7. Musculoskeletal Anatomy Flashcards
What is radiology?
The medical discipline that uses medical imaging to diagnose and treat diseases within the bodies of humans.
What are the different imaging technologies in current clinical use?
- X-rays
- Computer tomography (CT)
- Magnetic resonance imaging (MRI)
- Radiographic contrast agents -> Barium radiology + Angiography
- Ultrasound
What are some radiology safety measures?
- Dose should be kept as low as reasonably achievable (ALARA)
- Radiation techniques should be avoided in pregnancy
- Non-radiation techniques should be used where possible and appropriate
In radiology, what is the dose measured in?
mSv
Describe the principle on which radiography works.
- High energy EM waves (usually x-rays) are absorbed by different materials to varying extents.
- This means that the detector or film receives different intensities of the waves depening on what they pass through.
- The creation of 2D images using this technique is called projection radiography.
What are some advantages and disadvantages of plain x-rays?
ADV:
- Quick
- Cheap
- Great detail
- Widely availabke
DIS:
- 2D image only
How are x-rays produced?
High energy electrons striking a tungsten target within a vacuum tube.
Is it acceptable to call the image produced by an x-ray an x-ray?
No, it is better to call it a radiograph, image or film.
What colour will the following appear on a x-ray/CT image:
- Air
- Fat
- Bone
- Metal
- Calcium
- Organs, Muscles, Soft tissues
- Air -> Black
- Fat -> Black
- Bone -> White
- Metal -> White
- Calcium -> White
- Organs, Muscles, Soft tissues -> Shades of grey
In radiography, how are the different views of the image named?
It is named according to the direction of the x-rays, such as the anterposterior, posteroanterior, oblique and lateral views.
What are some applications of x-rays?
- Bone fractures
- Basic anatomy checks -> e.g. Dextrocardia of the heart, lung collapse, soft tissues
- Detecting abnormalities, such as tumours
Describe the principle on which ultrasound imaging works.
- High frequency ultrasound is passed into the tissue
- At every boundary where there is a change in density, part of the signal is reflected, which is picked up by the detector at the surface and used to produce an image
- The greater the difference in density, the more of the signal is reflected at that boundary.
What is the frequency of ultrasound typically used in imaging?
2-15 MHz
What are some advantages and disadvantages of ultrasound imaging?
ADV:
- High quality information about soft tissue
- No ionising radiation
- Inexpensive
- Flow information
DIS:
- Gas and bone block US beam
- Obesity degrades image quality
- Operator dependent
- Pixel brightness is not quantitive
Check how to interpret an ultrasound scan!!!
Not sure if it detects densities - more likely just differences between them.
What are some applications of ultrasound imaging?
- Obstetrics (pre-natal scan)
- Pediatric brain
- Testicle and prostate
- Female pelvis
- Abdomen (liver, kidneys, pancreas, gall bladder) -> Variable appearance can show infection, cancers, etc.
- Vascular disease
- Rotator cuff of the shoulder
What is a Doppler ultrasound?
- A form of ultrasound that employs the Doppler effect to generate imaging of the movement of tissues and body fluids (usually blood), and their relative velocity to the probe.
- A colour scale can be used to represent the direction of blood flow.
What is another name often used for ultrasound imaging?
Ultrasonography
Describe the principles of nuclear imaging.
(Note: This is not core material)
Nuclear imaging involves the use of a radioactive tracer within the body that emits usually gamma radiation. This can be detected by a detector and used to understand internal body structure.
What is the most common radionuclide used in nuclear medicine imaging studies?
(Note: This is not core material)
99mTc -> Half-life of 6 hours and a gamma emitter.
What are some of the scan types used in nuclear medicine imaging?
- 2D scintigraphy -> Bone, renal
- 3D -> PET
What is a PET CT scan?
A nuclear medicine imaging technique that uses both PET and CT scanning simultaneously. The images are superimposed.
What does CT stand for?
Computer tomography
Describe the principle on which CT works.
- An x-ray tube rotates around a patient, on the other side of which are multiple rows of detectors. This is used to assemble a cross-section of the patient.
- A CT can take multiple slices per rotation (up to 64).
- In spiral CT, the patient may move past the x-ray tube so that a multi-layer image is formed.
- The detector works by converting the x-rays to a flow of electrons, which is digitised to Hounsfield units (HU).
What are the colours on a CT scan homologous to?
The colours on an x-ray, since a CT is essentially just a series of x-ray images.
Describe the Hounsfield scale for CT scans.
The scale assigns the following values:
- +1000HU = Bone
- 0HU = Water
- -1000HU = Air
What are some advantages and disadvantages of multislice CT?
ADV:
- Static or movie images
- Noninvasive
- Rapid filming gives few motion artifacts
- Good spatial resolution
DIS:
- Expensive
What are some applications for CT?
- Trauma
- Intercranial haemorrhage
- Abdominal injury (especially to organs)
- Fractures
- Spinal alignment
- Diagnosis and staging of cancers
- Detection of foreign bodies in joints
What are radiographic contrast agents and how do they work?
- Chemicals that absorb radiation in a CT or x-ray scan, so that the tissue of interest can be ssen more clearly
- They work by changing the density of the tissue, changing its opacity to x-rays
Are radiographic contrast agents the same as radionuclides?
No, radiographic contrast agents do not emit radiation (like radionuclides used in nuclear medicine imaging), but change the opacity of the tissues of interest.
Name some radiographic contrast agents and their uses.
- Barium sulphate -> Gastrointestinal imaging
- Iodinated contrasts -> Vascular snd lymphatic imaging, Contrast CTs, Cavities
- Air -> Used alongside other contrast to provide double contrast, since the air is less opaque than the contrast tissue
What is an angiograph and how is it done?
- Imaging technique used to study blood vessels.
- Radiographic contrast (iodine) is injected into the blood vessels, which are then imaged using an x-ray based technique.
What is an arthrogram and how is it done?
(Note: This is not core information)
- An x-ray image or CT scan of a joint after a contrast has been injected into it
- The soft tissue is made clearer, so that injuries can be diagnosed more easily
What does MRI stand for?
Magnetic Resonance Imaging
Describe the principle on which MRI works, including the parts of the machine.
The machine is a tunnel consisting of:
- High strength magnets -> Apply a magnetic field to the patient, polarising the sample
- Shim coils -> Correct the magnetic field
- Gradient coils -> Localise the region to be scanned
- Radiofrequency coils -> Excite the sample and detect the resulting NMR signal
The time for each proton to stop resonating determines the type of tissue. The de-excitation of protons occurs in two phases (T1 and T2), each of which releases energy that can be detected.
What contrast agents are used in MRI?
Magnetically active agents, such as gadolinium.
What are some advantages and disadvantages of MRI?
ADV:
- Static or movie images
- Multiple plane images
- Good contrast
- No known health hazards
- Good for soft tissue injuries
DIS:
- More expensive than CT
- Long scans are not pleasant for those with claustrophobia
Whereas CT and x-ray imaging look at tissue density, what does MRI look at?
Proton energy
What colour will the following appear in an MRI scan:
- Air
- Fat
- Bone
- Bone Marrow
- Organs, Muscles, Soft tissues
- Gadolinium
- Water
- Air -> Black
- Fat -> White (or grey in T2)
- Bone -> Dark
- Bone Marrow -> White (or grey in T2)
- Organs, Muscles, Soft tissues -> Shades of grey
- Gadolinium -> White
- Water -> Dark (but WHITE in T2)
Describe how a T1 and T2 MRI scan can be differentiated.
Although fat will appear darker in T2, water will appear much brighter, so that, for example, fluids will be much lighter. Overall, T2 scans frequently seen lighter in general.
What are some safety precautions taken with MRI?
Aside from no metal being allowed in the room, these are some contraindications:
- Pacemakers
- Inner ear implants
- Cerebral aneurysms clipped by ferromagentic clips
- Metallic foreign bodies in and around the eyes
- Pregnancy (especially in the 1st trimester)
What are some applications of MRI?
- Neuroimaging -> Detection of tumours (better than CT because it separates grey and white matter
- Cardiac
- Musculoskeletal -> Spinal, joints and tumours
- Liver and gastrointestinal
- Angiography
Remember to practise differentiating between an MRI and CT scan, which can look similar.
Do it.
This website is very very useful: https://www.embodi3d.com/blogs/entry/373-how-to-easily-tell-the-difference-between-mri-and-ct-scan/
CT
MRI
Ultrasound
X-ray
What type of tissue is bone?
Connective tissue
Give an example of a disease which causes the conversion of one organ systemm to another.
Fibrodysplasia ossificans progressiva (FOP) is a very rare condition where muscle tissue and connective tissue such as tendons and ligaments are gradually replaced by bone (ossified), forming bone outside the skeleton (extra-skeletal or heterotopic bone) that constrains movement.
What is the average number of bones in the human skeleton?
206
What can alter the number of rib or digits in a human skeleton?
Homeotic mutations
What is sesamoid bone? Give an example.
A bone embedded in tendon (or muscle). An example is the patella.
Give some examples of variable human skeletal anatomy and how this is useful.
The human skeleton varies by age and geographic variation. Humans are moderately sexually dimorphic so on average female bones are smaller than those of males. This has an importance in forensic medicine.
Describe the divisions of the skeleton.
- Axial skeleton -> Head, Neck, Trunk
- Appendicular skeleton -> Upper and lower extremities (including the pectoral and pelvis girdle)
What are the pectoral and pelvic girdles?
The skeletal frameworks which provides attachment for the upper and lower limbs respectively. They consist of:
- Pectoral girdle = Scapulas + Clavicles
- Pelvic girdle = Hip bones, Sacrum + Coccyx
Describe some of the functions of the human skeleton.
- Providing a rigid framework
- Protection of soft tissues
- Facilitation of movement
- Resistance to forces (e.g. gravity)
- Surface for muscular attachment
- Maintenance of blood calcium
- Red marrow is important in blood cell formation
Describe the basic structure of bone as a tissue.
It is connective tissues so it contains cells embedded within a composite ECM containing:
- Organic matrix -> Mostly collagen, which provides tensile strength and some flexibility
- Inorganic material -> Hydroxyapatite (mostly calcium phosphate) that gives hardness and rigidity (the crystals impregnate the collagen matrix)
What are the two main materials in bone? Describe how the properties of both can be deduced experimentally.
- Collagen -> Heat can be used to disrupt the peptide bonds, which makes the bone brittle -> This shows that collagen provides elasticity and tensile strength
- Hydroxyapatite -> Acid can be used to remove the Ca2+ ions, which makes the bone curl up and be soft -> This shows that hydroxyapatite provides hardness and rigidity
Give an example of a bone disease caused by abnormal collagen.
Osteogenesis imperfecta (“brittle bone disease”)
What are the different morphological types of bone?
- Flat bones
- Long bones
- Short bones
- Irregular bones
- Sesamoid bones
Where are flat bones found?
- Cranial vault
- Thoracic cage
- Scapula
Where are long bones found?
- Limbs
- Hands
- Feet
Where are short bones found?
- Wrist
- Ankle
(Tend to be cuboidal)
Where are irregular bones found?
- Facial skeleton
- Pelvis
- Vertebral column
What is the function of sesamoid bones?
Act as pulleys and protect the tendons from excessive wear.
Describe the histological divisions of bone.
- Bone is divided into woven (immature) and lammellar (mature)
- Woven (or immature) bone is the first bone to develop when the skeleton forms, and it is also found in bone repair and tumours
- Lammellar (or mature) bone is what makes up all normal adult bones, and is divided into compact and spongy/trabecular bone
- Compact bone -> Dense bone found around the external surfaces of the bone, including the shaft
- Trabecular bone -> Lightweight bone found in the ends of long bones, short bones and in the bodies of vertebrae
What are the different names for roughened areas for the attachments of muscle tendons or ligaments?
- Tuberosities
- Trochanters
- Tubercles
- Ridge
- Line
- Epicondyle
What is the purpose of grooves on bones?
They are usually where blood vessels, nerves and tendons lay close to the bone.
What are holes in bone called? What is the purpose of these?
Foramina - these are usually the site of passage of nerves or blood vessels through the bone.
What is the name for a concave depression in a bone?
Fossa
What are condyles and epicondyles?
- Condyles -> Smooth round surfaces at the ends of bones, usually acting as articulating surfaces
- Epicondyles -> Rough projections on the condyle that act as attachment
What two types of bone are adult bones composed of? Describe the location and appearance of each.
- Compact (a.k.a cortical) bone -> Dense form of bone with a Haversian canal structure. Found on the external surfaces of the bone, including the shaft.
- Trabecular (a.k.a. spongy or cancellous) bone -> Lightweight form of bone with honeycomb structure. Found in the ends of long bones, short bones and in the bodies of vertebrae.
Describe the histological structure and parts of adult bone.
- Compact (a.k.a cortical) bone -> Dense form of bone with a Haversian canal structure. Found on the outside of the bone, including the shaft.
- Trabecular (a.k.a. spongy or cancellous) bone -> Lightweight form of bone with honeycomb structure. Found in the ends of long bones, short bones and in the bodies of vertebrae.
- Red bone marrow may be found within trabecular bone.
- Medullary cavity (a.k.a. marrow cavity) is in the centre of long bone shafts -> Contains yellow marrow, which contains fat cells
- The periosteum is a layer of dense irregular tissue that covers the entire outside of bones (except the joint surfaces)
- The endosteum is like the periosteum, except it lines the inside of the medullary cavity
Where is red bone marrow found in bones and what is its function?
- In trabecular bone.
- It contains stem cells that ultimately give rise to RBCs, WBCs and platelets.
What is the name for the production of blood cells and platelets in the bone marrow?
Haemotopoiesis
Where is yellow bone marrow found, what is it made of and how does it change over time?
- In the medullary cavity of long bones
- It is made of fat cells
- Over time, red bone marrow is converted to yellow bone marrow
What are the different areas of a long bone?
- Diaphysis -> Shaft, which develops from the primary ossification centre
- Epiphyses -> Ends,which develop from secondary ossification centres
- Metaphyses -> Expanded areas of the bone shafts, to which the epiphyses fuse in bone growth
Describe the structure of compact bone.
- Consists of units called osteons (or Haversian systems).
- Osteons are cylindrical structures that contain a mineral matrix and living osteocytes.
- Each osteon consists of lamellae, which are layers of compact matrix that surround a central canal called the Haversian canal. The Haversian canal (osteonic canal) contains the bone’s blood vessels and nerve fibers.
- The lamellae are joined by caniculi (microscopic canals).
- Osteons in compact bone tissue are aligned in the same direction along lines of stress and help the bone resist bending or fracturing. Therefore, compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions.
Describe the structure of spongy bone.
- Consists of trabeculae, which are lamellae that are arranged as rods or plates.
- Red bone marrow is found between the trabuculae.
- Blood vessels within this tissue deliver nutrients to osteocytes and remove waste.
Describe how bone is adapted for strength and force transmission.
- Compact bone around the outside
- Trabecular bone is present in parts of the bone where forces may be exerted in various directions
- Trabeculae are also largely arranged in the direction of stress and tension lines
Define ossification.
The laying down of bone material by osteoblasts (i.e. bone formation).
What are the two types of ossification and where does each occur?
Intramembranous ossfication (rapid):
- Bone is deposited directly onto an embryonic connective tissue membrane.
- This occurs in parts of the crania, mandible and most of the clavicle.
Endochondral ossification (slow):
- Hyaline cartilage model of the bone is formed, which is gradually replaced by bone.
- This occurs in the rest of the skeleton.
Draw a diagram showing where each type of ossification occurs.
What are the embryonic derivatives of bone and what does each form?
- Neural crest cells -> Form the skull, mandible and clavicle (by intramembranous ossification)
- Somites (sclerotome) -> Rest of the axial skeleton (by endochondral ossification)
- Lateral plate mesoderm -> Long bones (by endochondral ossification)
How can you remember which type of ossification occurs where in the body?
- Intramembranous ossification is required to form strong bone where it is necessary for protection from early-on, such as in the skull
- Endochondral ossification is required for growth over time
Describe the process of intramembranous ossification.
- Neural crest derived mesenchymal cells differentiate into osteoblasts and group into ossification centers
- Osteoblasts become entrapped by the osteoid they secrete, transforming them to osteocytes
- Trabecular bone forms
- Mesenchymal cells on the surface form a membrane called the periosteum
- Cells on the inner surface of the periosteum differentiate into osteoblasts and secrete osteoid parallel to that of the existing matrix, thus forming layers of cortical bone
- Blood vessels in the centre form the red marrow
Describe the process of endochondral ossification.
- Mesoderm-derived mesenchymal cells differentiate into chondrocytes and form the cartilage model for bone
- Chondrocytes near the center of the cartilage model undergo hypertrophy and alter the contents of the matrix they secrete, enabling mineralization
- Chondrocytes undergo apoptosis due to decreased nutrient availability
- Blood vessels invade and bring osteogenic cells
- Primary ossification center forms in the diaphyseal region of the bone -> This occurs where the major blood vessel enters
- Secondary ossification centers develop in the epiphyseal region after birth
What are the two types of growth in a long bone and how does each occur?
- Appositional growth -> Thickens the bone -> Bone is reabsorbed at the endosteal surface and added at the periosteal surface
- Interstitial growth -> Makes the bone longer -> At the epiphyseal plate, cartilage grows towards the extremity of the bone and is replaced by bone
When do the primary and secondary ossification centres form?
- Primary -> Before birth
- Secondary -> After birth (EXCEPT the distal femur and proximal tibia i.e. near the knee)
What is the name for the site of lengthening of long bones?
Epiphyseal plate (a.k.a. growth plate)
What is the metaphysis?
The section of the bone that is next to the epiphyseal plate, on the side of the diaphysis. It marks the growth of the bone.
How many ossification centres do bones have?
- Long bones -> Two secondary, one primary
- Short bones -> Form from just primary osssification (and may have many primary ossification centres)
When does the lengthening of the bone stop and what happens when this goes wrong?
- When the epiphyseal plate stops dividing and the epiphysis fuses with the metaphysis
- Premature ossification leads to premature interruption of limb extension
Can epiphyseal plates be seen on an x-ray?
They are seen as empty spaces that look sort of like a big fracture, but aren’t!
Name the divisions of the upper limb.
- Arm
- Forearm
- Wrist
- Hand
What bone is in the arm and what does it articulate with?
- Humerus
- Articulates with: Scapula, Radius, Ulna
What is it worth noting about the upper and lower limb in the anatomical position?
They are rotated differently so that the big toe and thumb are on opposite sides.
State some functional differences between the upper and lower limb.
- Glenohumeral joint is capable of a wider range of movement than the hip joint due to joint depth
- Forearm bones are capable of pronation and supination, which cannot happen in the leg
- Thumb allows opposition, which cannot happen in the foot
What are the bones in the wrist and hand what do they articulate with?
- Carpals, Metacarpals, Phalanges (proximal, intermediate, distal)
- Carpals articulate with the radius at the wrist
What is the proper name for the shoulder joint?
Glenohumeral joint
What are all of the bones of the upper limb?
(Shoulder = Scapula + Clavicle)
- Humerus
- Radius
- Ulna
- Carpals
- Metacarpals
- Phalanges (x3)
What is the pectoral girdle composed of?
- Clavicle
- Scapula
What does the clavicle articulate with and what are the names of these joints?
- Medially -> With manubrium of the sternum (sternoclavicular joint)
- Laterally -> With acromion of scapula (acromioclavicular joint a.k.a. AC joint)
What are the main landmarks and attachments of the clavicle?
Landmarks:
- Acromial facet (laterally)
- Sternal facet (medially)
- Conoid tubercle (for coracoclavicular ligament)
Muscle attachments:
- Trapezius (insertion)
- Deltoid (origin)
- Pectoralis major (origin)
- Subclavius muscle (insertion)
- Sternocleidomastoid (origin)
Ligment attachments:
- Acromioclavicular ligament (laterally)
- Coracoclavicular ligament (laterally)
- Sternoclavicular ligament (medially)
- Costoclavicular ligament (medially)
What is the clinical relevance of the clavicle?
The clavicle is a very frequent site of fracture, with fractures most commonly occuring in the middle third of the bone.
Is this the anterior or posterior view of the scapula?
Posterior
What does the scapula articulate with and what are the names of these joints?
- Humerus -> Glenohumeral joint
- Clavicle -> Acromioclavicular joint
What are the main landmarks and attachments of the scapula?
Landmarks:
- Subscapular fossa -> Subscapularis origin
- Coracoid process ->
- Muscles - Pectoralis minor (attachment), coracobrachialis (origin) and short head of biceps brachii (origin)
- Ligaments - Coracoclavicular, coracoacromial, coracohumeral
- Glenoid fossa -> Site of glenohumeral joint (glenohumeral ligaments)
- Supraglenoid tubercle -> Long head of biceps brachii
- Infraglenoid tubercle -> Long head of triceps brachii
- Spine -> Deltoid, Trapezius
- Acromion (at end of spine) -> Site of AC joint (AC ligaments), Coracoacromial ligament
- Infraspinous fossa -> Infraspinatus muscle
- Supraspinous fossa -> Supraspinatus muscle
Other muscle attachments:
- Latissimus dorsi
- Serratus anterior
- Teres minor
- Teres major
- Levator scapulae
- Rhomboideus major
- Rhomboideus minor
Other ligment attachments:
- Suprascapular ligament
What are the major palpable landmarks of the shoulder? Where are they found?
- Acromion (palpable above shoulder)
- Coracoid process (palpable below lateral clavicle)
Label this.
What is some clinical relevance related to the appearance of the scapula?
- The scapula may be winged when pushing with the arm
- This usually indicates damage to the long thoracic nerve, which innervates the serratus anterior muscle
- The serratus anterior muscle is responsible for holding the scapula close to the ribcage
What does the humerus articulate with?
- Scapula (glenohumeral joint)
- Head of radius + Trochlear notch of ulna (elbow joint)
What are the main landmarks and attachments of the humerus?
Landmarks:
- Head -> Glenohumeral joint
- Greater tuberosity (lateral) -> Supraspinatus, Infraspinatus, Teres minor
- Lesser tuberosity (anterior) -> Subscapularis
- Bicipital groove (a.k.a. intertubercular groove) -> Tendon of long head of biceps passes through this, Latissimus dorsi, Pectoralis major and Teres major attaches here
- Deltoid tuberosity (lateral side of shaft) -> Deltoid
- Radial groove (diagnal on posterior surface) -> Radial nerve and profunda brachii artery run through this
- Medial and lateral supracondylar ridge -> Lateral is rough and provides attachment for forearm extensor muscles
- Medial and lateral epicondyles -> Medial is larger and features a groove where the ulnar nerve passes through
- Trochlea (more medial) -> Articulates with trochlear notch of ulna
- Capitulum (more lateral) -> Articulates with head of radius
- Radial and coronoid fossa -> Receive forearm bones during flexion
- Olecranon fossa -> Receives olecranon of ulna during extension
Other muscle attachments along shaft:
- Anteriorly: Coracobrachialis, deltoid, brachialis, brachioradialis.
- Posteriorly: Medial and lateral heads of triceps
Ligaments:
- Medial collateral
- Lateral collateral
- Glenohumeral ligaments
Describe the position of the greater and lesser tubercles of the humerus. What attaches to each?
Greater tubercle:
- Lateral, with both posterior and anterior surfaces
- Supraspinatus attaches to superior facet
- Infraspinatus attaches to middle facet
- Teres minor attaches to inferior facet
Lesser tubercle:
- More medial, with anterior surface only
- Subscapularis attaches here
How can you remember the attachments of at the lips of the bicipital groove (intertubercular groove)?
“A lady between two majors”
The latissimus dorsi muscle attaches between the pectoralis major and teres major.
What are the two necks of the humerus? What is the significance of each?
- Anatomical neck -> Just below the head
- Surgical neck -> Further down the humerus -> It is a frequent point of fracture
Why might a knock to the elbow elicit a tingling feeling?
The ulnar nerve passes posterior to the medial epicondyle of the humerus, where it is very superficial and can easily be stimulated.
What is often seen with a fracture at:
- Surgical neck of the humerus
- Shaft of the humerus
- Surgical neck of humerus -> Damage to the axillary nerve
- Shaft of humerus -> Radial nerve
Label this:
Label this:
What does the radius articulate with?
Proximally:
- With capitulum of humerus (elbow joint)
- With radial notch of ulna (proximal radioulnar joint)
Distally:
- With head of ulna (distal radioulnar joint)
- With scaphoid and lunate (radiocarpal / wrist joint)
What does the ulna articulate with?
Proximally:
- Trochlea of humerus (elbow joint)
- Head of radius (proximal radioulnar joint)
Distally:
- Ulnar notch of radius (distal radioulnar joint)
What are the main landmarks and attachments of the radius?
Landmarks:
- Head -> Site of elbow joint (with capitulum of humerus)
- Radial tuberosity -> Biceps brachii
- Shaft
- Styloid process (lateral) -> Radial collateral ligament of the wrist + Site of radiocarpal joint
- Ulnar notch -> Site of distal radioulnar joint (with head of ulna)
Other muscles:
- Pronator teres
- Pronator quardatus
- Supinator teres
- Finger and thumb flexors and extensors
- Brachioradialis
Other ligaments:
- Radial collateral ligament (at elbow)
- Radial collateral ligament (at wrist)
- Radiocarpal ligaments
Note the intraosseous membrane between the radius and ulna.
What are the main landmarks and attachments of the ulna?
Landmarks:
- Trochlear notch - Site of elbow joint (with trochlea of humerus)
- Olecranon - Triceps brachii
- Coronoid process - Brachialis + Ulnar collateral ligament of elbow
- Ulnar tuberosity - Brachialis
- Radial notch - Site of proximal radioulnar joint + Annular ligament
- Styloid process - Ulnar collateral ligament of wrist
- Head - Site of distal radioulnar joint (with ulnar notch of radius)
Other muscles:
- Supinator
- Anconeus
- Finger and thumb flexors and extensors
Other ligaments:
- Radiocarpal ligaments
- Ulnar collateral ligament (wrist)
Does the head of ulna articulate with the bones of the wrist?
No, it is prevented from doing so by a cartilaginous articular disc.
Give some clinical relevance of the radius.
- Colles’ fracture
- Most common type of radial fracture
- Caused by fall on outstretched hands
- Fracture at distal end, so that the wrist area is dislocated posteriorly -> Gives dinner fork appearance
- Smith’s fracture
- Opposite of Colles’ fracture
- Caused by fall on back of hands
Label this image.
What must you remember exists between the radius and ulna?
Interosseous membrane
Which way does the palm face in pronation and supination of the forearm?
- Pronation -> Down
- Supination -> Up
During pronation and supination of the forearm, which bone rotates?
Radius
Describe all of the types of bones in the hand, starting from the tip of a finger.
- Distal phalanges
- Middle phalanges
- Proximal phalanges
- Metacarpals
- Carpals
Describe all of the joint in the hand, starting from the tip of a finger.
- Distal interphalangeal joint (DIP)
- Proximal interphalangeal joint (PIP)
- Metacarpophalangeal joint
- Carpometacarpal joints
Describe the bones in the thumb.
There is one metacarpal (as with the other fingers), but only two phalanges (there are 3 in the other fingers).
Label this.
How many carpals are there?
8
Name all of the carpals, starting from the side of the thumb.
Distal: Trapezium, Trapezoid, Capitate, Hamate
Proximal: Scaphoid, Lunate, Triquetrum, Pisiform
Give a good mnemonic for remembering the carpals.
Some lovers try positions that they can’t handle.
Out of the triquetrum and pisiform, which is on the palmar side of the hand?
Pisiform
Describe how a scaphoid fracture might occur, symptoms and why it is dangerous.
- Occurs when falling onto outstretched hand
- Characterised by pain in the anatomical snuffbox
- In many people the blood supply to the scaphoid is only in the distal to proximal direction, so a fracture can cause avascular necrosis of the proximal portion of the scaphoid
What stops the ulna articulating with the carpals?
An articular disc.
What is the wrist joint?
Articulation between the lower end of the radius and the articular disc covering the distal ulna, with the scaphoid, lunate and triquetrum.
Describe how the fingers are numbered.
From 1 to 5, with the thumb being number 1.
What are the divisions of the lower limb? What are the bones in each?
- Thigh -> Femur
- Leg -> Tibia, patella and fibula
- Ankle
- Foot -> Tarsals, metatarsals and phalanges
What are some adaptations of the lower limb that make it different to the upper limb?
- Hip joint is deeper than shoulder joint, which allows for greater stability + Rigid pelvic girdle
- Bicondylar angle of the femur allows for the centre of gravity to be directly above the knee, so that walking can happen
- Knee joint reinforced by internal ligaments
- Leg bones do not rotate around each other like the forearm bones do
What is another name for the hip bone?
Os coxae or innominate bone
What bones make up the hip bone? What is the position of each?
- Ilium -> Top
- Ischium -> Bottom, Back
- Pubis -> Bottom, Front
Describe the structure of the pelvis.
- Made up of two hip bones and the sacrum
- Each hip bone consists of the ilium, ischium and pubis, while the sacrum fits between the ilium of each hip bone
- The coccyx may be considered part of the pelvis too
Where are the three bones of the hip bone all united?
Acetabulum
Note that for the lower limbs I have not gone into as much detail about landmarks, ligaments and muscles as I have with the upper limb.
Ok.
What is the function of the pelvis?
It protects the lower abdominal and pelvic organs and forms points of articulation with the lower limbs.
Compare the pelvis and pelvic girdle.
The pelvis also includes the sacrum, while the pelvic girdle does not.
What does the pelvis girdle (two hip bones) articulate with?
- Sacrum (sacroiliac joint)
- Head of femur (hip joint
One hip bone also articulates with the other at the pubis symphysis.
Describe the development of the hip bone.
The three bones all have their own primary ossification centre and then eventually fuse together around the ages of 16 to 18.
What are the main landmarks of the hip bone?
Ilium:
- Iliac crest (palpable)
- Anterior superior iliac spine (ASIS) (palpable)
- Posterior superior iliac spine (PSIS) (palpable)
- Anterior inferior iliac spine (AIIS)
- Greater sciatic notch
Ischium:
- Ischial spine
- Ischial tuberosity (palpable)
Pubis:
- Pubic tubercle (palpable)
All 3:
- Acetabulum -> Articulates with head of femur
Name some important palpable landmarks of the hip bone.
- Iliac crest
- Anterior superior iliac spine (ASIS)
- Posterior superior iliac spine (PSIS)
- Ischial tuberosity
- Pubis tubercle
What is some clinical significance of the iliac crest?
A line drawn between the highest point on each iliac crest crosses at the level of the spine of the L4 vertebrae, which is useful when finding the spot to insert a lumbar puncture needle.
What is the significance of the ischial tuberosity?
The ischial tuberosities are what you sit on.
What is the acetabulum?
It is the point on the hip bone where the femur articulates.
What does the femur articulate with?
- Acetabulum of hip bone (hip joint)
- Tibia and patella (knee joint)
What are the main landmarks of the femur?
- Head -> Articulates with acetabulum
- Neck
- Greater trochanter (lateral and slightly posterior) -> Gluteus medius and minimus
- Lesser trochanter (medial and posterior, below neck) -> Powerful hip flexor iliopsoas
- Linea aspera (posterior) -> Adductors
- Lateral and medial epicondyles -> Articulate with tibia
What is the danger of a fracture of the neck of the femur?
If the fracture is inside the joint capsule, blood supply to the femoral head might be disrupted.
Name all of the articulations at the knee.
- 2 x Femur with the tibia
- 1 x Femur with the patella
Label this.
Is the fibula part of the knee joint?
No, it is sort of off to the side.
Name the surfaces that articulate between the femur and tibia.
The lateral and medial femoral condyles articulate with the lateral and medial tibial condyles. There is a raised intercondylar eminence on the tibia.
What type of bone is the patella?
Sesamoid
Give an interesting piece of information about the sesamoid bones near the knee.
A small fraction of people have a very small sesamoid bone that exists in the calf muscle tendon. It is called the fabella (small bean).
What is a name for the top of the tibia?
The tibial plateau
What does the tibia articulate with?
- Femur (tibiofemoral / knee joint)
- Fibula (x2) (proximal and distal tibiofibular joints)
- Talus (ankle joint)
Note that there is also an interosseous membrane between the tibia and fibula.
What are the main landmarks of the tibia?
- Tibial plateau -> Articulates with femur
- Intercondylar eminence -> ACL and PCL, Menisci of tibia
- Medial and lateral tibial condyles
- Tibial tuberosity (anterior) -> Quadriceps
- Tibial shaft
- Medial malleolus -> Articulates with talus
What does the fibula articulate with?
- Tibia (x2) (proximal and distal tibiofibular joints)
- Talus (ankle joint)
What are the main landmarks of the fibula?
- Head of fibula -> Articulates with tibia
- Fibula shaft
- Lateral malleolus -> Articulates with talus
Compare the main functions of the tibia and fibula.
- Tibia -> Weight bearing
- Fibula -> Muscle attachments
Label this.
Describe the articulations at the ankle joint.
The medial malleolus of the tibia and the lateral malleolus of the fibula “grip” the talus (a tarsal) bone.
Describe the bones in the foot.
- 7 tarsals -> Talus, Calcaneus, Cuboid, Navicular, Cuneiforms (x3)
- 5 metatarsals
- 14 phalanges (only 2 in the hallux)
Therefore the structure is homologous to the hand.
Name all of the tarsals.
- Calcaneus (forms the mass of the heel, very large)
- Talus (forms ankle joint)
- Cuboid
- Navicular
- Cuneiforms x 3 (Medial, intermediate, lateral)
Give the clinical relevance of the tubersity on the 5th metatarsal.
It is prone to an aversion fracture when the foot is everted excessively.
What is the technical name for the big toe?
Hallux
Do inversion and eversion of the foot happen at the ankle joint?
No, it is a hinge joint. Inversion and eversion happen at the joints between the tarsals.
Label this.
What are the three bones in the shoulder girdle?
Clavicle, scapula and humerus
Label this.
What are some features of the clavicle?
- First bone to ossify
- Among the last the fuse
- Most commonly fractured bone
- Only bony attachment of the upper extremity is via the sternoclavicular joint
* What component affects the direction of a break in the clavicle?
- Ligament action pulls the fragments in specific directions (medial fragment drawn upwards)
- These breaks aren’t overly benign as close to lung and brachial plexus - has been shown that fixing them surgically is a better treatment than just leaving them to recover
What type of joint is the sternoclavicular joint?
Synovial - with articular disc
Which ligament tears in a medial clavicle dislocation?
The ligament between the sternum and the clavicle No operating on this kind of dislocation, just try and reduce it
What is the AC joint?
The acromioclavicular joint - between the clavicle and the acromium process
How many ligaments are there that attach to the coracoid process and what are they?
There are 3:
- Coracoacromial ligament, between acromium and coracoid processes (both on scapula)
- Coracoclavicular ligament -> Trapezoid and conoid ligaments, attach the clavicle to the coracoid process
How can you remember the order of the coracoclavicular ligaments?
Medial to lateral: “CT” scan to diagnose (conoid then trapezium)
What is an acromioclavicular separation?
This is where the coracoclavicular ligaments tear, but the AC joint is only partially damaged
What happens in an AC dislocation?
Both the AC and coracoclavicular ligaments tear, resulting in full dislocation of the distal end of the clavicle
What type of joint is the AC joint?
Synovial, but with little movement
* What is a good indication for the side to which a scapula belongs?
The direction in which the coracoid process is pointing - it will always be pointing towards the arm and is on the front/anterior side of the bone
* How are humeral head fractures treated?
Conservative management is disproportionately successful (length/alignment/rotation), use a collar and cuff. Alternatively, surgical intervention can be used.
Where is and what are some characteristics of the glenohumeral joint?
The joint between the humeral head and the glenoid fossa/cavity Shallow joint, stability improved by the glenoid labrum and the ligaments Manipulated by the rotator cuff muscles amongst others Synovial joint, ball and socket
What are the three ligaments in the glenohumeral joint?
- SGHL: superior glenoid-humeral ligament
- MGHL: medial glenoid-humeral ligament
- IGHL: inferior glenoid-humeral ligament
How do the shoulder and hip joints compare? (In one sentence)
They are opposites - hip has a more restricted range of movement but is more stable, shoulder has a larger range of movement but is less stable. Shoulder is likened to a golfball on a golf tee
Which ribs articulate with the scapula?
Ribs 2-7 Major contributors to shoulder motion - bursas are present
What is a bursa?
Small fluid-filled sac contained within synovial joints - act as a cushion
How many muscles attach the upper limb to the axial skeleton?
17
Ones we need to know are:
- Deltoid
- Rotator cuff muscles (x4)
- Biceps/attachment of the biceps tendon
What is innervated by the axillary nerve?
Deltoid and teres minor (amongst others)
What happens if the axillary nerve is damaged?
Shoulder is weakened, ability to abduct is severely lessened
What are the four rotator cuff muscles?
Subscapularis, infraspinatus, supraspinatus, teres minor
What innervates supraspinatus and infraspinatus?
The suprascapular nerve
What innervates teres minor?
The axillary nerve
What innervates subscapularis?
The subscapular nerve
What acronym can be used to remember the four rotator cuff muscles/tendons?
SITS:
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
Where do the rotator cuff muscles attach?
- Supraspinatus, infraspinatus and teres minor attach to the greater tuberosity of the humerus
- Subscapularis attaches to the lesser tuberosity of the humerus (only one)
The other ends of the muscles attach to the scapula.
What is the function of the rotator cuff muscles?
- Move shoulder joint
- Provides stability (stops dislocation)
- Keeps deltoid from pulling humeral head up
Why is the biceps muscle called the biceps?
Bi - two Ceps - cephalus, means ‘head’ The biceps has two ‘heads’, the long head and the short head - long head goes over the humeral head, short goes anteriorly, both attach to the scapula.
Where are the origins and insertions of the biceps muscle?
Origins:
- Long head: Supraglenoid tuberosity (of scapula)
- Short head: Coracoid process
Insertions:
- Distal biceps tendon: Radius (at radial tuberosity)
What are the origins and insertions of the brachialis muscle?
Origins:
- Halfway up the humerus
Insertions:
- Coronoid process and tuberosity of the ulna.
* What is the failsafe mechanism of the biceps?
There are two heads, so if one ruptured the muscle is still functional as the other remains attached - contraction still results in movement of the bone. Results in ‘popeye’ muscle
* What are some of the problems that can occur within the shoulder?
- Adhesive capsulitis (frozen shoulder)
- Impingement syndrome
- Rotator cuff tears
- Dislocation
- Arthritis
* How can age affect outcome of shoulder dislocations?
- Younger patients have a higher dislocation rate
- Older patients have a higher rate of rotator cuff tears
* How should you manage a dislocated shoulder?
- Best to reduce the dislocation at time of accident, then short period of immobilisation (though external rotation splint or simple sling)
- Can be managed surgically, usually after recurrent dislocations (labrum can tear and will need to be repaired).
What is the most commonly dislocated joint?
The shoulder - inherently unstable (shallow joint)
* What is adhesive capsulitis?
Aka frozen shoulder, inflammation and thickening of the shoulder capsule eventually results in hugely reduced range of movement (especially external rotation). Associated with diabetes, but often idiopathic (arises spontaneously with unknown cause). Not self limiting (so won’t resolve itself without treatment), just stops hurting over time, doesn’t really improve.
* How can you treat adhesive capsulitis?
- Used to be conservative treatment/‘wait and see’
- Now can have glenohumeral injections
- More and more commonly manipulated under anaesthesia - only in stiff phase, and these is a slight risk of humeral fracture
- Generally resolved with time (1-2 years), residual stiffness is expected. But can only get it once in each shoulder!
What is shoulder impingement?
This is where the rotator cuff tendons within the coracoacromial arch are impinged - trapped or limited mobility of tendons, or inflamed bursa within the shoulder. This affects nearby nerves and causes pain. Association with ‘hooked’ acromion (specific shape, morphologically hooked around joint therefore increases risk of impingement)
What are the different movements of the scapula?
- Elevation (moving upwards)
- Depression (moving downwards)
- Retraction (moving inwards)
- Protraction (moving outwards)
- Medial rotation
- Lateral rotation
What are the movements of the pollux/thumb?
- Abduction (movement away from the hand along sagittal plane)
- Adduction (movement towards the hand along sagittal plane)
- Extension (movement away from the hand along the coronal plane)
- Flexion (movement towards and across the hand along the coronal plane)
- Opposition (UNIQUE, ability to touch little finger with thumb)
- Reposition (UNIQUE, ability to return hand to normal shape after opposition)
What are the three types of joint and all their subtypes?
- Fibrous
- Suture (flat bones)
- Syndesmosis (long bones)
- Cartilaginous
- Synchondrosis (primary)
- Symphysis (secondary)
- Synovial
- Uniaxial
- Biaxial
- Multiaxial
What are the different types of joint that are lined with hyaline cartilage?
- Plane joint (small gliding movement e.g. between cuneiform bones of foot)
- Saddle joint (e.g. interphalangeal)
- Hinge joint (e.g. knee)
- Pivot joint (e.g. wrist)
- Ball and socket joint (e.g. shoulder, hip)
- Ellipsoid/condylar joint (e.g. where the radius and ulna meet the wrist)
What are the ligaments involved in the pectoral girdle?
- Coracoacromial ligaments
- Acromioclavicular ligaments (AC)
- Coracoclavicular ligaments
- Glenohumeral ligaments
Draw the joints of the hand.
What secretes the synovial fluid at a synovial joint?
Synovial membrane
Describe the structure of a synovial joint.
- Fibrous joint capsule (continuous with the periosteum)
- Joint cavity containing synovial fluid
- Articulating surfaces lined with hyaline cartilage
- Synovial membrane lines the cavity (where hyaline cartilage is not present)
- Ligaments are present within joint capsule (but can be around it)
Draw the structure of the glenohumeral joint.
Draw the structure of the elbow joint.
Draw the hip joint.
Note that there is also the transverse acetabular ligament.
Draw the transverse acetabular ligament.
Draw the knee joint (not including the cruciate ligaments).
Draw the cruciate ligaments of the knee.
Draw the bones involved in the joints in the foot.
Draw all of the ligaments in the ankle and foot that you need to know about.
What are the different shapes of skeletal muscles?
- Circular
- Pennate -> Unipennate, Bipennate, Multipennate
- Parallel
- Fusiform
- Convergent
What are circular muscles? Give examples and their function.
- Example: Orbicularis oris
- Function: Sphincter muscles allowing opening and closing of an opening, in this case, the mouth.
What are unipennate muscles? Give examples and their function.
- Example: Extensor digitorum longus (unipennate)
- Function: Allow for a significant amount of power to be generated across the joint, since the fibres are oriented at an angle to muscle’s line of action (high muscle fibre density) and rotate as they shorten.
What are bipennate muscles? Give examples and their function.
- Example: Rectus femoris
- Function: Allow for a significant amount of power to be generated across the joint, since the fibres are oriented at an angle to muscle’s line of action (high muscle fibre density) and rotate as they shorten.
What are multipennate muscles? Give examples and their function.
- Example: Deltoid muscle
- Function: Allow for a significant amount of power to be generated across the joint, since the fibres are oriented at an angle to muscle’s line of action (high muscle fibre density) and rotate as they shorten.
What are parallel muscles? Give examples and their function.
- Example: sartorius, sternocleidomastoid
- Function: Fibres oriented parallel to the line of action of the muscle. Usually long muscles, bringing about large but typically weaker movements than pennate muscles.
What are fusiform muscles? Give examples and their function.
- Example: Biceps brachii
- Function: Spindle-shaped muscles containing a “muscle belly” that is wider than the points of origin and insertion. Provide large ranges of motion.
What are convergent muscles? Give examples and their function.
- Example: Pectoralis major
- Function: Triangular/fan-shaped muscles with wide origins and narrow points of insertions. Wide variation in muscle fibre angles allow for multiple actions across joints.
What are origins and insertions of muscles?
- The origin is the attachment site that doesn’t move during contraction, while the insertion is the attachment site that does move when the muscle contracts.
- The origin is usually proximal, while the insertion is usually distal.
Draw the structure of the bursa, bone and tendon at a joint.
What are the different compartments of the thigh and what are their functions?
- Anterior -> Hip flexors and knee extensors
- Posterior -> Hip extensors and knee flexors
- Medial -> Hip adductors
What are the different compartments of the leg and what are their functions?
- Anterior -> Dorsiflexion of foot
- Lateral -> Foot eversion
- Superficial posterior -> Plantarflexion of foot
- Deep posterior -> Plantarflexion of foot
Give some examples of rotator cuff injuries. [EXTRA?]
What are the compartments of the forearm and what is their function?
- Anterior -> Flexion of the wrist and pronation of the forearm [CHECK]
- Posterior -> Extension of the wrist and supination of the forearm
- Mobile wad
Label this.
What is tennis elbow? [EXTRA]
What is golfers’ elbow? [EXTRA]
Draw the cross section of the spinal cord showing how it produces nerve roots.
What happens to spinal nerves after they emerge from the spinal cord?
They split into primary rami: anterior and posterior rami.
Draw a diagram to show how a nerve root can supply a level of the thorax and connect with the sympathetic trunk.
Draw a diagram to show the dermatomes of the human body.
Describe which way limbs rotate during development and how this is demonstrated by dermatomes.
- UPPER LIMB rotates LATERALLY (dorsally)
- LOWER LIMB rotates MEDIALLY (ventrally)
Growth and rotation distort the segmental dermatome pattern -> Particularly in lower limb.
Name all of the nerve roots controlling the different upper limb movements.
Name all of the nerve roots controlling the different lower limb movements.
Draw the anatomical basis for the patellar tendon reflex.
Draw a diagram to show the innervation of the main body compartments [although you don’t need to know most of these probabaly].
Draw the structure of the brachial plexus. [EXTRA]
Draw the sensory territories of the different upper limb nerves.
For the musculocutaneous nerve, draw a diagram to show which muscles are innervated by it.
For the median nerve, draw a diagram to show which muscles are innervated by it. [EXTRA?]
For the ulnar nerve, draw a diagram to show which muscles are innervated by it. [EXTRA?]
For the radial nerve, draw a diagram to show which muscles are innervated by it.
For the femoral and obturator nerves, draw a diagram to show which muscles they innervate.
For the sciatic nerve, draw a diagram to show which muscles it innervates.
For the tibial nerve, draw a diagram to show which muscles it innervates. [EXTRA?]
For the fibular (a.k.a. peroneal) nerves, draw a diagram to show which muscles they innervate.
Draw the sensory territories of the lower limb.
How many of each type of vertebrae are there?
- Cervical -> 7
- Thoracic -> 12
- Lumbar -> 5
- Sacral -> 5 (fused)
- Coccygeal -> 4
Label this vertebra.
What is a pedicle of a vertebra?
- The two pedicles are the two short columns of bone that connects the lamina to the vertebral body to form the vertebral arch.
- They form a hollow archway that protects the spinal cord.
What is a lamina of a vertebra?
The lamina is the part of the vertebra that connects the spinous process and the transverse process. There are two laminae, located on either side of the spinous process.
What is the spinous process of a vertebra and what is the function?
- Spinous process is a bony projection off the posterior of each vertebra.
- The spinous process protrudes where the laminae of the vertebral arch join and provides the point of attachment for muscles and ligaments of the spine.
What are the transverse processes of vertebra and what is their function?
- Small bony projections off the right and left side of each vertebrae.
- The two transverse processes of each vertebrae function as the site of attachment for muscles and ligaments of the spine as well as the point of articulation of the ribs (in the thoracic spine).
What are the articulation facets of a vertebra and what is their function?
- Each vertebra has two sets of facet joints.
- One pair faces upward (superior articular facet) and one downward (inferior articular facet).
- There is one joint on each side (right and left). Facet joints are hinge–like and link vertebrae together.
Describe the curvature of the different parts of the spine.
- Cervical -> Lordosis
- Thoracic -> Kyphosis
- Lumbar -> Lordosis
- Sacral -> Lordosis
Describe how spinal curvature changes with age.
What are some forms of abnormal curvature of the spine?
Describe in detail the formation of the vertebrae when the sclerotome surrounds the neural tube.
Notice how a fissure in each somite followed by fusion of adjacent segments leads to the inter-vertebral contents (e.g. the nucleus pulposus) existing between the vertebrae.
What patterns the vertebrae in a cranio-caudal direction?
Hox genes
What causes spina bifida?
- Failure of neural tube closure:
- This occurs when the spines and arches of one or more vertebrae don’t fully develop
What type of vertebra is this?
Thoracic
What type of vertebra is this?
Sacral
What type of vertebra is this?
Coccygeal
What type of vertebra is this?
Lumbar
What type of vertebra is this?
Cervical
Draw the structure of the atlas.
Draw the structure of the axis.
Draw all of the ligaments that hold the dens of the axis in place.
Describe how ribs articulate with the vertebrae.
- Articulate with the thoracic vertebrae.
- Each rib forms two joints:
- Costotransverse joint -> Between the tubercle of the rib, and the transverse costal facet of the corresponding vertebrae.
- Costovertebral joint -> Between the head of the rib, superior costal facet of the corresponding vertebrae, and the inferior costal facet of the vertebrae above.
What is the joint type of intervertebral discs? Describe the structure.
Secondary cartilaginous:
- Nucleus pulposus -> Gelatinous with high water content
- Anulus fibrosus -> Fibrocartilage
Describe the different ligaments stabilising the spine.
What are some muscles that enable movement of the spine?
Describe lumbar puncture.
