickening of the skull.
Less than 30 cases have been reported in the li...