Upper Limb Bones Flashcards
What time of bone is the scapula?
A flat bone.
How many muscles attach to the scapula?
17.
Which side of the scapula is the costal surface?
The side facing the ribcage.
What is the subscapular fossa?
The concave depression over most of the costal surface.
Which muscle originates from the subscapular fossa?
The subscapularis.
Where does the coracoid process originate from?
The superolateral surface of the costal scapula.
Which muscles attach and originate from the coracoid process?
Biceps brachii and pectoralis major attach to the coracoid process.
Coracobrachialis originates here.
Which side of the scapula is the lateral surface?
The side facing the humerus.
Where is the site of the glenohumeral joint?
The lateral surface of the scapula.
What is the glenoid fossa?
A shallow cavity which articulates with the humerus to form the glenohumeral joint. The superior part of the lateral border articulates with the humerus.
What is the supraglenoid tubercle?
A roughening immediately superior to the glenoid fossa.
What muscle attaches to the supraglenoid tubercle?
The long head of the biceps brachii.
What is the infraglenoic tubercle?
A rougherning immediately inferior to the glenoid fossa.
What muscle attaches to the infraglenoid tubercle?
The long head of the triceps brachii.
Which side of the scapula is the posterior surface?
The side facing outwards.
What is the most prominent feature of the posterior surface?
The spine.
What is the spine of the scapula?
A transverse line across the scapula that divides it into two.
What is the infraspinous fossa?
The area below the spine of the scapula.
What muscle originates from the infraspinous fossa?
Infraspinatous.
What is the supraspinous fossa?
The area above the spine of the scapula.
Which muscle originates from the supraspinous fossa?
Supraspinatous.
What is the acromion?
Projection of the spine that arches over the glenohumeral joint and articulates with the clavicle.
What can fractures of the scapula be caused by?
Severe chest trauma, e.g. from high speed collisions.
Why does a fractures scapula not need much intervention?
The tone of the surrounding muscles hold the pieces in place for healing.
Which muscle pulls the scapula against the ribcage?
The serratus anterior.
What causes winging of the scapula and how?
Long thoracic nerve damage. This nerve innervates the serratus anterior so damage to it means the serratus anterior isn’t innervated. So the serratus anterior no longer holds the scapula against the ribcage and the scapula wings when pushing the arm.
What type of bone is the clavicle?
A long bone.
What are the three main functions of the clavicle?
Attach the upper limb to the trunk, protect underlying neurovascular structures supplying the upper limb, and transmit force from the upper limb to the axial skeleton.
What is the shape of the clavicle when facing forwards?
The medial aspect is convex and the lateral aspect is concave.
What does the sternal end of the clavicle articulate with?
The manubrim of the sternum.
What is the inferior surface of the sternal end marked by?
A rough oval depression for the costoclavicular ligament.
Which muscles originate from the shaft of the clavicle?
Deltoid, trapezius, subclavius, pectoralis major, sternocleidomastoid and sternohyoid.
Which two ligaments attach at the acromial end of the clavicle?
Conoid ligament at the conoid tubercle, trapezoid ligament at the trapezoid line.
Why is the clavicle the most commonly fractures bone in the body?
Because one of its functions is to transmit forces from the upper limb to the axial skeleton.
What do fractures of the clavicle commonly result from?
A fall onto the shoulder or on an outstretched hand.
Where is the common fracture site of the clavicle?
Medial 2/3 and lateral 1/3.
How is the clavicle displaced after fracture?
Inferiorly by weight of arm and medially by pectoralis major. Medial end is pulled superiorly by sternocleidomastoid muscle.
What nerve can be damaged by fracture of the clavicle?
Suprascapula nerve by the upwards movement of the medial part of the fracture.
What causes the waiter’s tip position after clavicle fracture?
The suprascapula nerve is damaged so the lateral rotators of the arm aren’t innervated and there is unopposed medial rotation of the upper limb.
What does the proximal humerus articulate with?
The scapula at the glenohumeral joint.
What are the important anatomical features of the proximal humerus?
Head, anatomical neck, surgical neck, greater and lesser tubercles and intertubercular sulcus.
What is a tubercle?
A round nodule, signifying the attachment site of muscles or ligaments.
Which part of the humerus articulates with the glenoid cavity?
The head when it projects medially.
What does the anatomical neck of the humerus connect?
The head and the tubercles.
Where is the greater tubercle of the humerus?
Laterally on the humerus. It has an anterior and posterior face.
Which muscles attach at the greater tubercle of the humerus?
Three of the rotator cuff muscles - supraspinatus, infraspinatus and teres minor.
Where is the lesser tubercle of the humerus?
More medially on the bone than greater tubercle. It only has an anterior face.
Which muscles attach at the lesser tubercle of the humerus?
The fourth rotator cuff muscle - subscapularis.