Bones of Extremities

Learning & Test Objectives

  1. Identifying bones
  2. Orientation: how is it placed in the body
  3. Parts of the bone
  4. Specific Structures and their functions
  5. Clinical Significance: Palpation, X-Rays, Common fracture sites, required notes

Description of the test

The test is held by the general rules of oral examination (see Continuous Testing – Organisation).

The student is given several bones from the upper and the lower extremity. The student is required to correctly name the bones in English and Latin. The student then has to orient the bone, determine whether the bone is from the left of the right extremity and demonstrate the ventral, dorsal, medial, lateral, proximal and distal aspects of the bone and how the bone is situated in the body. After this, the student will be asked several questions about the bones. These questions will be in the format ‘what is this’ or ‘please, show me the...’. The student may answer in either English or Latin, but is expected to know the name of all structures in both languages. The student should know the function of each structure (i.e. attachment site of a muscle, ligament or joint capsule, impression of a tendon, nerve or vessel etc.). For the majority of structure, it is sufficient to state the general function. However, for some structures it is necessary to know the specific function (e.g. the deltoid muscle inserts on the deltoid tuberosity, the quadriceps femoris inserts on the tibial tuberosity, the radial nerve passes along the groove for the radial nerve). The student is then given other bones of the extremities and will be examined on them in the same manner. The student will be required to identify palpable structures on himself/herself or on a classmate. All bones will be examined individually or on skeleton models of the hand and foot. Student has to recognize small bones of the hand and foot, but does not need orient them (except the talus and the calcaneus). The student will also receive a few questions concerning clinical correlations, morphometric parameters and other interesting features of the bones. The student may also be examined on X-ray pictures or be required to draw simple schemes of skeletal structures of the limbs.


Clinical notes

Fractures of the clavicle are commonly associated with fragment dislocation. The medial part of the clavicle tends to be pulled cranially by the sternocleidomastoid. The lateral part of the clavicle can become caudally displaced by the coracoclavicular ligament. Clavicle fractures occur in all age groups but most commonly in children.

The surgical neck of the humerus is an area of frequent fractures in adults. Injury to the anterior and posterior circumflex arteries can occur causing ischaemia and necrosis of the head of the humerus. 

Injuries of the diaphysis of the humerus can damage the radial nerve and deep brachial artery, which are located in the groove for the radial nerve.

Colles' fracture is an extra-articular fracture of the distal radius with dorsal dislocation of the fragments. It is caused by falling on an extended wrist. It is the most common type of fracture.

Smith's fracture is an extra-articular fracture of the distal radius with ventral dislocation of the fragments. It is caused by falling on a flexed wrist.

Fractures of the scaphoid are the most common fractures of the carpal bones. They are characterised by pain over the anatomical snuff box and can be complicated by avascular necrosis of the proximal fracture fragment.

Fractures of the neck of the femur are very common in elderly people with osteoporosis. They are more common in females and usually occur as a consequence of a fall.

Intra-osseous access to the tibia can be used in critical care medicine for application of infusions and medications. The bone marrow is accessed by a puncture approximately 1 cm below the tuberosity of the tibia.

Overload of the quadriceps femoris insertion on the tibial tuberosity can lead to disruption.

The common fibular nerve runs superficially behind the head and neck of the fibula. It can be injured by trauma or by an incorrectly positioned cast compressing the nerve. 

The calcaneus is the most frequently injured bone of the tarsus. Fracture of the calcaneus is a major risk factor for the development of compartment syndrome.

March fractures are a form of fatigue fractures that affect the second and third metatarsal bone after prolonged periods of marching or running. They occur most frequently in firm shoes with hard soles.

A bunion (hallux valgus) is a foot deformity, characterised by lateral deviation of the big toe. A bulge can develop in the area of the first metatarsophalangeal joint. This disorder is more common in women who wear shoes with stiletto heels.


Other interesting notes

Physisis a clinical term used for the growth plate. 

In clinical practice the metacarpals, metatarsals and phalanges are classified as short tubular bones. Anatomically they are classified as long bones. 

Ossification of the carpal bones proceeds in a circle starting with the capitate. It serves as an X-ray marker of bone age.

In children the individual parts of the pelvis are separated by cartilage at the acetabulum. This cartilage has a shape of an inverted letter Y (cartilagoypsiloformis) and ossifies between the 14th and 16thyear of life. 

The greater and lesser trochanters are apophyses and have their own ossification centres.

The pilon (or pylon) is a clinical term for the distal part of the tibia. The tibial plateau is a clinical term for the proximal part of the tibia. 

Almost 60 % of the surface area of the talus is covered by cartilage. It receives blood only from areas that are not covered by cartilage. Its blood supply is very liable to compromise in trauma.

The tarsal sinus is situated between the talarsulcus and calcaneal sulcus. It contains the interosseoustalocalcaneal ligament. 

Morphometric parameters

The length of the upper extremity is measured from the acromion to the dactylion (the most distal part of the upper extremity – the end of the tuberosity of the distal phalax of the third digit).  

The acromion is an anthropometric point. Its lateral edge can be used for measuring the shoulder-to-shoulder width and the length of the upper limb. When in the anatomical position, the long axis of the scapula is tilted slightly laterally and its medial margin is at an angle of 3–5° with the sagittal plane.

The axis of the glenoid cavity projects 9° dorsally from the axis of the scapula (retroversion of the glenoid cavity).

On frontal section, the scapula and clavicle form an angle of 30° with the fronal plane. This means that the scapula is tilted 30° ventrally (the glenoid cavity points obliquely forward) and the clavicle is tilted 30° dorsally. The scapula and the clavicle make an of 60° with each other.

The angle of inclination of the humerus is the angle between the head and body and is about 130°.

The carrying angle is an obtuse angle between the humerus and the ulna open laterally when the elbow is in the anatomical position (full extension). Its measure 170°.

The axis of the hand passes through the third finger.

The functional (relative) length of the lower extremity is measured from the anterior superior iliac spine to the medial malleolus.

The anatomical length of the lower extremity is measured from the greater trochanter to the lateral malleolus.

The length of the lower extremity is measured from the umbilicus to the medial malleolus when there is asymmetry of the pelvis.

The angle of inclination of the femur is formed between the neck and the body. In new-borns this angle measures approximately 150° and in adults it is about 125° (120–135°). Coxavalga refers to a more obtuse angle (more than 135°) and coxavara refers to a more acute angle (less than 120°).

The axis of the foot passes through the second toe.


3D Atlas of the Human Bones

Radiographs of the bones and joints of the upper extremity

Radiographs of the bones and joints of the lower extremity

Created: 11. 10. 2016 / Modified: / Responsible person: MUDr. Azzat Al-Redouan