Mandibular fractures are relatively common especially among young men. Although traditionally the mandible and base of skull are thought to form a complete bony ring, interrupted only by the TMJs. This should mean that the mandible should fracture in two places (akin to the bony pelvis) making s...
The Marshall classification of traumatic brain injury is a CT scan derived metric using only a few features and has been shown to predict outcome in patients with traumatic brain injury.
This system was first published in 1992 1 building on findings from a large cohort of head injury cases des...
Mayfield classification of carpal instability, also known as perilunate instability classification (carpal dislocations), describes carpal ligament injuries.
Instability has been divided into four stages 1-2:
stage I: scapholunate dissociation (rotatory subluxation of the scaphoid)
Mayo classification of scaphoid fractures divides them into three types according to anatomic location of the fracture line:
Fractures of the distal third are further divided into distal articular surface or the distal tubercle fractures:
McGrigor-Campbell lines are imaginary lines traced across the face on an occipitomental (Waters) view skull radiograph to assess for fractures:
first line is traced from one zygomaticofrontal suture to another, across the superior edge of the orbits
second line traces the zygomatic arch, cross...
A meniscal root tear is a type of meniscal tear in the knee where the tear extends to either the anterior or posterior meniscal root attachment to the central tibial plateau. They often tend to be radial tears extending into the root.
According to one source they are thought to a...
Metacarpal fractures are common. Fracture of the metacarpal bones account for 10% of all fractures and 40% of all hand fractures. The lifetime incidence of a metacarpal fracture is 2.5%.
Specific names are given to fractures of the base of the first metacarpal (see: fractures of th...
Metaphyseal fractures are fractures that involve the metaphysis of tubular bones. They may occur in paediatric or adult patients.
Examples of metaphyseal fractures:
surgical neck of humerus fracture
distal radial fracture
distal radial buckle fra...
Midcarpal (central carpal) dislocation describes an injury where there is dislocation of the capitate from the lunate, and subluxation of the lunate from the radius. This term is somewhat confusing because some authors use "midcarpal dislocation" to refer generally to perilunate and lunate dislo...
Middle phalanx fractures are the least common of the phalanx fractures.
These fractures are generally well visualised on plain radiographs. Ultrasonography can be used in unclear cases.
Treatment and prognosis
Non-displaced fractures can be treated conservatively with a...
Minimal aortic injuries are traumatic aortic lesions that usually involve the intima and are recognised more frequently due to the use of high-resolution imaging.
Minimal aortic injuries account for 10-28% of all blunt traumatic aortic injuries 1,6,7. The proportion of this type o...
Mixed temporal bone fractures are a combination of longitudinal and transverse fracture types, and are probably the most common type. They frequently involve the otic capsule, and are associated with both conductive and sensorineural hearing loss.
petrous temporal bone fracture
The modified Memphis criteria are a set of screening criteria for blunt cerebrovascular injury (BCVI) in trauma. The presence of one or more of these criteria makes necessary a complementary CTA or DSA study to exclude a BCVI.
The screening protocol criteria for BCVI are:
base of skull fractur...
Monteggia fracture-dislocations consist of a fracture of the ulnar shaft with concomitant dislocation of the radial head. The ulnar fracture is usually obvious, whereas the radial head dislocation can be overlooked, with potentially serious functional and medico-legal ramifications.
A Morel-Lavallée lesion is a closed degloving injury associated with severe trauma which then presents as a haemolymphatic mass. MRI and ultrasound are useful modalities for evaluation.
The lesions classically occur over the greater trochanter of the femur 1. Morel-Lavallée lesions...
The medical student musculoskeletal radiology curriculum represents a core set of common pathologies and presentations that are key to understand during any orthopaedic attachment in medical school.
Named fractures are usually eponymous or occupational. The simplest way of spiting them up is by body area:
upper extremity fractures
lower extremity fractures
Nasal bone fractures are the most common type of facial fractures, accounting for ~45% of facial fractures, and are often missed when significant facial swelling is present.
Unsurprisingly, nasal bone fractures occur when the nose impacts against a solid object (e.g. fis...
Naso-orbitoethmoid (NOE) fractures (also known as orbitoethmoid or nasoethmoidal complex fractures) are fractures which involve the central upper midface.
Naso-orbitoethmoid fractures are caused by a high-impact force applied anteriorly to the nose and transmitted posteriorly through...
The Neer classification of proximal humeral fractures is probably the most frequently used along with the AO classification of proximal humeral fractures. Even if an exact knowledge of this classification system is beyond the everyday use of many radiologists, the terminology and factors which i...
Nerve injury classification describes the various features of nerve injury on MRI with respect to pathological events.
grade I: there is increased T2/STIR signal in the nerve, however the muscle appears normal
grade II: increased T2/STIR signal in ne...
NEXUS Chest is a clinical decision rule that supports the appropriate use of thoracic imaging in trauma. There are seven criteria 1,2:
>60 years old
rapid deceleration defined as fall > 6 metres or motor vehicle crash >64 km/hour
abnormal alertness or mental status
Nightstick fractures are isolated fractures of the ulna, typically transverse and located in the mid-diaphysis and usually resulting from a direct blow. It is a characteristic defensive fracture when the patient tries to ward off an overhead blow from an assailant (or local law enforcement offic...
Oblique fractures are complete fractures that occur at a plane oblique to the long axis of the bone. Like transverse fractures, the term is predominantly used in the context of describing a fracture in a long bone.
Oblique fractures are particularly prone to angulation in the plane of the fract...
Occipital condylar fractures result from high-energy blunt trauma.
The exact incidence of these fractures is unknown but are reported to occur in 3-4% patients with moderate-severe traumatic brain injuries 3.
History and examination are unreliable, and high...
Occult fractures are those that are not visible on imaging, most commonly plain radiographs and sometimes CT, either due to lack of displacement or limitations of the imaging study. There may be signs of a fracture without one actually being seen. MRI or nuclear medicine studies are sometimes re...
Odontoid process fracture, also known as the peg or dens fracture, occurs where there is a fracture through the odontoid process of C2.
The mechanism of injury is variable, and can occur both during flexion or extension with or without compression 5.
There are two cl...
Oesophageal perforation is a rare but serious medical emergency with a very high mortality rate, especially if the diagnosis is delayed.
Most patients are in their 60s with a slight male predominance 5.
If a perforation is not detected during the procedure...
Olecranon fractures are clinically and radiographically obvious, and usually require open reduction and internal fixation.
Olecranon fractures occur as the result of one of four mechanisms 2:
direct blow (or fall directly on the elbow)
fall on outstretched hand with elbow flexed
Open book fracture of the pelvis is a pelvic fracture that results from an anteroposterior compression injury to the pelvis.
This causes disruption of pubic symphysis and the pelvis opens like a book. The pubic rami may be fractured in vertical orientation instead of the disruption o...
An open or compound fracture or dislocation refers to a fracture or dislocation associated with soft tissue injury where the fractured bone or dislocated joint is in direct communication with the outside environment.
It is of surgical importance due to the high risk of microbial contamination a...
Orbital blow-in fractures occur when there is displacement of bone fragments towards the orbits.
blow-in fracture effectively reduces the volume of the orbit
associated intraorbital injuries include extraocular muscle entrapment and optic nerve injury
as an isolated (pure) orbital ...
Orbital blow-out fractures occur when there is a fracture of one of the walls of orbit but the orbital rim remains intact. Typically, this is caused by a direct blow to the central orbit from a fist or ball.
The blow-out fracture is the commonest type of orbital fracture and is us...
Orbital emphysema is the presence of gas within the orbital soft tissues. It is usually due to orbital fractures communicating with the paranasal sinuses but can be caused by penetrating trauma and infection. It is a common finding also after orbital or ocular surgery.
Ossicular chain disruption (or ossicular discontinuity) is loss of normal alignment between the three middle ear ossicles. The condition is a cause of conductive hearing loss.
Exact incidence and prevalence are not known. Hearing loss associated with temporal bone fractures in chi...
Osteochondral defects are focal areas of articular damage with cartilage damage and injury of the adjacent subchondral bone. It is a term that encompasses osteochondritis dissecans and is used synonymously with osteochondral injury/defect in the paediatric population.
The recognised sites of os...
The pancreas is uncommonly injured in blunt trauma. However, pancreatic trauma has a high morbidity and mortality. Imaging features range between subtle to obvious.
The pancreas is injured in ~7.5% (range 2-13%) of blunt trauma cases 1,3. Motor vehicle accidents account for the va...
A number of pancreatic injury grading systems have been proposed.
American Association for the Surgery of Trauma (AAST)
grade 1: haematoma with minor contusion/laceration but without duct injury
grade 2: major contusion/laceration but without duct injury
grade 3: distal lace...
Patella fracture is one of the common knee injuries usually post direct trauma to the patella or sudden forceful contraction of the quadriceps muscles in a context of sport injury.
Patients present with marked swelling and pain over the patella with point tenderness and m...
Patellar sleeve fractures represent chondral or osteochondral avulsion injury at the inferior pole of the patella.
Patellar sleeve fractures occur in the paediatric population, typically between 8 and 12 years of age.
Unlike Sinding-Larsen-Johannson disease...
Pathological fractures are fractures that occur in abnormal bone. Although the term can be used in the setting of a generalized metabolic bone disease, it is usually reserved for fractures through a focal abnormality. The abnormality may be malignant or non-malignant in nature.
Harrington criteria can be used to predict which skeletal metastases are at high risk of pathological fracture and should undergo prophylactic internal fixation. It preceded the Mirel classification for impending pathological fracture but has not been validated and its use is debated.
Mirel classification is a system used to predict the highest risk of pathological fracture among bones affected by metastases.
involving <1/3 of bone diameter
involving 1/3-2/3 of bone diameter
The PECARN (Paediatric Emergency Care Applied Research Network) traumatic brain injury algorithm is a clinical decision rule that aims to identify children at very low risk of clinically important traumatic brain injury (ci-TBI) 1. This validated paediatric algorithm predicts likelihood of the a...
Bucket handle fractures of the pelvis are a result of anteroposterior compression energy vectors. It is described as a vertically-orientated fractures through the superior and inferior pubic rami on one side with contralateral sacro-iliac joint disruption/dislocation 1, 2.
Pelvic fractures can be simple or complex and can involve any part of the bony pelvis. Pelvic fractures can be fatal, and an unstable pelvis requires immediate management.
Pelvic fractures can be seen in any group of patients. Like much trauma, there is a bimodal distribution with...
Pelvic fractures are a heterogeneous group of injuries that can occur secondary to a variety of mechanisms that range from an innocuous simple fall to severe high-energy trauma in a road traffic collision.
This is a summary article. For more information, you can read a more i...
Penetrating thoracic trauma, namely gunshot and stab injuries, vary widely in incidence globally but nevertheless result in high mortality and serious morbidity. CT is the modality of choice in imaging these patients and can reduce the need for surgical exploration.
Penetrating traumatic neck injury can be a potentially devastating injury due to the high density of crucial anatomical structures within the neck.
Young males are highly represented in patients with a traumatic neck injury. In one study, 11:1 ratio of males to females were ident...
Penile fracture is a rare event, however requires emergency diagnosis and intervention.
It is a rupture of corpora cavernosa and penile sheath (tunica albuginea) caused by trauma to an erect penis, most commonly during sexual intercourse. What a urologist needs to known in such an emergency, is...
Perched facet joint is a vertebral facet joint whose inferior articular process appears to sit 'perched' on the ipsilateral superior articular process of the vertebra below.
Any further anterior subluxation will result in dislocation, with one facet "jumping" over the other and becoming locked...
Perilunate dislocations and perilunate fracture dislocations are potentially devastating closed wrist injuries that are often missed on initial imaging.
These injuries involve dislocation of the carpus relative to the lunate which remains in normal alignment with the distal radius. They should...
Periprosthetic fractures can occur around any joint replacement and commonly occur around knee and hip arthroplasties.
Periprosthetic fractures complicate around 1% of total hip arthroplasties and ~1.5% of total knee arthroplasties 1,2.
They can be difficul...
Several classification systems have been proposed for periprosthetic fractures of the hip:
American Academy of Orthopedic Surgeons (AAOS) classification
Cooke and Newman (modified Bethea) classification
Vancouver classification: most widely used
Peritalar dislocation, also referred to as subtalar dislocation, involves the combined dislocation of the talocalcaneal/subtalar and talonavicular joints without the involvement of the tibiotalar and calcaneonavicular joints. It is generally associated with high-energy trauma and accounts for a ...
Perthes lesion of the shoulder is one of the types of the anterior glenohumeral injury in which the anterior inferior labrum is torn and lifted from the edge of the glenoid 1 but still attached to the intact lifted periosteum from the anterior aspect of the glenoid. Although the labrum may be no...
Phalanx fractures are common injuries, although less common than metacarpal fractures. They have different prognosis and treatment depending on the location of the fracture.
Phalanx fractures can be intra- or extra-articular and can occur at the base, neck, shaft or head of the phala...
Physiological pelvic intraperitoneal fluid refers to the presence of a small volume of free fluid in the pelvis, particularly the pouch of Douglas. It occurs in young females of reproductive age and can be a mimic of traumatic free fluid in abdominal trauma.
Unfortunately, pelvic free fluid may...
Piedmont fractures have been variably defined in the literature. Many suggest that Piedmont fractures are synonymous with Galeazzi fractures. That is a fracture of the radius at the middle and distal third with associated disruption of the distal radioulnar joint.
The initial report about the s...
A pilon fracture is a type of fracture involving the distal tibia. These are considered to represent 1-10% of all lower limb fractures. 6
Typically occurs as a result of an axial loading injury which drives the talus into the tibial plafond.
Several classification sy...
Ping pong skull fracture or pond skull fracture refers to a depressed skull fracture of the infant skull caused by inner buckling of the calvarium. It is seen in newborns because of the soft and resilient nature of their bones (like greenstick fractures of long bones) and the fracture line is no...
Pipkin classification is the most commonly used classification for femoral head fractures, which are uncommon but are associated with hip dislocations.
type I: fracture distal to the fovea capitis, a small fracture not involving the weightbearing surface
type II: fracture proxi...
Pisiform fractures are uncommon type of fracture involving the carpal bones.
They are only thought to account ~0.2% of all carpal fractures. Approximately 50% occur in association with other carpal fractures.
Some can be occult on plain fi...
Pneumolipohaemarthrosis is the presence of intra-articular gas in a lipohaemarthrosis. It indicates an open intra-articular fracture.
Pneumomediastinum is the presence of extraluminal gas within the mediastinum. Gas may originate from the lungs, trachea, central bronchi, oesophagus, peritoneal cavity and track from the mediastinum to the neck or abdomen.
In the setting of trauma, if pneumomediastinum is visible o...
A pneumothorax does not display classical signs when a patient is positioned supine for a chest radiograph. Instead, the pneumothorax may be demonstrated by looking for the following signs:
relative lucency of the involved hemithorax
deep, sometimes tongue-like, costophrenic sulcus: deep sulcu...
Posterior ring apophysis fractures occur in the immature skeleton, most commonly in the lumbar spine.
Typically, adolescent males practicing sport activities.
muscle weakness related with root innervation
association with Scheuermann ...
Posterior cruciate ligament (PCL) avulsion fractures are a type of avulsion fracture of the knee that represent the most common isolated PCL lesion. This typically involves separation of the posterior tibial insertion of the PCL to variable degrees.
These injuries are commonly seen i...
Posterior dislocations of the hip, although uncommon, are the most common direction of dislocation for this joint, outnumbering anterior dislocations 9:1.
It most frequently occurs in the setting of significant trauma, given the large amount of force required. The most common scenari...
Posterior shoulder dislocations are far less common than anterior shoulder dislocations and can be tricky to identify if only AP projections are obtained.
Posterior shoulder dislocations account for only 2-4% of all shoulder dislocations (the vast majority are anterior) 1,3.
Posterior talar process fractures may involve medial or lateral tubercle of the posterior process of talus. The posterior talofibular ligament attaches on the lateral tubercle and flexor hallucis longus runs between these tubercles. Unfused ossification center of the lateral tubercle forms the o...
The pronator quadratus sign can be an indirect sign of distal forearm trauma. It relies on displacement of the fat pad that lies superficial to the pronator quadratus muscle.
On lateral wrist radiographs, the pronator fat pad normally appears a thin ra...
Proximal femoral fractures are a subset of fractures that occur in the hip region. They tend to occur in older patients, and in those who have osteoporosis. In this group of patients, fracture is usually the result of low-impact trauma although, in younger patients they are usually victims of hi...
Proximal femoral fractures are a heterogeneous group of fractures that occur in and around the hip. The commonest type of fracture in this region is the femoral neck fracture.
They can occur anywhere between the joint surface of the femoral head and the upper shaft (proximal diaphysis) of the f...
Proximal humeral fractures are common upper extremity fractures, particularly in older patients, and can result in significant disability.
Proximal humeral fractures represent around 5% of all fractures ?. They are most common in older populations and especially in those who are ...
Proximal humeral fractures are a heterogeneous group of fractures that include everything from relatively simple transverse fractures of the surgical neck of humerus, to complex, displaced, multi-part fractures of the proximal humerus that extend into the shoulder joint. The shoulder is a hugely...
Proximal phalanx fractures can be epiphyseal or shaft fractures and can be articular or extra-articular.
The fracture is generally well seen on plain radiographs. Ultrasonography can be used for fractures that are difficult to see or there are doubts.
Treatment and progn...
Proximal radial fractures are the commonest elbow injury in adult patients and the injury most likely to cause an elbow joint effusion. Radial head and neck fractures are often subtle and may be occult on initial imaging.
This is a summary article. For more information, you c...
Pseudosubluxation of the cervical spine is the physiological anterior displacement of C2 on C3 in children. It is common in children <7 years, and less often present in older children. Less often it is seen at C3 on C4. It is more pronounced in flexion and is of clinical significance as it can b...
Pulled elbow (also known as nursemaid's elbow) is a subluxation of the radial head into the annular ligament, which usually spontaneously or easily reduces and rarely demonstrates abnormal radiographic features. It should be distinguished from dislocation of the radial head.
A pulmonary contusion refers to an interstitial and/or alveolar lung injury without any frank laceration. It usually occurs secondary to non-penetrating trauma.
While contusion can affect anyone, children are considered more susceptible due to chest wall greater pliability in tha...
Pulmonary fat embolism is a specific subtype of pulmonary embolism where the embolic particles are composed of fat.
It usually occurs in the context of a long bone fracture and may occur in 1-3% of patients with simple tibial or femoral fractures and up to 20% of individuals with mor...
Pulmonary lacerations result from frank laceration of lung parenchyma secondary to trauma. There is almost always concurrent contusion.
Contusions and lacerations follow blunt or penetrating chest trauma, and are almost always seen with other chest (and abdominal) injuries. While ...
Radial head dislocation occurs when the radial head is displaced from its normal articulation with the ulna and the humerus.
The dislocation may be acquired or congenital (see the separate article on congenital radial head dislocation). Additionally, radial head dislocation should be distinguis...
The Rapid ultrasound in shock (RUSH) protocol is a structured point-of-care ultrasound examination performed at the time of presentation of a shocked patient. It is a more detailed and longer exam than the FAST scan, with the aim to differentiate between hypovolemic, cardiogenic, obstructive and...
Renal trauma can result from direct, blunt, penetrating and iatrogenic injury.
Renal injuries account for ~10% of abdominal trauma, and thus the demographic of affected individuals reflects that population. The incidence of renal injuries increases in pre-existing congenital or ac...
Renal vascular pedicle injury is a severe form of renal trauma, which if not recognised and treated expediently with lead to the loss of the kidney.
Contrast enhanced CT is the Imaging modality of choice. On CT it is recognised as a non-enhaning kidney. Perirenal ha...
Retroperitoneal haemorrhage can be a source of significant yet occult blood loss.
The clinical features are varied depending on the amount of hemorrhage present, rate of onset and ability of the surrounding structures to contain the hemostatic system. The classical featur...
Reverse Barton fractures, also known as volar type Barton fractures, represents an intra-articular distal radial fracture with volar displacement.
In fact, the reverse Barton fracture is a type II Smith fracture: intra-articular oblique distal radial fracture 1-2.
For a discussion of this frac...
A reverse Bennett fracture-dislocation is a fracture-dislocation of the base of the 5th metacarpal bone. It is pathologically and radiographically analogous to the Bennett's fracture of the thumb. It is quite unstable due to unopposed extensor carpi ulnaris force on the fracture fragment, which ...
Reverse Segond fracture is one of the avulsion fracture of the knee, which is due to avulsion of the deep fibers of the medial collateral ligament (also known as the menisciotibial or coronary ligament) involving the medial proximal tibia adjacent to the articular surface. It is the opposite of ...
Rib fractures are a common consequence of trauma and can cause life-threatening complications.
The 4th-10th ribs are the most commonly fractured 1. Fractures of the 1st-3rd ribs are associated with high-energy trauma 3.
When the rib is fractured twice, the term floating rib is used ...
Riseborough and Radin classification of intercondylar fractures of the humerus can be used to classify this injury, which is the result of direct trauma to the olecranon as it is driven as a wedge between the humeral condyles. Four types of fractures can be identified:
type I: no displacement ...