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 2 of the 3 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 Achilles t...
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 characterised 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 - professional requirement or requirement of a sports activity. The repetitive microtrauma results in thickening of the flexor tendon sheath a...
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 fracture is a carpal bone fracture that generally occurs on the dorsal surface of the triquetrum. It may be fractured by means of impingement from the ulnar styloid, shear forces, or avulsion from strong ligamentous attachments. It is the 2nd commonest carpal bone fracture, after the ...
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 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 ...
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 avulsion f...
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 discitis 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....
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...
Tumoral calcinosis is a rare familial condition characterised 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 tumours of muscular origin, which overall are relatively uncommon, representing only 1.7% of benign soft tissue tumours, and 10.3% of malignant soft tissue tumours1.
The tumours can be divided according to the type of muscle fibre:
Skeletal muscle origin
Tumours of the chest wall are varied, some of which are found most often in this region. They can be divided into benign and malignant tumours and into those which arise in the ribcage and those of soft tissue density.
Benign tumours include 1,3-4:
Tumours 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 t...
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 tumour.
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 bon...
Type II collagenopathies are a group of conditions collectively characterised 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 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 fibres 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).
The UMH is located between the ulnar styloid process and the triquetrum. It adheres to the ulnar joint capsule and merges with ...
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 ...
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 utilised 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 fibres...
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...
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 characterised most notably by mandibular enlargement and thickening of the skull.
Less than 30 cases have been reported in the li...
The Vancouver classification of periprosthetic hip fractures proposed by Duncan and Masri is the most widely used classification system. It takes into account the fracture site, the status of the femoral implant, and the quality of surrounding femoral bone stock.
type A: fractures involve the t...
The vastus intermedius muscle is one of the 4 quadriceps muscles in the anterior compartment of the thigh. The others are the vastus medialis, the vests laterals, and the rectus femoris.
origin: upper two thirds of the anterior and lateral surfaces of the femur
The vastus lateralis is largest of the four quadriceps muscles in the anterior compartment of the thigh. The others are the rectus femoris, the vastus intermedius, and the vastus medialis.
lateral part of intertrochanteric line
margin of greater trochanter
The vastus medialis muscle is one of the four quadriceps muscles in the anterior compartment of the thigh. The others are the rectus femoris, the vastus intermedius, and the vastus lateralis.
medial part of intertrochanteric line
medial lip of the linea ...
The vertebra (plural: vertebrae) is the fundamental segmental unit of the vertebral column (also know as the spine).
Vertebrae, apart from those that are atypical, have a similar basic structure which can be described as an anterior vertebral body and a posterior neural (or verte...
The vertebral column is affected by a range of anatomical variants of the body and/or neural arch as well as accessory ossicles. Knowledge of basic vertebral anatomy and ossification is essential for describing and understanding the range of anomalies.
The differential diagnosis for a vertebral body mass is broad and may range from a completely benign, sclerotic enostosis (bone island) to a malignant primary bone tumour.
Broadly, these lesions can be separated into:
primary bone tumours
Vertebral body squaring refers to the loss of normal concavity of the anterior border. It is seen in a variety of conditions including:
Ankylosing spondylitis is the most common cause of vertebral body squaring. It usually involves multiple level...
Vertebral haemangiomas are the most common benign vertebral neoplasms. They are usually asymptomatic and incidentally detected due to their characteristic features on imaging for other reasons.
Please refer on the article on primary intraosseous haemangioma for a general discussion in this enti...
Differential diagnosis of vertebral lesions includes:
Lesion originating in vertebral body
vertebral body osteomyelitis
giant cell tumour
Langerhans cell histiocytosis
Vertebral metastases represent the secondary involvement of the vertebral spine by haematogenously-disseminated metastatic cells. They must be included in any differential diagnosis of a bone lesion in a patient older 40 years.
This article will focus only on the metastasis involving the bony s...
Vertebral pneumatocysts are gas-filled cavities within the spinal vertebrae. They are most common at cervical levels. In general, vertebral pneumatocysts are less common than intraosseous pneumatocysts in the pelvis, especially adjacent to the sacroiliac joint.
Although not comple...
Vertebral scalloping is a concavity to the posterior (or less commonly anterior) aspect of the vertebral body when viewed in a lateral projection. A small amount of concavity is normal, as is concavity of the anterior vertebral body (see vertebral body squaring).
Vertebral vascular foramina are normal findings seen on cross-sectional imaging and should not be mistaken for a fracture, especially in the setting of trauma.
basivertebral veins (forms Hahn's canal): foramen is seen on the posterior surface of the vertebral body in the midline...
Vertebra plana (a.k.a. pancake / silver dollar / coin-on-edge vertebra) is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture. Plural is vertebrae planae. It can occur in a variety of settings, incl...
Mnemonics to remember the causes of vertebra plana include:
E: eosinophilic granuloma
T: trauma; tuberculosis
F: fracture (trauma)
E: eosinophilic granuloma
T: tumour (e.g. metastases, myelo...
Vertebroplasty is an imaging-guided procedure which entails percutaneous injection of surgical polymethylmethacrylate (PMMA) cement into a diseased vertebral body. Vertebroplasty provides pain relief and strengthening of the bone of vertebrae weakened by disease.
It can be used as ...
Very bizarre generalised lesions of bone tend to make you exclaim "Oh my! What is going here?" Although there are numerous potential causes, in this situation it is worth thinking of a number of entities:
skeletal dysplasias and metabolic diseases
Vickers ligament is a ligamentous structure connecting the lunate bone and TFCC to the distal radius and is seen in the vast majority of patients with Madelung deformity 1.
Release of this thickened ligament may help in improving symptoms associated with Madelung deformity 2.
Vitamin A (the retinoids) are a group of fat soluble vitamins required for many physiological functions, mainly vision, reproduction and epithelial maintenance. In the retina, a specific retinoid 11-cis-retinal is formed by photo-isomerisation within the rods and cones.
Vitamin C (ascorbic acid) is a water soluble vitamin that is a coenzyme for the formation of the structure protein collagen, particularly creating cross-linking of collagen fibres which greatly increases its tensile strength. It also acts as an antioxidant.
Vitamin D (calciferol) is used to describe a group of five fat-soluble secosteroid vitamins required for the homeostasis of serum calcium and phosphorus. Vitamin D exists in two main forms (vitamers) in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).
Vitamin D3 acts by re...
Volar intercalated segmental instability (VISI) is a type of instability involving the wrist. It is less often encountered than dorsal intercalated segmental instability (DISI).
It presents in most cases with nonspecific wrist pain and a "clunking" on the ulnar deviation ...