PDF Download

1. Understand the basics of bone markings/macroscopic bone anatomy terminology.

The macroscopic appearance of bone varies based on the function of that area of bone (e.g. muscle tendon/ligament attachment, neurovasculature entering/exiting bone, joint formation, etc.) and between individuals. Understanding the basic terminology of macroscopic bone anatomy will assist in further osteological analysis.

A basic division of osteological landmarks includes: depressions/openings & projections/processes.

Depressions and openings have two main functions: allowing the passage of soft tissue through or along bone and formation of joints. The articular surfaces of bone (joint formation) are smooth, as they were covered with articular cartilage during life.

See Table 1 for a list of depressions/openings that are commonly found on bones of upper/lower limbs.

Table 1: Osteological landmarks: depressions/openings (note: you do NOT have to memorize the definitions - these are here to help you understand and reference when learning pertinent named osteological structures)

Projections and processes have two main functions: formation of joints and attachment points for connective tissues (muscle tendons, ligaments). See Table 2 for a list of projections/processes that are commonly found on bones of upper/lower limbs.

Table 2: Osteological landmarks: projections/processes (note: you do NOT have to memorize the definitions - these are here to help you understand and reference when learning pertinent named osteological structures)

2. Identify bones and major bony landmarks of upper and lower limbs.

(Videos by Anatomy faculty showing and describing the bones and bony landmarks of upper & lower limbs. These specifics will help familiarize yourself with the osteology, and will be particularly helpful for the practical. These specifics will not be on the quiz/final exam unless also covered in another Learning Objective or Active Learning Session)

Upper Limb Osteology

Lower Limb Osteology

3. Describe the classification of joints. Discuss the basic characteristics of the three types of joints.

Joints classification schemes are often very specific to discipline, but two major means of classification are common: joint structure & range of motion allowed. You are responsible for knowing classification based on joint structure.

With this scheme, joints are classified according to the type of tissue that unites the articulating bones and how the tissue attaches the bones. There are 3 main types:

In fibrous joints, bones are joined by fibrous connective tissue, and the degree of movement depends on the length of fibers uniting the bones.

• • Examples include:

    • Sutures -- little movement

    • Syndesmosis -- degree of movement depends on the distance between the bones [e.g. interosseous membrane]

    • Gomphosis – unique joint between a tooth and the bone

In cartilaginous joints, the surfaces of the articulating bones are covered with hyaline cartilage (articular cartilage), and bones are united by strong fibrous tissue and cartilage. These joints tend to be strong and slightly moveable.

• • Examples include:

    • Epiphyseal growth plate

    • Intervertebral discs

    • Pubic symphysis

    • Manubriosternal joint

Synovial joints are unique in that bones are connected via an articular capsule rather than a continuous sheet of connective tissue. This organization allows for free movement between bones.

All synovial joints have:

• • Articular (synovial) capsule

    • There are 2 parts of the capsule: an outer fibrous layer and the inner synovial membrane, which secretes synovial fluid.

  • Articular (synovial) cavity

    • Synovial fluid lines the majority of the cavity

  • Articular cartilage (hyaline cartilage)

    • Mostly avascular and slow/does not heal

4. Describe accessory structures of synovial joints.

While all synovial joints have an articular capsule, articular cavity, and articular cartilage, many of the more complex synovial joints will have accessory structures that play a role in the protection, support, etc. of the joint.

The most common structures are ligaments. Ligaments connect bone to bone and can be either intrinsic (thickening of capsule) or extrinsic (separate from capsule). This differs from tendons, which connect muscle to bone. Both ligaments and tendons (and commonly muscle bellies) play important roles in structural integrity of joints.

Labra, articular discs, and menisci are all composed of predominantly fibrocartilage and have slightly different compositions and functions. Labra are typically associated with ball and socket joints and form a lip around the socket portion to provide a better fit for the ball portion of the joint. Articular discs can be complete or incomplete and can serve to divide an articular cavity into 2 components (as in the temporomandibular [TMJ] joint) or as a shock absorber. Menisci are similar in function to labra, but are typically incomplete.

Bursae are sac-like structures (very similar in composition to a synovial capsule with synovial fluid) that are often associated with synovial joints, particularly in areas of increased friction. Specialized bursae surrounding long tendons are often referred to as tendon sheaths.

5. Understand the types of movements that may occur at synovial joints.

• • Flexion/Extension/Hyperextension: typically sagittal plane (moving either anteriorly, or posteriorly)

    • Flexion: decrease in angle

      • Typically movement in an anterior direction (knee is a notable exception)

    • Extension: back to anatomical position

    • Hyperextension: past anatomical position

  • Abduction/Adduction: typically frontal plane (moving either laterally, or medially)

    • Abduction: away from midline

    • Adduction: back toward midline (‘Add’ back to the body)

  • Circumduction: circular motion

    • Combined motion: flexion, abduction, extension, adduction

  • Medial (internal) rotation/ Lateral (external) rotation: rotation of a part of the body around its longitudinal axis

    • Medial rotation: brings anterior surface of a limb closer to the median plane

    • Lateral rotation: takes anterior surface of a limb away from the median plane

6. List and describe the six types of synovial joints, and include examples of each type.

• • Hinge joint - flexion/extension

    • Elbow, knee, interphalangeal

  • Plane joint - gliding/sliding movements

    • Acromioclavicular (AC), intercarpal

  • Pivot joint - rotation

    • Atlanto-axial, proximal radio-ulnar

  • Saddle joint - flexion/extension, abduction/adduction, circumduction

    • Concave and convex where bones articulate

    • Carpometacarpal joint of thumb

  • Condyloid joint - flexion/extension, abduction/adduction, circumduction

    • Metacarpophalangeal joints of digits 2-5, radiocarpal (wrist)

  • Ball & socket - flexion/extension, abduction/adduction, circumduction, medial & lateral rotation

    • Shoulder, hip

Glenohumeral (shoulder) joint

The glenohumeral (shoulder) joint is the most mobile [ball and socket] joint in the body, and with this high level of mobility, there is decreased stability. Accessory structures play a dominant role in structural stability. The glenohumeral joint is formed by the head of the humerus and glenoid cavity of the scapula. The glenoid cavity is very shallow and accepts only ~1/3rd of the humeral head.

• Accessory structures:

  • Tendons

    • Rotator cuff tendons are the main source of stability for the glenohumeral joint. These tendons almost completely surround the joint with a notable and clinically important inferior deficiency.

    • Long head of biceps brachii tendon attaches to the supraglenoid tubercle of the scapula, which is within the articular capsule, making this tendon intracapsular.

  • Ligaments

    • Glenohumeral ligaments: 3 sets (superior, middle, & inferior); observed on internal portion of articular capsule

    • Coracohumeral ligament: extends from coracoid process of scapula to the greater & lesser tubercles of the humerus

    • Transverse humeral ligament: connects the greater & lesser tubercles of humerus; the long head of biceps brachii tendon runs between the tubercles [intertubercular sulcus/bicipital groove] and deep to this ligament

    • Coraco-acromial ligament: part of the coraco-acromial arch [between coracoid process and acromion of scapula] over the shoulder region and helps prevent superior dislocations of glenohumeral joint

  • [Glenoid] labrum

    • Fibrocartilaginous lip circumscribing the glenoid cavity, which helps to provide a better fit of the humeral head.

  • Bursae

    • Subacromial (subdeltoid) bursa: Located deep to the coraco-acromial arch and deltoid m., and superficial to the supraspinatus tendon and joint capsule. It facilitates movement of the supraspinatus tendon deep to the coraco-acromial arch. It does not typically communicate with the joint capsule.

    • Subtendinous bursa of subscapularis muscle: Located between the tendon of subscapularis m. and articular capsule. It protects the tendon of subscapularis as it passes across the neck of the scapula. This bursa is unique in that it typically communicates with the articular cavity via an opening of the articular capsule typically located between the superior and middle glenohumeral ligaments.

  • Clinical significance: 

    • Shoulder dislocations occur at the glenohumeral joint. Most dislocations occur inferiorly (due to a weak point in the musculotendinous rotator cuff). Clinically, dislocations are described as anterior (most frequent) or posterior dislocations.

    • Rotator cuff injuries are frequent causes of shoulder pain, particularly in cases over repetitive actions of rotator cuff muscles. The supraspinatus tendon (tendonitis) is the most commonly affected area.

    • Adhesive capsulitis [frozen shoulder] involves scarring/fibrosis between the articular capsule and surrounding structures, and often associated with other pathologies/injuries of the glenohumeral joint.

8. Identify the major joints and associated ligaments in the elbow & forearm region. Explain what kind of movements occur at the joints and other pertinent information.

Movement Videos

There are 3 articulations associated with a shared articular capsule in the elbow region.

• • Humero-ulnar [elbow] joint: hinge joint; articulation of trochlea and olecranon fossa of humerus and trochlear notch of ulna

  • Humeroradial joint: hinge joint; articulation of capitulum of humerus and head of radius

  • Proximal radio-ulnar joint: pivot joint; articulation of head of radius and radial notch of ulna

Accessory structures of elbow region:

• Ligaments:

  • Ulnar collateral ligament of elbow joint: intrinsic ligament spanning from medial epicondyle of humerus to olecranon/coranoid process of ulna

  • Radial collateral ligament of elbow joint: intrinsic ligament attached to lateral epicondyle of humerus and blending with anular ligament of radius

  • Anular ligament of radius: circumferential ligament surrounding head of radius and blending with radial collateral ligament of elbow joint

• Bursae

  • Olecranon bursae: typically 3 sets (intratendinous, subtendinous, & subcutaneous) associated with triceps tendon and olecranon of ulna

• Clinical significance

  • Bursitis of elbow: inflammation of bursa(e) associated with elbow joint; subcutaneous olecranon bursitis is the most common type

  • Subluxation or dislocation of radial head ["pulled elbow"]: common injury in juveniles after sudden pulling or lifting event; injury to the anular ligament of radius and displacement of radial head (typically distally)

Remaining joints of forearm:

• • Radio-ulnar syndesmosis: fibrous joint

    • Intermediate radio-ulnar joint; interosseous membrane of forearm connects the bodies of the radius & ulna

  • Distal radio-ulnar joint: synovial pivot joint (pronation and supination)

  • Accessory structures: articular disc [triangular ligament]

    • Unites radius and ulna in this region; separation point for synovial cavities of distal radio-ulnar & wrist joints

9. Identify the major joint and associated ligaments in the wrist region. Explain what kind of movements occur at the joints and other pertinent information.

Movement Videos

The radiocarpal (wrist) joint involves the articulation of the distal end of radius and proximal row of carpals (excluding the pisiform), and is a synovial, condyloid joint. In regards to surface anatomy, this joint is located approximately at the level of the proximal wrist crease. It is important to note that the ulna does not form a direct articulation at the wrist joint. The actions of the radiocarpal joint are very closely aligned with those created at the distal radio-ulnar and intercarpal joints.

Accessory structures of radiocarpal (wrist joint):

• Ligaments:

  • Palmar & dorsal radiocarpal ligaments limit wrist extension & flexion, respectively

    • Ulnar collateral ligament of wrist joint: spans between the ulnar styloid process and triquetrum

    • Radial collateral ligament of wrist joint: spans between the radial styloid process and scaphoid

• Clinical significance:

  • FOOSH (Falling On an Out-Stretched Hand)

    • Fracture of distal radius: can be caused by direct injury or FOOSH; most common fracture of upper extremity

      • Colles' fracture: specific fracture of distal radius

        • Complete (and often comminuted), transverse fracture of distal radius, which will displace in a dorsal direction causing a "dinner fork deformity" (posterior angulation)

    • Fracture of scaphoid: can be caused by direct injury or FOOSH; most commonly fractured carpal bone

      • Often misdiagnosed early because of difficulty of detection in early radiographs; necrosis and bone resorption in the area due to poor blood supply are common and easily detected in imaging completed ~10 days after injury

There are multiple joints in the hand including:

• Carpometacarpal (CMC) joints: between distal row of carpals and metacarpals

• Metacarpophalangeal (MP or MCP) joints: between metacarpals and proximal phalanges; 'knuckles'

• Proximal interphalangeal (PIP) joints: between proximal and intermediate (middle) phalanges

• Distal interphalangeal (DIP) joints: between intermediate and distal phalanges

10. Identify the major joint and associated ligaments in the hip region. Explain what kind of movements occur at the joints and other pertinent information.

Movement Videos

The hip joint is a synovial, ball and socket joint, and is the second most mobile joint in the body (2nd to the glenohumeral joint - both ball & socket joints). The joint is formed by the acetabulum of the coxal bone and head of the femur. Medial and lateral rotator muscles of the thigh play an important role in support and structure of the hip joint.

Accessory structures of hip joint:

• Acetabular labrum is similar in structure to the glenoid labrum of glenohumeral joint, and allows for a better fit between the acetabulum and head of femur. The labrum is incomplete at the level of the acetabular notch.

  • Transverse acetabular ligament completes the lip around the acetabulum at the acetabular notch.

• Ligaments:

  • Iliofemoral ligament is often considered to be the strongest ligament in the body, and it certainly is for the hip joint. It is expansive (more anteriorly-placed, ilium to femur) and Y-shaped.

    • This ligament plays a strong role in prevention of hyperextension of the hip joint.

  • Pubofemoral ligament is also more anteriorly-place (pubis to femur) and is closely associated with the iliofemoral ligament. This ligament plays a role in prevention of overabduction.

  • Ischiofemoral ligament is posteriorly positioned between the ischium and femur. This is the weakest of the 3 main hip ligaments, but does play a small role in limiting medial rotation and preventing hyperextension.

  • Ligament of head of femur extends from acetabular notch to fovea of femoral head. The primary function of this ligament is not hip joint strengthening but as a conduction site for the artery of the head of femur.

• Clinical significance:

  • Fracture of neck of femur ("fractured hip"): more common in osteoporotic individuals with ages greater than 60. With a fracture to the neck, disruption of the dominant supply of the head of the femur (medial circumflex femoral a.) is common and may lead to necrosis of the head.

11. Identify the major joint and associated ligaments in the knee region. Explain what kind of movements occur at the joints and other pertinent information.

Movement Video

The knee joint is a modified hinge joint which is capable of a small degree of medial and lateral rotation, particularly from a flexed position. The knee joint is actually a complex of 3 articulations: patellofemoral and lateral & medial tibiofemoral joints. When observing the articular surfaces of the medial and lateral condyles of the femur and tibia, one can observe the notable incongruence of the articulation structures. Due to this incongruence, accessory structures are vital to the structural integrity of this joint. 

Accessory structures of knee joint:

• Muscles and muscle tendons are more important in structural integrity of the knee joint than ligaments. Muscle conditioning can prevent numerous injuries in this area.

  • Most important set of muscles is the quadriceps femoris mm., particularly vastus lateralis and vastus medialis mm. These muscles and associated patellar ligament are the main source of stability for the anterior portion of this joint. 

  • The semimembranosus and popliteus mm. play an important roles as well for the posterior portions of the joint. 

• Ligaments of knee joint 

  • Patellar ligament: distal expansion [apex of patella to tibial tuberosity] of the quadriceps femoris tendon

    • Forms the anterior portion of the joint capsule

  • Fibular [lateral] collateral ligament (FCL/LCL) is an extracapsular ligament separated from the articular capsule by the tendon of the popliteus m. Similar to the tibial collateral ligament, the FCL checks hyperextension and is relaxed in flexion.

  • Tibial [medial] collateral ligament (TCL/MCL) is a substantial thickening of the medial articular capsule (capsular ligament). 

    • The TCL and medial meniscus are attached and are often damaged in unison due to this connection.

    • This ligament also plays the role of check ligament for excessive lateral rotation. 

• Intra-articular structures of knee joint (i.e. located within articular capsule)

  • Cruciate ligaments: important in checking lateral & medial rotation of the knee joint

    • Anterior cruciate ligament (ACL) limits hyperextension of the knee as well as prevention of femoral posterior displacement

      • This cruciate ligament is the weaker and more commonly injured of the two.

        • If ruptured and anterior tibial displacement allowed: anterior drawer sign

    • Posterior cruciate ligament (PCL) limits hyperflexion of the knee as well as prevention of femoral anterior displacement

      • In actions such as walking down stairs, the PCL plays a major role in femoral stabilization.

      • If ruptured and tibial posterior displacement allowed: posterior drawer sign

  • The menisci of the knee are fibrocartilaginous structures that deepen the articular surfaces and play a role in shock absorption.

    • Medial meniscus is the less mobile of the menisci, and there is considerable attachments to surrounding structures, including the TCL.

    • Lateral meniscus is smaller and more mobile than the medial meniscus.

• Bursae

  • There are approximately 12 bursae associated with the knee joint or surrounding regions.

  • There are 4 bursae that directly communicate with the joint cavity.

    • Suprapatellar bursa is the most clinically relevant of these bursa due to its very large size and is a common site of infection that may lead into the synovial cavity. This bursa serves to reduce friction between the quadriceps femoris tendon and femur.

    • Anserine bursa is located between the tendons of gracilis, sartorius, and semitendinosus at pes anserinus and TCL.

    • Gastrocnemius bursa is located between gastrocnemius, medial head and femur.

    • Popliteus bursa is located between the rope-like popliteus tendon and lateral condyle of tibia.

  • There are various infrapatellar bursae that help facilitate smooth movement of the patella and rest of knee joint.

• Clinical significance:

  • "Unhappy (terrible) triad" is a term used for knee injuries that involve the anterior cruciate ligament, medial meniscus, and tibial (medial) collateral ligament. Recall that the tibial collateral ligament has a strong attachment to the medial meniscus. The medial meniscus has a smaller attachment to the anterior cruciate ligament; thus, when there is injury to one of these structures, it may affect the others.

    • These types of injuries are more common in contact sports, and in cases of direct blows to lateral knee region during extension or excessive lateral twisting of a knee in flexion.

12. Identify the major joint and associated ligaments in the ankle & foot region. Explain what kind of movements occur at the joints and other pertinent information.

Movement Videos

The talocrural (ankle) joint is a hinge joint (dorsiflexion & plantarflexion) formed by distal fibula and tibia and the superior talus.

• • • Medial (deltoid) ligament is a complex of 4 parts all of which have a proximal attachment to the medial malleolus of the tibia. The distal attachments include calcaneus, navicular, and talus.

      • The medial ligaments of the ankle are the stronger of the collateral ligaments, and are important in joint stabilization during eversion.

    • Lateral ligaments of ankle: 3 separate structures (i.e. do not share a common proximal attachment point); these ligaments as a group are important in joint stabilization during inversion but are the weaker and more commonly injured of ankle collateral ligaments.

      • Anterior talofibular ligament: located between lateral malleolus of the fibula and talar neck; most commonly injured during ankle sprains

      • Calcaneofibular ligament: located between the lateral malleolus and calcaneus

      • Posterior talofibular ligament: located between the malleolar fossa to talus

• • Clinical significance:

    • Ankle sprains: most common injury of the ankle joint as well as any other major joint of the body.

      • These types of injuries are most common after over-inversion of the foot and injury of the lateral ligaments of the ankle.

The [anatomical] subtalar joint is located at the articulation of the talus and calcaneus. A [clinical] subtalar joint is often described due to the functional similarities between the anatomical subtalar joint and talocalcaneonavicular joint, talocalcaneal part. These separate joints function in unison and are often considered together.

• The main actions possible at the subtalar joint (both types) is inversion and eversion of the foot.

The transverse tarsal joint is a combined (compound) joint composed of the calcaneocuboid joint and the talocalcaneonavicular joint, talonavicular part. This joint assists and augments the eversion/inversion action.