Session 3 Flashcards
What are the functions of the skeleton?
Support, protection, movement, mineral & growth factor storage and heamatopoeisis.
List the different classifications of bones by shape
Long - eg femur Short - eg carpal Sesamoid - embedded within a tendon or muscle, eg patella Flat - eg frontal bone of cranium Irregular - eg vertebra Sutural bone - within a cranial suture
Describe the blood supply to long bones
Metaphyseal arteries enter metaphysis at the site of attachment of the capsule. Periosteal arteries supply the periosteum and 1/3 of the cortex. The nutrient artery enters the diaphysis via the nutrient foramen.
How many bones are in the vertebral column, upper limb and lower limb?
26 vertebral
64 upper limb
62 lower limb
What are the different structural classifications of joints?
Fibrous
Cartilaginous
Synovial
What are the different functional classifications of joints?
Synarthrosis - immovable
Amphiarthrosis - slightly moveable
Diarthrosis - freely moveable
What are the 3 different types of fibrous joints?
Suture - restricted to cranium. Synostosis (fusion) on completion of growth.
Syndesmosis - amphiarthrosis, two bones held together by connective tissue. Examples include inferior tibiofibular joint and radioulnar interosseous membrane.
Gomphosis - immovable joint between teeth and maxilla/mandible
What are the different types of cartilaginous joints?
Primary cartilaginous joint - hyaline cartilage, synarthrosis. Eg 1st sternocostal joint, ephyseal growth plates
Secondary cartilaginous joint - fibrocartilage, amphiarthrosis. Eg intervertebral disc, pubic symphysis
What are the characteristics of a synovial joint?
Articular hyaline cartilage (sternoclavicular, acromioclavicular, temporomandibular joints are fibrocartilage).
Fibrous capsule completely enclosing joint with longitudinal and interlacing collagen bundles - stabilises joint.
Thin, highly vascularised synovial membrane that lines the capsule and covers exposed osseous surfaces, tendon sheaths and bursa. Does not cover articular cartilage. Produces synovial fluid.
Clear synovial fluid composed of hyaluronic acid, lubricin,proteinase and collagenase. It reduces friction, absorbs shock and transports nutrients and waste.
What are bursae and tendon sheaths?
A bursa is a sac filled with synovial fluid. They can be communicating for non-communicating with the joint cavity.
A tendon sheath is an elongated bursa wrapped around a tendon.
Describe the blood supply over synovial joints
Periarticular arterial plexus. Articular cartilage is avascular. Fibrous cartilage and ligaments have poor blood supply. Synovial membrane has rich blood supply.
What is Hilton’s law?
The nerves supplying the joint capsule also supply the muscles moving the joint and the skin overlying the insertions of these muscles.
What are the different types of synovial joint? & examples
Pivot - uniaxial, eg proximal radioulnar joint and atlantoaxial joint
Hinge - uniaxial
Saddle - biaxial joint, one bone is concavoconvex, eg 1st carpometacarpal joint
Planar - flat articulating surface, sliding movements, no axis of movement. Eg sternoclavicular, acromioclavicular, intercarpal and vertebral facet joints.
Condyloid - biaxial joint, oval shaped condyle of one bone rests on the elliptical cavity of another. Eg metacarpophalangeal, radiocarpal joints
Ball and socket
What are the effects of ageing on joints?
Decreased production of synovial fluid. Thinning of articular cartilage. Shortening of ligaments and decreased flexibility.
What are the signs and symptoms of arthritis?
Pain, swelling, stiffness, redness
What is rheumatoid arthritis?
An auto immune disorder where antibodies attack the synovium. Women more commonly affected. Joint erosion and deformity - MCP and PIP joints of hands, cervical spine, feet, can involve large joints.
Describe the articulation of the glenohumeral joint
The large round humeral head articulates with the shallow glenoid cavity of the scapula, which is deepened by the glenoid labrum.
What factors contribute to the stability of the shoulder joint?
Rotator cuff muscles - their resting tone acts to pull the humeral head into the glenoid cavity.
Glenoid labrum - a fibrocartilaginous ridge surrounding and deepening the glenoid cavity.
Ligaments
Lesser extent - deltoid, long head of triceps and long head of biceps
Where does the glenohumeral joint capsule attach?
Glenoid labrum to anatomical neck of humerus
Why does the joint capsule of the shoulder joint have a small opening anteriorly?
Allows the synovial membrane to communicate with the subscapular bursa
What are the ligaments involved in stabilising the shoulder joint?
Glenohumeral ligaments (superior, middle and inferior) - part of the fibrous capsule. Stabilise the anterior aspect of the joint. Coracohumeral ligament - attaches the base of the Coracoid process to the greater tubercule of the humerus. Supports the superior part of the joint capsule. Transverse humeral ligament - spans between the two tubercules, holds the tendon of the long head of the biceps in place. Coracoacromial ligament - forms the coraco-acromial arch which overlies the shoulder joint to prevent superior displacement of humerus.
What are the two clinically important bursa in the shoulder joint?
Subacromial - located inferiorly to the deltoid and acromion and superiority to the supraspinatus tendon. It facilitates movement of these muscles. Inflammation causes painful arch syndrome.
Subscapular - located between the subscapularis tendon and the scapula, reducing wear and tear
Outline the movements at the shoulder joint and the muscles that produce them.
Flexion - clavicular head of pectoralis major, anterior deltoid, coracobrachialis and both heads of biceps brachii.
Extension - posterior deltoid, latissimus dorsi and teres major.
Abduction - first 15 degrees by supraspinatus. Middle deltoid up to 90 degrees. After this the trapezius and serratus anterior rotate the scapula.
Adduction - pectoralis major, latissimus dorsi and teres major
Medial rotation - subscapularis, teres major, pectoralis major and latissimus dorsi.
Lateral rotation - infraspinatus and teres minor.
Outline the neurovascular supply to the shoulder joint
Arterial supply via the posterior humeral and Suprascapular arteries. They form an Anastamotic network around the joint.
Nervous supply via the Suprascapular, axillary and lateral pectoral nerves (C5&6)
What direction is the shoulder most commonly dislocated? How is this caused?
Inferior - described as anterior dislocation because the humeral head locates anteriorly due to the pull of powerful adductors. Usually caused by excessive extension and lateral rotation of the humerus or by trauma on fully abducted arm.
Why does one dislocation increase the risk of further shoulder dislocations?
Tearing of the joint capsule
What nerve damage can result from a shoulder dislocation?
Axillary nerve.
What is rotator cuff tendinitis and how is it detected?
Inflammation of the muscle tendons, usually die to overuse. Causes degenerative changes in the subacromial bursa and supraspinatus tendon, increasing friction between structures. Results in pain during 50-130 degrees of abduction, due to impingement between acromion and head of humerus.
How is the accessory nerve damaged and assessed?
Iatrogenic. Ask patient to shrug shoulders against resistance (trapezius).
What are the superficial and deep extrinsic muscles of the shoulder?
Superficial - trapezius and latissimus dorsi
Deep - levator scapulae, rhomboid minor and rhomboid major
How many muscles are in each layer in the anterior forearm?
Superficial - 4. Intermediate - 1. Deep - 3.
4-1=3
Why is the flexor digitorum superficialis a useful anatomical landmark?
The median nerve and ulnar artery pass between its two heads
What nerve innervates the deep muscles of the anterior forearm?
Anterior interosseous branch of the median nerve
What structures form the border of the carpal tunnel?
Carpal arch - concave on the palmar side. Formed laterally by scaphoid and trapezium tubercules. Formed medially by the hook of hamate and the pisiform.
Flexor retinaculum - thick connective tissue that bridges between the medial and lateral parts of the arch.
What is the contents of the carpal tunnel?
The tendon of flexor pollicis longus, surrounded by its own synovial sheath.
The 4 tendons of the flexor digitorum superficialis and the 4 tendons of the flexor digitorum profundus, surrounded by a single synovial sheath.
Median nerve
What tendon is commonly confused as being in the carpal tunnel?
Flexor carpi radialis - located within the flexor retinaculum .
What causes carpel tunnel syndrome and how does it present?
Compression of the median nerve in the carpal tunnel due to thickened ligaments and tendon sheaths.
Weakness and atrophy of the thenar muscles - progressive loss of strength and coordination of the thumb
Paresthesia, hypoesthesia and anesthesia of the palmar surface and fingertips of the lateral 3.5 digits. The Palm is not affected because the palmar cutaneous branch of the median nerve does not pass through the carpal tunnel.
How is carpal tunnel syndrome tested and treated?
Tinel’s sign - tapping the nerve in the carpal tunnel to elicit pain in median nerve distribution
Phalen’s manoeuvre - hold the wrist in flexion for 60 seconds to elicit pain/numbness in median nerve distribution
Treatment involves using s splint to hold the wrist in dorsiflexion overnight. Corticosteroid injections or even carpal tunnel release tunnel surgery in severe cases.
What type of synovial joint is the sternoclavicular joint and what are its articulations?
Saddle. Sternal end of the Clavicle, manubrium and 1st costal cartilage.
What ligaments are present in the sternoclavicular joint?
Anterior and posterior sternoclavicular ligaments - strengthen the joint capsule anteriorly and posteriorly
Interclavicular ligament - spans the gap between the sternal ends of each clavicle and strengthens the joint capsule superiorly.
Costoclavicular ligament - joins the 1st rib and cartilage to the anterior and posterior borders of the clavicle.
Outline the neurovascular supply to the sternoclavicular joint.
Arterial - internal thoracic and Suprascapular arteries
Nervous - medial supraclavicular nerve and the nerve to subclavius
Outline the movements at the sternoclavicular joint
Elevation of the shoulders - shrugging of abductiong the arm over 90 degrees Depression of the shoulders Protraction of the shoulders Retraction of the shoulders Rotation
How can the sternoclavicular joint become dislocated and why are they rare?
By a blow to the anterior shoulder (anterior dislocation - more common) or posterior shoulder. Rare because the costoclavicular ligament and the articular disc is effective at absorbing and transmitting forces away from the joint.
What type of synovial joint is the acromioclavicular joint and what are its articulations?
Plane. Lateral end of the clavicle and acromion of the scapula.
What are the major ligaments of the acromioclavicular joint?
Acromioclavicular - reinforces the joint capsule superiorly
Coracoclavicular - made up of the trapezoid and conoid ligaments, effectively suspends the weight of the upper limb from the clavicle
Describe the movements of the acromioclavicular joint
A small amount of axial rotation and anteroposterior movement. Passive because no ,uncles act on the joint.
Outline the neurovascular supply to the acromioclavicular ligament
Arterial - Suprascapular and thoraco-acromial arteries
Nervous - Suprascapular and lateral pectoral nerves
How can a dislocation of the acromioclavicular joint become more serious?
If the coracoclavicular ligament is torn - the weight of the upper limb is not supported and the shoulder moves inferiorly.
