Dissection 11- Shoulder Joint, Posterior Arm and Posterior Forearm Flashcards
What type of joint is the glenohumeral joint?
Synovial ball and socket
What two features articulate to form the glenohumeral joint?
The large humeral head and the relatively small shallow cavity of the glenoid
What deepens the glenoid cavity?
Ring like, fibrocartilagenous glenoid labrum
What are all the articular surfaces of the glenohumeral joint covered with?
Hyaline cartilage
What holds the humeral head in place in the glenoid cavity?
The rotator cuff tendons
Where are the glenohumeral ligaments found? What do they strengthen?
Found only on the internal aspect of the joint capsule, to strengthen the anterior aspect of the capsule
Are the glenohumeral ligaments intrinsic or extrinsic?
Intrinsic- they are part of the fibrous layer of the joint capsule
Where do the coracohumeral ligaments pass to and from?
From the base of the coracoid process to the anterior aspect of the greater tubercle
What do the coracohumeral ligaments strengthen?
The joint capsule superiorly
The transverse humeral ligament runs to and from where? It converts the intertubercular sulcus into a canal for what tendon?
It runs from greater to lesser tubercle. It converts the sulcus into a canal for the tendon of the long head of biceps brachii
Where does the coracoacromial ligament pass to and from? The coracoacromial arch lies over this structure to prevent what movement?
Passes from acromion to the coracoid process of the scapula. The acromial arch prevents superior dislocation of the humeral head.
The subacromial bursa is located inferior to what?
Acromion, coracoacriomial ligament and deltoid
The subacromial bursa is located superior to what?
Supraspinatus tendon and glenohumeral joint capsule
The subacromial bursa facilitates what movements?
The supraspinatus tendon under the coracoacromial arch, and the deltoid over the joint capsule and greater tubercle of humerus
What type of shoulder dislocation is most common?
Anterior
Anterior and posterior shoulder dislocations indicate the direction of the humeral head movement in relation to what?
Infraglenoid tubercle and long head of triceps
Anterior shoulder dislocations are most common in young people. How do these occur?
Excessive extension and lateral rotation of the humerus
What structure may be injured when the shoulder joint dislocates?
Axillary nerve
The axillary nerve is found in the quadrangular space. What structures are found superior, inferior, medial and lateral to this?
Superior- teres minor
Inferior- teres major
Medial- long head of triceps
Lateral- humerus
What muscles does the axillary nerve supply?
Deltoid and teres minor
What nerve innervates the badge patch area?
Axillary nerve
How do you test the function of the axillary nerve?
Sensory- assessment of sensation in the badge patch area
Motor- abduction of the upper limb beyond 15 degrees
What are the nerve root values of the axillary nerve?
C5/6
What articulations make up the elbow joint?
The trochlea and capitellum of the humerus articulate with the trochlear notch of the ulna and the superior aspect of the head of the radius
Where does the lateral radial collateral ligament extend to and from?
Lateral epicondyle of humerus to blend with the anular ligament of the radius
What is the function of the anular ligament of the radius?
Holds the head of the radius in the radial notch of ulna to form the proximal radioulnar joint
Where des the medial ulnar collateral ligament extend to and from?
Medial epicondyle of humerus to the coronoid process and olecranon of ulna
Which band of the medial ulnar collateral ligament is the strongest?
Anterior band
What type of joint is the elbow joint?
Synovial hinge joint
What type of joint are the proximal and distal radioulnar joints?
Synovial pivot joints
What movement occurs at the distal radioulnar joint?
The radius moves around the relatively fixed distal end of the ulna
What articulation occurs at the distal radioulnar joint?
The head of the ulna articulates with the ulnar notch on the medial side of the radius
What injury can occur when children fall on their hands with their elbows flexed, or from hyperextension of the elbow?
Posterior dislocation of the elbow joint
Injury to what structure may occur with a posterior dislocation of the elbow?
Ulnar nerve
What injury is common in preschool children, especially girls when the child is suddenly lifted by the upper limb when the forearm is pronated?
Subluxation/dislocation of the radial head
What muscle makes up the posterior compartment of the arm?
Triceps brachii
What is the innervation of the triceps brachii?
Radial nerve
What is the proximal attachment of the long head of triceps brachii?
Infraglenoid tubercle of scapula
What is the proximal attachment of the lateral head of triceps brachii?
Superior to the radial groove of humerus
What is the proximal attachment of the medial head of triceps brachii?
Inferior to the radial groove of humerus
What is the distal attachment of the triceps tendon?
Olecranon process of ulna
What are the actions of the triceps brachii?
Weak extension of the arm at the shoulder joint, chief extensor of the forearm at the elbow joint
In the cubital fossa, what does the radial nerve divide into?
Superficial and deep branches
What gives the main arterial supply to the arm?
Brachial artery
Where does the brachial artery lie in relation to the triceps brachii?
Anterior
What is the main branch of the brachial artery? What aspect does it arise from?
Profunda brachii artery from the medial aspect of the brachial artery
What is the sensory innervation to the medial aspect of the posterior arm?
Anterior rami of spinal nerves C8, T1, T2
Why is the medial aspect of the posterior arm a site of cardiac referred pain?
Via the intercostobrachial nerve, medial and posterior cutaneous nerves of arm and posterior cutaneous nerve of forearm
What is the sensory innervation to the lateral aspect of the posterior arm?
Anterior rami of C5/6 via the axillary nerve
What is the function of the muscles of the posterior compartment of the forearm?
Extension
What is the nerve supply to the muscles of the posterior compartment of the forearm?
Deep branch of radial nerve
Which muscles of the posterior compartment of forearm are involved in extension, adduction and abduction of the wrist? Which are responsible for adduction? Which are responsible for abduction?
Extensor carpiradialis longus (ABD), extensor carpiradialis brevis (ABD), extensor carpi ulnaris (ADD)- they all extend
What muscles of the posterior compartment of forearm are involved in extension of the fingers? What role do all of these muscles also have?
Extensor digitorum, extensor indicis, extensor digiti minimi- they also extend the wrist
What two groups of posterior forearm compartment muscles make up the superficial layer?
Muscles which are involved in extension, adduction and abduction of the wrist and those which extend the fingers
Where do muscles of the superficial layer of the posterior forearm compartment attach proximally?
Lateral epicondyle of humerus
What muscles of the posterior compartment of forearm are involved in extension and abduction of the thumb?
Abductor pollicis brevis (BOTH), abductor pollicis longus (BOTH), extensor pollicis longus (EXT ONLY)
What two groups of posterior forearm compartment muscles make up the deep layer?
Those which allow extension and abduction of the thumb, and supinators of the forearm
Where do muscles of the deep layer of the posterior forearm compartment attach proximally?
Shafts of the radius and ulna and the interosseous membrane
The tendons of posterior forearm compartment muscles are held together at the wrist by what?
Extensor retinaculum
Why is the brachioradialis classed as a posterior forearm muscle?
It is supplied by the radial nerve
Where is the brachioradialis muscle located?
Between the posterior and anterior forearm compartments
What is the function of the brachioradialis muscle?
Flexion of the semi-pronated forearm
What is the main arterial supply to the posterior forearm compartment?
Posterior interosseous artery
The posterior interosseous artery is a branch of what?
Ulnar artery
What muscle has the role of extension of the wrist and extension of the lateral 4 digits?
Extensor digitorum
What muscle has the roles of extension of the wrist and the little finger?
Extensor digiti minimi
What muscle has the roles of extension of the wrist and index finger?
Extensor indicis
