Week 5 Anatomy - Upper Limb Flashcards
What are the articulations of the clavicle?
Manubrium sternum medially (large and triangular)
Acromion of scapula laterally (flat)
What is the functional importance of the scapula?
Only bony articulation of the scapula to axial skeleton (i.e. scapula doesn’t have any other skeletal points of contact for anchoring the shoulder joint)
What type of joint is the sternoclavicular joint?
Synovial - does have almost saddle type joint characteristics, as clavicle can move with movement of shoulder and respiration
What ligaments are involved in sternoclaviular joint?
Sternoclavicular ligaments (anterior and posterior)
Costo-clavicular ligaments
Interclavicular ligament
What ligaments are involved in the AC joint?
Conoid ligament (from conoid tubercle of clavicle to coracoid process of scapula)
Trapezoid ligament (coracoid to scapula)
What are the important bony features of the scapula?
Triangular shaped, flat/thin body. Laterally, glenoid fossa, coracoid process and acromion. Lateral border thicker than medial. Spine of scapula posteriorly continuous with the acromion.
What are the important features of the proximal humerus?
Rounded articulating part = head of humerus (articulates with glenoid fossa)
Laterally, greater tubercle (Supraspinatus, Infraspinatus, Teres minor)
Medially, lesser tubercle (subscapularis)
Compare anatomical versus surgical neck of humerus?
Anatomical neck = the groove immediately inferior to the head of humerus (superior to the tubercles)
Surgical neck is inferior to the tubercles , more likely to be site of fracture
What are the important mid-shaft features of the humerus?
- Radial groove runs in a spiral fashion posteriorly behind the humerus to bring it from posterior part of arm eventually into cubital fossa
- Deltoid tuberosity laterally
Which epicondyle sticks out further? What nerve relates to it?
Medial epicondyle - ulnar nerve runs inferiorly
What muscle group largely originates from medial epicondyle?
Anterior/flexor compartment of the forearm
What muscle group largely originates from lateral epicondyle?
Extensor muscles of forearm
What is the articulating surface of the humerus?
What are the two major components?
The condyle
Trochlea - articulates with ulna (medial)
Capitulum - articulates with head of radius (laterally)
Name the fossae at the distal end of the humerus that participate in the elbow joint? (hint, both anteriorly and posteriorly)
Medially = coronoid fossa
Laterally = radial fossa
Posteriorly = olecranon fossa
What are the important features of the proximal ulna?
What functional purpose does it serve?
- Olecranon on posterior aspect, articulates with the trochlear of humerus. Pronounced hinge joint.
Forms site of attachment for triceps brachii for elbow extension
- Coronoid process of ulna, also acts to be important part of hinge joint, and disappears into the the coronoid fossa of humerus when in full flexion
What is the connective tissue membrane that links the radius and the ulna?
Interosseous membrane
What are the important distal landmarks of the ulna?
Styloid process
Head of the ulna
What part of the humerus does the head of the radius articulate with?
Capitulum
What is the name of the tuberosity on the medial aspect of the proximal radius, and what is its purpose?
Radial tuberosity
Site of attachment for biceps brachii tendon
What two carpal bones does radius primarily articulate with?
Scaphoid laterally
Lunate medially
What is the role of the ulna notch?
Site of articulation of ulna and radius distally
What is the origin and insertion and innervation of the deltoid muscle?
Originates from the lateral 1/3 clavicle and spine of scapula.
Inserts onto deltoid tuberosity of humerus.
Innervated by the axillary nerve (C5-C6)
What are the two major functions of the deltoid muscle?
Abduction of shoulder
Support of glenohumeral joint/stability
What movements does deltoid assist in other than abduction?
Also forward flexion and extension (depending on what fibres are being used)
What is the origin, insertion and innervation of the trapezius muscle?
Originates from medial 1/3 superior nuchal line, occipital protuberance, and spinous processes of C7-T12.
Inserts onto lateral 1/3 posterior clavicle, acromion, and spine of scapula.
Innervated by spinal accessory nerve.
What is the major function of trapezius?
Suspends clavicle and scapula from axial skeleton.
Descending/superior aspect of muscle elevates scapula.
Ascending/inferior part depresses scapula
What is the origin, insertion, and innervation of the latissimus dorsi?
Originates from spinous process of inferior 6 thoracic vertebrae (7-12), posterior 1/3 iliac crest, and inferior 3-4 ribs.
Inserts onto the proximal humerus (inter tubercular groove).
Innervated by thoracodorsal nerve C6-C8W
What is the major function of latissimus dorsi?
Extension of humerus, as well as adduction and medial rotation.
Known as the ‘climber’s muscle, powerful muscle that helps extend humerus relative to axial skeleton.
What is the origin, insertion and innervation of pectoralis major?
Originates from medial half of clavicle and anterior surface of sternum and superior 6 costal cartilages, as well as aponeurosis of the external oblique muscle.
Inserts onto lateral lip intertubercular groove of humerus.
Innervated by Lateral and medial pectoral nerves
What is the major function of the pectoralis major muscle?
Think, throwing a ball
Adduction and medial rotation of the humerus. Bringing arm across body, responsible for throwing a ball.
Accessory muscle of inspiration when upper limb in fixed abduction (i.e. tripod)
What is the origin, insertion and innervation of pectoralis minor?
Originates from 3rd-5th ribs near costal cartilages.
Inserts onto medial border and superior surface of coracoid process.
Innervated by medial pectoral nerve
What is the origin, insertion and innervation of serratus anterior?
Originates from external surfaces of ribs 1-8
Inserts onto anterior surface of medial border of scapula.
Innervated by long thoracic nerve (C5-7)
What is the major function of serratus anterior?
Protraction os scapula, as well as anchoring the thoracic wall.
What is the origin, insertion and innervation of rhomboid major?
Originates from spinous processes of T2-T5.
Inserts onto medial border of spine of scapula
Innervation by dorsal scapular nerve C4-5
What is the origin, insertion and innervation of rhomboid minor?
Originate from the spinous processes of C7 and T1
Inserts onto the smooth triangular area at medial end of spine of scapula
What is the major function of the rhomboids?
Retracts scapula
Rotates to depresses the glenoid cavity
What is the origin, insertion and innervation of levator scapulae?
Originates from transverse processes of C1-C4
Inserts onto medial border of scapula (superior to spine)
Innervated by dorsal scapular nerve
What is the origin, insertion and innervation of teres major?
Originate from the inferior angle of the scapula
Inserts onto medial lip of the inter tubercular groove of humerus
Innervated by lower sub scapular nerve (C5-C6)
What is the major function of teres major?
Adduction of humerus, and medial rotation.
What is the primary function of the rotator cuff?
Securing the humeral head into the glenoid fossa
Where do the SIT muscles attach onto?
Greater tubercle of humerus
In anti-clockwise manner, starting superiorly, what are the muscles of the rotator cuff (think SITS)?
Supraspinatus - Superior facet
Infraspinatus - Middle facet
Teres minor - Inferior facet
Subscapularis - Lesser tubercle of humerus
Which rotator cuff muscles laterally rotate vs medially rotate?
Lateral = Infraspinatus and teres minor
Medial = subscapularis
What nerve supplies supraspinatus and Infraspinatus?
Suprascapular nerve C4-C6
What nerve supplies teres minor?
Axillary nerve
How many muscles link the scapula to the humerus?
6!
Rotator cuff muscles + deltoid and teres major