WEEK 6 (Upper extremities) Flashcards
How is the upper limb suspended from the trunk?
By muscles and by the STERNOCLAVICULAR JOINT between the clavicle and the sternum
Based on the position of the upper limb’s major joints and component bones, what is the upper limb divided into?
Shoulder, arm, forearm and hand
What is the shoulder?
The area of upper limb attachment to the trunk
What is the arm?
The part of the upper limb between the shoulder and the elbow joint
Where is the forearm located?
Between the elbow joint and the wrist joint
Where is the hand located?
Distal to the wrist joint
What does the bone framework of the shoulder consist of?
- The Clavicle and Scapula (which form the Pectoral girdle/Shoulder girdle)
- Proximal end of the humerus
What is distinguishable about the Clavicle?
- the only bony attachment between the trunk and the upper limb
- Acromial (end) of the clavicle is flat
- Sternal (medial) end is more robust and quadrangular in shape
What is the anatomy of the ends of the Clavicle that allow for articulation?
- Acromial end has a small oval facet on its surface for articulation with a similar facet on the medial surface of the Acromion of the scapula
-Sternal end has much larger facet for articulation (mainly with the Manubrium of the sternum)
What is distinguishable about the inferior surface of the lateral third of the clavicle?
It possesses a distinct tuberosity consisting of a tubercle (CONOID TUBERCLE) and lateral roughing (TRAPEZOID LINE) for attachment of CORACOCLAVICULAR LIGAMENT
Describe the Scapula
- large, flat triangular bone
- contains THREE ANGLES (lateral, superior and inferior)
- contains THREE BORDERS (superior, lateral and medial)
- contains TWO SURFACES (costal and posterior)
- contains THREE PROCESSES (acromion, spine and coracoid process)
What is the Glenoid cavity?
- a shallow, comma shaped cavity that marks the lateral angle of the scapula
- articulates with the head of the humerus to form the Glenohumeral joint
What is the site of attachment for the long head of the triceps brachii muscle?
The infraglenoid tubercle which is inferior to the Glenoid cavity
What is the Supraglenoid tubercle?
A tubercle located superior to the glenoid cavity and is the site of attachment for the long head of the Biceps brachii muscle
What is the function of the Spine of the Scapula?
Subdivides the posterior surface of the scapula into a small, SUPERIOR SUPRASPINOUS FOSSA and a much larger INFRASPINOUS FOSSA
What is the Acromion?
- an anterolateral projection of the spine
- arches over the glenohumeral joint
- articulates via a small oval facet on its distal end with the Clavicle
How is the Costal surface of the scapula characterised?
By a shallow concave SUBSCAPULAR FOSSA over much of its extent
How is the Costal surface of the scapula characterised?
By a shallow concave SUBSCAPULAR FOSSA over much of its extent
What is the difference between the lateral border of the scapula and the medial border & superior border?
- lateral border of the scapula is strong and thick for muscle attachment
- medial & superior border is thin and sharp
What is the superior border marked on its lateral by?
- CORACOID PROCESS
- SUPRASCAPULAR NOTCH
What is the Coracoid process?
a hook-like structure that projects anterolaterally and is positioned directly inferior to the lateral part of the clavicle
Where can the suprascapular notch be found?
The supra scapular notch (for supra scapular nerve and vessels) lies immediately medial to the root of the coracoid process
What does the proximal end of the humerus consist of?
- the Head
- the Anatomical neck
- the Greater and Lesser tubercles
- the Surgical neck
- the Superior half of the shaft of the humerus
What is distinguishable about the humerus head?
- half-spherical in shape
- projects medially and superiorly to articulate with the Glenoid cavity of the scapula
How can the anatomical neck of the humerus be determined?
- very short
- formed by narrow constriction immediately distal to the head
- lies between the head and the greater and lesser tubercles laterally
lies between the head and the shaft more medially
What are the greater and lesser tubercles of the humerus?
- prominent landmarks on the proximal end of the humerus
- serve as attachment sites for the four ROTATOR CUFF MUSCLES of the GLENOHUMERAL JOINT
A deep intertubercular sulcus (bicipital groove) separates _________________________ and continues inferiorly onto the proximal shaft of the humerus
lesser and greater tubercles
The tendon of the long head of the ______________________ passes through this sulcus
Biceps branchii
Describe the lateral lip of the Intertubercular sulcus
continuous inferiorly with a large V-shaped DELTOID TUBEROSITY on the lateral surface of the humerus midway along its length, which is where the DELTOID MUSCLE inserts onto the humerus
Where can the Surgical neck be found?
In the horizontal plane between the expanded proximal part of the humerus (HEAD, ANATOMICAL NECK and TUBERCLES) and the narrower shaft
Why is the surgical neck one of the sites where the humerus commonly fractures?
the surgical neck is weaker than more proximal regions of the bone
What does the shaft of the humerus look like in a cross-sectional view?
Triangular with anterior, lateral and medial borders with anterolateral, anteromedial and posterior surfaces
What are the important features of the Radial groove?
- passes diagonally down the bone
- marks the middle part of the posterior surface and adjacent part of the anterolateral surface
- shallow
Which groove can the radial nerve and the profound brachii artery lie in?
radial groove
Describe the distal end of the humerus
- bone becomes flattened in the anterioposterior plane
- borders expand as the LATERAL SUPRAEPICONDYLAR RIDGE (lateral supracondylar ridge) and the MEDIAL SUPRAEPICONDYLAR RIDGE (medial supracondylar ridge)
- bears a condyle, two epicondyles and three fossae
What are the important features of the lateral supraepicondylar ridge?
- more pronounced than the medial ridge
- roughened for the attachment of muscles found in the posterior compartment of the forearm
What is the forearm?
The part of the upper limb that extends between the elbow joint and the wrist joint
What are the two parallel bones that make up the forearm?
Radius & Ulna
What is distinguishable about the Radius?
- lateral in position
- small proximally where it articulates with humerus
- large distally where it forms the wrist joint with the Carpal bones of the hand
What is distinguishable about the Ulna?
- medial in the forearm
- large proximally and small distally
What does the proximal end of the radius consist of?
a head, a neck and the radial tuberosity
Describe the head of the radius
A thick disc shaped structure oriented in the horizontal plane